JL-1344亞共析石墨化易切削鋼無鉛低硫環(huán)保易車鐵

石墨易切削鋼是順應易切削鋼無鉛、低硫這一發(fā)展趨勢而提出的。具有亞共析組織的鋼種其石墨化過程一直很難，因此該鋼種開發(fā)的關鍵是促進其石墨化過程。基于增加石墨核心來加速石墨化過程進行了鋼種的成分設計與研制。結果表明，正是開發(fā)鋼中具有與石墨結構（簡單六方）相同的BN成為了石墨的形核位置，從而有效促進了開發(fā)鋼的石墨化過程。開發(fā)鋼的組織由鐵素體和石墨組成，其中，石墨的缺口效應和潤滑效果賦予了開發(fā)鋼較高的切削性能和冷成形性能。

Development of lowsulfur and Pbfree free cutting steel is significant because the use of S or Pb freecutting steel can result in serious pollution.The hypoeutectoid graphitized free cutting steel was proposed. The graphitization is difficult due to slow graphitization process,so it is crucial to accelerate the graphitization process. The composition design was based on the principle of increasing the number of graphite nucleus. The machinability of developed steel is improved by taking advantage of notch effect and lubrication action of dispersed fine graphite particles.