A control method for improving the shape of 301h stainless steel plate

Abstract

The present application relates to the stainless steel plate production manufacturing technical field, specifically to a kind of control method for improving 301H stainless steel plate shape, to solve the problem that the appearance quality of stainless steel plate product is influenced and the subsequent straightening processing cost of plate is higher due to the fact that the plate shape appears relatively large wave or uneven rib stripe in the process of recrystallization annealing due to the influence of internal stress release and annealing pickling line cooling uneven during the manufacture of 301H high-strength stainless steel plate at present, due to the strength of 301H high-strength stainless steel itself is large.The present application reserves reasonable reduction rate 1%-5% before 301H stainless steel plate rolling annealing pickling, and sets the annealing temperature at 1050-1150 ℃, so that 301H stainless steel plate material is fully recrystallized, the internal stress of material is completely released, and after multi-pass rolling, the plate shape of 301H high-strength stainless steel plate can be obviously improved, the appearance quality of product is improved, and the overall economic benefit of 301H high-strength stainless steel plate is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stainless steel plate production and manufacturing, in particular to a control method for improving the shape of 301H stainless steel plate. BACKGROUND

[0002] In the current conventional production process of 301H high-strength stainless steel, the production process is generally annealing and pickling, cold rolling, recrystallization annealing and pickling, leveling and shearing and packaging, etc. In actual rolling production, due to the high strength of 301H high-strength stainless steel, in the process of recrystallization annealing, the 301H high-strength stainless steel plate is often formed with large wave shape or uneven rib stripes due to the release of internal stress and uneven cooling of the annealing and pickling line. Such plate shape not only affects the appearance of the finished plate, but also causes the customer to need special plate shape straightening in the subsequent use and processing process, thereby increasing the production cost of the customer and being not conducive to the improvement of overall economic benefits. Generally, the method for improving the shape of 301H high-strength stainless steel plate includes leveling process or straightening process, etc. However, in actual production process, the straightening process is often limited by the capacity of the equipment, and the plate shape improvement effect is not obvious, and part of the thickness specifications of the stainless steel plate usually exceeds the design capacity of the straightening equipment and cannot be straightened. Therefore, it is necessary to further optimize the cold rolling production process of high-strength stainless steel to achieve the purpose of improving the shape of 301H high-strength stainless steel plate under the premise of reducing production cost and improving production efficiency. SUMMARY

[0003] The present application provides a control method for improving the shape of 301H stainless steel plate to solve the problems existing in the above background.

[0004] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0005] A control method for improving the shape of 301H stainless steel plate, comprising the following processes:

[0006] Step 1: taking 301H high-strength austenitic stainless steel hot-rolled and pickled steel coil as raw material, reserving 1%-5% of the reduction rate, using rolling mill for cold rolling, and using micrometer to calibrate the thickness of the cold-rolled strip steel;

[0007] Step 2: the cold-rolled strip steel in step 1 is annealed on a continuous annealing line, the annealing temperature is 1050-1150 DEG C, the annealing time is 2-4 min, the strip steel is cooled to below 80 DEG C by compressed air, the annealed strip steel enters a neutral salt solution section, the neutral salt solution is mixed in a ratio of 20% of Na2SO4 and 80% of desalted water, the temperature is controlled at 50-60 DEG C, the surface oxide of the strip steel is removed, then the strip steel enters a mixed acid solution section, the mixed acid solution is mixed in a ratio of 12% of nitric acid HNO3, 2% of hydrofluoric acid HF and 86% of desalted water, the temperature is controlled at 45-55 DEG C, the surface of the strip steel is passivated to obtain a 301H high-strength austenitic stainless steel cold-rolled and pickled strip steel;

[0008] Step 3: the cold-rolled and pickled strip steel obtained in step 2 is used as raw material, the unit tension is set to 180-240 N / mm2, the rolling speed is 80-100 m / min, the strip steel is single-pass re-rolled by adopting a 1%-3% reduction rate, and the reduction rate is adjusted by not more than 0.5% according to the actual plate shape of the 20-roller mill outlet, and when the reduction rate is 3%-5%, the strip steel is multi-pass re-rolled;

[0009] Step 4: the strip steel after re-rolling in step 3 is controlled to have a running speed of 20-25 m / min, is degreased on a degreasing line, NaOH or KOH is used as a degreasing agent, the conductivity is controlled to be 10-12 ms, the temperature is controlled to be 65-70 DEG C, the degreased strip steel is rinsed, desalted water is used for rinsing, the temperature is controlled to be 70-80 DEG C, the residual oil and lye on the surface of the strip steel are removed, the strip steel is dried by compressed air, the temperature is controlled to be 110-120 DEG C, and the residual water stains on the surface of the strip steel are removed;

[0010] Step 5: the strip steel obtained in step 4 is cut on a shearing machine according to the required weight and width, and finally the finished 301H high-strength austenitic stainless steel strip steel is obtained.

