CN115652221A

CN115652221A - Production method of hot-dip galvanized steel plate for household appliances

Info

Publication number: CN115652221A
Application number: CN202211394024.0A
Authority: CN
Inventors: 靳阳; 王敏莉; 郑之旺; 常智渊; 陈容; 周磊磊
Original assignee: Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
Current assignee: Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
Priority date: 2022-11-08
Filing date: 2022-11-08
Publication date: 2023-01-31

Abstract

The invention discloses a production method of a hot-dip galvanized steel plate for household appliances, and belongs to the technical field of production of cold-rolled hot-dip galvanized steel plates. The invention comprises the following chemical compositionsThe weight percentage of the components is as follows: c:0.0010% -0.003%, si: less than or equal to 0.010 percent, mn: 0.04-0.08%, P: less than or equal to 0.015 percent, S: less than or equal to 0.015 percent, als: 0.010-0.070%, ti:0.050% -0.080%; the balance being Fe and unavoidable impurities. The production method comprises smelting, hot rolling, alkali washing, cold rolling, continuous annealing, hot galvanizing and finishing. The hot-dip galvanized steel sheet for the household appliances produced by the method meets the use requirements of users. The mechanical property of the finished product reaches yield strength of 130-150 MPa, tensile strength of 280-310 MPa, elongation of more than or equal to 47.0 percent, r ₉₀ ≥2.9，n ₉₀ More than or equal to 0.27.

Description

Production method of hot-dip galvanized steel plate for household appliances

Technical Field

The invention belongs to the technical field of cold-rolled hot-dip galvanized steel sheet production, and particularly relates to a production method of a hot-dip galvanized steel sheet for household appliances.

Background

With the development of the household appliance industry, the requirement of the market on the stamping performance of the hot-dip galvanized steel plate is higher and higher.

Application number CN200710048926.8 discloses a production method of a deep drawing finishing hot-dip galvanized steel plate, which comprises the following components in percentage by weight: c:0.003 to 0.006%, ti: 0.02-0.04%, hot rolling coiling temperature of 700-780 ℃, and cold rolling annealing temperature of 780-880 ℃. The yield strength of the finished product is about 180MPa, the tensile strength is about 310MPa, the elongation is about 42.0 percent, _n about 0.21, r is about 1.9. Although the mechanical property strength is high, the elongation, the n value and the r value are low, and the forming performance of users is limited.

The application number of CN 201210338992.X discloses a hot-dip galvanized steel plate for automobiles and a production method thereof, and the hot-dip galvanized steel plate comprises the following components in percentage by weight: 0.001 to 0.003%, si: less than or equal to 0.03%, mn:0.05 to 0.15%, P: less than or equal to 0.02 percent, S:0.008 to 0.015%, als:0.02 to 0.07%, ti:0.05 to 0.09%, B:0.0002 to 0.01 percent, less than or equal to 0.004 percent of N, and the balance of Fe and trace elements. The yield strength of the finished product is about 160MPa, the tensile strength is about 280MPa, the elongation is about 44.0 percent, the r90 value is about 2.4, and the n90 value is 0.24. Although the mechanical property strength is high, the elongation, the n value and the r value are low, and the forming performance of users is limited.

Meanwhile, in the prior art, although the stamping performance of the hot-dip galvanized steel sheet is improved by various means, the preparation process is complex and the cost is high.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: provides a production method of a hot-dip galvanized steel sheet for household appliances, which meets the use requirements of users. The mechanical property of the finished product reaches yield strength of 130-150 MPa, tensile strength of 280-310 MPa, elongation of more than or equal to 47.0 percent, r ₉₀ ≥2.9，n ₉₀ More than or equal to 0.27.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a production method of a hot-dip galvanized steel plate for household appliances, which comprises the following steps of smelting, hot rolling, alkali rolling, continuous annealing, hot dipping and finishing:

