A production method of 410s stainless steel 2B product

Abstract

The invention relates to the technical field of metal materials, and specifically discloses a production method of a 410s stainless steel 2B product, comprising the following steps: 1) a 410s stainless steel white coil (NO.1) is subjected to a preparation unit to form a raw material for a rolling mill; 2) a Sendkimier type 20-roller rolling mill is used to roll a cold hard product with a thickness of 0.4-1.0 mm through 7-11 passes; 3) a degreasing unit is used for cleaning; 4) a bedroom continuous annealing furnace is used for annealing; 5) neutral salt electrolytic pickling; 6) nitric acid electrolytic pickling; 7) mixed acid pickling and passivation; 8) two-roller leveling machine is used for leveling; 9) re-coiling, trimming, and storage by coiling. The invention improves the surface glossiness of a 410s stainless steel 2B plate, has stable mechanical properties, and meets the basic market requirements for the surface quality and performance of 410s stainless steel 2B products.

Description

Technical Field

[0001] The invention relates to the technical field of metal materials, and in particular to a production method of a 410s stainless steel 2B product. Background Art

[0002] 410s stainless steel, also known as 06Cr13, is a martensitic stainless steel with good toughness, plasticity and cold deformation, high thermal conductivity, low expansion coefficient, good oxidation resistance, excellent stress corrosion resistance, high material strength, relatively light weight, especially after impact, it absorbs less energy than other metal materials, has good safety performance, and is a key material used in the automobile transportation industry. 410s stainless steel has been widely used in many fields due to its excellent performance, and is increasingly favored by the market due to its low price.

[0003] The mechanical properties of 410s stainless steel 2B plate directly affect its subsequent processing performance. Due to the complexity of its structure, martensitic steel has high requirements for the uniform distribution of internal grains, texture composition, and carbides. Therefore, during continuous annealing, the annealing temperature, holding time, and cooling rate must be strictly controlled. If the annealing process is not appropriate, on the one hand, the grains cannot grow fully, and a texture conducive to forming cannot be formed, and the carbide distribution is uneven. On the other hand, it is easy to form a martensitic structure, which seriously affects subsequent processing.

[0004] While 410s stainless steel is gaining popularity in the market, it also puts forward more stringent requirements on surface quality. The surface of 410s stainless steel produced by the conventional method is grayish white with poor glossiness, which cannot meet the customer's requirements on surface color. Therefore, it is necessary to design a 410s stainless steel that can achieve the mechanical properties and surface quality required for subsequent processing of 410s stainless steel through multiple rolling of a Sendkimier 20-roller mill, horizontal annealing, electrolytic pickling and mixed acid pickling, and two-roller leveling. Summary of the invention

[0005] In view of the problems existing in the prior art, the object of the present invention is to provide a production method of 410s stainless steel 2B product.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a production method of 410s stainless steel 2B product, comprising the following steps:

[0007] 1) The pickled white coil is re-reeled by the preparation unit, and the coiling tension is increased to 150KN;

[0008] 2) Use a rolling mill to roll the product to 0.4-1.0 mm cold hardened product through 7-11 passes;

[0009] 3) The cold-hardened products of the rolling mill are degreased and cleaned;

[0010] 4) Annealing in a horizontal annealing furnace, which includes a preheating section, a heating section, a heat preservation section, an air cooling section, and a mist cooling section. The steel strip is cooled to a temperature below 80°C before being taken out of the furnace;

[0011] 5) Using neutral salt electrolysis, including electrolysis stage one and electrolysis stage two;

[0012] 6) Using nitric acid electrolysis;

[0013] 7) Mixed acid pickling, including mixed acid stage one and mixed acid stage two;

[0014] 8) Use offline two-roller leveling;

[0015] 9) Use rewinding unit to trim the edges and pack the rolls into storage.

[0016] Specifically, the rolling mill in step 2) is a 20-roller Sendkimier rolling mill, the maximum deformation of the rolling mill pass is ≤23%, the rolling force of the pass is ≤4000KN, the roll gap rolling oil spray volume is ≥7000l / min, the final pass speed is ≤250m / min, and the final pass working roll roughness is 0.1-0.12μm.

