Rolling process for medium-carbon and high-sulfur alloy steel wire rod

Abstract

The invention belongs to the technical field of rolling, and relates to a rolling process for a medium-carbon and high-sulfur alloy steel wire rod. A continuously-cast blank is subjected to corner peeling, coated with a high-temperature coating material, and heated at a high temperature of 1230-1290 DEG C, and the heating time is not greater than 120min; high-temperature rolling at 1130-1190 DEG Cis adopted during initial rolling, and high-temperature rolling at a temperature of not lower than 1030 DEG C is adopted in a whole steel rolling process; and no cracks and no slip in a rolling process are ensured while the depth of a decarburization layer of the wire rod is controlled. The thickness of an iron oxide scale can be reduced separately by turning on a water tank, controlling a finishrolling temperature and controlling a laying temperature to be 895-920 DEG C, turning on three fans and carrying out air-cooling to reach a low temperature in the earlier stage of controlled cooling,and turning off the fans and opening a heat-insulation cover in the later stage of controlled cooling. Through the controlled rolling and controlled cooling process, the depth of the surface decarburization layer of the medium-carbon and high-sulfur alloy steel wire rod can be effectively controlled to be not greater than 0.5d%, the thickness of the iron oxide scale can be effectively controlledto be not greater than 15[mu]m, and the surface crack and pit defects of the wire rod are effectively controlled.

Description

technical field [0001] The invention belongs to the technical field of rolling, and relates to a method for rolling and cooling a medium-carbon high-sulfur alloy steel wire rod, in particular to a method for reducing the decarburization amount of a medium-carbon high-sulfur alloy steel wire rod and reducing the surface of the wire rod Controlled rolling and controlled cooling process of scale thickness. Background technique [0002] Adding an appropriate amount of sulfur to steel materials is mainly used to improve the cutting performance of the material. Some steel materials for precision instruments and meters with complex processing have higher requirements for cutting performance, so the added sulfur content is also relatively large. High-sulfur steel The sulfur content in the medium reaches more than 0.20%. [0003] Traditional free-cutting steel is mainly composed of lead elements, but lead is a heavy metal element, and lead is easy to volatilize in the high-temperatu...

AI Technical Summary

Problems solved by technology

[0004] Although sulfur-containing steel has many advantages, it is difficult to produce because sulfur-containing steel is a crack-sensitive steel. If the temperature is low during the rolling process, cracking will occur. The causes and improvement measures of cracking during processing are controlled by the rolling process, such as "CN201910888205.0 High-sulfur steel rolling process", in order to avoid hot rolling cracking, it is usually necessary to increase the heating temperature, starting rolling temperature, and finishing rolling Temperature and other conditions to solve the problem of cracking in hot rolling

However, if the temperature is too high, it will lead to serious surface decarburization, which will affect the strength of the material, especially the surface strength. In addition, the high temperature of the rolling process and the high spinning temperature of the wire rod will lead to excessive scale and oxidation of the wire rod. If the iron sheet is too thick, it will be difficult to remove it in the subsequent mechanical cracking process, which will eventually bring serious surface defects to the material and affect the final use of the user. Therefore, in order to reduce the decarburization layer, it is generally selected low processing temperature

From the above, it can be seen that the influencing factors of cracking and decarburization layer are mutual influences, even conflicting relations, and in this field, only one of the problems can often be solved and the other problem is difficult to solve, that is, it is difficult to solve the problems of cracking and decarburization at the same time

And in the prior art, there is no solution about simultaneously solving the technical problems of cracking and decarburization layer, especially for medium-carbon high-sulfur alloy steel, compared with low-carbon high-sulfur alloy steel, due to the high carbon content, Decarbonization is more likely to occur and therefore more difficult to control

Images