Welding in Cryogenic Applications with Stainless and Nickelbased Consumables

Abstract

Stainless austenitic materials and 9% nickle steels offer high ductility even at very low temperatures and are used for cryogenic applications. Consumables and procedures have been developed for welding of stainless and nickel alloyed cryogenic materials to give optimum strength/ductility in the welds and allow for safe operations.

Some ofthe essential factors influencing the ductility of austenitic weld metal at cryogenic temperatures is the level of ferrite in the weld metal and the amount of micro slags.

A number of vessels in 316 LN modified type of steel have been welded with a specially developed nitrogen alloyed weld metal allowing tensile strength >615 MPa and KV-196>35 J.

Nickelbased weld metals have been designed for 9% nickel steels to achieve the combination of tensile strength >680 MPa and KV-196>70 J.

This paper will present weld metal investigations and practical welding of 9% nickel steel LNG storage tanks, welding of the transonic wind tunnel project and welding of 316 LN transportation tanks for LNG.