Cor-ten, 4140, 4130

By buckroy Date 03-31-2006 17:14

The old drawings say the stack is built out of Cor-ten. The 2 different PMI readings (different guns, different inspectors) say it is 4140/4130. Another PMI reading (third gun, third inspector) says CS, but lists a Cr content of almost 1%. The new trunnions and re-pads were welded on with 7018 and inspected via mag-part and shear wave. This thing will be putting about 150,000 pounds on the rig when we finish the cut; does anybody think the welds will fail?

By medicinehawk (**)

Date 04-01-2006 22:27

I would certainly look into it to make sure. I have limited experience with corten steels and it was a long ,long time ago, but from what I remember....we welded it with 11018. You metioned it would be loaded at 150,000 pounds, then you already know that 7018 was not the rod to use. My opinion would be to get someone else with your company to ok that part otherwise you might be asking for a train wreck. My opinion is that the welds will not hold up.

By MBlaha

Date 04-02-2006 19:02

Several questions about this and maybe we can help you more.

Are you scrapping out this stack, or are you going to be putting it back up?
Is cutting holes large enough to put a beam or large heavy schedule pipe that will carry a load of this size through the holes, and toggleing the stack, then welding lifting lugs to the pipe, beam, square tubing, etc. a possiblitiy?

I know you know as well as the rest of us, you have to know what the material is if you are going to weld on the material, and even more so if you are going to be preforming a critical lift such as this. Someone getting hurt or worse, is not worth the guessing game. If the PMI readings are varying, I guess I would go to what is listed on the prints.
7018 might hold it, but the key word is might. Having both performed and supervised lifts such as this, I guess I would not chance it. There are too many things that could go wrong and once you have made the final cut, there is no turning back.

Have a nice day

Mike

By G.S.Crisi (****)

Date 04-03-2006 12:01

Corten is a brand name that belongs to United States Steel Corp.
Why don't you ask them, who know their product better than anybody else?
www.uss.com
Giovanni S. Crisi
Sao Paulo - Brazil