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Plant: 860-589-5511
Fax: 860-589-7411
TABLE 20: Some useful conversion factors
To convert from To metric Multiply by
(English unit) (SI) (Factor)
Inch (in) Millimeter (mm) 25.4
Inch (in) Meter (m) 0.0254
Feet (ft) Meter (m) 3.048
Pound (lb) Kilogram (kg) 2.2046
Ton (short; 2000 lb) Kilogram (kg) 907.18
Ton (long; 2240 lb) Kilogram (kg) 1016.0
lb/in2
(psi) N/mm2
(or 1 Mpa) 0.006896
lb/in2
(psi) kg/mm2
1422.334
lb/in2
(psi) Kilopascal 0.1450377
U.S. quart Liter 1.057
Microinch(µin) Micrometer (µm-micron) 0.0254
fpm (ft/minute) meter/minute 3.281
RA RMS 1.11
thou (milli-in or 0.001") Micron (mil) 0.03937
Fracture toughness-Ksi in Mpa m 1.098
PIW (lbs. per inch of width) kg/mm 0.017857
21
Your source for engineered steel
When you select Theis Precision Steel, you get
more than just a base metal supplier. You gain a
partner in the successful design and production
of your products. Through early and continuous
supplier involvement, Theis can help you design
your materials, parts and processes to work to-
gether to cut costs and improve delivery sched-
ules. It is our goal to help you produce better prod-
ucts and provide better service to your custom-
ers. Find out what Theis can do for you. Contact
us for a free needs analysis.
Strip Steel Weight Calculations:
Lbs per lineal foot = 3.4 x Thickness (in) x Width (in)
Lbs per foot = W (in) x T (in) x 0.283 x 12
Coil weight = lbs. per foot x coil width
PIW (lbs. per inch of width) = Coil weight/coil width
Coil length (feet) = Coil weight/lbs. per foot
7. Sales: 860-585-6610
Plant: 860-589-5511
Fax: 860-589-7411
Specifying
CustomEngineeredSteel
Product and end use requirements
Theinitialstepindevelopingadefinitivespecifica-
tionistoreviewthepartandapplicationcharacter-
istics: How will the part be formed? How many
bends and what angles are involved? What envi-
ronmentalconditions(temperatures,stresses,etc.)
will prevail during its use? If material is being
reordered for an on-going manufacturing pro-
gram, the production procedures should be re-
viewed,todiscloseanypossibleneedforchangein
the steel specification. Once manufacturing and
end use considerations have been analyzed, the
stage is set for writing the specification. For more
information on proper specifying criteria, see
page 19 of this brochure.
SIZE RANGES OF BAINITE:
TRM-14:0.015-0.080"(.38-2.0mm)
TRM-34:0.015-0.080"(.38-2.0mm)
TRM-26:0.025-0.080"(.64-2.0mm)
TRM-54:0.025-0.080"(.64-2.0mm)
Other sizes available upon request. TRM = Theis Raw Material
BARTEMP-B®
(BAINITE)
Furnishedinpre-hardenedcondition,thismaterial
is tougher than BARTEMP-M (MARTENSITE),
allowing the fabrication of parts where various
shaping technologies, such as blanking, bending,
drawing,stretching,extrusion,coining,orswaging
might be involved. Because the material is already
hardened, the following benefits can be realized:
a) Additionalstepstocorrectdistortioninherent
in part hardening are eliminated.
b) Closerdimensionaltolerancesandimproved
finish.
c) Partsrequirenofurtherheattreatment,saving
on labor, utility costs and capital equipment.
d) Lead times can be shortened.
This material is available in the following grades:
TRM-14 (AISI-1050), TRM-26 (AISI-1065),
TRM-34 (AISI-1074), TRM-54 (AISI-1095).
TRM = Theis Raw Material
BARTEMP-B, made out of TRM-14 and TRM-26, can
undergo considerable shaping. However, BARTEMP-B,
made out of TRM-34 and TRM-54, is suitable for lightly
shaped components. For applications where good wear
resistanceisneededmostlyalongtheedgesofthematerial,
itisrecommendedthathighergradeBARTEMP-Bbeused.
TABLE 2: BARTEMP-B
AISI TRM Thick- RC U.T.S. % Min.BendRadius
# ness KSI Elong I RollingDirection=
in (mm) in (mm) in. (mm)
1050 14 .020 (.51) 44 210 7 .040 (1.02) .080 (2.03)
1065 26 .028 (.71) 43 200 6 .060 (1.52) .095 (2.41)
1074 34 .040 (1.02) 41 190 6 .080 (2.03) .100 (2.54)
.040 (1.02) 48 225 5.5 .125 (3.17) .170 (4.32)
1095 54 .042 (1.07) 41 195 8.5 .090 (2.20) .110 (2.79)
PINPOINTCARBIDE
Thisstructureispre-heattreatedandcoldrolled.Itis
usedextensivelyforbandsawandothercuttingappli-
cations. Pinpoint carbide can have teeth punched,
milledorgroundeasilyathighhardnesslevels. Pulse
hardeningofthetipsgreatlyenhancescuttingproper-
ties.Itrespondswelltoheattreatment, offeringexcel-
lentfatigueandwearproperties.
Pinpoint Carbide is available in the following
grades:
TRM-37 (AISI-1086M), TRM-54 (AISI-1095),
TRM-64 (BARCOID®
).
SIZE RANGES OF PINPOINT CARBIDE:
TRM-37:0.008-0.050"(.20-1.27mm)
TRM-64:0.025"-0.050"(.64-1.27mm)
TRM-54:0.010"-0.050"(.25-1.27mm)
* Other grades and sizes by application
TRM = Theis Raw Material
HARDENED&TEMPEREDALLOYS
Theis offers hardened and tempered alloy steel
for many applications. The grades shown on page
4areselectedastypicalofouralloysteelofferings.
THEIS-ITE®
THEIS-ITE offers a combination of excellent form-
abilityandhighstrength.Thisallowsforpartstobe
intricately shaped without expensive final harden-
ingwithitsdistortionandsortingproblems. THEIS-
ITE is supplied pre-tempered in thicknesses from
0.004" through 0.065" (0.10-1.65 mm) and widths
from 0.25" through 12.5" (6.35-317.50 mm). Theis
TABLE 3: Pin Point Carbide
AISI TRM# Thickness:in(mm) Hardness
1086 37 .014 (.36) 15N 78 - 83
.025 (.64) 15N 76 - 79
1095 54 .010-.025 (.25-.64) 15N 76 - 83
.025 (.64) 15N 74 - 80
Barcoid®
64 .032 (.81) 30N 48 - 58
.035 (.89) 30N 48 - 57
3
8. THEIS Precision Steel Corporation
4
TABLE 4: Hardened and Tempered Alloys
Grade Thick- Hard- Ten- 0.2% % Vise Proper-
AISI TRM ness ness sile Y.S.Elong Break x ties
# in (mm) RC KSI KSI Thick
High
9260 92 .055 RC43 200 175 7.0 wear
mod. (1.40) resist.
