WO2021012692A1

WO2021012692A1 - Roller used for galvanized aluminium sheet and preparation method therefor

Info

Publication number: WO2021012692A1
Application number: PCT/CN2020/080612
Authority: WO
Inventors: 蔡友根
Original assignee: 江苏润孚机械轧辊制造有限公司
Priority date: 2019-07-22
Filing date: 2020-03-23
Publication date: 2021-01-28
Also published as: CN110527903B; CN110527903A

Abstract

Disclosed by the present invention are a roller used for galvanized aluminium sheet and a preparation method therefor. According to the present invention, the content of retained austenite is regulated as 8%-15%, and the rigidity is 93-95HSD. The raw materials are placed in a medium-frequency induction furnace to prepare an alloy liquid, and a semi-finished product is cast under a low temperature; a finished product is obtained after heat treatment, thermal refining, quenching treatment, cold treatment, tempering treatment and final fine grinding, the cold treatment temperature being -30 to 5 degrees centigrade. The austenite phase area is enlarged while elements such as Ni and Mn are added, thus a critical point of retained austenite meeting the manufacturing technique is found. That is, the rigidity regulation not only satisfies the rolling force, but also prevents the situation that the roller cannot be used at a minimum diameter due to low rolling rigidity. Meanwhile, the combination of different alloy components and different technologies not only improves the corrosion resistance of the galvanized aluminium roller but also enables the austenite to be stabilized in different working temperatures, thereby prolonging the service life of the roller while improving the surface quality.

Description

Roll for galvanized aluminum plate and preparation method thereof

Technical field

The invention relates to a roll for galvanized aluminum plate and a preparation method thereof.

Background technique

Rolls require wear resistance, and hardness has become a daily control indicator. However, hardness and wear resistance are not unconditionally unified, so when choosing a roll, in addition to hardness, it also depends on its composition, production method, structure, other properties and residual stress. Therefore, when choosing the hardness of the roll, it depends on the rolling mill conditions, rolling conditions, types of rolled products and operating experience. With the development of society, the automotive industry, real estate decoration and construction industries have used galvanized sheets and aluminized sheets as well as galvanized sheets. The demand for aluminum-zinc sheets is increasing, and the current production volume cannot meet the overall demand. The reason is that the large-area peeling phenomenon of the work rolls for rolling aluminum-zinc sheets is serious, which cannot fully meet the production requirements, resulting in a decrease in output.

We analyze the reasons for spalling: 1. Aluminum-zinc is corrosive to ordinary rolls. Rolls attached with zinc, aluminum or zinc-aluminum alloys will produce hydrogen due to chemical reactions caused by zinc or aluminum in contact with water, and hydrogen will penetrate into the rolls. After aggregation occurs, hydrogen molecules are formed, and the volume expansion causes hydrogen embrittlement, which is like peeling off the surface of the roll. 2. Hardness selection, usually the hardness of the roll is required to be 95-98HSD, so the work roll must increase the cryogenic treatment to reduce the existence of retained austenite, enhance the hardness of the roll, and avoid the spalling problem caused by the retained austenite; However, the higher the yield strength, the greater the susceptibility to hydrogen embrittlement, and the inclusion of sulfides and untempered martensite structures are prone to hydrogen embrittlement.

At present, the prior art has proposed not to use cryogenic treatment for the roll to address this hydrogen embrittlement problem, and increase the existence of retained austenite to resist hydrogen diffusion and reduce roll body spalling. Because in the manufacture of rolls, after a period of heating or holding time, ferrite will transform into austenite at 912°C to 1394°C, austenite grains will grow, and the grain boundaries may tend to be flattened. The dense structure prevents the penetration of hydrogen.

However, although the above methods alleviate the problem of hydrogen embrittlement, experiments show that the corrosiveness of rolls with zinc, aluminum or zinc-aluminum alloy attached to them is still the main factor affecting the life of the rolls, and it does not significantly improve the life of the rolls. , Frequent grinding and repairing of the rolls makes the size of the rolls quickly smaller than the specified value and shortens the scrap time. Even with the temperature changes in use, the retained austenite is not stable, and local hydrogen embrittlement problems will still occur randomly.

