定量的に評価されたオーステナイトステンレス鋼溶接金属組織と靱性の関係

抄録

The microstructures of stainless steel weld metals which had absorbed nitrogen were analyzed quantitatively by means of a computer-aided image analyzer. Then, the relationships between quantitative microstructural factors and the low-temperature fracture behaviors were investigated. Generally, the δ ferrite which is included in the stainless steel weld metal causes cleavage fracture at low temperatures and brings about a decrease in the fracture toughness property. There is much potential for improving the toughness by controlling the amount and shape of δ ferrite. The amount of δ ferrite decreased and its shape became more globular with increasing nitrogen content in weld metal. Consequently, cleavage fractures rarely occurred at low temperature, and the fracture toughness values were improved. The δ ferrite amount (A) and the shape factor ( S ) were combined into the factor of A·S. The A·S factor has a linear relationship with fracture toughness values.