Detail explanation of metal and the destructive testing that are used to find the properties of those metals

1. Metal Properties and
Destructive Testing

2. Metal PropertiesMetal Properties
• Physical properties (density)
• Mechanical properties *
• Alloy chemistry
• Alloy heat treatment
* Mechanical properties depend on alloy chemistry,
heat treatment and cold work.

3. StrengthStrength
“The ability of a material to bear an applied load”

4. StrengthStrength
Two common methods of expression:
• Ultimate tensile strength (UTS)
• Yield strength (or yield point)

5. Metal Behavior Under LoadMetal Behavior Under Load
• Elastic - No permanent deformation
• Plastic - Permanent deformation

6. ElasticElastic
Behavior ofBehavior of
SteelSteel

7. Temperature EffectsTemperature Effects
As metal temperatures increase:
• Strength decreases
• Hardness decreases
• Ductility increases

8. DuctilityDuctility
The ability of a metal to deform without breaking

9. Brittle Ductile
Brittle vs Ductile FailureBrittle vs Ductile Failure

10. Ductility TermsDuctility Terms
• Percent elongation
• Percent reduction of area

11. Directional PropertiesDirectional Properties
Both strength and ductility are affected by the rolling
direction of the metal. The three axes of rolling
direction are referred to as the X, Y, and Z directions.

12. Rolling DirectionsRolling Directions
X Direction Best Strength & Ductility
Y Direction 10 - 30% Less Strength
20 - 50% Less Ductility
2 Direction Still Lower Strength & Ductility

13. HardnessHardness
“Ability to resist indentation”

14. Indenter TypesIndenter Types

15. Hardness TesterHardness Tester

16. IndentationIndentation
ShapesShapes

17. ToughnessToughness
“The ability to absorb energy”

18. Toughness ComparisonToughness Comparison

19. Notch ToughnessNotch Toughness
“Toughness in the presence of surface notches and rapid
loading”
(also referred to as “Impact Strength”)

20. Stress RiserStress Riser
“A surface condition, or geometric feature, that
increases the applied stress at the condition or
geometry”

21. Stress Risers (Notch Effects)Stress Risers (Notch Effects)

22. Notch Effects on FatigueNotch Effects on Fatigue

23. Surface Finish Effects on FatigueSurface Finish Effects on Fatigue

24. Ductile - to - BrittleDuctile - to - Brittle
Transition TemperatureTransition Temperature
“The temperature at which a metal fracture mode
changes from ductile to brittle”

25. Fatigue StrengthFatigue Strength
“The strength of a metal when exposed to repeated
reversals of cyclic stresses”

26. Endurance LimitEndurance Limit
“The maximum stress at which no failure will occur,
regardless of cycles”

27. Typical S-N CurvesTypical S-N Curves

28. SoundnessSoundness
“Freedom from discontinuities”

29. Chemical PropertiesChemical Properties
• Metals are mixtures of elements, and are referred to
as alloys
• Minor changes in alloy composition can have major
effects on alloy properties such as mechanical
strength, corrosion resistance

30. Common Steel AlloysCommon Steel Alloys
Common Name C % Typical Use Weldability
Ingot iron .03* Deep drawing Excellent
Low C .15* Electrodes Excellent
Mild Steel .15-.30 Structural Good
Medium C .30-.50 Machinery Fair
High C .50-1.0 Springs, dies Poor
* Single values are maximums

31. Low Alloy SteelsLow Alloy Steels
• High strength, low alloy
• Automotive & machinery
• Low temperature
• Elevated temperature

32. High Alloy SteelsHigh Alloy Steels
• Corrosion resistant
• High temperature
• High strength

33. Stainless SteelsStainless Steels
Contain at least 12% Cr
• Austenitic
• Martensitic
• Ferritic
• Precipitation hardening
• Duplex

34. Elements in Steels - 1 of 2Elements in Steels - 1 of 2
• C - Most important
• S - Undesirable
• P - Undesirable
• Si - Deoxidizer
• Mn - Combines with S
• Cr - Hardenability, Corrosion Resistance

35. Elements in Steels - 2 of 2Elements in Steels - 2 of 2
• Mo - Hardenability
• Ni - Toughness, Ductility
• Al - Deoxidizer
• V - Hardenability
• Nb - Stabilizer

36. Dissolved GasesDissolved Gases
(Embrittle steels, cause porosity)(Embrittle steels, cause porosity)• Hydrogen
• Oxygen
• Nitrogen

37. Aluminum AlloysAluminum Alloys
Heat treatableHeat treatable
Major Alloying
Element
Aluminum Association
Number
Cu 2XXX
Mg & Si 6XXX
Zn 7XXX

38. Aluminum AlloysAluminum Alloys
Non-heat treatableNon-heat treatable
Major Alloying
Element
Aluminum Association
Number
Pure Al 1XXX
Mn 3XXX
Si 4XXX
Mg 5XXX

39. Nickel AlloysNickel Alloys
• Corrosion resistant
• Good low temperature properties
• Good high temperature properties

40. Copper AlloysCopper Alloys
• Electrical conductivity
• Resistance to corrosion
• Resistance to erosion
• Resistance to water and salt water

41. Destructive TestingDestructive Testing
“Failing, or destroying, a part, or a portion thereof, to
determine its properties”

42. Nondestructive TestingNondestructive Testing
“Does not affect the serviceability of the part after
testing is completed”

