Post Weld Heat Treat/Stress Relief Requirements

[USACompositeGuy]

Does anyone have any recommendations for books on the topic of post weld heat treatment/stress relief? I am having a hard time finding some general guidelines as to when PWHT is required and what the effects of not doing it actually are.

I am analyzing weld repairs on aircraft engines. The welds are primarily to the exhaust system and pressure ducts. The materials that I am primarily working with are 321 Stainless, 6-4 Ti, and 6061 al.

Most of the parts would require some sort of jig fixture to completely re-heat-treat due to shape and therefore would make them beyond economical repair.

I would like to know what the strength/durability lost due to the weld is and how much is restored by a PWHT or stress relief.

Any references that could help me with this would be appreciated.

 

[metengr]

Post weld heat treatment(PWHT) means different things to different people in the industry. Typically, for steel and low alloy steel PWHT is performed to reduce residual stresses from welding and to also reduce the hardness of the weld deposit and the base metal heat affected zone(s) surrounding the weld region.

For metals that do not harden by thermal treatment, like austenitic stainless steel, post weld heat treatment is not performed. In this case, the welded component may be subjected to a re-heat treatment to restore corrosion resistance.

For other metals that are heat treated to obtain desired properties, like some aluminium alloys, a re-heat treatment may be performed to restore original properties after welding.

As I stated above austenitic stainless steels do not require post weld heat treatment after welding. What I would suggest is to visit the web sites below for welding fabrication information on Al and Ti alloys;

http://www.alcotec.com/default.html

http://www.timet.com/Index2_content.html