Welding HSLA-70 steel tubing

By rodney Date 03-15-2002 22:19

This rectangular tubing, HSLA-70, is available from Joseph T Ryerson & Son, inc. It is a high strength steel, 70 ksi yield strength, that is obtained by the alloy elements. The material is not listed in AWS D1.1, and we do not find fabricators that have used it before. Most contacts say it is similiar to ASTM A500, but these materials are in the 33-46 ksi yield strength range.

The current design requires the strength of this material. The high strength material is used because of weight to strength ratio concerns.

We can start from the beginning and develop welding procedures, but we would like to find existing documents. Are welding procedure specifications and procedure qualification records available for this material (SMAW, GMAW, and/or GTAW processes)?

By DGXL

Date 03-17-2002 21:58

R,
I was wondering why there were not any responses to your post.

I would exercise caution about a comparison of your material to that of A500 tubing. There is a reason for the mechanical properties being much higher in your base metal. It is a "high strength" material for sure compared to that of the A500 tubing. Your material has a yield almost double that of A500 Grade B (yield = 42 ksi) structually approved tubing. You can be sure the chemical properites and primary alloying elements differ with the HSLA-70.

Many designs now use these higher strength materials to save weight. This is also convenient due to the continuing micro-alloying of todays materials. There are many "new" alloys being developed these days; higher strength with less weight, improved mechanical and chemical properties, availability, etc.

I would obtain the mill test report (MTR) and qualify the procedure as this material is not prequalified in accordance with the AWS D1.1. The type of service that your welds will be subject to will also determine the WPS/PQR target requirements.

The selection of the welding process can be determined by several factors including the availability of equipment, desired deposition rates, process efficiency, etc. I think the supplier (JTR) would be helpfull in providing assistance in the development of the WPS. I qualify lot's of non-prequalified materials and material combinations. It has almost become routine these days for my business.

Good luck.