[0017] Specifically, the degreasing liquid used in the step 3) has a conductivity of 7-10 ms / cm and a temperature of 75-80° C., and the conductivity of the rinsing water used for cleaning has a conductivity of ≤30 μs / cm.

[0018] Specifically, the insulation temperature of the insulation section of the annealing furnace in step 4) is 820°C, and the insulation time is greater than 13s; when the cooling temperature is greater than 450°C, the cooling rate is 25.45°C / s, and the cooling rate at 450-150°C is 18.2°C / s, the oxygen content in the annealing furnace is 3-8%, and the pressure in the annealing furnace is 12-16Pa.

[0019] Specifically, the neutral salt in step 5) uses sodium sulfate as the electrolyte, the electrolyte temperature is 70-75° C., the electrolyte concentration is 180-200 g / l, the electrolysis current is 5500-6000 A, and the pH is 3<PH≤6.

[0020] Specifically, the concentration of the nitric acid electrolyte in step 6) is 30-60 g / l, the temperature of the nitric acid electrolyte is 50-55° C., and the electrolysis current is 3500-4000 A.

[0021] Specifically, the concentration of nitric acid in the first mixed acid section in step 7) is 30-60 g / l, the temperature is 50-55° C., the second mixed acid section is desalted water, and the conductivity of the rinsing water in the rinsing section is ≤30 μs / cm.

[0022] Specifically, the leveling in step 8) is carried out by a two-high leveling machine. For a product with a thickness of 0.6 < h ≤ 1.0 mm, it is leveled for 2 passes, with a rolling force of 5500 - 6500 KN and a tension of 80 - 110 KN; for a product with a thickness of 0.4 ≤ h ≤ 0.6 mm, it is leveled for 3 passes, with a leveling rolling force of 7000 - 8500 KN and a tension of 70 - 90 KN; the roughness of the work roll is 0.08 - 0.12 μm.

[0023] The present invention has the following beneficial effects:

[0024] The production method of 410s stainless steel 2B products designed by the present invention

[0025] 1. The mechanical properties of the 410s stainless steel 2B products produced are stable, with a yield strength of 270 - 305 MPa, a tensile strength of 475 - 500 MPa, an elongation of 29 - 33%, and a grain size level of 6.5 - 8, meeting the requirements for subsequent processing such as stamping.

[0026] 2. The surface brightness of the 410s stainless steel 2B products produced is good, the surface does not turn white, and the surface glossiness reaches 500 - 550 GU (60°), meeting the requirements of customers for the surface glossiness of 410s stainless steel 2B products.

[0027] 3. Compared with the 410s stainless steel 2B products produced by ordinary methods, the products produced by the present invention have a uniform thickness (±0.01 mm), good flatness (wave height < 3 mm), stable performance, and are suitable for uses such as stamping; the plate surface does not turn grayish-white, has good glossiness, and reaches 500 - 550 GU. Therefore, the 410s stainless steel 2B products of the present invention have a broad market prospect. Specific embodiments

[0028] The technical solutions in the embodiments of the present invention will be further described clearly and completely below. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] Example 1

[0030] The production steps of a 410s stainless steel 2B product with a thickness of 0.4 mm are as follows:

[0031] (1) For a 410s white skin coil (NO.1) with a specification of 3.0 * 1245 mm, the steel strip tension is increased from the original 60 KN to 150 KN by the preparation unit.

[0032] (2) A 3.0*1245mm410s white coil is rolled into a 0.4*1245mm cold hardened product by 11 passes using a Sendkimier 20-roll rolling mill. The roughness of the rough roll is 0.4-0.6μm, and the roughness of the fine roll is 0.1-0.12μm. The rolling parameters are as follows:

[0033]

[0034] (3) The cold-hardened products of the rolling mill are degreased, the conductivity of the degreasing liquid is 7-11ms / cm, the temperature is 70-75℃, the brushing water pressure is 0.4-0.6MPa, the temperature is 75-80℃; the conductivity of the rinsing water is ≤30μs / cm, the temperature is 50-60℃, and the oil and impurities on the surface of the steel strip are removed.

