Welding of ASTM A197 to Carbon Steel Pipe

[Everynameistaken]

Hello,

I am a structural and I need to weld a threaded weldlette to a 36" pipe to use as a float, so I can fill the pipe with expanding foam and then thread in a cap to seal up the access port.

My question is:

I am specifying pretty generic low grade pipe, there is almost no pressure load on the pipe as its just the static water pressure so 1m of water head. The pipe is carbon steel to ASTM A252 or similar with 240 Map yield. Can I weld ASTM A197 Cupola Malleable Iron to the carbon steel?

If so, is there anything special about the weld?

If not, what is the type of threaded weldolette that I should use instead?

Thanks Very Much

 

[XL83NL]

Im not familiar with both steels, but as a minimum, Id check their carbon equivalents and from there on, get a first idea on the weldability (or not).

 

[EdStainless]

Welding these cheap cost fittings can be very problematic.
Just get a forged steel fitting.

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P.E. Metallurgy, Plymouth Tube

 

[Dhurjati Sen]

Dear Everynameistaken,

If you have to weld ONLY one weldolet with the pipe, you can try welding with Inconel electrode. Remember, this is a non-standard practice.

Regards.

DHURJATI SEN
Kolkata, India

 

[o_grid]

You're going to have a hell of a time welding anything to that cast iron.

It would require pre-heat, peening, or special filler metal. Even then, you're liable to encounter cracking issues.

I'd avoid this unless it's 100% necessary. It's possible, but not simple.

 

No one ever welds on cast iron willingly.
Go with carbon steel as EdS says, and sleep at night.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Everynameistaken]

Thanks everyone.

We have gone back to our client and suggested a forged steel equivalent.

If the contractor still has to use the cheaper malleable iron fitting then we have asked for the welding procedure to be specifically designed by the fabricators welding engineer to ensure the right processes are utilized.

 

[mk3223]

IMO, just simply reject the Contractor idea to have a malleable iron fitting welded on CS pipe. And, don't need to review the welding procedure if even proposed by the Contractor, because it isn't an engineer's responsibility to endorse it.