Environment-friendly leadless free-cutting steel and metallurgy method thereof

Abstract

The invention relates to an environment-friendly leadless free-cutting steel which comprise the following components by weight percent: 0.04 to 0.15 % of C, 0.95 to 1.40 % of Mn, 0.04 to 0.09 % of P. 0.25 to 0.45 % of S, less than or equal to 0.03 % of Si, 0.025 to 0.25 % of Bi, 0.10 to 0.35 % of Ca, less than or equal to 0.03 % of As, less than or equal to 0.03 % of Cu, less than or equal to 0.03 % of Cr, less than or equal to 0.03 % of Ni, less than or equal to 0.03 % of Mo, less than or equal to 0.03 % of Al and the balance being Fe. A metallurgy method of the environment-friendly leadless free-cutting steel comprises smelting by using a converter or an electric furnace firstly and a refining furnace secondly, and then continuously casting or molding into blanks, wherein nano-graphite accounting for 0.008 to 0.015 % of a total weight of molten steel is added during a smelting process in the refining furnace, so that 0.008 to 0.015 % of nano-solid C is contained in the product. By adding bismuth with a melting point less than that of the lead and carbon materials with excellent lubricating effect, lubrication effect on cutting tools is relatively good during a metallic material machining process, being nontoxic and harmless as well; and the method has advantages of simple process, strong operationality and low production cost.

Description

technical field [0001] The invention relates to a steel product, in particular to an environment-friendly lead-free free-cutting steel and a metallurgical method thereof. Background technique [0002] With the rapid development of intelligent machining, various free-cutting steels are constantly being developed and produced in the world. Products with lower cost and more mature technology are generally recognized as sulfur-based free-cutting steels and lead-based free-cutting steels. The representative steel number of sulfur-based free-cutting steel is 1215; the representative steel number of lead-based free-cutting steel is 12L14. [0003] The chemical composition of sulfur-based free-cutting steel 1215 and lead-based free-cutting steel 12L14 is shown in Table 1. [0004] Table 1 [0005] steel number C mn P S Si Pb 1215 ≤0.09 0.75～1.05 0.04～0.09 0.26～0.35 ≤0.10～0.35 12L14 ≤0...

AI Technical Summary

Problems solved by technology

[0008] Due to this shortcoming of chalcogenide steel, the processing speed cannot be increased

The processing tool is vulnerable and the processing speed is low, and the surface quality of the workpiece is poor, resulting in high production costs