welding 4130 low alloy steel and A333

[larryli2004]

Hi,

Is there any problem to weld API 5000 4130 low alloy steel flange with A333 Gr. 6 pipe? Does anyone see any welding issue here? I appreciate your advice.

Thanks.

 

[stanweld]

There are issues of preheat and PWHT and filler metal. A WPS will have to be qualified (impacts @ -50F are assumed). The two materials can be successfully welded.

 

[larryli2004]

Thanks Standweld.

For this particular case, the pipe thickness is less than 19 mm, so PWHT is not really required as per ASME.

Regarding preheat, do you mean preheat temperature?

 

[stanweld]

The 4130 HAZ may need PWHT.

 

[MikeMet]

The answer is yes you could have problems welding AISI 4130 to A333. AISI 4130 will develop a very hard heat affected zone that is prone to cracking during welding and after if not preheated. You can get away with a very high preheat above to prevent formation of too much martensite. I have used 500F and higher. However, this will not fully prevent martensite formation, so a post weld stress relief may be necessary depending on the service. You need to take the service conditions and consequence of failure into consideration when deciding whether to PWHT.