High
D6A 81 .042(1.07) 8615N 215 200 5.0 17-20 fatigue
.010(.25) 275 245 4.0 20-23 appln
6150 72 .020 30N73 298 240 5.0 20-22 Saw
(.51) parts
Hotmetal
Barco 73 .022 30N65 215 191 6.0 13-15 cutting
Sil®
(.56) appln
High
Theis- 15 .031(.30) 8015N 204 171 5.0 Forma-
ite®
.015(.38) 18.7 162 5.0 bility
TABLE 5: Theisite
Test WithMax.Strength WithMax.Ductility
Parameters .015" .020" .030" .042" .015" .042"
in.(mm) (.38) (.51) (.76) (1.07) (.38) (1.07)
Tensile* 187 220 204 185 130 160
0.1%Y.S.* 156 134 163 91
0.2%Y.S.* 163 152 171 105
%Elong. 5.0 5.5 5.0 8.0 10.0
Modulus X106
29.6 29.7 30.0
Hardness:
15N 82.5 73
30N 60 64.0
RC 40.5# 44.0# 42.0 42.0 28# 35
ViceBreak 0.200
Min.B.R**
Long. 1.7xT 3.5xT 2.0xT Flat on
itself
Trans. 1.0xT 2.5xT 2.0xT 1.5xT Flat on 0.040
itself 1.0xT
45Deg 1.2xT 3.0xT 1.7xT Flat on
itself
* = KSI, # = Converted, T = Thickness, ** = Bend Radius
will custom make THEIS-ITE to suit your require-
ments.Theaccompanyingtableshowssometypi-
cal data of THEIS-ITE at various thicknesses.
TABLE 6: Thickness and width tolerances
Size +Tolerancefor Max.Variation
Variation indicated withinasingle
Limit: thickness coil
.004" to .009" 0.0003" 0.0003"
(.10 to .23 mm) (.0076 mm) (.0076 mm)
Thickness .009" to .025" 0.0004" 0.0004"
(.23 to .64 mm) (.01 mm) (.01 mm)
Width Tolerances for all coils within a lot:
+0.0040" (.10 mm)
BARTEX®
BARTEX is a specially heat treated, cold rolled
high carbon steel. In its delivered condition, Bartex
has a significantly higher tensile strength and yield
to tensile ratio compared to hardened and tem-
pered material of similar dimensions. The mechani-
cal properties of Bartex are further enhanced by
using a controlled strain aging heat treatment.
Based on specific applications, strain aging process
canbeappliedtotheformedspring(aswithconstant
force springs) or the material prior to fabrication of
springs (as with power springs).
Bartex uses selected raw material with a low
inclusion level, smooth and tight surface finish, and
textured grain orientation resulting from heavy cold
reduction and close control of metallurgical proper-
ties. This results in considerably improved fatigue
properties, provided that good practices are used to
control stress raisers.
Although plain carbon steels having a carbon
rangeof0.60%through1.25%canbeconsideredto
make a textured material, the most suitable grade is
an eutectoid plain carbon steel (carbon 80%) which
is cold rolled to produce a 100% textured condition,
and this is known as Bartex.
The following is some typical Bartex data:
Dimensions:
Availablethickness:0.004-0.025"(.10-.64mm)
Availablewidth:0.093-12.0"(2.36-304.8mm)
Size: 16" (406 mm) I.D. unless otherwise specified.
Maximum O.D. 48" (1219 mm) unless otherwise
specified.
Surface Finish: Bright cold rolled, uncoated
condition.
Surface Coating: Parts made out of Bartex can be
coatedwithmetalorpolymerprovidedtheprocess
temperaturedoesnotexceed480°F(249°C).
Mechanical Properties: The properties vary ac-
cording to the rolling direction. Material transverse
to rolling direction has the maximum ductility. The
material is somewhat limited for forming.
Customers must do a low temperature strain age
at @
464o
F (240o
C) for 1/2 hour for optimum
spring properties.
9. Sales: 860-585-6610
Plant: 860-589-5511
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TypicalMaterialHardness(asdelivered)
Hardness
H.S.S. Edging: HV 350 max (15N 78 max)
E.B. Weld: HV 420 max (15N 82 max)
Backing material (D6A): HV 250 max
(15N 70 max)
Microstructure
Edging: Fully spheroidized with primary carbide
sizes of 1 to 3, with some large alloy carbides.
Free from carbide segregation and total decar-
burization (free ferrite). Partial decarburization
of 0.00040" (0.011 mm) maximum per side is
allowed. No carburization is allowed.
E.B. Weld: Typical annealed cast microstructure.
Small uniform carbides of sizes 1 to 2 in an alloy
ferrite matrix.
Backing:Spheroidizedwithoccasionalareasof
fine lamellar pearlite. Partial decarburization of
0.0005" (0.013 mm) maximum per side allowed.
No total decarburization (free ferrite) is allowed.
WeldSeam
No misalignment of edge and backing, overfill
or undercut of the weld, and no excessive
porosity, blowholes or cracks.
Surface
Typical lightly cold rolled dull surface, free from
excessive scratches or roll marks. Material is
lightly coated with rust preventative oil. We can
also provide material with ground surface.
Edges
The backing edge shall be a square edge with
chamfered corners (corner radius) of
.002 - .010" (.05 - .25 mm) or blunt round.
The H.S.S. edge shall be #1 sharp square with
maximum chamfer of .003" (.076 mm)
Theis uses electron beam welding technology
extensively for welding high speed tool steel to
high strength low alloy backing steel for the saw
industry. The same technology is used in fabrica-
tions in these industries:
Electronics:
Stainless steel and various nickel alloys.
Papermanufacturing:
Moneltolowalloysteelfordoctorbladeapplications.
TextileIndustries:
Hardenedhighcarbonsteelsofdissimilarthicknesses.
Scoringrules:
Carbonsteelsofdissimilarshapes,whicharedifficult
tofabricateusingconventionalshapingtechnology.
5
The following typical mechanical properties
are obtained after a 464o
F (240o
C) stress relief:
Thickness Range: Less than 0.006" (0.15
mm)
Tensile: 340-380 KSI (2346-2621 N/mm2
)
Vise Break: < 23 x Thickness
% Elongation: < 1.0
ThicknessRange:0.0098M
-0.006"(.25-.15mm)
Tensile: 320-355 KSI (2205-2448 N/mm2
)
Modulus: 29-30 Million PSI
0.2%/UTS Ratio: 95-98 %
0.010% Proof Stress: 310 KSI (2138 N/mm2
)
%Elongation: < 1.0
Vise Break: Less than 22 x Thickness
15N Hardness: 15N 86 - 88
Thickness Range: 0.025" -.010" (.64-.25 mm)
Tensile: 270-330 KSI (1862-2276 N/mm2
)
%Elongation: 3 - 1
Vise Break: 14 - 20 x Thick
ELECTRON BEAM WELDING (BARCOMP®
)
Ductility: Good - Fair
Consult Theis Precision Steel for your specific
application.
Other Grades of Textured Material:
Textured Materials using other carbon grades,
such as TRM-26 (AISI 1065), TRM-34 (AISI
1074M), TRM-54 (AISI 1095), etc. are produced
byTheis.Eachtexturedmaterialhasitsownunique
propertiesandtypicalproductapplications.Some
typical data is as follows:TABLE 7: Bartex- Other Grades
Grade Thickness Tensile Vise Break
TRM# in (mm) KSI x thick
.005 (.12) 298 13
26 .006 (.15) 287 12
.0076 (.19) 280 10.5
34 .0075 (.19) 305 14
.0094 (.24) 288 13
.0045 (.114) 280 16
54 .0051 (.129) 270 15
.022 (.558) 255 14
10. THEIS Precision Steel Corporation
Sizes and Tolerances
Many sizes are available. The following typical
sizesavailablewithrespecttosawtypes:
Typicaltolerances:
Width: +0.002" (+0.051 mm)
Thickness: +0.0010" (+0.025 mm)
Camber: <0.180" in 6'
(<4.6 mm in 1.83 m)
Flatness: <0.001"/1" of width
(<0.025 mm/25.4 mm width)
Wedge/crown <0.001"/1" of width
(<0.025 mm/25.4 mm width)
Dog legs (TIR) <0.020" in 20.0"
(<0.50 mm in 508 mm)
Coils
Theis will meet customer specifications for coil
I.D., O.D., length, matched coils, color code,
butt weld and packaging.
