Manufacturing process of high-carbon tool steel SK85 cold-rolled wide steel strip

Abstract

The invention discloses a manufacturing process of a high-carbon tool steel SK85 cold-rolled wide steel strip. The process is characterized in that steel is subjected to converter smelting, LF furnacerefining and slab continuous casting to obtain continuous casting slabs with the thickness ranging from 210 mm to 230 mm, the continuous casting slabs are heated and subjected to hot continuous rolling and laminar cooling to reach the coiling temperature, a hot-rolled wide steel strip with the thickness ranging from 2.5 mm to 6.0 mm is obtained, the coiled hot-rolled wide steel strip is put in storage and slowly cooled to the room temperature, and the obtained metallographic structure is thin-sheet-shaped pearlite; the total reduction of first cold rolling is controlled to be 20%-50% after acid pickling of the hot-rolled wide steel strip, then spheroidizing annealing is conducted, the Vickers hardness HV5 is 180 or below, and the spheroidizing rate is 92% or above; after the steel strip is subjected to primary spheroidizing annealing, secondary cold rolling is conducted, the total reduction of cold rolling is controlled to be 30%-85%, and a cold-rolled wide steel strip with the finished product specification being 0.70-3.00 mm thick is obtained; the steel strip subjected to secondary cold rolling is further spheroidized and annealed, the Vickers hardness HV5 is 175 or below, and the spheroidizing rate is 94% or above; and then third cold rolling is conducted, the total reduction of cold rolling is controlled to be 50%-85%, and the cold-rolled wide steel strip with the finishedproduct specification being 0.10-0.70 mm thick is obtained.

Description

technical field [0001] The invention relates to the technical field of metal material forming, in particular to a manufacturing process of a high-carbon tool steel SK85 cold-rolled wide steel strip. Background technique [0002] SK85 steel is a grade set by the Japanese standard JISG4401. The chemical composition (mass percentage) of the steel: C: 0.80~0.90%, Si: 0.10~0.35%, Mn: 0.10~0.50%, P≤0.030%, S≤0.030 %, Cr≤0.30%, Ni≤0.25%, Cu≤0.25%. The product forms include hot-rolled round bar, hot-rolled steel plate and steel strip. [0003] High-carbon tool steel SK85 belongs to hypereutectoid steel with a carbon content of 0.80% to 0.90%. After heat treatment, it has good strength, hardness and toughness, excellent wear resistance, superior comprehensive performance and long service life. Mainly used to make knives, measuring tools, saw blades, precision hardware tools, pen tips, needles, etc., widely used in construction machinery, textile industry, electronics, automobiles a...

AI Technical Summary

Problems solved by technology

If the coiling temperature is too high and the cooling speed is too slow, coarse network carbides are formed during the cooling process, the pearlite structure is also coarser, the plasticity is poor, the strip is easy to break during rolling, and the production risk is high

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