[0011] The application has the following beneficial effects:

[0012] The application provides a control method for improving the shape of a 301H stainless steel plate, which comprises the following steps: reserving a reasonable reduction of 1-5% before rolling, annealing and pickling of the 301H stainless steel plate, setting the annealing temperature at 1050-1150 DEG C, so that the 301H stainless steel plate material is fully recrystallized, the internal stress of the material is completely released, and the shape of the 301H high-strength stainless steel plate is obviously improved through multi-pass rolling, the appearance quality of the product is improved, the overall economic benefit of the 301H high-strength stainless steel plate is effectively improved, and the problem that the shape of the 301H high-strength stainless steel plate is affected by the release of internal stress and uneven cooling of the annealing and pickling line during the recrystallization annealing process due to the high strength of the 301H high-strength stainless steel, so that large waves or uneven rib stripes appear on the plate, thereby affecting the appearance quality of the stainless steel plate product and causing high cost of subsequent straightening processing of the plate. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 Fig. 1 is a schematic diagram of the shape of the plate when the annealing temperature is 1050 DEG C.

[0014] Figure 2 Fig. 2 is a schematic diagram of the shape of the plate when the annealing temperature is 1090 DEG C.

[0015] Figure 3 Fig. 3 is a schematic diagram of the shape of the plate when the annealing temperature is 1150 DEG C.

[0016] Figure 4 Fig. 4 is a schematic diagram of the shape of the plate when the annealing temperature is 1160 DEG C.

[0017] Figure 5 Fig. 5 is a schematic diagram of the shape of the plate when the reduction is 1%.

[0018] Figure 6 Fig. 6 is a schematic diagram of the shape of the plate when the reduction is 3%.

[0019] Figure 7 Fig. 7 is a schematic diagram of the shape of the plate when the reduction is 5%.

[0020] Figure 8 Fig. 8 is a schematic diagram of the shape of the plate when the reduction is 7%.

[0021] Table 1 is the mechanical properties corresponding to different annealing temperatures of the 301H high-strength stainless steel plate.

[0022] Table 2 is the mechanical properties corresponding to different reductions of the 301H high-strength stainless steel plate. DETAILED DESCRIPTION

[0023] The application will be further described below in combination with the drawings and specific embodiments.

[0024] Example 1

[0025] The finished thickness of the 301H high-strength austenitic stainless steel plate required by the customer is 3.03 mm. The control method for improving the shape of the 301H stainless steel plate according to the present application includes the following process:

[0026] Step 1: Take the 301H high-strength austenitic stainless steel hot-rolled and pickled steel coil as the raw material, reserve 1%-5% of the reduction rate, and use a 20-roller mill to cold roll. After the rolling force stabilizes, the 20-roller mill is stopped, and the thickness of the cold-rolled strip is calibrated using a micrometer.

[0027] Step 2: Anneal the cold-rolled strip in step 1 on a continuous annealing line, with an annealing temperature of 1050℃ and an annealing time of 3.5 min. Compressed air is used to cool the strip to below 80℃. The annealed strip then enters the neutral salt solution section, with a neutral salt solution ratio of 20% Na2SO4 and 80% desalinated water, and a temperature control of 50-60℃. The surface scale of the strip is removed, and then the strip enters the mixed acid solution section, with a mixed acid solution ratio of 12% nitric acid HNO3, 2% hydrofluoric acid HF, and 86% desalinated water, and a temperature control of 45-55℃. The surface of the strip is passivated to obtain a 301H high-strength austenitic stainless steel cold-rolled and pickled strip.

[0028] Step 3: Take the 301H high-strength austenitic stainless steel cold-rolled and pickled strip obtained in step 2 as the raw material, start the 20-roller mill, set the unit tension to 230 N / mm², and the rolling speed to 90 m / min. The strip is re-cold rolled in multiple passes with a reduction rate of 3%.

