Filler wire for 4130, Reynolds 853: ER70s2 or Weldmold 880

by Robert
(Scotland)

Your advice on Tig welding 4130 is to use ER70s2 which works fine and most people agree: but I have seen that some people recommend using Weldmold 880 on cromoly, 4130, Reynolds 853 etc bike frames.
Can you suggest what, if any, advantages there might be in using Weldmold 880 compared with ER70s2?
Plus, is Weldmold 880 similar to 312? and would it be possible to weld 4130 to stainless steel?

--------------------------------------------------

I just visited the weldmold site and did not see any weldmold 880.

my reasons for recommending er70s2 are:

**Wyatt Swaim aka "Mr. Tig" recommends er70s2 and cites several studies that provide substantiation for applications under .120" for use without post weld heat treatment

**er70s2 is dirt cheap compared to anything else

**er70s2 provides a ductile weld that has some give to it

** welds made using er70s2 can be repaired in the field more easily than the rest...

This is all assuming the weld will not be heat treated after welding.

For some products made from 4130, full strength and hardness is needed in which case an extensive heat treatment probably involving a full anneal followed by heat and quench and tempering.
For parts like that, 4130 filler metal or possibly some other filler metal that responds to heat treatment is used.

Thats pretty rare. Bicycles, racing roll cages, airplane fuselages, etc, are usually used as welded...with not heat treatment or at the most a local stress relief.