ScoringRuleApplications:
Colddrawnhighcarbonshapedwireintypicalsizesof
0.084"x0.150"(2.13 x3.81mm)and0.112"x0.150"
(2.84 x3.81mm)areelectronbeamweldedtoasec-
tion of 0.042" x 1.10" (1.07 x 27.94 mm) of similar
grade.Thiscreatesashapedifficulttomakeusingcon-
ventional rolling and/or wire drawing methods. It is
alsopossibletowelddissimilarsteels.
PaperIndustryApplications:
Solid high strength Monel (copper-nickel alloy) is
anexpensivematerialusedtomakedoctorblades.
When it is reduced by usage to a predetermined
width, the blade must be discarded. To reduce
costs, thin strips can be welded to less expensive
low alloy steel. Typical size configuration of a
0.035" (0.89 mm) thick trimetal application:
Monel Low Alloy Steel Monel
6
TABLE 9:
Saw Types wih Thickness/Width Tolerances
Saw type Thickness Width Edge width
inch (mm) inch (mm) inch (mm)
Hand hack 0.024 (0.61) 0.500 (12.7) 0.040 (1.02)
Power hack 0.050 (1.30) 1.125 (28.6) 0.156 (4.00)
& 0.186 (4.73)
0.088 (2.23) 1.075 (27.3) 0.250 (6.35)
Hole 0.050 (1.27) 1.500 (38.1) 0.187 (4.75)
Band 0.025 (0.63) 0.250 (6.35) 0.040 (1.02)
0.042 (1.07) 1.250 (31.75) 0.060 (1.52)
Reciprocating 0.035 (0.89) 0.750 (19.0) 0.040 (1.02)
Saber 0.050 (1.27) 0.750 (19.0) 0.060 (1.52)
Porta band 0.020 (0.51) 0.500 (12.7) 0.040 (1.02)
TABLE 8: Typical chemical composition of backing and edging material
M2 M3T1 M42 MATRIXII D6A 3% CR- AISI6150 AISI6135 TRM 84
Element HSSedge HSSedge HSSedge HSSedge backing backing backing backing backing
C .79-.86 1.00-1.10 1.05-1.10 0.70-0.75 0.45-0.50 0.30-0.35 0.48-0.53 0.30-0.37 0.26-0.32
Mn <0.35 0.20-0.35 0.15-0.30 0.15-0.40 0.60-0.90 0.65-0.80 0.70-0.90 0.60-0.90 0.95-1.10
Cr 3.90-4.40 3.75-4.50 3.50-4.00 3.90-4.40 0.90-1.10 3.00-3.20 0.80-1.10 0.80-1.10 1.90-2.10
Mo 4.75-5.25 6.00-6.50 9.25-9.75 4.75-5.25 0.90-1.10 2.00-2.20 0.40-0.60 0.15-0.36 1.40-1.60
V 1.75-2.05 2.40-2.80 1.00-1.30 0.80-1.10 0.08-0.15 0.30-0.40 0.15-0.25 0.15-0.25 0.20-0.80
W 6.00-6.75 6.00-6.50 1.30-1.70 0.80-1.10 1.40-1.60
Co 7.75-8.25 7.75-8.25
Ni 0.50-0.70 0.30-0.90
Cu <0.20 0.20
Al 0.05-0.10 0.05-0.10 0.03-0.10 0.05-0.10 0.05-0.10 0.40-0.80 0.04-0.10 0.04-0.10 0.04-0.80
Si 0.15-0.35 0.20-0.35 0.20-0.35 0.15-0.30 0.10-0.25 0.30-0.45 0.20-0.35 0.15-0.30 0.30-0.50
S <0.015 <0.01 <0.010 <0.010 <0.007 <0.010 <0.010 <0.010 <0.004
P <0.025 <0.025 <0.025 <0.025 <0.015 <0.015 <0.025 <0.025 <0.020
NOTE: Theis will be pleased to work with customers in developing new grades of HSS edging and backing material
SawProducts
11. Sales: 860-585-6610
Plant: 860-589-5511
Fax: 860-589-7411
of the application requirements. As a guide for
testing and specifying, it should be noted that the
relationship between tensile strength and hard-
ness is similar for all high carbon steels.
Hardness or tensile strength should be speci-
fied as a range of minimum-maximum values to
avoid costly overspecification. This range can be
based on tests of hardness or tensile strength or
can be deduced from desired performance char-
acteristics.
Whenperformancecharacteristicsareusedto
determine hardness, design stresses, tensile
strength or temper they should be explicitly noted
sothatthesupplierandusercandouble-checkthe
specification.
By analyzing design stresses in a strip steel
application, design engineers can estimate the
required yield strength and then calculate the
ultimate tensile strength for the material. For most
hardened and tempered high carbon strip, mini-
mum yield strength is approximately 85% of the
ultimate tensile strength.
Whetherhardnessspecificationsarebasedon
calculated mechanical properties or on test re-
sults,anunderstandingofcommonhardnesstests
can help designers, engineers and purchasers
specifyhardnessaccurately.
Specification Based on Tests
Strip steel specifications should be based on
tests whenever samples are available. Rockwell
hardnesstestsarethemostwidelyusedintheU.S.
for several reasons, including speed and the rela-
tivelylowcostoftheequipment.InaRockwelltest,
the material is simply placed on an anvil and
subjectedtothepressureofeitheradiamondcone
or a ball penetrator, first under the weight of a
relatively light, or “minor” load, and then subse-
quently under the greater weight of a “major”
load. Exact load weights involved determine the
specific scale. Test values directly indicate the
difference in depth of penetration under the
weight of the minor and major loads.
Two types of Rockwell testers are used for
different strip thickness ranges, and each type,
using a diamond cone penetrator, provides mea-
surements in three hardness scales, which are
differentiated by the mass of the major load. (The
diamond cone penetrator scales are used when-
ever hardened and tempered steel or other hard
materials are to be tested.)
7
Testing and Specifying
MechanicalProperties
Hardness and Tensile Strength
Themostcommonmechanicalpropertiesspeci-
fied are hardness and/or tensile strength. These
are controlled by annealing, cold working or hard-
ening and tempering, and always specified in light
FIGURE 1:
Enlargements of weld cross sections
ElectronicApplications:
Iron-nickel alloy is typically welded to AISI 304
type of stainless steel as tri-metal in various sizes.
This welding requires a high degree of skill and
precision.
Typicalsizeconfigurationofatrimetalapplication:
S.S. Invar S.S.
37 X
Standard band saw
18 X 50 X
8 X 18 X
Dissimilar Shapes
Dissimilar Thicknesses
12. THEIS Precision Steel Corporation
The standard tester is armed with relatively
massivemajorloadsof150kg,100kg,and60kgfor
the Rockwell C, D, and A scales, respectively; the
minor load in all three cases is 10kg. The superfi-
cialtestermakesuseofmajorloadsof45kg,30kg,
and 15 kg for the Rockwell 45N, 30N, and 15N
scales, respectively; the minor load for each of
those three scales is 3kg.
