Steel wire material and method for manufacturing same

Abstract

This steel wire material contains 0.05%-1.2% C (“%” means “% by mass,” same hereinafter for chemical components.), 0.01%-0.7% Si, 0.1%-1.5% Mn, 0.02% max. P (not including 0%), 0.02% max. S (not including 0%), and 0.005% max. N (not including 0%), with the remainder being iron and unavoidable impurities. The steel wire material has a scale 6.0-20 μm thick and holes of an equivalent circle diameter of 1 μm max. in said scale that occupy 10% by area max. Said scale does not detach in the cooling process after hot rolling or during storage or transportation but can readily detach during mechanical descaling.

Description

TECHNICAL FIELD[0001]The present invention relates to a steel wire material and a method for manufacturing the same, and relates more specifically to a steel wire material (“steel wire material” is hereinafter simply referred to as “wire material”) for mechanical descaling formed with a scale easily removable by mechanical descaling and a method for manufacturing the same.BACKGROUND ART[0002]A scale is formed normally on the surface of a wire material manufactured by hot rolling, and it is required to remove the scale before subjecting the wire material to secondary work such as drawing and the like. As such a scale removing method before secondary work, a batch type acid cleaning method was employed in prior arts, however, in recent years, from the viewpoints of the environmental pollution and cost reduction, a mechanical descaling (hereinafter referred to as MD) method has come to be employed. Therefore, the wire material is required to be formed with a scale with excellent MD per...

AI Technical Summary

Benefits of technology

[0014]In the steel wire material of the present invention, the thickness of the scale is adjusted to a predetermined range, and the fine holes inside the scale are suppressed. Thus, since the scale easily peels off at the time of MD, sufficient peeling performance can be secured with a simple descaling device, adverse effects (a flaw on the surface of the wire material, defective lubrication and the like due to leaving the scale unremoved) are not exerted in secondary work such as drawing and the like, and the steel wire material of high quality can be provided. Also, because the scale loss is less, high yield can be maintained.

Problems solved by technology

However, Patent Literatures 1-4 described above have problems as described below.

According to the method of forming the scale thick as Patent Literatures 1, 2, even when a bending strain is applied to the wire material by the MD method and the wire material surface is subjected to brushing, it is difficult to perfectly remove the scale.

More specifically, according to the MD method, different from the batch type acid cleaning method, it is difficult to remove the entire scale evenly and stably, and even when the wire material formed with thick scale is subjected to MD, the surface of the wire material may occasionally be spotted with finely crushed scale powder.

When the remaining scale remaining locally thus increases, in the secondary work such as drawing and the like, problems such as occurrence of a flaw due to the defective lubrication, lowering of the lifetime of the dice and the like are caused.

Also, it is difficult to stably lower the boundary face roughness by the method of lowering the boundary face roughness such as Patent Literature 3, it is difficult to stably form the holes even by the method of forming large holes of 1 μm or more inside the scale such as Patent Literature 4, and it is difficult to stably reduce the remaining scale amount according to either of these technologies.