3 Reasons To Not Weld Free Machining Steels

Any type of arc welding of resulfurized steels is generally avoided. This post will give you some  reasons why. Resulfurized steels are free machining steels. This includes steel grades in the 11XX and 12XX series,  such as 1215, 12L14,  1117, 1137, and 1144. These steels contain sulfur and may contain lead. These two elements will create low melting temperature constituents that will cause cracks.

Here are 3 reasons not to weld resulfurized free machining steels:

  1. Sulfur reduces weldability.  The higher levels of sulfur make a slaggy joint.
  2. The high volume fraction of manganese sulfides also hold hydrogen. This hydrogen can then create post weld cracking.
  3. Both sulfur and lead  can become a fume inhalation hazard at welding temperature.

Finally, with the exception of grade 1144, resulfurized steels are generally not sold to mechanical property requirements. Welding implies mechanical property performance.

We have seen 1215 welded using an inertial or friction welding process. But these welds are  usually not subject to mechanical loads, merely attachment. Here’s a video of a friction weld process for truck axles from Thompson Friction Welding in the UK.

Want a second opinion? Dave Barton at Lincoln Electric hosts a column   Barton’s Q&A in Welding Magazine published by Penton.  The second question in this column deals with welding 12L14.

Think of weldability and machinability as two sides of the material coin.

Heads it machines well, welds lousy, Tails...

Heads it machines well, welds lousy, Tails...

You can usually win on one, but at the expense of the other. If you need to weld, a low carbon plain carbon steel is your best bet.


9 Responses to 3 Reasons To Not Weld Free Machining Steels

  1. ali says:

    casting parameter of resulfurized free cutting steel?

  2. ali says:

    what are the parameters in c.c to avoid cracking of AISI 1144 grade?

  3. I worked at a company that did not pay attention to what they wanted welded. I finally showed them how weak a 12L14 weld was by welding a round onto some 1020 flat bar and I welded a smaller piece of 1018 and told them to hit the two pieces. I made the 12L14 weld twice as big as the cold roll weld. They couldn’t break my cold roll weld with a three lb hammer, but the 12L14 went flying with the first hit. I had to tell them one time when I had 12l and 1150 something that I couldn’t weld it without it cracking. They fired me as soon as they could. They didn’t appreciate my 30+ years of TIG experience.

  4. 1144 has to simply be preheated. I used to weld shafts rings made of it and I simply welded it twice! Once to heat it up and the second time to clear the cracks and counter heat any warp.

    • Jim, I don’t doubt that you got the pieces to stick together. I am not at all confident that such a weld has mechanical properties worth bragging about. Thanks for sharing your experience.

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