Welding AISI 4130 / 4140 to TStE 420 2

[FIF99]

Hi,

One of our fabricators intends to supply a piping component machined from AISI 4130/AISI 4140 material which must be welded to TStE 420 piping.
Anybody having experience with welding issues regarding both discimmilar materials?
The Carbon content is different, i.e. 0.28 respectively 0.38 for the AISI grades and 0.20 for TStE 420.

Thanks in advance for any help.

Regards.

 

[metengr]

According to the information I have, the equivalent material for DIN 17102 Tste 420 is ASME SA 516 Grade 60 carbon steel.

The welding between a low alloy steel and carbon steel is not that difficult with any of the conventional processes like SMAW. Because of the higher carbon content and alloying effects, the critical welding variable will be preheat. Preheat and post weld heat treatment requirements should be dictated by the low alloy steel (AISI Type 4130/4140) versus the carbon steel. Given a typical carbon equivalent for AISI Type 4140, the preheat will be around 350 deg F.

As far as filler metal, you have two choices - carbon steel (E7018) or low alloy like E8018 B2. For either weld filler metal, specify low hydrogen electrodes.

 

[Carburize]

Depending on the service environment and applicable codes you may also need a post weld heat treatment. If that is the case you will need to check on the thermal history of the materials to make sure that the PWHT cycle does not degrade the strength properties of the 4130/4140 material or the TStE 420 piping

 

[FIF99]

Hi metengr, Carburize,

Thanks for your help! We will pay attention to the welding procedures regarding pre-heat and PWHT.

Thanks!!

Regards.