The Diamond Pyramid Hardness (DPH) test
uses even lighter loads - 2 kg, 1 kg, and 1/2 kg - to
measure the hardness of the very thinnest gauges
of strip steel. Each test involves only one load;
there is no minor load. Diagonal dimensions,
rather than the depth of the indentation are
measured, and a single scale is used for all
penetrator loads.
Toguaranteeaccuracy,sensitivity,andrepeat-
ability of the measured values, it is essential to
select the test and scale appropriate to the thick-
ness of the strip to be tested. Refer to Table 10 for
hardnessscalevs.thicknessofstriprequirements.
Normally, a hardness test should be carried
out with the largest recommended load allowed
on the penetrator to minimize the test’s sensitivity
to surface variations and imperfections, such as
machiningmarksanddecarburization.Scalesbased
on lighter loads should be avoided.
If, however, the strip is too thin to support the
penetrator load, the impression of the penetrator
into the strip will result in a bump or bulge on the
underside of the strip. The formation of such a
bulge is known as the “anvil effect” and usually
indicates an inaccurate hardness reading.
Furthermore, with extremely thin strip, there
is the danger that the penetrator might actually
pierce the strip and dent the anvil itself, giving an
improper reading and impairing the accuracy of
the tester in future use.
Stacking several strips of the same material is
notrecommended.Thecushion-likespringaction
betweenthestripswillpreventanaccuratereading.
Tensilestrengthtests
Tensile strength testing involves pulling a
sampleintensionuntilitbreaks. Itismoretime-con-
sumingthanhardnesstesting,buthastheimportant
advantageofalwaysusingthesameunitofmeasure-
ment (psi), regardless of strip thickness.
Because tensile strength and hardness are
related, the specifier can cite just tensile strength,
or convert to a hardness value by using appropri-
ate conversion charts included in this brochure.
Conversion to other hardness scales on
tensile values according to ASTM E-18
Thereisnogeneralmethodforaccuratelyconvert-
ing the Rockwell hardness numbers on one scale
to hardness numbers on another Rockwell Scale,
or to other types of hardness numbers, or to
tensilestrengthvalues. Suchconversionsare,atbest,
approximationsandthereforeshouldbeavoided,except
forspecialcaseswhereareliablebasisfortheapproxi-
mateconversionhasbeenobtainedbycomparisontests.
SpecifyingCautions
Manysteelbuyershavelearnedthroughexperience
whatspecificRockwellC-scalevaluesareassociated
with their own applications. Other scales, such as
Rockwell15Nor30N,arelesswellunderstood,and
thusnotasreadilyassociatedwithproductapplica-
tions. Asaresult,specifiersmayciteaRockwellC-
scalehardness,regardlessofthestripthickness,in
order to obtain a certain temper quality.
For example, a user may specify Rc48 hard-
ness,eventhoughtherequestedstripisonly0.020
inches (0.508 mm) thick, just to indicate that the
strip should be given a full temper. This practice
can cause misunderstandings if the specifier fails
toexplainthatitisnotthetestedC-scalehardness
itself that is desired, but the performance associ-
ated with it.
Even more misleading is improper use of
hardness conversion charts. A person without
expert knowledge of the lighter hardness scales
should never convert a C-scale value to a lighter
scale for an equivalent temper. Even when a se-
lected chart lists values that convert accurately in
terms of hardness, the converted values may not
yield equivalent strip characteristics. To provide
equal temper and spring characteristics in differ-
ent thicknesses of a given steel, hardness and
tensile strength must be increased when strip
thicknessisdecreased.
A Rc48 hardness, for example, will be a full
temper in strip more than 0.035 in. (0.89 mm)
thick, but the equivalent hardness (by conversion)
of R30N 66.5 will be less than a full temper in strip
that is 0.025 in. (0.63 mm) thick.
Those who wish to specify a Rockwell 15N or
30Nhardnessofferingspringcharacteristicsequiva-
lent to those of a known C-scale hardness can use
the comparison charts shown in Table 10.
8
14. THEIS Precision Steel Corporation
TABLE 10 (continued): Approximate equivalent hardness numbers and tensile strengths
DPH TENSILE TENSILE
ROCKWELL (VICKERS) STRENGTH STRENGTH
HRC HRA 30 N 15 N HRB 30 T 15 T
150 kgf 60 kgf 30 kgf 15 kgf 60 kgf 30 kgf 15 kgf 10 kgf N/mm2
KPSI
Brale Brale Brale Brale 1/16"Brale 1/16"Brale 1/16"Brale
Hardness Scale vs. Thickness of Strip Requirements:
RC: > 0.030" (0.76 mm) RA: > 0.030" (0.76 mm) 30 N: > 0.020" (0.51 mm) - < 0.030" (0.76 mm) 15N: 0.008" (0.20 mm) - < 0.020" (0.51 mm)
HB: > 0.030" (0.76 mm) 30T: > 0.020" (0.51 mm) - < 0.030 (0.76 mm) 15T: 0.008" (0.20 mm) - < 0.020" (0.51 mm) DPH: < 0.008" (0.20 mm)
29.8 65.2 50.2 74.9 (105.5) 300 952 138
29.2 64.8 49.7 74.6 (104.5) 295 938 136
28.5 64.5 49.0 74.2 (104) 290 917 133
27.8 64.2 48.4 73.8 285 897 131
27.1 63.8 47.8 73.4 (103) 280 889 129
26.4 63.5 47.2 73.0 (102.5) 275 876 127
25.6 63.1 46.4 72.6 (102) 270 862 124
24.8 62.7 45.7 72.1 265 841 122
24.0 62.4 45.0 71.6 (101) 260 827 120
23.0 62.0 44.2 71.1 100 255 807 117
22.5 61.5 43.4 70.6 250 800 116
21.3 61.2 42.5 70.1 98.5 82.0 93.0 248 781 114
20.3 60.7 41.7 69.6 98.0 81.8 92.5 240 758 110
(18.0) 59.0 97.0 81.1 92.1 230 717 104
(17.0) 58.9 96.0 80.4 91.8 222 703 102
(15.7) 58.3 95.0 79.8 91.5 218 689 100
(14.3) 57.6 94.0 79.1 91.2 213 676 98
(13.0) 57.0 93.0 78.4 90.8 207 662 96
(11.7) 56.4 92.0 77.8 90.5 204 648 94
(10.2) 55.8 91.0 77.1 90.2 196 620 90
(9.2) 55.2 90.0 76.4 89.9 188 600 87
(8.0) 54.6 89.0 75.8 89.5 184 593 86
(6.9) 54.0 88.0 75.1 89.2 180 579 84
(5.8) 53.4 87.0 74.4 88.9 177 565 82
(4.7) 52.8 86.0 73.8 88.6 173 552 80
(3.6) 52.3 85.0 73.1 88.2 169 545 79
FIGURE 2:
Formability sketch
FORMABILITY
Formability - the capacity of steel to sustain trans-
verse or longitudinal bends without failure - de-
pendsonstripductility. Thisisdevelopedthrough
proper specification of analysis, hardness and
microstructure. Also, formability is greatly influ-
enced by the manufacturing conditions: fabricat-
ing method (e.g., stamping, piercing, coining),
orientation of bending axis to direction of grain,
and the bending radius relative to stock thickness
and hardness. It is important to specify and
understand all factors affecting formability.
