Cracks in Fillet, 316L to 316L??
Cracks in Fillet, 316L to 316L??
(OP)
hello All: We are welding Ø 1.25 sch 40 pipe to a slip-on flange mfg'd to ASME B16.5, SA 182 alloy. Both are 316L with 316L filler made to MIL-E-19933. We are experiencing circumferential cracks. No toe cracks though. Ø 1/16 filler putting a 1/16 fillet on using manual GTAW. Argon purge. No preheat or PWHT used. Cracks appear upon solidification. We are using 2 different suppliers of flanges also. Could a gas contamination cause these??? What should I look for??? HELP........





RE: Cracks in Fillet, 316L to 316L??
RE: Cracks in Fillet, 316L to 316L??
RE: Cracks in Fillet, 316L to 316L??
RE: Cracks in Fillet, 316L to 316L??
I don’ ever remember have a problem welding 316 S/S pipe and slip-ons that involved the materials.
Exactly where is the weld cracking?
Are you welding on both sides of the flange?
Is this a true slip-on or is it possibly a lap-joint flange?
RE: Cracks in Fillet, 316L to 316L??
Please note that when I asked for the ferrite content, I meant the actual weld deposit ferrite, which is measured with a magnetic ferrite gage - not as calculated from the chemistry provided with the wire by the wire supplier. The deposited weld metal chemistry is a combination of the base metal chemistry and the filler metal chemistry. More than once, I have found that supporting MTR was in no way representative of the material received.
RE: Cracks in Fillet, 316L to 316L??
You also need to be aware that in a small fillet weld like that there is a lot of dilution with the base material, consequently you will end up with a FN a lot closer of that of the base material not of the filler. Usually the base material has less ferrite than the filler. So, you may want to look into the base material, too. It's always more difficult to weld 300SS autogenously than with filler wire addition which brings the extra ferrite that makes the weld deposit more resistant to cracking. However, don't forget that 310SS welded with 310 filler is also possible even it's fully austenitic, but with precautions.
In addition to the above you can either try to increase the size of the weld (which will take care of the solidification stresses better and increase the participation of the filler)and/or use a low heat input and technique which will minimize the dilution with the base material and keep the heat input low. Also try to produce a convex weld not a concave one that is too shallow and cannot accommodate the stresses. You can also break the weld into shorter beads which will solidify one at a time, reducing the cracking risk but increasing the potential of start/stops defects.
RE: Cracks in Fillet, 316L to 316L??
RE: Cracks in Fillet, 316L to 316L??
Thanks!
RE: Cracks in Fillet, 316L to 316L??