Development of Ultrafine Grain Microstructure Wire Rod for Cold Heading Products

摘要

A thermomechanical control rolling and cooling processes have be developed for producing high performance wire rod in the new high speed wire rod mill of Masteel after revamping. This paper describes the main features of the new mill and the development of ultra-fine grain structure wire rod for cold heading products. The ferrite grain size was larger than No.13.5 (about 4 μm ) produced by thermomechanical control rolling and cooling process. The new type of ultra-fine grain structure non-heat treatment cold heading steel wire rod (MFT8) and the eliminated annealing treatment directly cold heading medium carbon wire rod (CH35K-M) have been developed for making high strength bolts, threads of 8.8 class.