[0029] Step 4: Control the travel speed of the strip after re-cold rolling in step 3 to 25 m / min, and perform degreasing on the degreasing line. Use NaOH or KOH as the degreasing agent, control the conductivity to 10-12 ms, and control the temperature to 65-70℃. Then rinse the degreased strip, use desalinated water for rinsing, control the temperature to 70-80℃, remove the residual oil and lye on the surface of the strip, and dry the strip with compressed air, control the temperature to 110-120℃, and remove the residual water stains on the surface of the strip.

[0030] Step 5: Cut the strip obtained in step 4 on a shearing machine according to the required weight and width requirements to obtain the finished 301H high-strength austenitic stainless steel strip. The shape of the obtained plate is as shown in Figure 1 .

[0031] Example 2

[0032] The finished thickness of the 301H high-strength austenitic stainless steel plate required by the customer is 3.03 mm, and the method for improving the shape control of the 301H stainless steel plate of the application comprises the following processes:

[0033] Step 1: Take the 301H high-strength austenitic stainless steel hot-rolled and pickled steel coil as the raw material, reserve 1%-5% of the reduction rate, and use a 20-roller mill to cold roll. After the rolling force stabilizes, the 20-roller mill stops, and the thickness of the cold-rolled strip is calibrated using a micrometer.

[0034] Step 2: Anneal the cold-rolled strip in step 1 on a continuous annealing line, with an annealing temperature of 1090℃ and an annealing time of 3.5 min. Compressed air is used to cool the strip to below 80℃. The annealed strip then enters the neutral salt solution section, with a neutral salt solution ratio of 20% Na2SO4 and 80% desalinated water, and a temperature control of 50-60℃. The surface scale of the strip is removed, and then the strip enters the mixed acid solution section, with a mixed acid solution ratio of 12% nitric acid HNO3, 2% hydrofluoric acid HF, and 86% desalinated water, and a temperature control of 45-55℃. The surface of the strip is passivated to obtain a 301H high-strength austenitic stainless steel cold-rolled and pickled strip.

[0035] Step 3: Take the 301H high-strength austenitic stainless steel cold-rolled and pickled strip obtained in step 2 as the raw material, start the 20-roller mill, set the unit tension to 230 N / mm², and the rolling speed to 90 m / min. The strip is re-cold rolled in multiple passes with a reduction rate of 3%.

[0036] Step 4: Control the travel speed of the strip after re-cold rolling in step 3 to 25 m / min, and degrease it on the degreasing line. Use NaOH or KOH as the degreasing agent, control the conductivity to 10-12 ms, and the temperature to 65-70℃. Rinse the degreased strip, use desalinated water for rinsing, control the temperature to 70-80℃, remove the residual oil and lye on the surface of the strip, and dry it with compressed air, control the temperature to 110-120℃, and remove the residual water stains on the surface of the strip.

[0037] Step 5: Cut the strip obtained in step 4 on a shearing machine according to the required weight and width, and finally obtain the finished 301H high-strength austenitic stainless steel strip. The shape of the obtained plate is as shown in Figure 2 .

[0038] Example 3:

[0039] The finished thickness of the 301H high-strength austenitic stainless steel plate required by the customer is 3.03 mm, and the method for improving the shape control of the 301H stainless steel plate of the application comprises the following processes:

[0040] Step 1: taking a 301H high-strength austenitic stainless steel hot-rolled and pickled steel coil as a raw material, reserving a 1%-5% reduction rate, and using a 20-roller mill to perform cold rolling, and after the rolling force is stable, the 20-roller mill is stopped, and a micrometer is used to calibrate the thickness of the cold-rolled strip.

[0041] Step 2: annealing the cold-rolled strip in step 1 on a continuous annealing line, the annealing temperature is 1150℃, the annealing time is 3.5min, the strip is cooled to below 80℃ by using compressed air, and the annealed strip enters a neutral salt solution section, the neutral salt solution ratio is 20% of Na2SO4 and 80% of desalted water, the temperature is controlled at 50-60℃, the surface oxide scale of the strip is removed, then the strip enters a mixed acid solution section, the mixed acid solution ratio is 12% of nitric acid HNO3, 2% of hydrofluoric acid HF, and 86% of desalted water, the temperature is controlled at 45-55℃, the surface of the strip is passivated, and a 301H high-strength austenitic stainless steel cold-rolled and pickled strip is obtained.

