Effect of BC addition on the solidus and liquidus temperatures, density and surface tension of type 316 austenitic stainless steel in the liquid state

BC添加による316系オーステナイトステンレス鋼の固相線・液相線温度,液相密度及び表面張力への影響

福山 博之*; 東 英生*; 山野 秀将   

Fukuyama, Hiroyuki*; Higashi, Hideo*; Yamano, Hidemasa

ステンレス鋼(SUS316L)の固相線及び液相線温度,密度並びに表面張力に及ぼす炭化ホウ素(BC)添加の影響を実験的に調べた。BC含有SUS(0から10mass%まで)の固相線温度は1666Kから1307KまでBC添加につれて単調に減少した。液相線温度は2.5mass%BCで最小点となり、10mass%までBC添加につれて増加した。BC含有SUSの密度と表面張力は電磁浮遊法で(過冷却領域を含めて)幅広い温度域で計測できた。密度は温度に対して線形的に減少した。また、BC添加量に応じて密度は単調に減少した。BC含有SUSの表面張力については、BC添加による影響は明確な影響は見られなかったが、SS316Lに含まれる硫黄が表面張力を有意に低下させた。

The effects of BC addition on the solidus and liquidus temperatures of type 316 austenitic stainless steel (SS), and on the density and surface tension of molten SS, were experimentally studied. The solidus temperature of SS-x mass% BC (from 0 to 10) monotonically decreased from 1666 to 1307 K with BC addition. The liquidus temperature had a minimum at around 2.5 mass% BC, and increased with further BC addition up to 10 mass%. The density and surface tension of molten SS-x mass %BC were successfully measured over a wide temperature range (including an undercooling region) via an electromagnetic-levitation technique. The density of each sample decreased linearly with temperature. The density also monotonically decreased with BC content. Although the addition of BC had no clear effect on the surface tension of SS-x mass %BC, sulfur dissolved in SS316L caused a significant decrease in the surface tension.