阅读说明：本技术 一种宽幅薄规格高镍钼奥氏体不锈钢板的轧制方法 (Rolling method of wide and thin high-nickel-molybdenum austenitic stainless steel plate ) 是由 顾丽 靳淑静 王光磊 党军 于 2020-12-03 设计创作，主要内容包括：本发明公开一种宽幅薄规格高镍钼奥氏体不锈钢板的轧制方法,其特征在于包括如下步骤：坯料准备,控制坯料厚度、宽度和长度；采用高温加热策略；采用单机架四辊可逆轧机进行轧制,轧制辊期安排在轧机辊前期；采用12+1道次和快速轧钢策略；控制终轧温度≥850℃；轧后钢板送至预矫直机,进行2-4道次往复预矫直；轧后钢板空冷不浇水。本发明使用中厚板轧机轧制,能使薄规格高镍钼不锈钢板的宽度扩大到2500～3000mm,可减少产品使用时的焊缝数量,降低成本,增加安全性和使用寿命。(The invention discloses a rolling method of a wide and thin high-nickel-molybdenum austenitic stainless steel plate, which is characterized by comprising the following steps: preparing a blank, and controlling the thickness, width and length of the blank; adopting a high-temperature heating strategy; rolling by adopting a single-stand four-roller reversible rolling mill, wherein the rolling roller period is arranged in the early stage of the rolling mill; adopting a 12+1 pass and rapid steel rolling strategy; controlling the finishing temperature to be more than or equal to 850 ℃; sending the rolled steel plate to a pre-straightening machine for 2-4 times of reciprocating pre-straightening; and the rolled steel plate is air-cooled and does not need watering. According to the invention, the width of the thin high-nickel molybdenum stainless steel plate can be enlarged to 2500-3000 mm by using a heavy and medium plate mill for rolling, so that the number of welding seams of the product in use can be reduced, the cost is reduced, the safety is improved, and the service life is prolonged.)

1. A rolling method of a wide and thin high-nickel-molybdenum austenitic stainless steel plate is characterized by comprising the following steps:

preparing a blank: cogging the continuous casting billet, and controlling the thickness of the billet to be 110-150 mm, the width to be 1500-2800 mm and the length to be 2050-4500 mm;

heating: a high-temperature heating strategy is adopted, the steel billet is sent to a stepping heating furnace to be heated, the total heating time is controlled according to the thickness of the steel billet in the time of 13-20 min/cm, the temperature of a soaking section is 1230-1270 ℃, the time of the soaking section is at least 25min, and the tapping temperature is controlled at 1250-1270 ℃;

rolling: rolling by adopting a single-stand four-roller reversible rolling mill, wherein the rolling roller period is arranged at the early stage of the rolling mill roller, and the number of rolled kilometers in the rolling mill roller period is less than or equal to 15 km; adopting 12+1 passes, gradually increasing the reduction rate from about 11% of the 1 st pass to 15% -29% of the 5 th pass, and then gradually decreasing, wherein the reduction rate of the 11 th pass is 13-14%, and the reduction rate of the 12 th pass is 7-9%; a rapid steel rolling strategy is adopted, the rolling speed is 1.20-2.50 m/s, and the steel throwing distance and the inter-pass interval are reduced as much as possible; controlling the finishing temperature to be more than or equal to 850 ℃;

straightening: sending the rolled steel plate to a pre-straightening machine for 2-4 times of reciprocating pre-straightening;

and (3) cooling: and the rolled steel plate is air-cooled and does not need watering.

2. The rolling method of the wide and thin gauge high nickel molybdenum austenitic stainless steel plate according to claim 1, wherein the finished high nickel molybdenum austenitic stainless steel plate has a thickness ranging from 8mm to 12mm and a width ranging from 2500mm to 3000 mm.

3. The method of rolling a wide and thin gauge niclcm austenitic stainless steel sheet according to claim 1, wherein 2 to 4 normal flaw detection steel sheets wider than the width of the finished niclcm austenitic stainless steel sheet are arranged to be rolled before rolling, and the rolls are sufficiently ironed.

4. The method of rolling a wide width thin gauge nickel-molybdenum-rich austenitic stainless steel sheet according to claim 1, wherein the entire process is not descaled.