(1) Smelting the low alloy steel into a continuous casting billet according to the chemical components of the low alloy steel, wherein the continuous casting billet comprises the following chemical components in percentage by weight: c:0.0010% -0.003%, si: less than or equal to 0.010 percent, mn: 0.04-0.08%, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, als: 0.010-0.070%, ti:0.050% -0.080%; the balance of Fe and inevitable impurities;

(2) Heating, dephosphorizing, hot rolling, cooling and coiling the continuous casting billet to obtain a hot rolled coil; wherein the initial rolling temperature of finish rolling is 1150-1190 ℃, the final rolling temperature is 900-950 ℃, and the curling temperature is 700-730 ℃;

(3) Cleaning a hot rolled coil by alkali washing, and cold-rolling the cleaned hot rolled coil into thin strip steel;

(4) Continuously annealing, hot galvanizing and finishing the thin strip steel to obtain a hot galvanized steel plate; wherein the running speed of the continuously annealed thin strip steel is controlled to be 90-110 m/min, the soaking temperature of the continuous annealing is 860-880 ℃, the temperature of a zinc pot of the hot galvanizing is controlled to be 450-465 ℃, and the finishing elongation is controlled to be 0.2-0.5%.

Further, in the step (2), the continuous casting slab is heated to 1220-1250 ℃, the furnace time is 200-260 min, and then rough rolling is carried out.

Further, in the step (2), 5-pass rolling is adopted for rough rolling, phosphorus is removed from the whole length, and a heat preservation cover is used in the rolling process.

Further, in the step (2), after rough rolling, the thickness of the hot-rolled intermediate slab is 42mm to 46mm.

Further, in the step (2), after finish rolling, the steel is cooled by a front-stage cooling mode to 700-730 ℃ and coiled.

Further, in the step (2), the thickness of the hot rolled plate after finish rolling is 2.5-5.5mm.

Further, in the step (3), the cold rolling reduction is determined to be 65% to 85% in combination with the capacity of the cold rolling mill.

Furthermore, in the step (4), the hot galvanizing time is 10-20s, and the zinc layer in the hot galvanized steel sheet is 60-80g/m ² 。

On the other hand, the invention provides the hot-dip galvanized steel plate for the household appliances, which is prepared by the method, the mechanical property of the finished product reaches that the yield strength is 130-150 MPa, the tensile strength is 280-310 MPa, the elongation is more than or equal to 47.0 percent, r ₉₀ ≥2.9，n ₉₀ More than or equal to 0.27.

The invention has the beneficial effects that:

the hot-dip galvanized steel sheet for the household appliances produced by the method meets the use requirements of users. The mechanical property of the finished product reaches yield strength of 130-150 MPa, tensile strength of 280-310 MPa, elongation of more than or equal to 47.0 percent, r ₉₀ ≥2.9，n ₉₀ More than or equal to 0.27. Meanwhile, the preparation process is simple and the cost is low.

Detailed Description

The following non-limiting examples will allow one of ordinary skill in the art to more fully understand the present invention, but are not intended to limit the invention in any way.

Examples

The invention provides a preparation method of a hot-dip galvanized steel plate for household appliances, which comprises the following steps:

(1) Through a smelting process, steel slabs with the chemical components shown in the following table 1 are prepared, and the balance is Fe and inevitable impurities:

table 1 chemical composition (wt.%)

(2) Heating the steel plate blank, wherein the furnace time is 240min, then carrying out rough rolling, wherein the rough rolling adopts 5-pass rolling, the whole length and the whole number of phosphorus are removed, and a heat preservation cover is used in the rolling process; the thickness of the intermediate plate blank after rough rolling is 43mm; and after rough rolling, finish rolling is carried out, after finish rolling, the steel is cooled by adopting a front-stage cooling mode and then coiled, and a hot rolled coil is obtained.