[0035] (4) A horizontal annealing furnace is used. After degreasing, the steel strip passes through the preheating section, heating section, air cooling section, mist cooling section, and drying section of the annealing furnace. The holding temperature is 820°C, the holding time is 13s, the cooling rate is 25.45°C / s when the temperature is greater than 450°C, and the cooling rate is 18.2°C / s at 450-150°C. The oxygen content in the furnace is 3-8%, and the pressure in the furnace is 12-16Pa.

[0036] (5) Use neutral salt (sodium sulfate) electrolysis, neutral salt section temperature 70-75°C, concentration 180-200g / l, electrolysis current 5500-6000A, 3<PH≤6, metal ion content ≤50g / l.

[0037] (6) Using nitric acid electrolysis, the concentration of nitric acid electrolyte is 30-60g / l, the temperature is 50-55°C, the electrolysis current is 3500-4000A, and the metal ion content is ≤45g / l.

[0038] (7) Mixed acid pickling is adopted, the nitric acid concentration of the mixed acid stage is 30-60g / l, the temperature is 50-55°C, the mixed acid stage 2 is desalted water, and the conductivity of the rinsing water in the rinsing stage is ≤30μs / cm.

[0039] (8) Use two-roller leveling machine for leveling, 0.4*1250mm, 3 leveling passes, leveling rolling force 7000-8500KN, tension 70-90KN; working roll roughness 0.08-0.12μm.

[0040] (9) After leveling, the steel strip is trimmed by the rewinding line, and then rolled and packaged for storage.

[0041] The 410s stainless steel 2B plate produced by the above process has a bright surface, a glossiness of 500-550GU (60°), uniform thickness, a thickness fluctuation of ±0.01mm, and a flat plate shape (wave height <3mm). The mechanical properties are stable, with a yield strength of 270-290MPa, a tensile strength of 475-490MPa, and an elongation of 28-30%.

[0042] Example 2

[0043] The production steps of 1.0mm thick 410s stainless steel 2B products are as follows:

[0044] (1) 410s white coil (NO.1), specification 3.0*1245mm, the preparation unit increases the steel strip tension from the original 80KN to 150KN.

[0045] (2) A 3.5*1245mm410s white coil is rolled into a 1.0*1245mm cold hardened product by 8 passes using a Sendkimier 20-roll rolling mill. The roughness of the rough roll is 0.4-0.6μm, and the roughness of the fine roll is 0.1-0.12μm. The rolling parameters are as follows:

[0046]

[0047] (3) The cold-hardened products of the rolling mill are degreased, the conductivity of the degreasing liquid is 7-11ms / cm, the temperature is 70-75℃, the brushing water pressure is 0.4-0.6MPa, the temperature is 75-80℃; the conductivity of the rinsing water is ≤30μs / cm, the temperature is 50-60℃, and the oil and impurities on the surface of the steel strip are removed.

[0048] (4) A horizontal annealing furnace is used, and the steel strip passes through the preheating section, heating section, air cooling section, mist cooling section, and drying section of the annealing furnace. The insulation temperature is 820°C, the insulation time is 18.9s, the cooling rate is 22.42°C / s when the temperature is greater than 450°C, and the cooling rate is 18.2°C / s at 450-150°C. The oxygen content in the furnace is 3-8%, and the pressure in the furnace is 12-16Pa.

[0049] (5) Use neutral salt (sodium sulfate) electrolysis, neutral salt section temperature 70-75°C, concentration 180-200g / l, electrolysis current 5000-5500A, 3<PH≤6, metal ion content ≤50g / l.

[0050] (6) The concentration of nitric acid electrolyte is 30-60 g / l, the temperature is 50-55°C, the electrolysis current is 3000-3500 A, and the metal ion content is ≤45 g / l.

[0051] (7) The nitric acid concentration of the mixed acid pickling stage is 30-60g / l, the temperature is 50-55℃, the mixed acid second stage is desalted water, and the conductivity of the rinse water in the rinse stage is ≤30μs / cm

[0052] (8) Use two-roller leveling machine for leveling, 1.0*1250mm, 2 leveling passes, leveling rolling force 6500-7000KN, tension 110-90KN; working roll roughness 0.08-0.12μm.

[0053] (9) After leveling, the products are trimmed and rolled on a rewinding line before packaging and storage.

