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Repair cast iron using welding and heat treating?

asked Mar 27, 2015 in Material by bxander (1,180 points)
I have a question about Cast Iron Welding and Heat Treating. There is a defect after the cast iron was done and the part was machined (a machinist cut too deep into the part of the cast). I know we can weld to repair the casting, but does it have to be heat treated afterward and the recommendation if so?

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answered Mar 27, 2015 by GerritMcLane (870 points)

All casting should be suitably heat treated after any welding operation is performed. This requirement also applies to weld repair of defects irrespective of size. The casting weld repairs should be heat treated as follows:

  • Carbon and low alloy steels: thermal stress relief to reduce residual stress and to reduce the hardness of the casting below 22 HRC.
  • Martensitic stainless steels: re-heat treated completely per NACE MR 0175 / ISO 15156 Part 3 or double tempering when complete re-heat treatment is not possible.
  • Austenitic, duplex, and super duplex stainless steels: solution annealed.
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answered Mar 27, 2015 by GerritMcLane (870 points)
In addition, you should take a hardness sample of the cross-section of a representative weld test coupon to ensure welding procedures demonstrate hardness control. The weld test coupon should be similar to the casting in terms of geometry, mass, and material specification.
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