Low-carbon high-sulfur free-cutting steel with excellent cutting performance and manufacturing method thereof

Abstract

The invention discloses low-carbon high-sulfur free-cutting steel with excellent cutting performance and a manufacturing method thereof, and belongs to the technical field of free-cutting steel. the free-cutting steel contains the following ingredients by mass percentage composition: 0.05 to 0.2 percent of C, 0.6 to 2.0 percent of Mn, 0.04 to 0.1 percent of P, 0.2 to 0.45 percent of S, 0.005 to 0.02 percent of O, less than or equal to 0.02 percent of N, less than or equal to 0.005 percent of Si and less than or equal to 0.001 percent of Al. Generated MnS impurities have the following characteristics: (1) over 95 percent of MnS impurities in as cast steel are Class I MnS, and the proportion of single-phase MnS impurities is equal to or larger than 80 percent; (2) the length of at least 70 percent of MnS impurities in the rolling direction is equal to or larger than 5 micron, and the length-width ratio is lower than or equal to 6; and (3) the average area of MnS impurities in 1 square mm in the rolling direction is no less than 50 square micron. C is adopted for deoxygenation, the cooling rate of ingoting is controlled to range from 2 to 4 mm / min, the roll opening temperature is controlled to range from 1200 to 1250 DEG C, and the roll closing temperature is controlled to be equal to or larger than 1050 DEG C. The low-carbon high-sulfur free-cutting steel has excellent cutting performance. After cutting, the surface fineness of parts is improved. The low-carbon high-sulfur free-cutting steel is generally close to or matches the lead-containing low-carbon free-cutting steel, and is suitable for high-speed cutting.

Description

technical field [0001] The invention relates to the technical field of free-cutting steel, in particular to a low-carbon high-sulfur free-cutting steel with excellent cutting performance and a production method thereof. Background technique [0002] With the rapid development and rapid growth of my country's industry, especially modern industries such as home appliances, communications / communications, automobiles, and office equipment, and the trend of global economic integration becoming more and more prominent, the domestic and international demand for various precision parts is increasing. More and more prosperous, most of the small-sized parts, such as: shafts, screws, nuts, nails and other standard components, are now mostly processed by free-cutting steel masterbatch. Free-cutting steel is a steel grade characterized by excellent cutting performance. Because this steel grade has low cutting force and cutting temperature, good chip handling, good surface finish and impro...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the problems of high-sulfur free-cutting steel chips in the prior art and the poor surface finish of parts after cutting, to provide a low-carbon high-sulfur free-cutting steel with excellent cutting performance and its production method. Low-carbon high-sulfur free-cutting steel does not contain Pb, has excellent cutting performance, and the surface finish of parts after cutting is better

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