Summary of the invention

In view of the above-mentioned defects in the prior art, the main purpose of the present invention is to overcome the deficiencies of the prior art, and discloses a roll for galvanized aluminum plate. The composition and weight percentage of the roll are: C: 0.80% -1.2%, Si: 0.9%-1.5%, Ni: 1.41%-1.52%, Mn: 0.75%-0.9%, Cr: 5.95%-6.25%, Cu: 0.05%-0.1%, Mo: 0.31%-0.62 %, Sb: 0.005%-0.01%, Bi: 0.001%-0.002%, Pb: 0.001%-0.002%, Sn: 0.01%-0.015%, As: 0.003%-0.01%, P<0.02%, S<0.003 %, the remainder Fe, the sum of the components is 100%; the retained austenite content of the roll is 8%-15%, and the hardness is 93-95HSD.

Further, the composition of the roller and its weight percentage are: C: 1.00%, Si: 1.2%, Ni: 1.48%, Mn: 0.88%, Cr: 6%, Cu: 0.07%, Mo: 0.45%, Sb: 0.007%, Bi: 0.001%, Pb: 0.001%, Sn: 0.013%, As: 0.007%, P: 0.015%, S: 0.002%, the balance Fe, and the sum of the components is 100%.

Further, it includes:

1) Melting and casting alloy steel, place the raw materials in an intermediate frequency induction electric furnace, and stir them fully to make an alloy liquid; the composition of the raw materials in weight percentage is: C: 0.80%-1.2%, Si: 0.9%-1.5%, Ni ：1.41%-1.52%, Mn: 0.75%-0.9%, Cr: 5.95%-6.25%, Cu: 0.05%-0.1%, Mo: 0.31%-0.62%, Sb: 0.005%-0.01%, Bi: 0.001 %-0.002%, Pb: 0.001%-0.002%, Sn: 0.01%-0.015%, As: 0.003%-0.01%, P<0.02%, S<0.003%, the balance Fe, the sum of the components is 100%;

2) Low-temperature casting, using low-pressure pouring method to pour the alloy liquid in step 1) into the roll mold. After the alloy liquid is solidified and formed, the pressure is relieved and the mold is released to obtain roll castings;

3) Heat treatment: rough turning the roll castings obtained in step 2) to obtain semi-finished products, then undergo quenching and tempering treatment, quenching treatment, cold treatment, tempering treatment, and finally fine grinding to obtain the finished product; the cold treatment temperature is -30 to 5°C The weight percentage of retained austenite of the galvanized aluminum roll is 8%-15%, and the hardness is 93-95HSD.

Further, the quenching temperature of the quenching treatment is 905-960°C.

Further, the tempering temperature of the tempering treatment is 150-180°C, and the holding time is 80 hours.

Further, the tempering treatment is a three-stage tempering heat treatment;

In the first stage, put the semi-finished product into the tempering furnace, heat it up to 150-160°C at a rate of 50-60°C/h, and keep it for 20 hours;

In the second stage, continue to heat up to 160-170°C at a rate of 50-60°C/h and keep it for 20 hours;

In the third stage, continue to heat up to 170-180°C at a rate of 50-60°C/h and keep it for 40 hours.

The beneficial effects achieved by the present invention:

While expanding the austenite phase zone, elements such as Ni and Mn are added to find the critical point of retained austenite that meets the production process. That is, the adjustment of the hardness can meet the rolling force and does not allow the roll to be used gradually. When the minimum diameter is reached, it cannot be used due to low rolling hardness. At the same time, using the combination of different alloy compositions and processes, while increasing the corrosion resistance of the galvanized aluminum roll, it can also stabilize the austenite at different working temperatures and improve the surface quality of the roll. Increased service life.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

The present invention provides a roll for galvanized aluminum, the weight percentage of each component is: C: 0.80%-1.2%, Si: 0.9%-1.5%, Ni: 1.41%-1.52%, Mn: 0.75%- 0.9%, Cr: 5.95%-6.25%, Cu: 0.05%-0.1%, Mo: 0.31%-0.62%, Sb: 0.005%-0.01%, Bi: 0.001%-0.002%, Pb: 0.001%-0.002% , Sn: 0.01%-0.015%, As: 0.003%-0.01%, P <0.02%, S <0.003%, the balance Fe, the sum of the components is 100%. The retained austenite content of the roll is 8%-15%, and the hardness is 93-95HSD.

specific:

Example 1

1) Raw materials, according to weight percentage, C: 0.80%, Si: 0.9%, Ni: 1.41%, Mn: 0.75%, Cr: 5.95%, Cu: 0.05%, Mo: 0.31%, Sb: 0.005%, Bi: 0.001%, Pb: 0.001%, Sn: 0.01%, As: 0.003%, P: 0.02%, S: 0.003%, the balance is Fe, the sum of the components is 100%;

