weld cooling/heating rate

Date 10-28-2010 06:36

Hi there,

Could you explain how to control cooling and heating rate during welding high strength quenched and tempered steel such as pad welding on Ø 15” shaft AISI 4140. Is there way in practice how to avoid the martensite formation in HAZ? It would be much appreciated if you advise of some articles discussing this issue. What cooling/heating rates would you recommend and how to achieve it?

Thanks

By 803056

Date 10-28-2010 17:26

You can purchase an atlas of cooling curves published by ASM that may be of interest to you.

Best regards - Al

By MMyers

Date 10-29-2010 18:15

Given the composition of your material and some additional info, you can predict TTT and CCT diagrams. If you cool slow enough to miss the nose of the martensite start, you'll not form martensite. From my initial looks at the graph (best guess on composition), you'll need to cool VERY slowly to avoid forming martensite. This might not be possible without very high preheat temps.

http://calculations.ewi.org/vjp/secure/TTTCCTPlots.asp

By zambrota (**)

Date 10-31-2010 22:09

Thank you Mike

Straight to the point. That is what I was looking for.

All the best