Mechanical Characteristics of Austenitic Stainless Steel 316LN Weldments at Cryogenic Temparature

KSTAR (Korea superconducting tokamak advanced research) has chosen the stainless steel 316LN as main material for the magnet structure. Two welding methods such as GTAW (gas tungsten arc welding) and EBW (electron beam welding) have applied to achieve proper weld condition and good weld properties. In order to determine the strength and toughness of stainless steel 316LN at low temperature, mechanical tests were carried out at 4 K, 77 K, and room temperature. The weld joint specimens are successfully produced without weld defects. Also yield strength and fracture toughness at 4 K satisfy the structural design criteria