SSAB Oxelösund and AGA, Linde Group have started a co-operation in the field of process development of welding technology for high-strength steels. The process involved is known as RAPID PROCESSING®, a process which can increase the welding speed up to three times.

High strength in the welded joint, rapid welding speed and small deformations are some of the advantages with RAPID PROCESSING welding of high-strength steels. The process can make use of existing MAG equipment and therefore does not require major investments. RAPID PROCESSING is an advancement of the MAG process that makes it possible to weld high-strength steel up to about three
times faster than with a conventional MAG process.

And Daniel Stemne, Research engineer within welding technology at SSAB Oxelösund, says there are also better results. He says that with the process, static strength in the welded joint can be very high, despite the fact that filler metal with relatively low strength can be used. “For example, welding technique trials have been carried out on butt joints that contain the high-strength structural steel WELDOX® 1100,” Stemne says. “The yield strength for this steel is at least 1100 MPa.

In this case, the static strength in the welded joint could be on a par with the demands for WELDOX 1100. The toughness can also be very good. It meets the requirements for the WELDOX 1100 steel by a long way.”

“Because we can weld with lower heat input, in other words with lower energy per unit of time in
comparison with conventional welding processes, the deformations are smaller, which also means lower
deformations for the entire construction. This greatly widens the scope to reduce straightening on the
construction after welding.”
The improvements come as a result of the cooperation between SSAB Oxelösund, which is responsible for the material technology competence and AGA, Linde Group which is responsible for the development of the process technology.

Loader crane manufacturer HIAB in Zaragoza, Spain, will be the first to evaluate the process in welding production, using WELDOX 700 and WELDOX 900 of plate thickness 7-8 mm. In this case, the type of welded joints will be Butt welds in the structure of loader cranes. The goal for HIAB is principally to increase manufacturing speed, and secondly to achieve high static strength in the welded joints.

 

Stemne says “This is the first attempt in practice using RAPID PROCESSING when welding high strength steels and it is very likely that it can also be used for all WELDOX grades as well as for welding all grades of HARDOX wear plate".