Hot continuous rolling process of high-sulfur (sulfur-phosphorus) free cutting structural steel

Abstract

The present invention is hot continuous rolling process of high-sulfur (sulfur-phosphorus) easy-to-cut structural steel, and features that the billet is hot rolled into rod or wire by means of controlling billet heating, coarse rolling speed, area reduction and cooling water flow rate. The present invention solves the difficult problem of rolling easy-to-cut structural steel with high high-sulfur (sulfur-phosphorus) content without producing crack, and has high production efficiency, stable quality and high material utilization.

Description

technical field [0001] The invention relates to a thermal processing and rolling method of free-cutting structural steel in the metallurgical industry, in particular to a thermal processing and rolling method of high-sulfur (or sulfur-phosphorus composite) system easy-cutting structural steel. Background technique [0002] Structural steel is a common type of steel, mainly low-alloy structural steel and carbon structural steel. With the rapid development of the machinery and equipment manufacturing industry, higher requirements have been placed on the machining and cutting performance of structural steel (for example, in Japan, the cutting time of parts on the automatic production line can be saved by 1 second for every 1 second). Yuan.), that is, the ease of cutting of structural steel materials (the cutting cost is doubled, the product quality is greatly improved, and the production efficiency is doubled). In order to meet the easy-cutting requirements of metal materials ...

AI Technical Summary

Problems solved by technology

[0005] Hot rolling (deformation) of high-sulfur (sulfur-phosphorus) free-cutting structural steel (Mn / S≤5, even Mn / S≤3) has always been a difficult problem for rolling engineers (searching a large number of documents, no Mn / S Related technical reports on hot continuous rolling of high-sulfur phosphorus free-cutting structural steel with S≤5, no relevant technical data reports on hot continuous rolling of high-sulfur phosphorus free-cutting structural steel with Mn / S≤3 in foreign countries)

At present, the hot-working rolling method of domestic high-sulfur (sulfur-phosphorus) phosphorus free-cutting structural steel is: firstly measure the hot-working brittle zone of the steel, and then avoid the brittle zone for rolling. The advantage is that it can be hot-rolled continuously, and the disadvantage is that It is impossible to solve the technical problems of slipping and head cracking at the same time. On the one hand, the billet yield is generally low (below 90%). Causes longer thermal downtime and lower production efficiency