窒化物及び酸化物分散による溶接ボンド部の靱性改善
1983 年 52 巻 2 号 p. 117-124
詳細
1983 年 52 巻 2 号 p. 117-124
For low temperature service at -45°C-60°C, steel plates with little Ni content are used generally. The base metals of these plates have good toughness, because of various thermal or thermo-mechanical treatment. But the heat-affected zones of weldments in these plates have poor toughness frequently, because of disappearing of these treatment's effects by welding thermal cycles.
In this paper, ultra low S-Ca treatment is combined with already well known TiN dispersing treatment. This new treatment is developed more effective to keep good toughness of welded HAZ than only TiN dispersing treatment. This treatment is dispersing not only TiN particles but also Ca (O, S) particles. So, for example, vTrs is improved about 10°C-20°C from one of the only TiN dispersing treatment on Charpy test.
In this case, it is better to control Ti/N ratio near by 2. Ca (O, S) particles dispersed in steel are existing very stable at high temperature which TiN particles already are unstable at. So, Ca (O, S) particles take an important part of improving HAZ toughness.
