heat input for stainless 5

[mcguire]

Do any of the welding gurus know of a source for an internally consistent set of recommendations for heat input limits for welding the various types of stainless?

Michael McGuire

http://stainlesssteelforengineers.blogspot.com/

 

[EdStainless]

No

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[GRoberts]

I don't either. If someone was to come up with one though, to be completely accurate, it would have to accont for:
Material type and condition
Material thickness
Welding process (i.e. heat input efficiency)
Preheat temperature
PWHT condition
Properties required
Probably several more I am not thinking of right now.

Seems like a monumental task to me.

 

[metengr]

I am only aware of limited heat input studies and recommendations for the duplex and superduplex stainless steels. See below

Welding Duplex and Superduplex Stainless Steels, NIDI paper by L.van Nassau, H. Meelker, and J. Hilkes

Electrode Manufacturer - Avesta Polarit and others
They list recommended heat inputs for their duplex and superduxlex welding consumables.

 

[HEC]

Another good source on a "by application" basis is the good people at Sandvic.

Mark Hutton

 

[stanweld]

Back in the early '70s, Bechtel required low heat inputs (maximum approximately 22 KJ/in.) when welding 304 piping in nuclear applications to preclude HAZ sensitization. It didn't work.

 

[HEC]

Rule of thumb heat inputs for say SAF2507 0.2 - 1.5 kJ/mm. This is higher than the limit stanweld has stated. HAZ sensitisation, cna also be caused by the wrong cooling rate as well as over heating the parent material. A key point that has been raised is the shielding gas applied to the weld. This is vital to assuring weld integrity, In pipe welding the back purge gas is also important.

Mark Hutton

 

[mcguire]

The literature sugests that 0.2-1.5kJ/mm is correct to avoid excessive ferrite in the HAZ.

Michael McGuire

http://stainlesssteelforengineers.blogspot.com/

 

[unclesyd]

Way back before stanweld's stated time there was a tremendous amount of work was done with heat input into SS welds. I remember that McKay, DuPont, Monsanto, and Chemstrand were some of the participants. I just called to see if the records of the work that we did in 50's and 60's was still available. It seems that they wiped the library in the Metallurgical lab by getting rid of any data over 7 years old because anything you need is on the net.

Our part of the work centered around the heat input form the SMAW and TIG welding process. At the initiation of the work the accepted method for welding SS with SMAW was using the stringer technique with absolutely no form of weaning. Tig, Heliarc, was frowned on for the amount of heat input. There were quite a few variables for either process as the primary power source was the "PIG", motor generator set. Testing was accomplished both by laboratory and on stream. Laboratory test were the Huey, Striker, and Metallographic evaluation. On stream process exposure was by exposure to a process stream with a very high corrosion rate for 304 SS.
In short, as the base materials improved, 304L got to be 304L, the welding electrodes, flux, improved, the welding power supplies improved the overal heat input rapidly declined with a marked improvement in the carbide precipitation problem. Accompanying this was improvement in the higher temperature properties of the Austenitic SS. This study also included testing of carbon arc gouging of SS. Also included was using the GTAW torch for washing out welds and beveling plate.

testing with better equipment showed that above the theoretical minimum there was a physical minimum of heat input that could only be achieved by the better welders. We actually used this information to select welders in areas where IGC was the major concern.