5. The method for rolling a wide and thin gauge high nickel molybdenum austenitic stainless steel plate according to claim 1, wherein after the slab is discharged from the heating furnace and before the rolling is started, the roller cooling water and the rolling mill side water cooling device are shut down.

Technical Field

The invention relates to a rolling production technology of stainless steel, in particular to a rolling production method of a wide and thin high-nickel-molybdenum austenitic stainless steel plate.

Background

With increasingly harsh service environments in the fields of petroleum, chemical industry, military industry, ocean development and the like, the traditional stainless steels such as 304, 316 and the like cannot meet the use requirements of special function fields. The high-nickel and high-molybdenum austenitic stainless steel has good corrosion resistance in non-oxidizing acids such as sulfuric acid, acetic acid, formic acid and phosphoric acid, good pitting corrosion resistance in a neutral chloride ion-containing medium, and good crevice corrosion resistance and stress corrosion resistance, so that the high-nickel and high-molybdenum austenitic stainless steel is widely applied to the fields of petrochemical equipment, sulfuric acid storage and transportation equipment, flue gas desulfurization devices and the like. In recent years, with the limit of the international maritime convention on the content of the sulfur oxides in the ship exhaust gas, the demand of ship flue gas desulfurization devices is increased rapidly, and the market demand for thin-gauge high-nickel-molybdenum steel is also driven.

The wider such products, the fewer the number of welds, the more cost effective and the greater the safety. However, such stainless steel has large deformation resistance at high temperature and high rolling difficulty, and is difficult to achieve a product with both thin specification and wide breadth. At present, the production of thin gauge is usually performed by hot continuous rolling, but this also limits the width of the finished product. The main stream width of wide-breadth high-nickel-molybdenum austenitic stainless steel plates in the market is less than 2 m.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects of the prior art and provides a rolling scheme of a wide and thin high-nickel-molybdenum austenitic stainless steel plate by using a heavy and medium plate mill. By adopting the rolling method, the high-nickel molybdenum austenitic stainless steel plate with the thickness of 8 mm-12 mm and the width of 2.5 m-3 m and the wide and thin specification can be produced.

In order to solve the technical problems, the invention specifically adopts the following technical scheme:

a rolling method of a wide and thin high-nickel-molybdenum austenitic stainless steel plate is characterized by comprising the following steps:

preparing a blank: cogging the continuous casting billet, and controlling the thickness of the billet to be 110-150 mm, the width to be 1500-2800 mm and the length to be 2050-4500 mm;

heating: a high-temperature heating strategy is adopted, the steel billet is sent to a stepping heating furnace to be heated, the total heating time is controlled according to the thickness of the steel billet in the time of 13-20 min/cm, the temperature of a soaking section is 1230-1270 ℃, the time of the soaking section is at least 25min, and the tapping temperature is controlled at 1250-1270 ℃;

rolling: rolling by adopting a single-stand four-roller reversible rolling mill, wherein the rolling roller period is arranged at the early stage of the rolling mill roller, and the number of rolled kilometers in the rolling mill roller period is less than or equal to 15 km; adopting 12+1 passes, gradually increasing the reduction rate from about 11% of the 1 st pass to 15% -29% of the 5 th pass, and then gradually decreasing, wherein the reduction rate of the 11 th pass is 13-14%, and the reduction rate of the 12 th pass is 7-9%; a rapid steel rolling strategy is adopted, the rolling speed is 1.20-2.50 m/s, and the steel throwing distance and the inter-pass interval are reduced as much as possible; controlling the finishing temperature to be more than or equal to 850 ℃;

straightening: sending the rolled steel plate to a pre-straightening machine for 2-4 times of reciprocating pre-straightening;

and (3) cooling: and the rolled steel plate is air-cooled and does not need watering.

Preferably, the thickness of the finished product of the high-nickel molybdenum austenitic stainless steel plate ranges from 8mm to 12mm, and the width ranges from 2500mm to 3000 mm.

Preferably, 2-4 common flaw detection steel plates with the width wider than that of the finished high-nickel-molybdenum austenitic stainless steel plate are arranged to be rolled before rolling, and the rolls are fully ironed.