[0042] Step 3: taking the 301H high-strength austenitic stainless steel cold-rolled and pickled strip obtained in step 2 as a raw material, starting the 20-roller mill, setting the unit tension to 230N / mm², the rolling speed to 90m / min, and using a 3% reduction rate to perform multi-pass re-rolling on the strip.

[0043] Step 4: controlling the running speed of the strip after re-rolling in step 3 to 25m / min, degreasing the strip on a degreasing line, using NaOH or KOH as a degreasing agent, controlling the conductivity to 10-12ms, and controlling the temperature to 65-70℃, then rinsing the degreased strip, using desalted water for rinsing, controlling the temperature to 70-80℃, removing the residual grease and lye on the surface of the strip, and drying the strip with compressed air, controlling the temperature to 110-120℃, and removing the residual water stains on the surface of the strip.

[0044] Step 5: cutting the strip obtained in step 4 on a shearing machine according to the required weight and width, and finally obtaining a finished 301H high-strength austenitic stainless steel strip, and the plate shape state is as shown in Figure 3 .

[0045] Example 4:

[0046] The finished thickness of the 301H high-strength austenitic stainless steel plate required by the customer is 3.03mm, and the control method for improving the shape of the 301H stainless steel plate of the present application comprises the following process:

[0047] Step 1: taking 301H high-strength austenitic stainless steel hot-rolled and pickled steel coil as raw material, reserving 1%-5% reduction rate, using 20-roller mill to cold roll, when the rolling force is stable, stopping the 20-roller mill, and using micrometer to calibrate the thickness of the cold-rolled strip.

[0048] Step 2: annealing the cold-rolled strip in step 1 on a continuous annealing line, annealing temperature is 1160℃, annealing time is 3.5min, using compressed air to cool the strip to below 80℃, the annealed strip enters the neutral salt solution section, the neutral salt solution ratio is 20% Na2SO4, 80% desalted water, the temperature is controlled at 50-60℃, removing the oxide skin on the surface of the strip, then the strip enters the mixed acid solution section, the mixed acid solution ratio is 12% nitric acid HNO3, 2% hydrofluoric acid HF, 86% desalted water, the temperature is controlled at 45-55℃, passivating the surface of the strip, obtaining 301H high-strength austenitic stainless steel cold-rolled and pickled strip.

[0049] Step 3: taking the 301H high-strength austenitic stainless steel cold-rolled and pickled strip obtained in step 2 as raw material, starting the 20-roller mill, setting the unit tension to 230N / mm², the rolling speed to 90m / min, using 3% reduction rate, multi-pass re-rolling the strip.

[0050] Step 4: controlling the running speed of the strip after re-rolling in step 3 to 25m / min, degreasing on the degreasing line, using NaOH or KOH as degreasing agent, controlling the conductivity to 10-12ms, controlling the temperature to 65-70℃, then rinsing the degreased strip, using desalted water for rinsing, controlling the temperature to 70-80℃, removing the residual oil and lye on the surface of the strip, and drying with compressed air, controlling the temperature to 110-120℃, removing the residual water stains on the surface of the strip.

[0051] Step 5: cutting the strip obtained in step 4 on the shearing machine according to the required weight and width, finally obtaining the finished 301H high-strength austenitic stainless steel strip, and the plate shape state is as shown in Figure 4

[0052] Under the condition of preset 20-roller mill reduction rate of 3%, 301H high-strength stainless steel is annealed at four temperatures of 1050℃, 1090℃, 1150℃ and 1160℃, respectively, and different plate shape states are obtained as shown in Figure 1 Figure 2 Figure 3 Figure 4 ​​​​The mechanical property data are shown in Table 1. Analysis of the detection results shows that when the annealing temperature is controlled in the range of 1050-1150 DEG C, the shape of the 301H high-strength stainless steel plate is well controlled, the amplitude is small, and the subsequent small reduction ratio plate shape is easy to correct; when the annealing temperature is 1160 DEG C, the plate shape deteriorates sharply, and the plate surface is curved, therefore, the plate shape when the annealing temperature is controlled in the range of 1050-1150 DEG C is better than that when the annealing temperature is 1160 DEG C, and the plate shape when the annealing temperature is 1090 DEG C is the best. At the same time, the mechanical properties of the 301H high-strength stainless steel plate under the condition are small, and are within the qualified range of the finished product.