The raw materials are smelted in an intermediate frequency induction electric furnace, and fully stirred to obtain an alloy solution;

3) Heat treatment, rough turning the roll casting obtained in step 2) to obtain a semi-finished product;

4) Quenching and tempering treatment, the semi-finished product is heated to 900°C, then quenched by oil cooling, and then tempered at 600°C. Due to the fast induction heating speed, the austenite transformation temperature increases, and the carbon concentration difference in the austenite increases. When the original structure of steel is coarse and contains more bulk ferrite, the original bulk ferrite part will often become carbon-poor austenite after austenitization, and the hardness will decrease. Therefore, the preliminary heat treatment before quenching can obtain a fine and uniform structure, make the roll core and roll neck achieve good mechanical properties, increase the yield ratio of the roll, and effectively increase the fatigue life of the roll; at the same time, it can be used for the later surface quenching of the roll. Organization preparation, after quenching and tempering, some carbides of the roll are dispersed and precipitated. These carbides are easier to dissolve in the final surface quenching; and can improve the matrix structure, especially the distribution of carbides.

Semi-finishing and ultrasonic flaw detection after quenching and tempering: According to the requirements of the processing drawings, semi-finishing is performed on the lathe, using ultrasonic energy to penetrate into the depth of the metal material, and when one section enters another section, it occurs at the edge of the interface Reflective features to check for part defects. Then it is quenched.

5) Quenching treatment. On the quenching machine tool, the semi-finished product is heated to 905℃ by means of power frequency induction coil induction heating; specifically, when passing through the energized induction coil, electromagnetic induction forms an induced current on the surface of the roll, which makes the surface After being heated, adjust the power to adjust the heating temperature through temperature measurement feedback, so that the surface of the roll can obtain a certain depth of hardened layer and good hardness uniformity. Through tempering at medium temperature, the internal stress of the roll is reduced, and the spalling during use of the roll is reduced and greatly improved Improve the usability of the middle roller.

6) Cold treatment, cold treatment at -30°C for 10 hours.

7) Tempering treatment, tempering treatment is divided into three-stage tempering heat treatment;

8) Finishing, polishing the surface of the tempered semi-finished product to obtain a finished product.

The weight percentage of retained austenite of the zinc-aluminum-coated roll obtained in this embodiment is 8%, and the hardness is 95HSD.

After quenching and tempering treatment, quenching treatment, cold treatment, tempering treatment, and finally fine grinding to obtain the finished product; the cold treatment temperature is -30-5°C, the weight percentage of retained austenite of the galvanized aluminum roll is 8%-15%, The hardness is 93-95HSD.

Example 2

1) Raw materials, according to weight percentages, C: 1.00%, Si: 1.2%, Ni: 1.48%, Mn: 0.88%, Cr: 6%, Cu: 0.07%, Mo: 0.45%, Sb: 0.007%, Bi: 0.001%, Pb: 0.001%, Sn: 0.013%, As: 0.007%, P: 0.015%, S: 0.002%, the balance Fe, the sum of the components is 100%;

4) Quenching and tempering treatment, the semi-finished product is heated to 900°C, then quenched by oil cooling, and then tempered at 600°C. Due to the fast induction heating speed, the austenite transformation temperature increases and the carbon concentration difference in the austenite increases. When the original structure of the steel is coarse and contains more bulk ferrite, the original bulk ferrite part will often become carbon-poor austenite after austenitization, and the hardness will decrease. Therefore, the preliminary heat treatment before quenching can obtain a fine and uniform structure, make the roll core and roll neck achieve good mechanical properties, increase the yield ratio of the roll, and effectively increase the fatigue life of the roll; at the same time, it can be used for the later surface quenching of the roll. Organization preparation, after quenching and tempering, some carbides of the roll are dispersed and precipitated. These carbides are easier to dissolve in the final surface quenching; and can improve the matrix structure, especially the distribution of carbides.

5) Quenching treatment. On the quenching machine tool, the semi-finished product is heated to 905℃ by means of power frequency induction coil induction heating; specifically, when passing through the energized induction coil, electromagnetic induction forms an induced current on the surface of the roll, which makes the surface After being heated, adjust the power to adjust the heating temperature through temperature measurement feedback, so that the surface of the roll can obtain a certain depth of hardened layer and good hardness uniformity. Through tempering at medium temperature, the internal stress of the roll is reduced, and the spalling during use of the roll is reduced and greatly improved Improve the usability of the intermediate roller.

