Please help: how to eliminate Stud Welding cracks? 3

[shmultz]

Hi,

I tried to weld 0.25' 304SS stud on p11, p22 and carbon steel with no PWHT (DA Stud Welding). the welds look good, passed hammer test and with very good tensile strength (only the stud brakes, not the weld) but when I cross-section the samples (that haven't gone through hammer test), I find cracks in the weld, cold cracks from solidification perhaps? (directional cracks). Can you please advice how to eliminate these cracks with no PWHT?

Attached is an example of the weld cross-sectioned.

Many thanks,
Best Regards,
S.

 

[metengr]

Use a different stud material - 309 ss. The problem is dilution of the 304 with the low alloy steel. If you review a Schaeffler or Delong diagram you can see what phases (like martensite or lack of ferrite) are formed in the weld itself.

http://www.bssa.org.uk/topics.php?article=121

 

[Duwe6]

Depending on the total quantity of studs needed, hand-welding your 304 studs using a 309 filler might be cheaper. SMAW would be my choice for less than 150 pieces. For over 50 or so, FCAW would be a better choice.

For multiple hundreds, buy the 309 studs metengr recommended, and stud-weld them.

Then fire the estimator that didn't know that 304 will not weld directly to carbon steel and failed to notice the large price difference between 304 and 309 studs.

 

[chicopee]

"Then fire the estimator that didn't know that 304 will not weld directly to carbon steel..." Wasn't that the job of the shop engineer to specify SS309.

 

[msquared48]

shmultz:

Your example of the cross-welded section did not post.

Mike McCann
MMC Engineering

 

[Duwe6]

Actually, I was able to get the Cross-Section to open as a jpg picture file. Excellent 'shot', and am using it to educate an MI engineer. Thank you, schmultz