Low carbon sulfur free cutting steel

Abstract

A low-carbon sulfur free-cutting steel containing C: more than 0.02% and less than 0.20%; Si: more than 0.10% and less than 1.5%; Mn: 0.8-2.2%; P: 0.005-0.25%; S: more than 0.40% , less than 0.8%; O: <0.010%; N≤0.025%; Ca: 0.0003~0.005%, the balance is composed of Fe and impurities, among which Al<0.005%, Mg<0.0003%, Ti≤0.002%, Zr ≤0.002%, REM<0.0003%, satisfying "2.0<Mn / S<4.0" and "0.0005≤10Ca×Si≤0.050", compared with the existing Pb-free Low-carbon free-cutting steel has a smaller surface roughness than low-carbon free-cutting steel, and is also excellent in chip disposability. The low carbon sulfur free cutting steel may also contain one or more of Te≤0.05%, Bi≤0.15%, Sn≤0.5%, and / or Cr≤2.0%, Mo≤0.5%, V≤0.3%, Nb≤ One or more of 0.3%.

Description

technical field [0001] The present invention relates to a low-carbon sulfur free-cutting steel, and relates to a Pb-free steel that has excellent machinability in finishing turning using a superhard process, and is particularly suitable for use in OA parts such as small-diameter printer shafts. Low carbon sulfur free cutting steel. Background technique [0002] Conventionally, in the raw materials of soft small parts, such as brake parts of automobile parts, printer shafts of OA parts, and electrical equipment parts, so-called "quick" steel materials with excellent machinability have been used in order to improve productivity. cut steel". [0003] As the free-cut steel material, there is known a steel material specified in JIS G 4804 (1999), that is, a "sulfur free-cut steel material" (hereinafter referred to as "S free-cut steel material") in which a large amount of S is added and machinability is improved by using MnS. ), "sulfur composite free-cutting steel" with both S...

AI Technical Summary

Problems solved by technology

[0024] Although the technologies proposed in the above-mentioned patent documents 1 to 5 can all improve the machinability during forming processing using HSS tools, when such superhard tools are used for finishing turning processing, the machined surface roughness is not necessarily sufficient.

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