Formability of untempered strip is determined by
abendtest. Asampleisslowlybentover180°until
its ends are parallel. The measured distance be-
tween ends (Nt) is the multiple of strip thickness
(t) that should be specified, for transverse ( l ) and
longitudinal (=) bends.
10
Longitudinal Bend
N1 t
Indicates direction of rolling
N1
Traverse Bend
t
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FIGURE 4: Effect of hardness and bend axis to
rolling angle on formability of AISI 1050 strip
Table 11 lists mechanical properties for vari-
ousthicknessesandgradesofas-rolled,annealed
and BarcoForm®
steel; Table 12 adds formability
values for the same annealed and Barco-Form
grades. (Barco-Form is a spheroidized annealed
product of Theis Precision Steel.) Obviously, the
low-hardness,annealedmaterialshavethehighest
ductility and will accept the most severe bends.
Table 12 indicates that Nt/t is 2, parallel to the
grain (=), when t=0.040" (1.016 mm). Therefore,
themeasureddistancebetweenparallelendsNt=2
X 0.040" (1.016 mm), or 0.080" (2.032 mm).
Formability of pretempered strip
Bothbendandbreaktestsareusedtomeasurethe
formability of pretempered steel, with the choice
usually based on relative strip hardness.
Another means of judging the formability of
pretempered material is the vise break test, in
which a sample strip is bent into a “U” shape in the
jaws of a vise until it breaks. The vise break
distance - space between jaws at fracture - is
specified in terms of a “go” and “no-go” range
which defines the required ductility. A large break
distance indicates low ductility; a small distance
represents a steel with better ductility but lower
resistance to service stresses. (The specified vise
break range must be compatible with the speci-
fied hardness range.)
Table 13 shows formability values for 0.70 to
1.05% carbon strip, plotting the break ratio V/t
(vise break distance divided by strip thickness)
againsthardness.
FIGURE 3:
Blanking and bending angles in relation to grain flow in steel strip
11
Formability Test - Untempered Strip
BendAxis:
Special consideration may be needed in the
formability section of a specification, in light of
the ultimate part configuration and bends re-
quired to achieve that shape. Ideally, the axis of
each bend should be oriented transverse (90°) to
the direction of rolling direction. In practice, com-
promises to this rule are often necessary. For ex-
ample, the bend axis may be altered from the ideal
for blanking economy, to minimize scrap. If the
part will receive several bends at various angles,
it must be oriented for the best overall result.
Figure 3 illustrates how selection of the blanking
angle will affect bend axis, and can be ma-
nipulated to yield the most desirable bending
angle. It is recommended that critical bends be ori-
ented a minimum of 30° to grain direction; more if
possible.
Figure 4 shows formability of AISI 1050 strip of
varying hardness, and different degrees of bend
axis orientation to rolling direction.
Fractures occur
above curve
Radius of bend=
1 X thickness of stock
(1Nt)
42
40
38
36
34
32
Hardness,Rc
0o
15o
30o
45o
60o
75o
90o
0o
90o
60o
30o
45o
30o
0o
Blanking Angle
60o
45o
90o
> > > > Rolling Direction > > > >
Bending Angle
16. THEIS Precision Steel Corporation
TABLE 12: Formability values for annealed grades
Thickness,t Direction Nt/t Nt/t Nt/t
inches(mm) of bend Ann BarcoForm Ann BarcoForm Ann BarcoForm
.076" (1.93 mm) _I_ 2 0 2 0 2 0
and over = 4 3 4 3 4 5
0.036-0.075" _I_ 1 0 1 0 2 0
(.914-1.905 mm) = 2 1 2 1 3 2
0.015-0.036" _I_ 0 0 1 0 1 0
(0.381-0.914 mm) = 1 0 1.5 1 2 1
0.008-0.014" _I_ 0 0 1 0 1 0
(0.2037-0.356 mm) = 0 0 1 0 1 .5
TABLE 11: Mechanical property ranges of annealed and hard rolled carbon steel
TRM and range of carbon and manganese content
TRM-14 TRM-31 TRM-34 TRM-54
C .47-.56 C .65-.75 C. 68-.80 C .90-1.05
Strip HDNS Mn.60-.90 Mn.35-.50 Mn.50-.80 Mn.30-.50
Thickness or UTS As hard Barco As hard Barco As hard Barco As hard Barco
rolled Ann.* Form rolled Ann.* Form rolled Ann.* Form rolled Ann.* Form
.076 " RC 14-29 16-30 16-30 16-32
(1.93 mm) RB 95-106 85 80 97-107 87 85 97-107 89 87 95-107 92 90
and UTS (KSI) 95-135 85 80 105-150 87 84 105-150 88 85 105-160 95 92
over % EL-2" min 20 28 15 20 15 20 15 20
.036" RC 14-27 15-29 15-29 15-30
(0.914 mm) RB 95-105 85 80 95-105 87 83 97-105 89 86 97-107 92 88
and UTS (KSI) 97-130 85 80 105-145 87 83 105-145 87 85 97-155 95 90
over % EL-2" min 20 28 15 20 15 20 15 20
.015" 30T 74-84 73 70 78-84 74 72 78-84 75 73 78-85 77 74
(0.381 mm) UTS (KSI) 95-130 85 80 90-118 85 83 92-118 85 83 97-150 92 85
TO .035" % EL-2" min 20 28 20 25 20 25 15 20
(.889 mm)
.008" 15T 90-93 87 86 90-93 87 86 90-93 88 87 90-94 91 89
(0.203 mm) 15N 90-125 78 89-118 80 89-118 83 89-125 90
to .014" UTS
(0.356 mm) (KSI)
under .008" DPH-KG 210-290 175 210-290 175 210-290 175 210-320 180
(.203 mm) 2KG
BendRadius
Forming capability of a strip steel determines the
severity of bends it can withstand during part
production. In order to avoid a borderline situa-
tion where a tight bend might involve fracturing,
the manufacturer can often increase the bend
radius slightly and lessen the bending stresses
generated.
At the specifying stage, it is the specification
writer’s responsibility to assure sufficient form-
ability for required bends, by controlling strip
hardness and/or radii of bends.
Figure 5 gives minimum 90° bend radii for AISI
1075 to 1095 steel strip of varying thickness and
hardness; Figure 6 shows the relationship of hard-
ness to minimum 90° radii for longitudinal and
transversebends.
12
18. THEIS Precision Steel Corporation
FIGURE 7: Photomicrographs of carbon strip steel at 1000x
FIGURE 8: Minimum bending radii for AISI 1050 martensite
and bainite; bend axis transverse to grain direction
ture, such as Theis BarcoForm, have a low hard-
ness relative to grade, and therefore maximum
ductility for forming operations.
Permissible partial decarburization should be
specified in quantitative terms - that is, the depth
below the surface to which carbon depletion may
extend.Arecommendedlimitforgeneraluseisup
to 2% of thickness, with “no free ferrite evident”.
For some applications, such as cyclic loaded
parts, decarburization may affect fatigue strength
and shorten life due to lower surface strength. In
other applications where the strip edge becomes
the working part of the tool, the softness of a
decarburized surface would be detrimental. Such
cases call for closer limitation by specifying abso-
lute limits of partial decarburization allowed.
MICROSTRUCTURE
Reference to steel microstructure is not always
required in a specification. In the case of parts to
bestampedorblanked,pretemperedstripmaybe
selected in order to maintain uniformly close
tolerances and avoid warpage during heat treat-
ment. Pretempered material is usually hardened,
quenched and tempered to a martensitic micro-
structure.
