US 2019/0169708 A1 · 1900 MPa GRADE PRESS HARDENING STEEL BY MEDIUM THIN SLAB CASTING AND DIRECT ROLLING AND METHOD FOR PRODUCING THE SAME

Abstract

A press hardening steel by a medium and thin slab casting and direct rolling has a tensile strength 1900 MPa or more. The press hardening steel includes following chemical components by weight percent: C: 0.31-0.40%, Si: 0.36-0.44%, Mn: 1.6-2.0%, P≤0.006%, S≤0.004%, Als: 0.015-0.060%, Cr: 0.36-0.49%, Ti: 0.036-0.045% or Nb: 0.036-0.045% or V: 0.036-0.045%, or a mixture of the above two or more in any ratio, B: 0.004-0.005%, Mo: 0.26-0.35%, Ni: 0.11-0.20%, and N≤0.005%. A method for producing the press hardening steel includes following steps: desulphurizing molten iron; electric furnace or converter smelting and refining; continuous casting; descaling treatment before entering a soaking furnace; heating and soaking; high-pressure water descaling before entering a rolling mill; hot rolling; cooling; coiling; austenitizing; die deforming and quenching.

Claims3

Dependent claims

A press hardening steel, produced by a medium and thin slab casting and direct rolling and having a tensile strength 1900 MPa or more, the press hardening steel comprising following components by weight percent:

C:
0.31%-0.40%, Si:
0.36%-0.44%, Mn:
1.6%-2.0%, P≤0.006%, S≤0.004%, Als:
0.015%-0.060%, Cr:
0.36%-0.49%, Ti:
0.036%-0.045% or Nb:
0.036%-0.045% or V:
0.036%-0.045%, or a mixture of the above two or more in any ratio, B:
0.004%-0.005%, Mo:
0.26%-0.35%, Ni:
0.11%-0.20%, N≤0.005%, and a balance of Fe and inevitable impurities, wherein a quenched microstructure is a full lath martensite;
and mechanical properties are that a yield strength is larger than or equal to 1300 MPa, a tensile strength is larger than or equal to 1900 MPa, and elongation A80 mm is larger than or equal to 5%.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application

16/321,833Filed 1 Aug 2017

Priority

CN 201610713643.X24 Aug 2016

Published

6 Jun 2019

Term ends

Not estimatedThe source records don’t support an estimate.

Classification32 codes

C21D 9/46
Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor: for sheet metals
B21B 1/22
Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section ; Sequence of operations in milling trains;…:…
B21B 45/08
For de-scaling , e.g. by brushing: hydraulically
C21D 6/004
Heat treatment of ferrous alloys: containing Cr and Ni

1900 MPa GRADE PRESS HARDENING STEEL BY MEDIUM THIN SLAB CASTING AND DIRECT ROLLING AND METHOD FOR PRODUCING THE SAME

Life of this patent

1900 MPa GRADE PRESS HARDENING STEEL BY MEDIUM THIN SLAB CASTING AND DIRECT ROLLING AND METHOD FOR PRODUCING THE SAME

Life of this patent

Abstract

Claims3