question on tig welding chromoly tubbing

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was told by a chassis builder that he welds all his chromoly roll cage tubing up with stainless rod. now being im new to welding chromoly tubing and searching the ole interweb most use ER70S2 rod. but he said the reason he uses the stainless rod is that it makes the weld less brittle and not want to crack, this is welding 083 and 095 wall tubing. someone give me a run down on if this is true thanks..
Reply:Welding 4130 with 309 or 312 happens on a regular basis in a lot of shops. By the book, er70s-2 (or -6) or er80s-d2 is a more appropriate choice, but fabricators make their own choices unless a specific rod is called out on a print. To his specific point about crack sensitivity, with proper prep and technique, the mild steel fillers will produce an adequately ductile weld deposit.
Reply:Ok cool deal. Just wanted to get a idea on this cuz I have some chrome moly to weld..
Reply:Originally Posted by stroker52Ok cool deal. Just wanted to get a idea on this cuz I have some chrome moly to weld..
Reply:I agree, use er70s-2Welding/Fab Pics: www.UtahWeld.com
Reply:70s-2 costs much less to purchase. Stainless filler costs much more.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Originally Posted by makoman1860The aerospace world uses ER70s-2 for 99% of tig welding on SAE 4130. Racing people use......seemingly whatever depending on the latest flashy magazine article, loudmouth builder or web article. The "stainless" fillers no not make the HAZ less brittle.
Reply:2003 article by an ESAB welding engineer and consultant to NASCAR fabricators:  http://www.aws.org/wj/apr03/AWfeature.html."Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:I have always used 80sd2 on chromoly
Reply:ok so I can just use a normal ole er70s-2 rod and be just fine? just making sure cuz im fixing to build a set of upper and lower control arms for my drag truck.. they take a beating an don't want them to break by using the wrong rod..
Reply:70s-2 is fine, if you want extra security do a localized PWHT on each weldment.
Reply:http://www.lincolnelectric.com/en-us...ly-detail.aspxhttp://www.netwelding.com/Metalurgic...al%20Buckling:http://www.millerwelds.com/resources...hromoly-tubing.. 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:ok fixing to build a set of control arms and the ball joint cups I get, I can only get them in mild steel. is this going to be a big problem welding the 1inch 095 wall chrome moly tubbing to the mild steel and not have it break? also if im welding a say the 1 5/8 083 wall tubbing to say the 1/8 thick mild steel frame what rod would I use? ER80S-D2 or the ER70S-2 or 6?
Reply:I'm pretty sure it would be ER70S-2/6.  The ER80S-D2 would be suitable if doing CrMo-to-CrMo and you needed a stronger, but less ductile weld. 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:Stroker, are you sure your capable of producing the quality of welds required on control arms for a dragtruck?  The questions you're asking are usually answered in books that most of us have/had.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:Originally Posted by OscarI'm pretty sure it would be ER70S-2/6.  The ER80S-D2 would be suitable if doing CrMo-to-CrMo and you needed a stronger, but less ductile weld.
Reply:Originally Posted by SquirmyPugStroker, are you sure your capable of producing the quality of welds required on control arms for a dragtruck?  The questions you're asking are usually answered in books that most of us have/had.
Reply:Originally Posted by stroker52im new to the tig welding world but have been doing fab work for a long time. I would just use my mig and build them out of mild steel but I want them built out of something lighter and stronger. so to answer your question yes I feel that iam, but I just needed a few details covered before I tackle them. I will do some trial runs before I jump on them so I can get the feel for the tig and post pix for yall..
Reply:Originally Posted by sausage450rWhat he said, AWS standard is 70s-2 unless calls for heat treating, then 4130 rod.  stainless will be fine, but with the logic of it doesn't crack, why not just weld it with silicon bronze then.....and I'm not kidding i've seen a guy weld over a 4130 joint that kept cracking with SIB, to stop cracking, what a tool. I work in the heart of the big off road race shops, and they all use 70s-2 on 4130
Reply:Originally Posted by slotardAre you calling the guy who brazed it a tool, or saying that SIB is a good tool to use?I've seen some TIG brazed 4130 motorcycle frames that were beautiful.
Reply:I haven't seen oxy/fuel brazed joints as pretty as TIG brazed, though. One example of TIG brazingLincoln 175HD
Reply:Wow that is beautiful!!! Someone has got some skills. .
Reply:Originally Posted by SquirmyPugIf your more comfortable with mig, then mig the control arms. Mig is used on 4130 everyday. Even with a fab background, you need to know your tig welds are sound before using them on something like this.
Reply:Originally Posted by slotardI haven't seen oxy/fuel brazed joints as pretty as TIG brazed, though. One example of TIG brazing
Reply:Hey, those remind me of something