CN107604242B

CN107604242B - Cold-rolled automobile sheet and preparation method thereof

Info

Publication number: CN107604242B
Application number: CN201710649498.8A
Authority: CN
Inventors: 黄利; 张玮; 张秀飞
Original assignee: Baotou Iron and Steel Group Co Ltd
Current assignee: Baotou Iron and Steel Group Co Ltd
Priority date: 2017-08-02
Filing date: 2017-08-02
Publication date: 2020-02-21
Anticipated expiration: 2037-08-02
Also published as: CN107604242A

Abstract

The invention relates to a cold-rolled automobile sheet and a preparation method thereof. The cold-rolled automobile sheet comprises the following chemical components in percentage by weight: c: 0.01 to 0.05%, Si: 0.01 to 0.04%, Mn: 0.10-0.50%, P is less than or equal to 0.02%, S is less than or equal to 0.01%, N is less than or equal to 0.004%, O is less than or equal to 0.003%, Al: 0.015 to 0.035%, RE (Ce): not less than 0.0010%, and the balance of iron and other inevitable impurities. The preparation method comprises the following steps: the low-carbon continuous casting billet is taken as a hot rolling raw material, and hot rolling, cold rolling, cover annealing and leveling are sequentially carried out. The cold-rolled automobile plate steel provided by the invention has low silicon and phosphorus content and low O, N content, and the product has excellent deep drawing performance.

Description

Cold-rolled automobile sheet and preparation method thereof

Technical Field

The invention relates to the technical field of metallurgical materials, in particular to a cold-rolled automobile sheet and a preparation method thereof.

Background

The cold-rolled sheet is the most used variety in automobile production and is mainly used for manufacturing a cab and a carriage of a truck, and a body of a car and a surface covering vehicle. The cold-rolled steel sheet for the automobile has high quality requirement, good surface quality to ensure the beautiful appearance of parts, small thickness tolerance to meet the requirement of a stamping process, and good stamping performance to stamp out parts with complex shapes.

Disclosure of Invention

In view of the above, the present invention provides a cold-rolled automobile sheet and a method for manufacturing the same.

The invention provides a cold-rolled automobile sheet, which comprises the following chemical components in percentage by weight:

c: 0.01 to 0.05%, Si: 0.01 to 0.04%, Mn: 0.10-0.50%, P is less than or equal to 0.02%, S is less than or equal to 0.01%, N is less than or equal to 0.004%, O is less than or equal to 0.003%, Al: 0.015 to 0.035%, RE (Ce): not less than 0.0010%, and the balance of iron and other inevitable impurities.

Further, the deep drawing property of the cold-rolled automobile sheet is as follows: r is 1.8-2.5, n is 0.19-0.25.

The invention also provides a preparation method of the cold-rolled automobile sheet, which comprises the following steps: the low-carbon continuous casting billet is taken as a hot rolling raw material, and hot rolling, cold rolling, cover annealing and leveling are sequentially carried out.

Furthermore, the heating temperature of the casting blank is 920-1160 ℃, and the heating time is 0.5-1 h.

Further, the hot rolling is carried out by adopting hot continuous rolling of a CSP production line 7 frame, the hot rolling start rolling temperature is 1010-1130 ℃, the finish rolling temperature is 870-920 ℃, the coiling temperature is 530-590 ℃, and the thickness of the steel plate is 2.0-5.0 mm.

Further, the cold rolling specifically comprises: after acid pickling, performing 5-frame cold continuous rolling, wherein the total reduction rate is 70-90%; the cover annealing comprises the following specific steps: and annealing the cold-rolled steel coil in a hood-type annealing furnace with 80% nitrogen and 20% hydrogen as protective gases at the annealing temperature of 650-710 ℃.

Further, the smooth reduction rate is 0.8-3.0%.

Compared with the prior art, the cold-rolled automobile plate steel provided by the invention has the advantages that the silicon and phosphorus content is low, the O, N content is low, and the product has excellent deep drawing performance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

FIG. 1 is a metallographic structure diagram of a steel sheet prepared in example 1 of the present invention.

Detailed Description

The invention discloses a cold-rolled automobile sheet and a preparation method thereof, and a person skilled in the art can realize the cold-rolled automobile sheet by properly improving process parameters by referring to the content. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

Preferably, the cold rolling is specifically: after acid pickling, performing 5-frame cold continuous rolling, wherein the total reduction rate is 70-90%; the cover annealing comprises the following specific steps: and annealing the cold-rolled steel coil in a hood-type annealing furnace with 80% nitrogen and 20% hydrogen as protective gases at the annealing temperature of 650-710 ℃.