The hot rolling process parameters are shown in table 2 below:

TABLE 2 Hot Rolling Main Process parameters

(3) Cleaning the hot rolled coil by alkali washing, and cold-rolling into thin strip steel; wherein the thickness of the hot rolled plate is 4.0mm, and the cold rolling reduction is 80.0%.

(4) Continuously annealing, hot galvanizing and finishing the thin strip steel to obtain a hot galvanized steel plate; wherein the running speed of the continuously annealed thin strip steel is controlled at 95m/min, and the annealing temperature refers to soaking temperature; the zinc layer in the hot dip galvanized steel sheet is 80g/m ² 。

The continuous annealing process parameters are shown in table 3:

TABLE 3 main process parameters of continuous hot galvanizing annealing

Numbering	Annealing temperature/. Degree.C	Temperature of zinc pot/DEG C	Percent of the finished elongation
				Example 1	863	464	0.25
Example 2	865	465	0.21
				Example 3	866	460	0.25
Comparative example 1	821	461	0.62
				Comparative example 2	823	462	0.61

(5) The thickness of the hot dip galvanized steel sheet prepared by the process is 0.8mm, and the mechanical properties of the hot dip galvanized steel sheet are shown in the following table 4:

TABLE 4 mechanical Properties of hot-dip galvanized steel sheets

It will be apparent to those skilled in the art from this disclosure that many changes and modifications can be made, or equivalents modified, in the embodiments of the invention without departing from the scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.

Claims

1. A production method of a hot dip galvanized steel sheet for household appliances is characterized by comprising the following steps:

(1) Smelting the steel into a continuous casting billet according to the chemical components of the steel, wherein the chemical components comprise the following components in percentage by weight: c: 0.0010-0.003%, si: less than or equal to 0.010 percent, mn: 0.04-0.08%, P: less than or equal to 0.015 percent, S: less than or equal to 0.015 percent, als: 0.010-0.070%, ti:0.050% -0.080%; the balance of Fe and inevitable impurities;

(2) Heating, dephosphorizing, hot rolling, cooling and coiling the continuous casting billet to obtain a hot rolled coil; wherein the start rolling temperature of finish rolling is 1150-1190 ℃, the finish rolling temperature is 900-950 ℃, and the crimping temperature is 700-730 ℃;

(3) Cleaning a hot-rolled coil by alkali washing, and cold-rolling the hot-rolled coil into thin strip steel;

(4) Continuously annealing, hot galvanizing and finishing the thin strip steel to obtain a hot galvanized steel plate; wherein the running speed of the continuous annealing thin strip steel is controlled to be 90-110 m/min, the soaking temperature of the continuous annealing is 860-880 ℃, and the temperature of a zinc pot for hot galvanizing is controlled to be 450-465 ℃.

2. The method according to claim 1, wherein in the step (2), the continuous casting slab is heated to 1220 to 1250 ℃ for 200 to 260min.

3. The method according to claim 1, wherein in the step (2), 5-pass rolling is adopted for rough rolling, phosphorus is removed from the whole length, and a heat preservation cover is used in the rolling process.

4. The method according to claim 1, wherein the thickness of the hot-rolled intermediate slab after the rough rolling in the step (2) is 42mm to 46mm.

5. The method according to claim 1, wherein in the step (2), the finish rolling is performed, and then the steel sheet is cooled to 700 to 730 ℃ by a front-end cooling method to be coiled.

6. The method according to claim 1, wherein in the step (2), the thickness of the hot rolled plate after finish rolling is 2.5 to 5.5mm.

7. The method as set forth in claim 1, wherein the cold rolling reduction is determined to be 65% to 85% in the step (3).

8. A hot-dip galvanized steel sheet for home appliances produced by the method according to any one of claims 1 to 7.

9. The hot-dip galvanized steel sheet for household appliances according to claim 8, characterized in that the mechanical properties of the finished product are 130 to 150MPa in yield strength, 280 to 310MPa in tensile strength, 47.0% or more in elongation, r ₉₀ ≥2.9，n ₉₀ ≥0.27。