Abstract: A test piece preparation step of preparing a test piece (50) including a welding structure in which a welding material formed of an austenitic alloy is welded to a member formed of low-alloy steel or low-carbon steel, a hydrogen supply step of supplying hydrogen to the test piece (50), and a characteristic stress acquisition step of applying a load (F) to the test piece (50) to which hydrogen was supplied and acquiring a characteristic stress showing material mechanical properties of the test piece (50) are executed.

Abstract: A test piece preparation step of preparing a test piece (50) including a welding structure in which a welding material formed of an austenitic alloy is welded to a member formed of low-alloy steel or low-carbon steel, a hydrogen supply step of supplying hydrogen to the test piece (50), and a characteristic stress acquisition step of applying a load (F) to the test piece (50) to which hydrogen was supplied and acquiring a characteristic stress showing material mechanical properties of the test piece (50) are executed.

Abstract: A welding structure (30A) includes a welding layer (60A) which is configured of a first built-up layer (33) which is formed of low-alloy steel or carbon steel having a carbon content of less than low-alloy steel and which is formed on a base metal (31), a second built-up layer (34) which is formed of a 600-type nickel-based alloy and which is formed on the first built-up layer (33) and a third built-up layer (35) which is formed of a 690-type nickel-based alloy and which is formed on the second built-up layer (34).

Abstract: In a dissimilar material joint structure that joins together an anti vibration bar (first member) 14 and a end cap (second member) 15, which is a dissimilar metal material to the anti vibration bar 14, the anti vibration bar 14 is sandwiched by a plurality of end caps (second members) 151 and 152, and these respective end caps 151 and 152 are joined together by welding. Due to contraction of a weld material 153 welding the end caps 151 and 152, the anti vibration bar 14 is sandwiched between the end caps 151 and 152, whereby the anti vibration bar 14 and the end cap 15 are joined. Consequently, a thermal treatment for welding dissimilar metal materials is not required, and the welding operation can be carried out easily.