Welding cast steel coupling to steel tub 1

[dwelding]

Is it possible to weld cast steel coupling to steel tubing(1.500
x .375 wall,low carbon steel)without preheating the cast steel.
Is there a cast steel material that doesn't require preheating.
What welding process is best for cast steel.

 

[rustbuster1]

What is so difficult in preheating the steel casting?
Would a heating source like a oxy acetylene or propane torch not be easy to use?

How large is the cast steel coupling?
What is composition/ type of steel in casting?

What preheat temperature are you considering - this relates to Q 2 and 3 above?

As usual, more information will generate a better answer.

 

[welding1]

Pre-heat is mainly dependant on carbon content and thickness.

In carbon steels Pre-heat is mainly to stop hydrogen cracking.

You may find that if your carbon content is low preheat may not be required.

There is an article on preheat on my web site

http://www.gowelding.com,

which you may find useful; it also includes a pre-heat calculator.

 

[musashi]

1)cast iron welding rod 3/32
2)if it does not fuse right cast w/ nickle gives a smoother
more controled pass, cleaner appearance with penertation
3)gas weld w/brazing rod

cast weld should be pitted after weld ( # 1, 2 )
and 3 don't need to ( but it good ) depends on your situation

it all depends what it will be use for and what type of work this it calls for and doing

 

[GRoberts]

You need to know what kind of cast steel the coupling is. It could be anything from ASTM A216 WCB or A27 Gr. 60-30, which you could weld without preheat to A148 Gr. 260-210 or A958 Grade SC4340, both of which you would run into problems without preheat. If it is cast ironas musashi's comments pertain to, it is a whole different ballgame.

 

[unclesyd]

If you don't know the material is for sure go with "rustbuster1's" comment on preheat. Nothing has to be precise about the temperature 200°F-300°F and after welding slow cool. If there is any doubt about welding to the casting try a little tab, 1/8"-1/4" piece of the tube or plain carbon steel on edge and weld it to some inconspicious place on the casting and when cool hit with a hammer to break it off. If it come off with base metal preheat will defiantly be required. If it breaks in the weld a little more weld metal or a different welding electrode is needed. It should not break in the tab.

Your best rod will probably be a utility rod, We used, USA, ALLSTATE 275 (essentially 312 S/S) for all this type welding.