Preferably, the entire production process is not descaled to reduce temperature drop.

Preferably, after the slab is discharged from the heating furnace and before rolling begins, in order to reduce the temperature reduction rate of the steel plate and ensure that the rolling process is finished smoothly, water cooling devices such as roller cooling water, side spraying of a rolling mill and the like are closed.

Compared with the prior art, the invention has the beneficial effects that:

at present, most of domestic high-nickel molybdenum austenitic stainless steel plates depend on import, and meanwhile, the width of a product with the thickness of 8-12 mm is basically below 2000 mm. The difficulty of preparing a product with the thickness of 8-12 mm and the width of more than 2000mm by using a medium plate mill instead of a hot continuous rolling technology is high. According to the invention, the medium plate mill is used for rolling, the width of the thin high nickel molybdenum stainless steel plate can be expanded to 2500-3000 mm through the 5m rolling range and the large reduction capacity (the maximum reduction force reaches 120000 kN in normal production) of the medium plate mill, and after a series of trial-manufacture adjustment rolling rules and reduction forces, the number of welding seams of the product in use can be reduced, the cost is reduced, the safety is increased, and the service life is prolonged.

Detailed Description

The process of the present invention is described in further detail below with reference to specific examples.

Example 1

This example provides a rolling method of a wide-width thin-gauge nickel-molybdenum austenitic stainless steel plate, selecting N08904 steel with blank size of 124mm (thickness) × 1532mm (width) × 3430mm (length), and chemical components (weight percentage): 0.01 percent of C, 0.10 percent of Mn, 0.01 percent of P, 0.01 percent of S, 0.10 percent of Si, 20.1 percent of Cr, 24.3 percent of Ni, 4.2 percent of Mo and the balance of Fe, and the steel plate with the planned rolling finished product size of 10.6mm multiplied by 2820mm multiplied by 21755 mm.

And (3) after the appearance size of the blank is inspected to be qualified, adopting a high-temperature heating strategy, and sending the steel blank to a stepping heating furnace for heating, wherein the furnace time is 218min, the temperature of a soaking section is 1264-1270 ℃, the soaking time is 29min, and the tapping temperature is 1270 ℃. And (2) rolling by adopting a single-stand four-roller reversible rolling mill, wherein the rolling roller period is arranged in the early stage of the rolling mill roller, the number of rolled kilometers in the rolling mill roller period is required to be less than or equal to 15km, and 2-4 common flaw detection steel plates with widths wider than that of the stainless steel plates are arranged before rolling to roll and fully scald the rollers. And closing the roller way cooling water and the rolling mill side-spraying water cooling devices. In order to reduce the temperature drop, the high-pressure water tank does not descale, and the high-pressure water tank does not descale in the rolling process, but the purging is started.

The rolling process is carried out for 12+1 times, the reduction rate is gradually increased from about 11% of the 1 st time to 15% -29% of the 5 th time, and then the reduction rate is gradually reduced. The reduction rate of the 11 th pass is 13-14%, and the reduction rate of the 12 th pass is 7-9%. And (3) adopting a rapid steel rolling strategy, wherein the rolling speed reaches 1.20-2.50 m/s, the steel throwing distance and the inter-pass spacing are reduced as much as possible, and the final rolling temperature is 866 ℃. And (4) opening the rolled steel plate to a pre-straightening machine for 2-4 times of reciprocating pre-straightening. After rolling, air cooling is carried out without watering. The final product size is 10.55mm x 2806mm x 21700mm, the surface is flat and the plate shape is good.

Example 2

This example provides a rolling method of a wide-width thin-gauge nickel-molybdenum austenitic stainless steel plate, selecting N08904 steel with a blank size of 123mm (thickness) × 1532mm (width) × 3597mm (length), and chemical components (weight percent): 0.01 percent of C, 0.10 percent of Mn, 0.01 percent of P, 0.01 percent of S, 0.10 percent of Si, 20.1 percent of Cr, 24.3 percent of Ni, 4.2 percent of Mo and the balance of Fe, and the steel plate with the planned rolling finished product size of 10.6mm multiplied by 2620mm multiplied by 25627 mm.

