Hi, I'm having troubles welding 1117 to 1018 with the TIG process. I keep getting cracks. I have tried 70S-6, 70S-3 and 70S-2. The 70S-6 and the -3 are cracking the worse, the 70S-2 seems better but will still get an occasional crack. I have also tried a 220 filler rod made by Crown Alloy, which is a maintenence type filler rod with little success. The 1117 is generally at least 1inch thick plate. I also have problems with the MIG process, but it's not cracking. When I MIG it I get worm hole prosity and 'blowouts' in the craters. If anyone has any recomendations I would greatly appreciate it.
Thanks, Al W.
Are the cracks in the centerline of the weld or possibly transverse to the weld? The 1117 steel is a resulphurized, free machining steel with 0.08 - 0.13% sulphur added to make it easy to machine. It is generally recommended that these steels not be welded. The high sulfur makes the welds prone to "hot cracking", in which cracking occurs during welding. Normal steels that are welded have a maximum sulphur content of 0.04% and they are usually around 0.015% or even less.
If you cannot change the steel, try using SMAW with small diameter electrodes, low current and fast travel to minimize the melting of the base metal.
If you are a member of AWS, look in your AWS Handbook Volume 4 for more on free machining steels. If you are not a member, you should join and get copies of the handbooks. They are excellent references and could answer a lot of questions like this one.
Regards.
I had a similar problem with identical materials with greater thicknesses a number of years back. The solution was an easy one, and I was humbled as a welder. Try the backstepping (backhand) technique. In other words, reverse your direction of travel normally used for GTAW. It worked for me on the first try, and I continued to use through the rest of the welding without any problems.
I agree. I have also seen this. But keep in mind, you must requalify your procedure.
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