welding P20 tool steel (nitrided) 1

[408]

Hi I work in the tooling industry, and we often repair damaged tools that have been nitrided. For this we use TIG welding, but we usualy have a problem of bubbles forming in the weld, due to nitrogen in the steel from the nitriding process. We grind some off the area and this helps to a degree but we still get bubbles around the edges. Has anyone found a way to overcome this problem. Thanks, Harvey

 

[unclesyd]

You could completely “denitride” the metal and then weld and the nitride the part. Another approach might be to change the welding procedures to use a flux cored electrode.
There is some information on this website. Also I try to find my information on some of the particulars of the “denitriding” that we accomplished.
Are you concerned with one tool steel or several?

http://www.lincolnelectric.com/knowledge/articles/content/cored.asp

 

[408]

Thanks for the reply unclesyd, I think we have had de nitriding done before, and still had problems, The process requires heating the whole die plate, something you don`t wont to do unless absolutely necessary. The tools are P20 tool steel and can have mirror finish in the cavitys.I don`t know much about flux cored electrodes I will look into that.Thanks.

 

[funnelguy]

This unit might be suitable for repairing/restoring the edges of the TIG welds. I have no experience with the unit, but have always wondered about its capabilities. Worth a look anyway...

http://www.gesswein.com/catalog/cat...bsub=1&catalog=2&CFID=351985&CFTOKEN=52038148