High-formability hot galvanized aluminum-zinc or hot galvanized aluminum-magnesium dual-phase steel and rapid heat treatment hot dipping fabrication method therefor

Patent metadata

Field	Value
Publication number	US-12545985-B2
Application number	US-202218552934-A
Country	US
Kind code	B2
Filing date	Mar 31, 2022
Priority date	Apr 2, 2021
Publication date	Feb 10, 2026
Grant date	Feb 10, 2026

Abstract

A high-formability hot galvanized aluminum-zinc or hot galvanized aluminum-magnesium dual-phase steel having a tensile strength of ≥590 MPa and a rapid heat treatment hot dipping fabrication method, the steel comprising the following components in mass percentage: C: 0.045-0.12%; Si: 0.1-0.5%; Mn: 1.0-2.0%; P: ≤0.02%; S: ≤0.006%; and Al: 0.02-0.055%. The steel may also contain one or two among Cr, Mo, Ti, Nb, and V, wherein the Cr+Mo+Ti+Nb+V≤0.5%, and the remainder is Fe and other inevitable impurities. The present invention changes the recovery of a deformed structure, ferrite recrystallization and austenite transformation processes during annealing by means of rapid heat treatment, and the nucleation point of a crystal is increased, grain growth time is shortened, the strength and formability (n90 value) of the material is improved while heat treatment efficiency is improved, which thus extends the performance range of the material.

First claim

What is claimed is:

1 . A hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability comprises the following chemical components in mass percentages: C: 0.045˜0.12%, Si: 0.1˜0.5%, Mn: 1.0˜2.0%, P≤0.02%, S≤0.006%, Al: 0.02˜0.055%, optionally one or two of Cr, Mo, Ti, Nb, V, and Cr+Mo+Ti+Nb+V≤0.5%, with a balance of Fe and other unavoidable impurities;
wherein the hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability has a yield strength of ≥300 MPa, a tensile strength of 630˜860 MPa, an elongation of ≥20%, a product of tensile strength and elongation of ≥15 GPa % and a strain hardening index n 90 value greater than 0.20; and
wherein the hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability has a metallographic structure which is an uniformly distributed ferritic and martensitic dual-phase structure having an average grain size of 1˜5 μm.

2 . The hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability according to claim 1 ,
wherein the C content is 0.045˜0.105%, 0.05˜0.12%, 0.065˜0.085% or 0.07˜0.10%; and/or wherein the Si content is 0.15˜0.25% or 0.1˜0.4%; and/or wherein the Mn content is 1.0%˜1.5%, 1.2%˜2.0%, 1.2%˜1.35% or 1.5˜1.8%; and/or wherein Cr+Mo+Ti+Nb+V≤0.4%, or ≤0.2%.

3 . The hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability according to claim 1 , wherein the hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability has a yield strength of 300˜560 MPa, 300˜400 MPa or 450˜560 MPa, a tensile an elongation of 20˜30%, and a product of tensile strength and elongation of 15˜21 GPa %.

4 . The hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability according to claim 1 , wherein the hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability comprises the following chemical components in mass percentages: C: 0.045˜0.105%, Si: 0.1˜0.4%, Mn: 1.0˜1.5%, P≤0.02%, S≤0.006%, Al: 0.02˜0.055%, optionally one or two of Cr, Mo, Ti, Nb, V, and Cr+Mo+Ti+Nb+V≤0.3%, with a balance of Fe and other unavoidable impurities.

5 . The hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability according to claim 4 , wherein:
the hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability has a yield strength of 300-400 MPa, a tensile strength of 630˜700 MPa, an elongation of 22˜30%, a product of tensile strength and elongation of 15˜20 GPa % and a strain hardening index n 90 value greater than 0.21; or the hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability has a yield strength of 304˜398 MPa, a tensile strength of 630˜698 MPa, an elongation of 22.3˜29.4%, a product of tensile strength and elongation of 15.3˜19.4 GPa % and a strain hardening index n 90 value greater than 0.21.

