新型低碳硫系易切削钢切削性能试验

以几种最新开发的低碳高硫易切削钢材料为对象，通过对材料显微组织的分析得出其主要元素对材料中硫化物夹杂的形状、大小、分布的影响规律。系统研究车削过程中切削力、刀具磨损、工件表面粗糙度、切屑变形和断屑性能，揭示了新型易切削钢的切削机理及各元素对材料可加工性的影响规律。试验结果表明，硫化物夹杂长宽比小、形状大、分布均匀，并且密集的材料切削加工性能好；材料中硫元素质量分数增加可以提高刀具寿命；采用Al、Si进行脱氧时应合理控制其质量分数，脱氧剂使用过多不仅对硫化物形态的控制不利而且容易形成很多氧化物硬质点，加剧刀具磨损并降低加工表面粗糙度。研究结果对完善材料切削性能评价体系和开发新型易切削钢材料具有重要价值。

EXPERIMENT ON MACHINABILITY OF NEW DEVELOPED LOW CARBON SULPHUR FREE-CUTTING STEEL

Several new developed kinds of low carbon sulphur flee-cunning steel are studied.Influences of major elements on the shape,size and distribution of sulphide inclusion are inves- tigated by means of their metallographic structures.The cunning force,tool wear,surface quality,chip deformation and mor- phology are studied systematically,which reveals the cunning mechanism and influences of major elements on machinability of the new low carbon sulphur free-cutting steel.Experiment conclusions show that materials containing the sulphide inclu- sion with small length width ratio,big size,homogeneous and dense distribution have better machinability.The tool life can be prolonged by increasing the content of sulphur.The content oral and Si which serves as deoxidizer should be controlled in a proper range.With overabundant deoxidizer the morphology of sulphide inclusion is bad,additionally,much solidness is formed which is bad for the tool life and surface quality.Ex- periment results have great practical significance to improve the evaluation system of material machinability and the devel- opment of new types of free cunning steel.