Supermatensitics - Welding Properties

With the introduction of the new 13% Cr supermartensitic stainless steel grades the efficient welding procedures under practical circumstances have become a key issue for successful application. First of all one has to select the appropriate weld metal type which is basically determined by the need:

· To match strength
· To achieve adequate toughness
· To keep hardness at an acceptable level
· To match corrosion resistance
· To minimise or avoid post-weld heat treatment (PWHT)

Although promising results have been achieved with the so-called soft martensitic alloys of the 13% Cr 4% Ni + Mo type and duplex or superduplex consumables, supermartensitic consumables can offer a number of advantages.
An almost complete product program for welding supermartensitic stainless steels has now been established.

Furthermore a wide variety of welding conditions and processes are available for prefabrication and site welding. In particular the welding of the root runs determine the productivity and the corrosion resistance. Welding processes include GTAW, GMAW (regular pulse and STT), FCAW and SAW. The welding parameters, typical for these welding processes determine qualification aspects such as hardness and toughness properties in the weldment. With the current programme of welding consumables and welding processes the fabricator can handle all welding positions with productive welding procedures.
As a result the production of longitudinally welded large diameter pipe can be done on a commercial basis. Several processes such as the Electron Beam welding process, super laser welding the HF-ERW process but also conventional methods have shown good results in terms of corrosion and mechanical properties when manufacturing welded longitudinally welded pipe.

Below you will find some papers on the welding and fabrication of supermartensitic stainless steels. Please also check the Library & References page.

Mechanical Properties and ageing response of supermartensitic weld metals
By Leif Karlsson et al, Esab AB, Gothenburg, Sweden), Stainless Steel World 2001 Conference (Paper SSW P 0128).

Development of weldable martensitic stainless steel line pipe by HF-ERW process,
By Naoshi Ayukama, et al, Nippon Steel Corporation, Japan, Stainless Steel World 2001 (Paper SSW99-042)

Efficient Procedures for welding 11-13% Cr Supermartensitic stainless steel with duplex & superduplex stainless steel welding consumables.
By L. Van Nassau et al, Lincoln Smitweld, the Netherlands, Supermartensitic Stainless Steels 99, (Paper S99-26)

EB Welding of Supermartensitic 13% Cr Steel
By Karl Schäfer and Ingo Stiebe-Springer, Butting Edelstahlrohre, Germany, Supermartensitic Stainless Steels 99 (Paper S99-14)