6 . The hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability according to claim 4 , wherein the dual-phase steel is obtained by the following process:
a) Smelting, casting wherein the chemical components are subjected to smelting and casting to form a slab; b) Hot rolling, coiling wherein a coiling temperature is 550˜680° C.; c) Cold rolling wherein a cold rolling reduction rate is 40˜85%; d) Rapid heat treatment, hot-dipping aluminum-zinc or hot-dipping zinc-aluminum-magnesium wherein a steel plate after cold rolling is rapidly heated to 750˜845° C., wherein the rapid heating is performed in one stage or two stages; when the rapid heating is performed in one stage, a heating rate is 50˜500° C./s; when the rapid heating is performed in two stages, the steel plate is heated in the first stage from room temperature to 550˜650° C. at a heating rate of 15˜500° C./s, and heated in the second stage from 550˜650° C. to 750˜845° C. at a heating rate of 50˜500° C./s; then soaked at a soaking temperature of 750˜845° C. for a soaking time of 10˜60 s; wherein after soaking, the steel plate is slowly cooled to 670˜770° C. at a cooling rate of 5˜15° C./s, then rapidly cooled to 580˜600° C. at a cooling rate of 50˜150° C./s, and immersed in a zinc pot for hot-dipping aluminum-zinc or hot-dipping zinc-aluminum-magnesium; after hot-dipping aluminum-zinc, the steel plate is rapidly cooled to room temperature at a cooling rate of 30˜200° C./s to obtain a hot-dip aluminum-zinc AZ product; or after hot-dipping zinc-aluminum-magnesium, the steel plate is rapidly cooled to room temperature at a cooling rate of 30˜180° C./s to obtain a hot-dip zinc-aluminum-magnesium AM product.

7 . The hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability according to claim 6 , wherein
a total time of performing step d) is 29˜122 s; and/or in step b), a hot rolling finishing temperature is ≥Ar 3 ; and/or in step b), the coiling temperature is 580˜650° C.; and/or in step c), the cold rolling reduction rate is 60˜80%; and/or in step d), when the rapid heating is performed in one stage, the heating rate is 50˜300° C./s; and/or in step d), the rapid heating is performed in two stages, wherein the steel plate is heated in the first stage from room temperature to 550˜650° C. at a heating rate of 15˜300° C./s, and heated in the second stage from 550˜650° C. to 750˜845° C. at a heating rate of 50˜300° C./s; or in step d), the rapid heating is performed in two stages, wherein the steel plate is heated in the first stage from room temperature to 550˜650° C. at a heating rate of 30˜300° C./s, and heated in the second stage from 550˜650° C. to 750˜845° C. at a heating rate of 80˜300° C./s.

8 . The hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability according to claim 1 , wherein the hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability comprises the following chemical components in mass percentages: C: 0.05˜0.12%, Si: 0.1˜0.5%, Mn: 1.2˜2.0%, P≤0.015%, S≤0.003%, Al: 0.02˜0.055%, optionally one or two of Cr, Mo, Ti, Nb, V, and Cr+Mo+Ti+Nb+V≤0.5%, with a balance of Fe and other unavoidable impurities.

9 . The hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability according to claim 8 , wherein the hot-dip aluminum-zinc or hot-dip zinc-aluminum-magnesium dual-phase steel with high formability is obtained by the following process:
A) Smelting, casting wherein the above components are subjected to smelting and casting to form a slab; B) Hot rolling, coiling wherein a coiling temperature is 550˜680° C.; C) Cold rolling wherein a cold rolling reduction rate is 40˜85%; D) Rapid heat treatment, hot-dipping aluminum-zinc or hot-dipping zinc-aluminum-magnesium Wherein a steel plate after cold rolling is rapidly heated to 750˜845° C., wherein the rapid heating is performed in one stage or two stages; when the rapid heating is performed in one stage, a heating rate is 50˜500° C./s; when the rapid heating is performed in two stages, the steel plate is heated in the first stage from room temperature to 550˜650° C. at a heating rate of 15˜500° C./s, and heated in the second stage from 550˜650° C. to 750˜845° C. at a heating rate of 50˜500° C./s; then soaked at a soaking temperature of 750˜845° C. for a soaking time of 10˜60 s; wherein after soaking, the steel plate is slowly cooled to 670˜770° C. at a cooling rate of 5˜15° C./s, then rapidly cooled to 580˜600° C. at a cooling rate of 50˜150° C./s, and immersed in a zinc pot for hot-dipping alumin

Assignees

• Baoshan Iron & Steel

Inventors

• Wang Jian
• Li Jun
• Zhang Liyang
• Du Xiaofeng
• Ding Zhilong
• Liu Huafei
• Ren Yuling
• Du Yao
• Lin Chuanhua
• Yang Yi

Classifications

• C23C2/40

  Plates; Strips · CPC title

• C23C2/06 Primary

  Zinc or cadmium or alloys based thereon · CPC title

• C22C38/06

  containing aluminium · CPC title

• C22C38/04 Primary

  containing manganese · CPC title

• C22C38/02

  containing silicon · CPC title