[0054] The 1.0*1250mm410s stainless steel 2B plate produced by the above process has a bright surface, a glossiness of 480-500GU (60°), uniform thickness, thickness fluctuation of -0.02~0mm, and a flat plate shape (wave height <3mm). The mechanical properties are stable, the yield strength reaches 280-305MPa, the tensile strength reaches 470-490MPa, and the elongation reaches 29-33%.

[0055] The present invention is not limited to the above-mentioned implementation modes, and anyone should be aware of the structural changes made under the enlightenment of the present invention, and all those having the same or similar technical solutions as the present invention fall within the protection scope of the present invention.

[0056] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. A method for producing a 410s stainless steel 2B product, characterized in that: It includes the following steps: 1) The pickled white skin coil is rewound by the preparation unit, and the coiling tension is increased to 150 KN; 2) The cold hard product is rolled to 0.4 - 1.0 mm through 7 - 11 passes by the rolling mill; 3) The cold hard product of the rolling mill is degreased and cleaned. The conductivity of the degreasing solution used for degreasing is 7 - 10 ms / cm, and the temperature is 75 - 80 °C. The conductivity of the rinsing water used for cleaning is ≤ 30 μs / cm; 4) Annealing in a horizontal annealing furnace. The annealing furnace includes a preheating section, a heating section, a heat preservation section, an air cooling section, and a mist cooling section. The heat preservation temperature of the heat preservation section of the annealing furnace is 820 °C, and the heat preservation time is greater than 13 s; when cooling, the cooling rate is 25.45 °C / s when the temperature is greater than 450 °C, and the cooling rate is 18.2 °C / s when the temperature is 450 - 150 °C. The oxygen content in the annealing furnace is 3 - 8%, the pressure in the annealing furnace is 12 - 16 Pa, and the steel strip temperature is cooled to below 80 °C before discharging; 5) Neutral salt electrolysis is adopted, including electrolysis stage 1 and electrolysis stage 2. Sodium sulfate is used as the electrolyte for the neutral salt. The temperature of the electrolyte is 70 - 75 °C, the concentration of the electrolyte is 180 - 200 g / l, the electrolysis current is 5500 - 6000 A, and the pH value is 3 < PH ≤ 6; 6) Nitric acid electrolysis is adopted; 7) Mixed acid pickling is adopted, including mixed acid stage 1 and mixed acid stage 2; 8) Offline two - roll skin pass rolling is adopted; 9) The edges are trimmed by the rewinding unit, and then it is slit and packaged and stored in the warehouse.

2. The method for producing a 410s stainless steel 2B product according to claim 1, characterized in that: The rolling mill in step 2) is a 20 - high Sendzimir mill. The maximum reduction per pass of the rolling mill is ≤ 23%, the rolling force per pass is ≤ 4000 KN, the spraying amount of rolling oil at the roll gap is ≥ 7000 l / min, the speed of the last pass is ≤ 250 m / min, and the roughness of the working roll of the last pass is 0.1 - 0.12 μm.

3. The method for producing a 410s stainless steel 2B product according to claim 1, characterized in that: The concentration of the nitric acid electrolyte in step 6) is 30 - 60 g / l, the temperature of the nitric acid electrolyte is 50 - 55 °C, and the electrolysis current is 3500 - 4000 A.

4. The method for producing a 410s stainless steel 2B product according to claim 1, characterized in that: The nitric acid concentration in mixed acid stage 1 of step 7) is 30 - 60 g / l, the temperature is 50 - 55 °C, mixed acid stage 2 is demineralized water, and the conductivity of the rinsing water in the rinsing section is ≤ 30 μs / cm.

5. The method for producing a 410s stainless steel 2B product according to claim 1, characterized in that: In step 8), skin pass rolling is carried out by a two - roll skin pass rolling mill. When the product thickness is 0.6 < h ≤ 1.0 mm, it is skin pass rolled for 2 passes, the rolling force is 5500 - 6500 KN, and the tension is 80 - 110 KN; when the product thickness is 0.4 ≤ h ≤ 0.6 mm, it is skin pass rolled for 3 passes, the skin pass rolling force is 7000 - 8500 KN, and the tension is 70 - 90 KN; the roughness of the working roll is 0.08 - 0.12 μm.

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