[0053]

[0054] Table 1

[0055] Example 5:

[0056] The finished product thickness of the 301H high-strength austenitic stainless steel plate required by the customer is 3.03 mm, and the control method for improving the shape of the 301H stainless steel plate of the application comprises the following processes:

[0057] Step 1: taking the 301H high-strength austenitic stainless steel hot-rolled and pickled steel coil as the raw material, reserving 1%-5% of the reduction ratio, using a 20-roller mill to cold roll, after the rolling force is stable, stopping the 20-roller mill, and using a micrometer to calibrate the thickness of the cold-rolled strip.

[0058] Step 2: annealing the cold-rolled strip in step 1 on a continuous annealing line, the annealing temperature is 1090 DEG C, the annealing time is 3.5 min, the strip is cooled to below 80 DEG C by compressed air, the annealed strip enters a neutral salt solution section, the neutral salt solution ratio is 20% of Na2SO4 and 80% of desalted water, the temperature is controlled at 50-60 DEG C, the surface oxide of the strip is removed, then the strip enters a mixed acid solution section, the mixed acid solution ratio is 12% of nitric acid HNO3, 2% of hydrofluoric acid HF, and 86% of desalted water, the temperature is controlled at 45-55 DEG C, the surface of the strip is passivated, and the 301H high-strength austenitic stainless steel cold-rolled and pickled strip is obtained.

[0059] Step 3: taking the 301H high-strength austenitic stainless steel cold-rolled and pickled strip obtained in step 2 as the raw material, starting the 20-roller mill, setting the unit tension to 230 N / mm2, and the rolling speed to 90 m / min, and using 1% of the reduction ratio to cold roll the strip in a single pass.

[0060] Step 4: After the re-rolling of the strip steel in step 3 is completed, the strip steel is subjected to degreasing on a degreasing line at a running speed of 25 m / min, using NaOH or KOH as the degreasing agent, with the conductivity controlled at 10-12 ms and the temperature controlled at 65-70°C. The degreased strip steel is then rinsed using desalted water at a temperature of 70-80°C to remove residual grease and alkali solution on the surface of the strip steel, and dried using compressed air at a temperature of 110-120°C to remove residual water stains on the surface of the strip steel.

[0061] Step 5: The strip steel obtained in step 4 is cut on a shearing machine according to the required weight and width to obtain the finished 301H high-strength austenitic stainless steel strip steel, and the plate shape is as shown in Figure 5

[0062] Example 6

[0063] The finished thickness of the 301H high-strength austenitic stainless steel plate required by the customer is 3.03 mm, and the control method for improving the shape of the 301H stainless steel plate according to the present application includes the following process:

[0064] Step 1: Using a 301H high-strength austenitic stainless steel hot-rolled pickled steel coil as the raw material, a 20-roller mill is used to cold roll the strip steel with a reserved reduction rate of 1%-5%, and after the rolling force stabilizes, the 20-roller mill is stopped, and a micrometer is used to calibrate the thickness of the cold-rolled strip steel.

[0065] Step 2: The cold-rolled strip steel in step 1 is subjected to annealing treatment on a continuous annealing line, with the annealing temperature being 1090°C and the annealing time being 3.5 min. The strip steel is cooled to below 80°C using compressed air, and then enters a neutral salt solution section, with the neutral salt solution having a ratio of 20% Na2SO4 and 80% desalted water, and the temperature being controlled at 50-60°C to remove the oxide scale on the surface of the strip steel. The strip steel then enters a mixed acid solution section, with the mixed acid solution having a ratio of 12% nitric acid HNO3, 2% hydrofluoric acid HF, and 86% desalted water, and the temperature being controlled at 45-55°C to perform passivation treatment on the surface of the strip steel, thereby obtaining a 301H high-strength austenitic stainless steel cold-rolled pickled strip steel.

[0066] Step 3: Using the 301H high-strength austenitic stainless steel cold-rolled pickled strip steel obtained in step 2 as the raw material, a 20-roller mill is started, with the unit tension being set at 230 N / mm² and the rolling speed being set at 90 m / min. The strip steel is subjected to multi-pass re-rolling using a reduction rate of 3%.

