4340 Steel

Date 08-27-2013 21:04

Hello, all

We have been asked to quote a weldment made from 4340 1.25 thick

Is this weldable by FCAW or GMAW? If so, what wire have you had success with?

According to the info I can find, we would need to preheat to 800 degrees?

After weld, I was going to bury the part in clean sand to slow the cooling rate. After weld, we will perform PWHT to 150-170 ksi.

Thanks for your replies.

Darrell

By Joey

Date 09-30-2013 02:42

You can get the answer by google

Low hydrogen electrodes are recommended. Pre-heat at 200°C –
300°C and maintain during welding. Cool slowly in ashes or sand etc and
stress relieve if this is possible.

By Drumsdw Date 10-09-2013 04:24

I have welded a lot if AISI 4340 high carbon steel both to itself and dissimilar metals. The best practice is develop welding procedures which allow for preheat in accordance with the CE ( carbon equivalency) calculation, but anywhere from 400-600 F should be plenty. Whether you match or under match the filler material strictly is based on the service condition and type of loading and/or stress applied. I have welded dissimilarly to 572 gr. 50 using GMAW-spray with ER70S-6 wire and used heat shield blankets to cover the part until cooled to ambient temperature to allow sufficient time for any H2 to exit the weldment eliminating post cracking. Let me know how it turns out.