16. Which castings are weldable ? Process Alloys Processes Wrought alloys All except > 0,25% copper addition - (some exceptions <0,4%) and free machining alloys All - Rolling, extrusion, forging, etc Cast alloys All except > 0,25% copper additions, and free machining alloys Sand, gravity, permanent mould, low pressure. Not standard high pressure die casting (i.e . unless vacuum cast.)
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19. Aluminium 660 o C 231 o C- 327 o C Se, Sn, Bi, Cd, Pb, 97,7 o C Na 44.2 o C P- 650 o C Mg 630 o C Sb 420 o C Zn 1410 o C Si 1245 o C Mn 1150 o C Fe 1083 o C Cu 1852 o C – 2625 o C Zr, Ti, Cr, B, V, Mo Which castings are weldable ? Composition - What do we add - Summary 768 o C Sr hardeners Grain refiners (never melts) Free machining Grain modifiers (casting) affects micro porosity (early freeze c.f. Si) MgSi composition 6xxx
21. Which castings are weldable ? Composition relationship between filler/parent metal and weld cracking – (Note: long copper sensitivity above 0,25%) Dilution by 4043 – thus choose 5356 Dilution by 4043 – avoid 5356 5xxx 6xxx 2xxx
22. Which c astings are weldable ? Compostion NOTE Log scale! l n Cu upper limit % (wrought and cast alloys) (Other alloy elements, eg silicon, also have a role) Welding Rating Excellent A Very good B Good C Poor D 0.1 0.2 0.3 0.5 1 2 3 3+ ****** (1xxx) ** ******* *** * ** * (3xxx, 5xxx, 51000 (LM0,LM5) ) **** * * ** * (6xxx, LM25, LM6 ) **** * *** ** *** ** ** ** ( LM20 ) * ******** ******** (2xxx, LM4, 21,22,24,26 )
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29. Designations of comparable casting alloys (unalloyed and aluminium silicon) CEN Chemical designat-ion UK BS1450/ AEA France NF A50 Germany DIN 1725 Italy UNI USA AA / ASTM Japan JIS H5202 H5302 Unalloyed aluminium – generally weldable Al 99,5 LM0 A5 Al99,5H 3950 150.1 Al 99,7 A7 Al99,7H 3950 Aluminium Silicon – generally weldable 42000 AlSi7Mg0,3 AEA 44525 (A –S7G03) (G AlSi7Mg) 42100 AlSi7Mg (Fe) LM25 A-S7G03 G- AlSi5Mg 3599 A356,1 AC4C 42200 AlSi7Mg(0,6) AEA 44530 (A-S7G06) (G -AlSi7Mg) A357 43100 AlSi10Mg LM9 A-S10G (G –AlSi10Mg) 3049 A360 AC4A 43200 AlSi10Mg(Cu) (LM9) (A-S9G) A360 44000 AlSi11 (LM9) A-S13 (G –AlSi12) 44100 AlSi12(Fe) LM6 A-S12U G –AlSi12 4514 A413 AC3A 44200 AlSi12 AEA46330 /LM6 A-S13 AC3A 44300 AlSi12(Fe) (LM20) A-S12 (G –AlSi12)
30. Designations of comparable casting alloys (aluminium silicon copper) CEN Chemical designat-ion UK BS1450/ AEA France NF A50 Germany DIN 1725 Italy UNI USA AA / ASTM Japan JIS H5202 H5302 Aluminium Silicon Copper – generally not weldable 45000 AlSi6Cu4Mn LM21 A-S5UZ G-AlSi6Cu4 7369/4 A308 AC2A 45100 AlSi5Cu3Mg (LM4) (LM22) A-S5U3G (G-AlSi6Cu4) 45200 AlSi5Cu3Mn LM4 A-S5U3 (G-AlSi7Mg) 3052 A319.2 AC2A 45400 AlSi5Cu4Mn LM22 A-S5U G-AlSi6Cu4 3052 A319.2 AC2A 46000 AlSi9Cu3 (LM26) A-S10G A335 AC4B 46100 AlSi9Cu3 LM2 A-S10UG 5067 A384.1 ADC12 46200 AlSi9Cu3(Fe) (LM24) A-SGU3 46500 AlSi9Cu3(Fe)(Zn) LM24 A-S9U3 G-AlSi8Cu3 5075/3601 A380.1 AC4B/ ADC10 47000 AlSi12(Cu) LM20 A-S12 G-AlSi12(Cu) 5079 A313.1 47100 AlSi12Cu1 (Fe) (LM6)(LM20) A-S12 G-AlSi12(Cu)
31. Designations of comparable casting alloys (Aluminium copper/aluminium magnesium and piston alloys) Note: Designations in brackets are considered fairly comparable For export purposes the LM series is not recognised CEN Chemical designat-ion UK BS1450/ AEA France NF A50 Germany DIN 1725 Italy UNI USA AA / ASTM Japan JIS H5202 H5302 Aluminium Copper – not weldable 21000 Al Cu4MgTi AEA 24850 A-U5GT A204.2 AC1B Aluminium Magnesium – weldable 51000 AlMg3 LM5 A-G3T G-AlSiMg5 3059 Piston Alloys 48100 AlSi18Cu1 Mg1Ni1 LM28 (KS 2811) A392.1 (AC9B) 48000 AlSi12Cu1 Mg1Ni1 LM13 A-S12UN (KS 1275) A336.0 AC8A
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41. Cast Alloys – filler alloy choice Selection of filler rods and wires for MIG and TIG welding Parent metal combination LM25 LM20 LM9 LM6 LM5 LM4 1070, 1200, 1350, 5251, 5454, 6082, 6061, 6063, 4043 4043 4043 4043 5356 4043 5083 4043 NR 4043 NR 5356 4043 7020 NR NR NR NR 5356/5556 NR LM4 4043 4043 4043 4043 NR 4043 LM5 NR NR NR NR 5356/5056 NR LM6 4043/4047 4043/4047 4043/4047 4043/4047 LM9 4043/4047 4043/4047 4043/4047 LM20 4043/4047 4043/4047 LM25 4043/4047
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61. Welding problems Gas porosity in aluminium welds – always caused by hydrogen (Low solubility in solid and high solubility in liquid aluminium)
65. Welding problems Composition relationship between filler/parent metal and weld cracking – (Note: long copper sensitivity above 0,25%) Dilution by 4043 – thus choose 5356 Dilution by 4043 – avoid 5356 5xxx 6xxx 2xxx
66. Good Fair Poor Filler Alloy 5356 Parent Alloy 6061 Filler Alloy 4043 a b d c 1 2 3 4 5 6 Silicon in the Weld Bead (%) 0 1 2 3 4 5 6 7 8 Magnesium in the Weld Bead (%) Figure 1. Resistance to hot cracking
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68. The welding of aluminium castings Tony Paterson (082 602 4517) Questions??