[0067] ​Step 4: After the re-rolling of the strip steel in step 3 is completed, the strip steel is subjected to degreasing on a degreasing line at a running speed of 25 m / min, using NaOH or KOH as the degreasing agent, controlling the conductivity at 10-12 ms, and controlling the temperature at 65-70 DEG C. The degreased strip steel is then rinsed using desalted water at a temperature of 70-80 DEG C to remove residual grease and alkali solution on the surface of the strip steel, and dried using compressed air at a temperature of 110-120 DEG C to remove residual water stains on the surface of the strip steel.

[0068] Step 5: The strip steel obtained in step 4 is cut on a shearing machine according to the required weight and width to obtain the finished 301H high-strength austenitic stainless steel strip, and the plate shape is as shown in Figure 6 .

[0069] Example 7

[0070] The finished thickness of the 301H high-strength austenitic stainless steel plate required by the customer is 3.03 mm, and the control method for improving the shape of the 301H stainless steel plate according to the present application comprises the following process:

[0071] Step 1: Using a 301H high-strength austenitic stainless steel hot-rolled pickled steel coil as the raw material, a 20-roller mill is used to cold roll the strip steel with a reserved reduction rate of 1%-5%, and after the rolling force stabilizes, the 20-roller mill is stopped, and a micrometer is used to calibrate the thickness of the cold-rolled strip steel.

[0072] Step 2: The cold-rolled strip steel in step 1 is subjected to annealing treatment on a continuous annealing line, the annealing temperature is 1090 DEG C, the annealing time is 3.5 min, the strip steel is cooled to below 80 DEG C using compressed air, and the annealed strip steel is then subjected to neutral salt solution treatment, the neutral salt solution is composed of 20% Na2SO4 and 80% desalted water, the temperature is controlled at 50-60 DEG C, the surface oxide scale of the strip steel is removed, and then the strip steel is subjected to mixed acid solution treatment, the mixed acid solution is composed of 12% HNO3, 2% HF, and 86% desalted water, the temperature is controlled at 45-55 DEG C, and the surface of the strip steel is subjected to passivation treatment to obtain a 301H high-strength austenitic stainless steel cold-rolled pickled strip.

[0073] Step 3: Using the 301H high-strength austenitic stainless steel cold-rolled pickled strip obtained in step 2 as the raw material, the 20-roller mill is started, the unit tension is set to 230 N / mm2, the rolling speed is 90 m / min, and the strip steel is subjected to multi-pass re-rolling with a reduction rate of 5%.

[0074] Step 4: After the re-rolling of the strip steel in step 3 is completed, the strip steel is subjected to degreasing on a degreasing line at a running speed of 25 m / min, using NaOH or KOH as the degreasing agent, controlling the conductivity at 10-12 ms, and controlling the temperature at 65-70°C. The degreased strip steel is then rinsed using desalted water at a temperature of 70-80°C to remove residual grease and alkali solution on the surface of the strip steel, and dried using compressed air at a temperature of 110-120°C to remove residual water stains on the surface of the strip steel.

[0075] Step 5: The strip steel obtained in step 4 is cut on a shearing machine according to the required weight and width to obtain the finished 301H high-strength austenitic stainless steel strip steel, and the plate shape is as shown in Figure 7

[0076] Example 8

[0077] The finished thickness of the 301H high-strength austenitic stainless steel plate required by the customer is 3.03 mm, and the control method for improving the shape of the 301H stainless steel plate according to the present application includes the following process:

[0078] Step 1: Using a 301H high-strength austenitic stainless steel hot-rolled pickled steel coil as the raw material, a 20-roller mill is used to cold roll the strip steel with a reserved reduction rate of 1%-5%, and after the rolling force stabilizes, the 20-roller mill is stopped, and a micrometer is used to calibrate the thickness of the cold-rolled strip steel.

[0079] Step 2: The cold-rolled strip steel in step 1 is subjected to annealing treatment on a continuous annealing line, the annealing temperature is 1090°C, the annealing time is 3.5 min, the strip steel is cooled to below 80°C using compressed air, and the annealed strip steel enters a neutral salt solution section, the neutral salt solution ratio is 20% Na2SO4 and 80% desalted water, the temperature is controlled at 50-60°C, the surface scale of the strip steel is removed, then the strip steel enters a mixed acid solution section, the mixed acid solution ratio is 12% nitric acid HNO3, 2% hydrofluoric acid HF, and 86% desalted water, the temperature is controlled at 45-55°C, the surface of the strip steel is passivated, and the 301H high-strength austenitic stainless steel cold-rolled pickled strip steel is obtained.