And after the appearance size of the blank is inspected to be qualified, a high-temperature heating strategy is adopted, the steel blank is sent to a stepping heating furnace to be heated, the furnace time is 223min, the temperature of a soaking section is 1267-1270 ℃, the soaking time is 36min, and the tapping temperature is 1269 ℃. The method is characterized in that a single-stand four-roller reversible rolling mill is adopted for rolling, the rolling roller period is arranged in the early stage of the rolling mill roller, the number of rolled kilometers in the rolling mill roller period is less than or equal to 15km, 2-4 common flaw detection steel plates with widths wider than that of the stainless steel plates are arranged for rolling before rolling, and the rollers are fully scalded. And after the slab is discharged from the heating furnace and before rolling begins, closing roller cooling water, rolling mill side-spraying and other water cooling devices to reduce the temperature reduction rate of the steel plate and ensure that the rolling process is finished smoothly. In order to reduce the temperature drop, the high-pressure water tank does not descale, and the high-pressure water tank does not descale in the rolling process, but the purging is started.

The rolling process is carried out for 12+1 times, the reduction rate is gradually increased from about 11% of the 1 st time to 15% -29% of the 5 th time, and then the reduction rate is gradually reduced. The reduction rate of the 11 th pass is 13-14%, and the reduction rate of the 12 th pass is 7-9%. And (3) adopting a rapid steel rolling strategy, wherein the rolling speed reaches 1.20-2.50 m/s, the steel throwing distance and the inter-pass spacing are reduced as much as possible, and the final rolling temperature is 862 ℃. And (4) opening the rolled steel plate to a pre-straightening machine for 2-4 times of reciprocating pre-straightening. After rolling, air cooling is carried out without watering. The final product has dimensions of 10.48mm × 2654mm × 24587mm, flat surface and good plate shape.

Example 3

This example provides a rolling method of a wide-width thin-gauge nickel-molybdenum austenitic stainless steel plate, selecting N08904 steel with a blank size of 122mm (thickness) × 1532mm (width) × 2920mm (length), and chemical components (weight percent): 0.01 percent of C, 0.10 percent of Mn, 0.01 percent of P, 0.01 percent of S, 0.10 percent of Si, 20.1 percent of Cr, 24.3 percent of Ni, 4.2 percent of Mo and the balance of Fe, and the steel plate with the planned rolling finished product size of 10.6mm multiplied by 2980mm multiplied by 18140 mm.

And after the appearance size of the blank is inspected to be qualified, a high-temperature heating strategy is adopted, the steel blank is sent to a stepping heating furnace to be heated, the furnace time is 218min, the temperature of a soaking section is 1260-1268 ℃, the soaking time is 25min, and the tapping temperature is 1268 ℃. And a single-stand four-roller reversible rolling mill is adopted for rolling, the rolling roller period is arranged in the roller early stage, the number of rolled kilometers in the roller period is less than or equal to 15km, and 2-4 common flaw detection steel plates with the width wider than that of the stainless steel plate are arranged for rolling before rolling, so that the rollers are fully scalded. And after the slab is discharged from the heating furnace and before rolling begins, closing roller cooling water, rolling mill side-spraying and other water cooling devices to reduce the temperature reduction rate of the steel plate and ensure that the rolling process is finished smoothly. In order to reduce the temperature drop, the high-pressure water tank does not descale, and the high-pressure water tank does not descale in the rolling process, but the purging is started.

The rolling process is carried out for 12+1 times, the reduction rate is gradually increased from about 11% of the 1 st time to 15% -29% of the 5 th time, and then the reduction rate is gradually reduced. The reduction rate of the 11 th pass is 13-14%, and the reduction rate of the 12 th pass is 7-9%. And (3) adopting a rapid steel rolling strategy, wherein the rolling speed reaches 1.20-2.50 m/s, the steel throwing distance and the inter-pass spacing are reduced as much as possible, and the final rolling temperature is 858 ℃. And (4) opening the rolled steel plate to a pre-straightening machine for 2-4 times of reciprocating pre-straightening. After rolling, air cooling is carried out without watering. The final product size is 10.57mm × 2997mm × 17655mm, the surface is flat, and the plate shape is good.

Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.