If bends are also required during part produc-
tion, proper manipulation of bend radius, angle
tograin,hardnessandanalysiswillusuallyprovide
sufficient formability in pretempered strip.
However, in some cases with severe bends, a
higher degree of formability will be required than
that offered by martensitic pretempered steel.
Ratherthanautomaticallyselectingannealedstock,
the customer should consider strip with bainitic
microstructure.Formabilitywillbeenhancedwith-
out sacrifice in dimensional stability or wear resis-
tance.
Figure 8 illustrates the improved formability of
bainite over martensite. It indicates the minimum
bending radii possible for given hardnesses of
bainitic and martensitic AISI 1050 material. For
example, bainite hardened to Rc42 can be bent
over a radius just twice its thickness (or greater)
without breaking, whereas comparable marten-
site strip requires a radius at least 3.4 times its
thickness for safe bending.
If even greater formability is required for sharp
part bending, fully spheroidized annealed strip
should be specified. Steels with this microstruc-
14
5
4
3
2
1
30 32 34 36 38 40 42 44 46
Hardness,Rc
RadiusofBend(N1)
NumberofThicknesses
Martinsite
Bainite (Bartemp B)
Martensite BainitePinpoint Spheroidized
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TABLE 14: Standard finishes
Finish Description
Scaleless Dark tight oxide film of varying blue
tempered or gray color, result of liquid or block
quenching & tempering.
Bright Non-oxidized surface, result of
tempered controlled-atmosphere quenching
& tempering.
Tempered Absolutely clean surface, result of
& polished polishing after hardening & tempering.
Tempered, Blue or straw surface color, result of
polished & colored thermal treatment after polishing.
(blue or straw)
SURFACECONDITION
SurfaceImperfections
The specification section on surface condition
usuallybeginswithastatementaboutundesirable
surface imperfections. In many cases, this state-
mentreads:“Thesurfacemustbefreeofscratches.
It shall have no stress raisers, pits or seams.” This
is a generalized statement which, if taken literally,
constitutes overspecification. Strip with “no”
surface imperfections can be produced only at
greatexpenseunderlaboratory-qualityconditions.
A more realistic and economical approach is to
consider the effect of surface imperfections on
the finished part. This effect will be determined
by the configuration, direction, depth and sever-
ity of the imperfections, and by the deflections,
loads and stresses imposed on the part.
Usually, surface imperfections are not detri-
mental if they are light and longitudinal, and if
stress concentrations are negligible. Thus, mini-
mal stress raisers can often be tolerated.
Conversely,relativefreedomfromstressraisers
is critical in circular parts that deflect in all direc-
tions under load. Otherwise, application of load
andresultantdeflectionmightcausefatigueprob-
lems.
Typeanddepthofimperfectionmustbeconsid-
ered. A sharp V-notch in some parts can cause
early fatigue failure in high loading situations. In
thesamecircumstances,ashallowU-shapednotch
might prove much less sensitive.
Twotypesofflaws-seamsandlaminations-are
usually detrimental to a part. They are the most
common cause of surface-related fatigue failure.
Seams, slivers and laminations result from steel-
making processes. A seam can be created, for
example, if foreign particles are trapped in the
steel ingot during pouring, or if the strip is
scratched in hot rolling.
SpecifyingSurfaceRoughness
Surface roughness in high carbon strip is com-
monly measured and specified in terms of RA
(arithmetical average roughness) value. For non-
critical applications, users frequently do not des-
ignateanRAvalue.Inthesecases,cold-rolledand
hardened strip will have a surface roughness
ranging from 6-15 RA (the exact figure depends
on strip processing operations).
SometimesitisdesirabletospecifyanRAvalue.
For example, manufacturers who require a mirror
bright finish on their parts might request strip
with an RA of 3-6. To convert RA to RMS, multiply
RA x 1.1 = RMS.
MeasuringSurfaceProfile
To measure surface roughness, a profilmeter is
used.Theprofilometer’ssensitivestylusrunsacross
the width of the strip sample, recording surface
variations in microns. An arithmetic average of
these variations is displayed.
The profilometer can provide an average value
and an RA value, based on customer need for
surface texture requirements. We can also mea-
sure scratch depth with the Rmd value.
FINISH
A variety of finishes are available for both an-
nealed and pretempered strip, with selection be-
ing guided by finished part requirements. How-
ever, for most strip applications finish is not
significant, and the least expensive choice is the
bestone.
When annealed strip is ordered, the standard
finish is No. 2 bright. This finish is so widely
accepted that it is usually supplied automatically
without specification. This finish offers an aver-
age reflectivity and surface roughness of 3-8 RA.
Four standard finishes are available for
pretempered strip. They result naturally from the
quench and tempering medium used for a given
strip thickness. For most applications, the speci-
fier will choose either scaleless and bright, or
tempered, polished and colored- all of which can
15
20. THEIS Precision Steel Corporation
FIGURE 9: Available edges for cold-rolled strip
beproducedwithanRAof3-30.Maximumscratch
depth allowance is 1.0% depth of strip thickness.
A polished and colored surface is required even
less often than a polished surface. At one time,
colored surfaces carried some significance be-
causetheyindicatedthestriphadreceivedproper
heat treatment. Today, this finish is primarily
cosmetic.
EDGE
Selectionofedgeconfigurationisdependentupon
part production processes and finished part con-
tour.Anumberofedgeshapesareavailable(Figure
9); of these the most prevalent are No. 1 (square
and round), No. 3 (slit) and No. 5 (deburred).
No. 1 is an edge prepared to a specific contour-
usually round or square. It entails a price pre-
mium and should be the preferred choice when:
• The edge is part of the finished product and
mayaffectappearance
• The condition of the edge may affect fatigue in
application
• A very accurate width is required
• An edge suitable for electroplating or welding is
required
No. 3 is an approximately square edge pro-
duced by slitting, with evidence of slitting frac-
ture, burr, and toe-down (edge deformation).
No. 5 is a No. 3 edge with the burr removed
through filing or similar method. Slitting fracture
and toe-down will still be present.
Other edge configurations available are blunt,
chamfered,beveled,andsquarewithradiusorbro-
ken corners. When special edges are ordered, a
cross-sectional sketch or detailed print of the de-
siredcontourshouldaccompanythespecification.
Thevarietyofpossibleedgesmakesthisaprime
area for confusion during specifying. One point
to remember is that special edge configuration or
preparation entails added cost. The application
should always be considered first. For example, it
would be overspecifying to request a No. 1 edge
when a part will be blanked between strip edges.
On the other hand, underspecifying would be
involved if a user requested a No. 3 “with mini-
mum burr.” This is a contradiction in terms as a
No. 3 edge has maximum burr. What is really
needed is a No. 1 or No. 5 edge.
SIZETOLERANCES
A basic step in order preparation is specifying
size and tolerances. Every application is unique in
thateachhasanoptimumstripsizewithacompat-
ible tolerance range. It is essential that tolerances
are expressed as equal values above and below a
nominal (target) dimension. In the use of Statisti-
cal Process Control (SPC) techniques, it is always
beneficial to aim for the center of the specified
range so the variations realized will be centered at
the nominal and be maintained well within limits.
Strip thickness and width should be given in
decimal inches or millimeters. When cut lengths
are required instead of typical continuous coils,
the length should be expressed in inches or feet
(centimeters or meters). The use of gauge num-
bersorfractionaldimensionsislessaccurate,and
therefore undesirable.
Ingeneral,asstripwidth,thickness,orlengthin-
creases,itismoredifficulttoholdclosetolerances.