[0080] Step 3: Using the 301H high-strength austenitic stainless steel cold-rolled pickled strip steel obtained in step 2 as the raw material, the 20-roller mill is started, the unit tension is set to 230 N / mm², the rolling speed is 90 m / min, and the strip steel is subjected to multi-pass re-rolling with a reduction rate of 7%.

[0081] ​Step 4: After the strip steel is finished with the re-rolling in step 3, the strip steel is degreased on the degreasing line at a running speed of 25 m / min, using NaOH or KOH as the degreasing agent, with the conductivity controlled at 10-12 ms and the temperature controlled at 65-70°C. The degreased strip steel is then rinsed using desalted water at a temperature of 70-80°C to remove the residual grease and alkali solution on the surface of the strip steel, and dried using compressed air at a temperature of 110-120°C to remove the residual water spots on the surface of the strip steel.

[0082] Step 5: The strip steel obtained in step 4 is cut on a shearing machine according to the required weight and width to obtain the finished 301H high-strength austenitic stainless steel strip steel, and the plate shape is as shown in Figure 8 .

[0083] When the annealing temperature is in the range of 1090°C, the 301H high-strength stainless steel is re-rolled at four different reduction ratios of 1%, 3%, 5% and 7%, respectively, to obtain different plate shapes as shown in Figure 5 , Figure 6 , Figure 7 , Figure 8 . The mechanical property data are shown in Table 2. The analysis and detection results show that when the reduction ratio is controlled in the range of 1%-5%, the plate shape of the 301H high-strength stainless steel plate is obviously improved, the appearance is well controlled, the width is small, and the plate shape is flat. When the reduction ratio is controlled at 7%, the plate shape is obviously deteriorated, and the plate surface is curved. Therefore, the plate shape when the reduction ratio is controlled in the range of 1%-5% is better than that when the reduction ratio is controlled at 7%, and the plate shape when the reduction ratio is controlled at 3% is the best. At the same time, the mechanical properties of the 301H high-strength stainless steel plate under the above conditions are relatively small, and are within the range of the finished product.

[0084]

[0085] Table 2

Claims

1. A control method for improving the shape of 301H stainless steel plate, characterized in that: The following processes are included: Step 1: Use 301H high-strength austenitic stainless steel hot-rolled pickled steel coil as raw material, reserve a reduction rate of 1%-5%, use a rolling mill to perform cold rolling, and then use a micrometer to calibrate the thickness of the cold-rolled strip; Step 2: The cold-rolled steel strip in step 1 is annealed on a continuous annealing line at an annealing temperature of 1050-1150°C for 2-4 minutes. Compressed air is used to cool the steel strip to below 80°C. The annealed steel strip then enters a neutral salt solution section with a ratio of 20% Na2SO4 and 80% desalted water. The temperature is controlled at 50-60°C to remove the oxide scale on the surface of the steel strip. The steel strip then enters a mixed acid solution section with a ratio of 12% nitric acid HNO3, 2% hydrofluoric acid HF, and 86% desalted water. The temperature is controlled at 45-55°C to passivate the surface of the steel strip, thereby obtaining 301H high-strength austenitic stainless steel cold-rolled pickled strip. Step 3: Using the cold-rolled pickled steel strip obtained in step 2 as raw material, setting the unit tension to 180-240 N / mm², the rolling speed to 80-100 m / min, and the reduction rate to 1%-3%, the steel strip is subjected to single-pass cold rolling. Then, according to the actual plate shape at the exit of the 20-high mill, the reduction rate is increased by no more than 0.5% each time. When the reduction rate reaches 3%-5%, the steel strip is subjected to multiple-pass cold rolling. Step 4: The steel strip after the cold rolling in step 3 is degreased on a degreasing line at a speed of 20-25 m / min, using NaOH or KOH as a degreasing agent, controlling the conductivity to 10-12 ms, and controlling the temperature to 65-70°C. The degreased steel strip is then rinsed with desalted water at a temperature of 70-80°C to remove residual grease and alkali on the surface of the steel strip, and then dried with compressed air at a temperature of 110-120°C to remove residual water stains on the surface of the steel strip. Step 5: The strip steel obtained in step 4 is cut on a shearing unit according to the required weight and width requirements, and finally a finished strip steel of 301H high-strength austenitic stainless steel is obtained, and the thickness of the finished strip steel is 3.03 mm.

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