6) Cold treatment, cold treatment at -10°C for 10 hours.

The weight percentage of retained austenite of the galvanized aluminum roll obtained in this embodiment is 13%, and the hardness is 94HSD.

Example 3

1) Raw materials, according to weight percentage, C: 1.2%, Si: 1.5%, Ni: 1.52%, Mn: 0.9%, Cr: 6.25%, Cu: 0.1%, Mo: 0.62%, Sb: 0.01%, Bi: 0.002%, Pb: 0.002%, Sn: 0.015%, As: 0.01%, P: 0.02%, S: 0.003%, the balance Fe, the sum of the components is 100%;

6) Cold treatment, cold treatment at -10°C for 10 hours.

The weight percentage of retained austenite of the galvanized aluminum roll obtained in this embodiment is 15%, and the hardness is 93HSD.

The above are only the preferred embodiments of the present invention, and are not used to limit the scope of implementation of the present invention; if the present invention is modified or equivalently replaced without departing from the spirit and scope of the present invention, it shall be covered by the protection scope of the claims of the present invention among.

Claims

A roll for galvanized aluminum sheet, characterized in that the composition and weight percentage of the roll are: C: 0.80%-1.2%, Si: 0.9%-1.5%, Ni: 1.41%-1.52%, Mn: 0.75%-0.9%, Cr: 5.95%-6.25%, Cu: 0.05%-0.1%, Mo: 0.31%-0.62%, Sb: 0.005%-0.01%, Bi: 0.001%-0.002%, Pb: 0.001% -0.002%, Sn: 0.01%-0.015%, As: 0.003%-0.01%, P<0.02%, S<0.003%, the balance Fe, the sum of the components is 100%; the retained austenite content of the roll is 8%-15%, hardness: 93-95HSD.
The roll for galvanized aluminum sheet according to claim 1, wherein the composition and weight percentage of the roll are: C: 1.00%, Si: 1.2%, Ni: 1.48%, Mn: 0.88% , Cr: 6%, Cu: 0.07%, Mo: 0.45%, Sb: 0.007%, Bi: 0.001%, Pb: 0.001%, Sn: 0.013%, As: 0.007%, P: 0.015%, S: 0.002% , The balance Fe, the sum of the components is 100%.
A method for preparing a roll for galvanized aluminum sheet, which is characterized in that it comprises:

1) Melting and casting alloy steel, place the raw materials in an intermediate frequency induction electric furnace, and stir them fully to make an alloy liquid; the composition of the raw materials in weight percentage is: C: 0.80%-1.2%, Si: 0.9%-1.5%, Ni ：1.41%-1.52%, Mn: 0.75%-0.9%, Cr: 5.95%-6.25%, Cu: 0.05%-0.1%, Mo: 0.31%-0.62%, Sb: 0.005%-0.01%, Bi: 0.001 %-0.002%, Pb: 0.001%-0.002%, Sn: 0.01%-0.015%, As: 0.003%-0.01%, P<0.02%, S<0.003%, the balance Fe, the sum of the components is 100%;

2) Low-temperature casting, using low-pressure pouring method to pour the alloy liquid in step 1) into the roll mold. After the alloy liquid is solidified and formed, the pressure is relieved and the mold is released to obtain roll castings;

3) Heat treatment: rough turning the roll castings obtained in step 2) to obtain semi-finished products, then undergo quenching and tempering treatment, quenching treatment, cold treatment, tempering treatment, and finally fine grinding to obtain the finished product; the cold treatment temperature is -30 to 5°C The weight percentage of retained austenite of the galvanized aluminum roll is 8%-15%, and the hardness is 93-95HSD.
The method for preparing a roll for galvanized aluminum plate according to claim 3, wherein the quenching temperature of the quenching treatment is 905-960°C.
The method for preparing a roll for galvanized aluminum sheet according to claim 3, wherein the tempering temperature of the tempering treatment is 150-180°C, and the holding time is 80 hours.
The method for preparing a roll for galvanized aluminum sheet according to claim 5, wherein the tempering treatment is a three-stage tempering heat treatment;

In the first stage, put the semi-finished product into the tempering furnace, heat it up to 150-160°C at a rate of 50-60°C/h, and keep it for 20 hours;

In the second stage, continue to heat up to 160-170°C at a rate of 50-60°C/h and keep it for 20 hours;

In the third stage, continue to heat up to 170-180°C at a rate of 50-60°C/h and keep it for 40 hours.