Welding stainless steel to carbon steel
Welding stainless steel to carbon steel
(OP)
I apologize if this is a redundant post, but I need to specify the proper electrode for welding a 3/4" diameter stainless steel rod (304) to a schedule 40 steel pipe. This will be done in the field and is part of a life line attachment.





RE: Welding stainless steel to carbon steel
Filler metals that have been used in other circumstances to weld low carbon steel to 300 series stainles include 309, 310, ENiCrFe and other nickel based alloys.
Before proceeding with any welding on fall protection equipment I would check with a competent person responsible for the design.
Gerald Austin
Iuka, Mississippi
http://www.weldinginspectionsvcs.com
RE: Welding stainless steel to carbon steel
RE: Welding stainless steel to carbon steel
If you are restricting the process to SMAW then the an example would be E309-xx .
That method, used often on engineering drawings still today is one that theoretically restricts the process to shielded metal arc welding when often FCAW/GMAW or GTAW are being used. All of the previous listed process would have different designators.
Another option is to just refer to the filler metal type as E309-XX or equivelant type for other processes.
Hope that helps.
Gerald Austin .
Gerald Austin
Iuka, Mississippi
http://www.weldinginspectionsvcs.com
RE: Welding stainless steel to carbon steel
RE: Welding stainless steel to carbon steel
RE: Welding stainless steel to carbon steel
There may be a welder or welding foreman in your organization that could give you some information on this subject and may be a good resource for future questions. Though I do enjoy running off at the fingers :)
Have a nice day
Gerald Austin
Iuka, Mississippi
http://www.weldinginspectionsvcs.com
RE: Welding stainless steel to carbon steel
1. Make sure the carbon steel pipe surface you are welding to is clean of rust, scale or paint and is above 50 deg F.
2. Use the SMAW process with SFA 5.9 E309 welding electrodes.
3. After the completion of welding, perform a Liquid Penetrant inspection of weld and surrounding base metal.
As mentioned previously, and I want to stress that you should make sure that the weld design is adequate for a life line attachment. If necessary, have a registered, Professional Engineer review your design detail - the cost will be well worth the investment.
RE: Welding stainless steel to carbon steel
RE: Welding stainless steel to carbon steel
My $.02
RE: Welding stainless steel to carbon steel
Finally, all anchorages will be tested to 2500 lbs. Lifeline systems as well as window wasing equipment must also have annual inspections.
RE: Welding stainless steel to carbon steel
If it has been done before, I can be very confident that there are small cracks along the toe of the SS weld metal adjacent to the stainless.
I have seen this on numerous occasions where welders attached the wrong type pipe doubler for a support on a SS pipe. It has always cracked.
Forgive me for seeming a bit forward but I suggest consulting with a welding engineer even if you are the PE.
I am just a welder/inspector but there seems to be some basic items you could use some help with. I have a tremendous respect for the the many things an engineer must know and I have always enjoyed picking the brain of the ones I have had the priviledge of working with.
In this case here is some of my brain. If I am wrong about this I'm sure someone will straighten me out.
Gerald Austin
Iuka, Mississippi
http://www.weldinginspectionsvcs.com
RE: Welding stainless steel to carbon steel
RE: Welding stainless steel to carbon steel
RE: Welding stainless steel to carbon steel
Grinding will not remove all the galvanizing a thin layer will be smeared over the surface. After grinding heat the surface with a neutral torch to 600F, the steel will turn brown in color and any zinc on the surface will be silver in color.
Consult a PE Welding Engineer, granted there are very few of them, since Ohio is the only state that gives the PE Welding Engineering Exam.
On another note- After any welding you need to perform NDE looking for cracking beneath the galvanized coating in any areas that has reached 280F. An eutectic of tin, and/or bismuth (galvanizing alloys) and zinc can form that can penetrate the grain boundaries of the steel cause them to unzip, i.e. crack.
Still more information- Galvanized pipe is NDE inspected, usually with eddy current, prior to galvanizing, however no inspection is done after galvanizing. Galvanizing is not a coating like paint by a metallurgical coating that can affect the mechanical properties of the steel. Since this application is for lifeline anchorages think about more NDE inspection.
RE: Welding stainless steel to carbon steel
When I have done spot work welding SS to galv we always required a chemical (acid) cleaning to remove the Zn residue.
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Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: Welding stainless steel to carbon steel
Edstainless, just curious though, is the chemical cleaning reliable? To answer a previous post, regarding NDE, the job has independant monitoring and inspection as well as load testing on every single piece of equipment.
RE: Welding stainless steel to carbon steel
RE: Welding stainless steel to carbon steel
You can use pickling acid to strip Zn, and almost anything else. If you have to do spot work a grind and then using a pickling paste might get you by. Actually I would first grind, then heat with a torch to oxidize remaining Zn, grind or sand with fresh abrasive, then pickle clean.
I know that it sounds like overkill, but I have seen what trace amounts of Zn and Cu can do to SS welds.
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Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: Welding stainless steel to carbon steel
RE: Welding stainless steel to carbon steel
Whipping can be done with SS electrodes but the arc is just NOTHING like an E6010 or 6011.
Depending on the application, the mixture may not be a problem.
Gerald Austin
Iuka, Mississippi
http://www.weldinginspectionsvcs.com
RE: Welding stainless steel to carbon steel
Can you explain/describe what you mean by "whipping"?
RE: Welding stainless steel to carbon steel
Gerald Austin
Iuka, Mississippi
http://www.weldinginspectionsvcs.com
RE: Welding stainless steel to carbon steel
I think I understand (at least in principal) what you were trying to accomplish, but, relying on whipping to avoid zinc contamination sounds like a dangerous practice.