ASTMhaspublishedwidelyacceptedtolerancesfor
different widths and thicknesses. Table 16 lists
TheisPrecisionSteelthicknesstoleranceswhichare
considerably tighter than ASTM standards.
16
No. 1 EDGES
No. 3
SLIT EDGE
No. 5 EDGE
SQUARE
Standard
ROUND
Standard
BLUNT ROUND
Standard
BROKEN CORNERS
Special
Maximum corner radius:
0.003" (0.0762 mm)
BEVEL
Special
Deburred
only
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FIGURE 10: Control chart characteristic:
Strip thickness
Target thickness: 7.10 Thickness values in mils (0.001 in)
USL=0.80 LSL = -0.80
x = 0.002 UCLx = 0.18 LCLX=-0.18
R = 0.125 UCLR= 0.72 σ=0.054
ZUSL = 14.88 ZLSL=-14.94 Zmin=14.88
Cpk = 4.96 Total number of out of tolerance points: 0
XI = 0.00 σi
=0.056
X=ΣX/k R=ΣR/k
UCLx=X+A2*R LCLx=X-A2*R
UCLR=D4*R σ=R/d2
ZUSL=(USL-X)/σ ZLSL=(LSL-X)/σ
Zmin=minimum of ZUSL or -ZLSL Cpk=Zmin/3
n=5 k=50 A2=0.58 D4=2.11 d2=2.326
Xi=ΣXi/N σi=SQRT((ΣXi
2
-N*Xi2)/(N-1))
When extra-close tolerances are required, de-
pending on the size and condition, additional
processing can be performed to achieve these
tighter tolerances (i.e. thickness tolerances of
+/- .0001" [0.0025 mm] or width tolerances of
+/- .0005" [0.0127 mm]).
Computer-assistedrollingmills
with automated gauging
Every major rolling mill in operation at Theis
Precision Steel utilizes state-of-the-art computer
controls. The systems are closed-loop, feed for-
wardmass-flowcontrolusingnon-contactgamma-
ray gauges at the entry and exit of the mills. The
computer automatically adjusts the roll pressure
to assure uniform thickness throughout the entire
length of the coil and maintain the tightest con-
trols in the industry. Every coil which we produce
off our mills requires a minimum Cpk value. Each
mill can produce an SPC printout showing statis-
tical and operational results (see Control Chart).
These records are maintained on file within our
computer database and can be retrieved at any
time.
17
TABLE 15: Width tolerances for cold rolled steel
Edge Width Thickness Tolerances
no. in. (mm) in. (mm) +/- in. (mm)
1 To 0.75 (19) incl <0.0938 (2.4) 0.003 (0.08)
Over 0.75
1 to 9.5 <0.125 (3.2) 0.004 (0.10)
(19.1 to 241) incl.
3 0.094 to 14.0 To .025
(2.4 to 355) incl. (0.64) incl. 0.004 (0.10)
0.375 to 14.0 Over .025
3 (9.5 to 355) incl. (0.64) to .068 0.005 (0.13)
(1.7) incl.
Over .068
3 0.5 to 14.0 (1.7) to .099 0.005 (0.13)
(12.7 to 355) incl. (2.5) incl.
5 To 0.75 (1.90) incl. <0.0938 (0.24) 0.004 (0.10)
5 Over 0.75 to 5.0
(19 to 127) incl. <0.125 (3.2) 0.005 (0.13)
5 Over 5.0 to 9.0 .008 (0.02) to
(127 to 228) incl. .125 (3.2) incl. 0.005 (0.13)
5 Over 9.0 to 14.0 .015 (038) to
(228 to 355) incl. .105 (2.7) incl. 0.005 (0.13)
Tighter tolerances can be achieved. Consult your Theis
representative.
FIGURE 11: Exit thickness distribution
Length Deviation PercentofTotalLength
(ft) (pct) (mils) 0 10 20 30 40 50 60 70 80 90 100
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
1 0.0
2 0.0
14 0.2
230 3.3
6478.0 93.6
162 2.3
25 0.4
7 0.1
0 0.0
1 0.0
0 0.0
0 0.0
0 0.0
0 0.0
-1.00
-0.90
-0.80
-0.70
-0.60
-0.50
-0.40
-0.30
-0.20
-0.10
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0 10 20 30 40 50 60 70 80 90 100
USL: 0.47 mils Zusl: 15.928
LSL: -0.47 mils Zlsl: -15.899
Cpk: 5.300 Zmin:15.899
Subgroup
Number R 0.0 +0.2 +0.4 +0.6 +0.8 x -0.2 -0.1 0.0 +0.1 +0.2
1 0.27 -0.01
2 0.46 -0.05
3 0.15 -0.01
4 0.08 -0.00
5 0.07
48 0.14 0.02
49 0.11 -0.04
50 0.12 -0.01
x UCL LCL x UCL
22. THEIS Precision Steel Corporation
18
TABLE 16: Thickness Tolerances for Cold-Rolled Steel A,B
Width, inches (mm)
Specified thickness Up to 3" (85 mm) 3" to 6" (85 to 170 mm) Over 6" to 14"
excl incl (170 to 397 mm) incl
Thickness tolerances in inches (mm) over and under
Under 0.010 (0.254) 0.0003 (0.008) 0.0003 (0.008) 0.0003 (0.008)
0.010 to 0.015 (0.25 to 0.38) incl. 0.0004 (0.010) 0.0004 (0.010) 0.0004 (0.010)
Over 0.015 to 0.020 (0.38 to 0.51) incl. 0.0005 (0.013) 0.0005 (0.013) 0.0005 (0.013)
Over 0.020 to 0.030 (0.51 to 0.76) incl. 0.0005 (0.013) 0.0005 (0.013) 0.0005 (0.013)
Over 0.030 to 0.040 (0.76 to 1.0) incl. 0.0008 (0.020) 0.0008 (0.020) 0.0010 (0.025)
Over 0.040 to 0.070 (1.0 to 1.78) incl. 0.0010 (0.025) 0.0010 (0.025) 0.0012 (0.030)
Over 0.70 to 0.100 (1.78 to 2.54) incl. 0.0012 (0.030) 0.0012 (0.030) 0.0015 (0.038)
Over 0.100 to 0.125 (2.54 to 3.18) incl. 0.0015 (0.038) 0.0018 (0.046) 0.0020 (0.051)
A:Thickness measurements are taken 3/8 in. (9.5 mm) in from edge of strip, except on widths less than 1 in. (25 mm), the tolerances
are applicable for measurements at all locations.
B:Tighter tolerances can be achieved - consult your Theis representative.
OTHERTOLERANCES
Depending upon the application, other dimen-
sionalcharacteristicsmaybeveryimportanttothe
success of the processing and/or function of the
finished product. In these cases, it is important to
include tolerances for these other attributes (such
ascamber,crossbow,etc.).
The measurement technique utilized is critical
in achieving correlation of results between sup-
plier and user. If a specific gauge or technique is
used for measurement of a particular attribute, it
isextremelyhelpfultopassthisinformationalong,
so we can be more precise in our measurement of
your specified tolerance.
