Smelting method of lead-tellurium-sulfur composite free-cutting steel

Abstract

The invention discloses a method for smelting lead-tellurium-sulfur composite free-cutting steel, which comprises the following steps of: adopting a process of electric furnace-LF (ladle furnace) refining-continuous casting of 50-150 tons of full scrap steel, and controlling the mass percent of C element in molten steel to be 0.02-0.08% during tapping at the end point of electric furnace smelting; the temperature of the molten steel is 1620-1650 DEG C, and aluminum precipitation deoxidation is adopted for tapping; lF refining is carried out, the content of C, Si, Mn, P, S and Pb elements is adjusted to be within the control range, an aluminum wire is fed into molten steel, and it is ensured that the oxygen activity of the molten steel reaches 10-30 ppm at the temperature of 1570-1580 DEG C; industrial pure tellurium blocks wrapped by low-carbon steel iron sheets are added into the molten steel, and argon is blown from the bottom of a steel ladle; after the LF refining components are adjusted to reach the standard, steel ladle soft argon blowing stirring is carried out; and finally, a small square billet continuous casting machine is adopted for continuous steel casting. The novel smelting method of the lead-tellurium-sulfur composite free-cutting steel is developed, the yield of Pb can be 75% or above, the yield of Te can be 68% or above, the abrasion degree of a tool is reduced by 20% or above, and the surface roughness of a machined product is improved by 10% or above.

Description

technical field [0001] The invention relates to a smelting method of lead-tellurium-sulfur composite free-cutting steel, belonging to the technical field of metallurgy. Background technique [0002] Modern industries continue to develop towards automation, high-speed and precision machining. The cutting speed of metal materials has been increased to more than 100m / min, up to 300m / min. Machining cost is an important part of the manufacturing cost of manufacturing parts (even reaching 40-60% of the manufacturing cost of parts), which puts forward higher requirements for the cutting performance of steel. [0003] Free-cutting steel is a steel whose cutting performance is significantly improved by adding one or more free-cutting elements (such as sulfur, phosphorus, lead, calcium, selenium, tellurium, etc.). At present, the world consumes more than 4 million tons of free-cutting steel every year, and the market demand is huge. In recent years, Japan has successively developed ...

AI Technical Summary

Problems solved by technology

However, the segregation control of Pb element in this composition system, the alloying stability control of Te element, and the smooth rolling have become the main technical bottlenecks restricting its industrial production.

In particular, Te ingot is a precious alloy, which is expensive, and there is a certain loss when it is made into a cored wire, the melting point and boiling point are low, the feeding wire is volatile, and the yield is low.

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