43. Tensile TestingTensile Testing

44. Typical Stress/Strain Curve - SteelTypical Stress/Strain Curve - Steel

45. Sample PreparationSample Preparation

46. Area of a Circular Cross SectionArea of a Circular Cross Section
Example 1Example 1
Area (circle) = π x Radius2
=  R2
= π x Diameter2
=  D2
4 4
Sample Diameter, D = 0.505 in.
Sample Radius, R = 0.2525 in.
Area = 3.1416 x 0.25252
Area = 0.20 in2

47. Alternate CalculationAlternate Calculation
Example 2 (using diameter directly)Example 2 (using diameter directly)
Area =  D2
4
Area = 3.1416 x (0.505) 2
4
Area = 0.20 in2

48. Calculation ShortcutCalculation Shortcut
Area of Circle shortcut:
Area = 0.7854 x D2
because:
π ÷ 4 = 3.1416 ÷ 4 = 0.7854

49. Calculation of Tensile StrengthCalculation of Tensile Strength
Example 3Example 3
Load to break = 12,500 lbs
Area of sample = 0.20 in. 2
Tensile strength = load ÷ area
Tensile strength = 12,500 ÷ 0.20
Tensile strength = 62,500 psi

50. Unit Strain e e
Offset MethodOffset Method

51. Stress-Strain DiagramStress-Strain Diagram
High and Medium Strength SteelsHigh and Medium Strength Steels

52. Percent ElongationPercent Elongation
Original gage length = 2.0 in.
Final gage length = 2.6 in.
%Elongation = final length - original length x 100
original length
%Elongation = 2.6 - 2.0 x 100 = 30%
2.0

53. Percent Reduction of AreaPercent Reduction of Area
Original area = 0.2 in.2
Final area = 0.1 in. 2
%Reduction of area (%RA) = ?
%RA = original area - final area x 100
original area
%RA = 0.2 - 0.1 x 100 = 50%
0.2

54. Hardness TestsHardness Tests
BrinellBrinell

56. Hardness TestsHardness Tests
MicrohardnessMicrohardness

57. Hardness Testing StepsHardness Testing Steps
• Prepare surface
• Make indentation
• ‘Measure’ indentation
• Determine hardness

58. Toughness TestingToughness Testing
• Impact testing
• Notch toughness
• Transition temperature

59. Charpy TestCharpy Test
• Prepare notched specimens (sets of 3)
• Test each specimen set at a specific temperature
• Impact sample
• Plot results

60. Charpy SpecimensCharpy Specimens

61. TypicalTypical
CharpyCharpy
TestingTesting
MachineMachine

62. Charpy Test ResultsCharpy Test Results
• Energy absorption - Ft. lbs.
• Percent shear - %
• Lateral expansion - Mils

63. TransitionTransition
TemperatureTemperature
DeterminationsDeterminations

64. Transition Temperature SamplesTransition Temperature Samples

65. Soundness TestingSoundness Testing
• Bend testing
• Nick-break
• Fillet break

66. Bend Test SamplesBend Test Samples
Transverse Weld Bend SpecimensTransverse Weld Bend Specimens

67. Bend Test SamplesBend Test Samples
Longitudinal Weld Bend SpecimensLongitudinal Weld Bend Specimens

68. Guided Bend Test JigGuided Bend Test Jig

69. Wrap-aroundWrap-around
Bend Test JigBend Test Jig

70. Bend Test ProcedureBend Test Procedure
• Prepare sample
• Orient in jig
• Bend sample (weld and HAZ in bend)
• Evaluate bend to Code

71. Nick Break TestNick Break Test

72. Evaluation of Nick-Break TestEvaluation of Nick-Break Test

73. Fillet Break TestFillet Break Test
• Prepare sample
• Break sample
• Evaluate fracture

74. Fillet Break - Sample FractureFillet Break - Sample Fracture

75. Fillet Break Specimen - T-JointFillet Break Specimen - T-Joint

76. Fatigue TestingFatigue Testing
• Prepare samples
• Test series of various loads
• Test to failure, record cycles
• Test at maximum load vs no failure
• Plot data
• Determine endurance limit

77. Chemical TestingChemical Testing
Determines Chemistry of MetalsDetermines Chemistry of Metals• Spectrographic
• Combustion (CO, CO2 determination)
• Wet chemistry (titration)
• X-Ray fluorescence (XRF)

78. Corrosion TestingCorrosion Testing
“Evaluates metals in corrosive environments”

79. Metallographic TestingMetallographic Testing
• Shows structure of metal
• Macroscopic - less than 10X
• Microscopic - typically more than 100X

80. PhotomacrographPhotomacrograph

81. PhotomicrographPhotomicrograph

82. Heat Treatment - 1 of 3Heat Treatment - 1 of 3
• Mechanical properties are often very dependent upon
heat treat condition
• Many types of heat treatment
• Determine heat treat condition prior to welding on
base metal or mech. testing
• Consider effects of welding on heat treat condition
and mechanical properties

83. Heat Treatment - 2 of 3Heat Treatment - 2 of 3
Heat Treatments For Steels:
• Preheating
• Stress Relieving
• Normalizing
• Annealing
• Quenching and Tempering
• Others

84. Heat Treatment - 3 of 3Heat Treatment - 3 of 3
Heat Treatments For Stainless Steels:
• Preheating
• Stress Relieving
• Solution Annealing, Water Quench (Solution
Treatment)
• Quenching and Tempering
• Others
More on heat treating in Module 8