Preferably, the flat rolling reduction is 0.8-3.0%.

The preparation method of the invention adopts low-carbon continuous casting billets as hot rolling raw materials, and carries out 7-frame hot continuous rolling, 5-frame cold continuous rolling, cover annealing and leveling on the CSP production line, thereby finally obtaining the automobile plate with excellent deep drawing performance.

The invention is further illustrated by the following examples:

example 1

The chemical composition of the slab is shown in table 1:

TABLE 1 continuous casting billet chemical composition (unit:%)

Examples	C	Si	Mn	P	S	Al	O	N	RE(Ce)
										1	0.025	0.015	0.140	0.008	0.004	0.23	0.0020	0.0028	0.0015

The continuous casting plate blank adopts a roller hearth type heating furnace, the heating temperature is 1110 ℃, and the heating time is 0.6 h. The initial rolling temperature of hot rolling is 1080 ℃ and the final rolling temperature is 885 ℃. The coiling temperature is 565 ℃, and the thickness of the steel plate is 4.0mm after 7 stands are subjected to hot continuous rolling; after pickling, carrying out 5-frame cold continuous rolling, adopting 75% of cold rolling total reduction rate, annealing the cold-rolled steel coil by a hood type annealing furnace with 80% of nitrogen and 20% of hydrogen as protective gas, wherein the annealing temperature is 670 ℃, cooling to room temperature, then carrying out leveling, wherein the leveling reduction rate is 0.85%, then carrying out a product deep drawing performance test, and the test result is shown in a table 2, and the product metallographic structure is shown in a figure 1.

TABLE 2 deep drawability of the product

Example 2

The chemical composition of the slab is shown in table 3:

TABLE 3 continuous casting billet chemical composition (unit:%)

Examples	C	Si	Mn	P	S	Al	O	N	RE(Ce)
										2	0.020	0.014	0.120	0.006	0.003	0.24	0.0015	0.0020	0.0025

The continuous casting plate blank adopts a roller hearth type heating furnace, the heating temperature is 1130 ℃, and the heating time is 0.7 h. The initial rolling temperature of hot rolling is 1100 ℃, and the final rolling temperature is 890 ℃. The coiling temperature is 575 ℃, and the thickness of the steel plate is 3.5mm after 7 frames are subjected to hot continuous rolling; after pickling, the steel coil is subjected to 5-frame cold continuous rolling, the total rolling reduction rate of the cold rolling is 80%, the steel coil after the cold rolling is subjected to cover annealing furnace annealing by using 80% nitrogen and 20% hydrogen as protective gas, the annealing temperature is 685 ℃, the steel coil is cooled to the room temperature and then leveled, the leveling reduction rate is 0.90%, and then the deep drawing performance of the product is tested, wherein the test results are shown in table 4.

TABLE 4 deep drawability of the product

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A cold-rolled automobile sheet is characterized by comprising the following chemical components in percentage by weight:

c: 0.01 to 0.025%, Si: 0.01-0.015%, Mn: 0.10-0.14%, P is less than or equal to 0.008%, S is less than or equal to 0.004%, N is less than or equal to 0.0028%, O is less than or equal to 0.002%, Al: 0.024%, Ce: not less than 0.0015 percent, and the balance of iron and other inevitable impurities;

wherein the deep drawing property of the cold-rolled automobile sheet is as follows: r is 1.8-2.5, n is 0.19-0.25;

the preparation method of the cold-rolled automobile sheet comprises the following steps: taking a low-carbon continuous casting billet as a hot rolling raw material, and sequentially carrying out hot rolling, cold rolling, cover annealing and leveling; wherein:

the heating temperature of the casting blank is 920-1160 ℃, and the heating time is 0.5-1 h;

the hot rolling is carried out by adopting hot continuous rolling of a CSP production line 7 frame, the hot rolling start rolling temperature is 1010-1130 ℃, the finish rolling temperature is 870-920 ℃, the coiling temperature is 530-590 ℃, and the thickness of the steel plate is 2.0-5.0 mm;

the cold rolling specifically comprises the following steps: after acid pickling, performing 5-frame cold continuous rolling, wherein the total reduction rate is 70-90%; the cover annealing comprises the following specific steps: annealing the cold-rolled steel coil in a hood-type annealing furnace with 80% nitrogen and 20% hydrogen as protective gases at the annealing temperature of 650-710 ℃;

the smooth reduction rate is 0.8-3.0%.