关键词: 硫系, 切削性能, 易切削钢, 元素影响

Abstract: Several new developed kinds of low carbon sulphur free-cutting 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 cutting force, tool wear, surface quality, chip deformation and mor-phology are studied systematically, which reveals the cutting 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 of Al 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 cutting steel.

Key words: Machinability, Free-cutting steel, Influence of elements, Sulphur