FLATNESS (crossbow/concavity)
Depending upon the application, users may also
need to specify flatness and camber. There are no
industry standards for flatness per ASTM. A
standard flatness tolerance used in the past was
0.003 inches per inch (.076 mm/25.4 mm) of
strip width (i.e. .003" PIW). This tolerance is not
an accurate measure of flatness for the wider
widths, as flatness does not vary in direct propor-
tion to the width. Flatness is best described as an
arc (see Figure 12) and the flatness tolerance
increasesexponentially. However,itisnotalways
a true arc and therefore is very difficult to utilize
a standard formula. The type of edge, condition,
thickness and width of material all play a role in
determining a suitable tolerance for flatness. A
more accurate determination for a No. 1 edge
material is one which uses the PIW formulas as
shown in Table 17. Flatness on No. 3 and No. 5
edge material will be slightly higher due to toe-
TABLE 17: Theis flatness/crossbows PIW formulas A,B
This table is applicable only for
hardenedandtemperedwithfinishededge
Width in inches (mm)
Specified Up to 1" 1 to 4" Over 4 to 9.5"
thickness (25.4mm) (25.4 to 101.6 mm) (101.6 to 241.3 mm)
inches(mm) excl. incl. incl.
PIWflatnesstolerances,in.(mm)maximum
(Multiplyactualwidthbyvaluebelow)
Under 0.010 0.003 0.003 0.003
(0.25) (0.08) (0.08) (0.08)
0.010 to 0.025 0.002 0.003 0.003
(0.25 to 0.635) (0.05) (0.08) (0.08)
incl.
Over
0.025 to 0.050 0.0015 0.002 0.003
(0.635 to 1.27) (0.04) (0.05) (0.08)
incl.
Over
0.050 to 0.125 0.001 0.0015 0.003
(1.2 to 3.18) incl. (0.025) (0.04) (0.08)
A. Tolerances apply only to strip with No. 1 edge
B. For tighter tolerances, consult your Theis representative
FIGURE 12:
Establishing cross bow limits with Theis flatness standard
Example: When strip width (W) is 2 inches (56 mm) maximum,
maximum allowable arc height (A) is 0.006 inches (0.170 mm)
W
A
23. Sales: 860-585-6610
Plant: 860-589-5511
Fax: 860-589-7411
19
FIGURE 13:
Standard camber tolerances for strip 4 and 8 ft. long,
(1.22mand2.44m)
between0.5in.and1.5in.(12.7and38.1mm)wide
(diagramexaggeratedforemphasis)
PACKAGING
Specification of packaging involves recognizing
any particular limitations or requirements of the
strip user’s production and materials handling
equipment.Specialinstructionsmightinvolvecoil
characteristics such as inside and outside diam-
eter, weight, and type of winding, or the coil
MAJORSPECIFYINGCRITERIA:
To accurately fill your order to fit your exact
requirements, please supply as much of the fol-
lowing data as is applicable:
Scope:Ageneralstatementofpurpose,including:
A ) Condition of steel strip: Cold rolled, skin
pass,hardened,tempered,etc.
B) Application for which the product is
intended.
Steel description: Name, type and steel grade
number, e.g. AISI 1074M (TRM 34) or equivalent.
Product form: Strip and coil size requirements.
Nominal dimensions: Thickness and width with
tolerances.
Preferred edge condition: Number and style,
e.g., #1 round, #5 deburred, #3 slit, etc.
Surface finish and roughness: For instance,
scaleless,brightpolishedorhardrolledwithanRa
of 15 max.
Metallurgical requirements (if any): Specify de-
carburization limits, inclusion limits, microstruc-
ture (bainite, sorbite, etc.), any special heat treat-
ments required.
Other requirements: Specify in ranges any
hardness, tensile/elongation, bend, break
requirements to be met.
Samples: Include a drawing, part or material
whichisacceptable.
Packaging: Indicate skid, bundle, or tag
requirements.Specifyanyspecialpacking,marking
or rust preventative oil applications.
Certification: Describe any test certificates
required for cast analysis and/or mechanical
properties.
Other:Describeanyotherspecialrequirementsand
include any notes that will facilitate your order.
TABLE 18: Standard camber tolerances
Strip Standard Equivilent camber limits: in. (mm)
width camber For various strip lengths: ft. (m)
W, tolerance
in. Ct, in/ft
(mm) (mm/m)
8 4 6 10 12 16 20
(2.44) (1.22) (1.83) (3.05) (3.66) (4.88) (6.09)
0.5-1.50 0.50 0.125 0.281 0.781 1.125 2.0 3.125
(12.7-38.1) (12.7) (3.18) (7.14) (19.84) (28.58) (50.8) (79.38)
1.5-13.0 .25 .0625 0.141 0.391 0.563 1.0 1.562
(38.1-330.2) (6.35) (1.59) (3.58) (9.93) (14.30) (25.4) (39.68)
down. In measuring flatness on slit material, it is
imperative to remove any burr to eliminate the
burr height from the flatness measurement.
CAMBER(edgeboworsweep)
If camber is measured over a strip length not
shown in Table 18, it can be easily converted to an
equivalent value for comparison with the standard
tolerance, using the formula:
Cu = Ck x (Lu / Lk)2
where Cu = Unknown Camber
Ck = Known Camber
Lu = Unknown Length
Lk = Known Length
packaging - skids, cartons, and other protective
measures. Any requirements that are outside
standard mill practice should be identified in the
packaging section of the specification.
Coil ID (Standards - 12"/14"/16"/20"
[300/350/400/500 mm])
Coil OD (Minimum/Maximum)
Coil Length
Coil Set Requirement
For special requirements, please consult your
Theis representative.
W
0.125"
(3.18 mm)
0.5" (12.7 mm)
4 ft.
(1.22 meters) 8 feet (2.44 meters)
24. THEIS Precision Steel Corporation
TABLE 19: Typical Applications of Various TPS Grades of Steel
TRM 14 TRM 15 TRM 26 TRM 34 TRM 37 TRM 54 TRM 64 TRM 73 TRM 92 Welded
• AISI 1050 • AISI 1527 • AISI 1065 • AISI 1074 • 1086 • AISI 1095 • BARCOID®
• AISI 9262 • AISI 9260 • BAR-
• DIN CK 55 • DIN CK 67 • DIN CK 75 • DIN CK 85 • DIN CK 101 •AISI W1C • DIN 67SiCr5 • JIS SUP 7 COMP®
• JIS S 50 C • JIS S 65 C • JIS S 70 C • JIS SK5 • JIS SK4 • JIS SK2
• DIN 125W
• Clock • Belville
springs washer
• Power • Cantilever
springs • Power
spring
• Constant
force
spring
• Retractor
spring
• Putty knife • Tape steel- • Chain
• Window measuring saw bar
regulator tape
•Trowels • Disposable
• Hand saw utility knife
blade
• Surgical
blades
•Trowels
• Industrial
knives
• Hand hack
• Filler gages
• Severely • Horn • Seat belt • Flapper
formed diaphragm retractor valve
springs • Piston ring • Shock
• Expander absorber
steel • Thrust
• Clutch washer
cushion • Fuel injection
parts
• Scoring • Perforating • Doctor • Coater • Doctor
rule die blade blade blade
• Rotary • Cutting • Creping • Rotogravure
die rule blade blade
• Leather • Leather • Leather
splitting splitting splitting
knife knife knife
• Machete • Foam
splitting
• Wood • Wood • Metal • Friction • Bimetal
cutting cutting cutting cutting saws
• Meat/fish • Meat/fish
cutting cutting
• Shuttle • Reed steel
grip • Sinker • Sinkers
• Heddle bar • Jacks
• Cylinder walls
• Sliders
TextileSaw
Steel
Band
Knife
Pulp&
Paper
AutomotiveHardwareSpring
20
