Method of manufacturing a steel sheet

US5085714A · kind A · utility

Assignee

• Kabushiki Kaisha Kobe Seiko Sho · JP

Inventors

• Mitsuru Kitamura · Tokyo, JP
• Shunichi Hashimoto · Sapporo, JP

Key dates

• Filing date: Aug 9, 1990
• Grant date: Feb 4, 1992
• Expiry date: Aug 9, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D8/0473
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A method of manufacturing steel sheets by applying continuous annealing after applying hot rolling or hot rolling and cold rolling by a customary method to steel material, containing less than 0.007% of C, less than 0.1% of Si, from 0.05 to 0.50% of Mn, less than 0.10% of P, less than 0.015% of S, from 0.005 to 0.05% of sol.Al and less than 0.006% of N, further, containing Ti and/or Nb added solely or in combination within such a range that the relationship of the effective amount of Ti (referred to as Ti*) and the amount of Nb in accordance with the following formula (1) with the amount of C can satisfy the following formula (2): EQU Ti*(%)=total Ti(%)-((48/32).times.S(%)+(48/14).times.N(%)) (1) EQU 1.ltoreq.(Ti*/48+Nb/93)/(C/12).ltoreq.4.5 (2) if necessary, further containing from 0.0001 to 0.0030% of B and the balance of Fe and inevitable impurities, wherein continuous carburization and/or nitriding is applied, simultaneously, with the annealing such that the amount of solid-solute C and/or the amount of solid-solute N in the steel sheet is from 2 to 30 ppm. Steel sheets having excellent resistance to the cold-work embrittlement or provided with the BH property can be produced w…