Hot rolling production process for stainless steel material

Abstract

The invention relates to the technical field of stainless steel production, in particular to a stainless steel material hot rolling production process. The problem that stainless steel produced through a traditional hot rolling technology is poor in quality is solved. Segmented heating is adopted in the heating stage, and the preheating area, the heating area and the heat preservation area are arranged, so that the mechanical property of the material is improved; through the multi-stage rolling technology, different deformation amounts are set in the rough rolling stage, the intermediate rolling stage and the finish rolling stage, different rolling speeds and temperatures are combined, grain refinement and structure homogenization are achieved, and the mechanical property of the material is improved; ultrasonic surface treatment and plasma surface treatment are combined, and a rolling lubricant is used in the rolling process, so that the corrosion resistance of the material is improved; and through the gradient cooling technology and microalloying component optimization design, the grain structure of the stainless steel material is remarkably refined, the mechanical property of the material is improved, and the quality of the finally prepared nickel-containing stainless steel is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of stainless steel production, and particularly to a hot rolling production process for stainless steel materials. Background Art

[0002] In the production system of stainless steel materials, the hot rolling process is a key link determining product quality and performance. Many problems have emerged in the actual application of traditional stainless steel hot rolling production processes. For example, in the heating stage, due to limitations in temperature control technology, it is difficult to precisely control the heating rate of the billet and the final heating temperature, resulting in uneven development of the metallographic structure inside the stainless steel and affecting its mechanical properties and corrosion resistance; during the rolling process, it is difficult to achieve dynamic optimization and matching of the rolling force and rolling speed. This not only makes it difficult to control the sheet shape of the product, resulting in defects such as waviness and camber, but also makes it difficult to stabilize the thickness tolerance within the ideal range, seriously affecting subsequent processing and use; in the cooling stage, the cooling rate cannot be flexibly adjusted according to the characteristics of different steel grades, making it difficult for the organizational structure and performance of the stainless steel material to reach the optimal state.

[0003] In recent years, with the continuous increase in the quality and performance requirements for stainless steel materials in fields such as construction, automotive, and aerospace, traditional hot rolling processes are increasingly unable to meet market demands. Therefore, it is urgent to develop a new stainless steel hot rolling production process that can effectively improve product quality.

[0004] For this reason, a hot rolling production process for stainless steel materials is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a hot rolling production process for stainless steel materials. By adopting segmented heating in the heating stage, setting a preheating zone, a heating zone, and a heat preservation zone, the mechanical properties of the material are improved; through a multi-stage rolling process, different deformation amounts are set in the rough rolling, medium rolling, and finish rolling stages, combined with different rolling speeds and temperatures, to achieve grain refinement and tissue homogenization, and the mechanical properties of the material are improved; by combining ultrasonic surface treatment and plasma surface treatment, and using rolling lubricants during the rolling process, the corrosion resistance of the material is improved; through gradient cooling technology and optimized design of microalloying components, the grain structure of the stainless steel material is significantly refined, the mechanical properties of the material are improved, and finally the quality of the nickel-containing stainless steel produced is significantly improved.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a hot rolling production process for stainless steel materials, and the production process is as follows:

[0008] S1 Segment Heating: Introduce argon into the heating furnace, add the component raw materials of the stainless steel material to the preheating zone of the heating furnace and heat for 25 - 50 min, then heat in the heating zone for 45 - 65 min, and finally keep warm in the heat preservation zone for 20 - 40 min to obtain a slab; the preheating zone uses stepped cyclic temperature increase;

[0009] S2 Multi - stage Rolling: Rough - roll the slab with a rough - rolling deformation of 50%, a rolling speed of 0.3 - 0.8 m / s, and a rolling temperature of 1050°C; then perform medium - rolling with the medium - rolling deformation adjusted to 30%, a rolling speed of 0.8 - 1.3 m / s, and a rolling temperature of 1000°C; finally perform finish - rolling with a finish - rolling deformation of 20%, a rolling speed of 1.3 - 1.9 m / s, and a rolling temperature of 950°C to obtain a rolled plate; during the rolling process, evenly spray the rolling lubricant on the surfaces of the rolls and the slab;

[0010] S3 Surface Treatment: Subject the rolled plate to ultrasonic surface treatment and plasma surface treatment to obtain a steel plate;

[0011] S4 Gradient Cooling: Gradient - cool the steel plate. When the temperature of the steel plate is above 650°C, perform high - speed air - flow cooling; when the temperature drops below 650°C, perform spray cooling and cool to 400°C to obtain a cooled steel plate;

[0012] S5 Coiling: Coil the cooled steel plate to obtain the stainless steel material. The coiling temperature is 550°C, the coiling tension is 50 kN, and the coiling speed is 1.2 m / s.

[0013] Preferably, in S1, the temperature of the preheating zone is 800°C; the temperature of the heating zone is 1100°C; the temperature of the heat - preservation zone is 950°C; the stepped cyclic temperature increase is that after the preheating zone is heated to 700°C, keep warm for 5 min, then heat to 750°C and keep warm for 5 min, and finally heat to 800°C.

[0014] Preferably, in S2 multi - stage rolling, the surface temperature of the roll is controlled by dynamically adjusting the coolant flow rate so that the surface temperature of the roll is 250°C; the coolant flow rate is 5 - 10 L / min.

[0015] Preferably, the preparation method of the rolling lubricant is as follows: by mass, 60 parts of polyglycerol ricinoleate are added to a reaction kettle, stirred at a speed of 130 rpm at 55 °C, and 5 parts of sodium stearate are added while stirring to obtain a first mixed solution; 8 parts of nano-molybdenum dioxide are dispersed in absolute ethanol to obtain a dispersion with a mass fraction of 8%; the dispersion and 1.2 parts of tocopherol are added to the mixed solution, and stirring is continued for 35 min to obtain a second mixed solution; 6.5 parts of Tween 60 are added to 22 parts of deionized water to obtain an emulsion; the emulsion is added to the second mixed solution, the stirring speed is increased to 450 rpm, and after reacting for 60 - 90 min, it is passed through a microporous filter with a pore size of 0.3 μm to obtain the rolling lubricant.

[0016] Preferably, in S3, the ultrasonic surface treatment power is 100 - 500 W, the frequency is 30 kHz, and the treatment time is 4 min.

[0017] Preferably, the plasma surface treatment process in S3 is as follows: the rolled plate after ultrasonic surface treatment is placed in a vacuum treatment chamber, evacuated to 10 -3 Pa, then a mixed gas of argon and nitrogen is introduced, the flow rate range is 5 - 50 sccm, the radio frequency plasma generator is turned on, the power is 500 - 2000 W, the working frequency is 13.56 MHz, and it is treated for 8 min to obtain a steel plate; the mixed volume ratio of argon and nitrogen is 1:1.

[0018] Preferably, in S4, the wind speed of high-speed air cooling is 10 - 30 m / s; the spray pressure of spray cooling is 0.1 - 0.6 MPa.

[0019] Preferably, by mass percentage, the component raw materials of the stainless steel material in S1 include the following components: nickel 12.00%; niobium 0.04% - 0.10%; vanadium 0.02% - 0.06%; titanium 0.01% - 0.06%.

[0020] The component raw materials of the stainless steel material by mass percentage further include: carbon 0.06%; silicon 0.80%; manganese 1.60%; chromium 17.00%; phosphorus ≤ 0.035%; sulfur ≤ 0.030%; the balance is iron.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. By adopting segmented heating in the heating stage, the strength and toughness of the nickel-containing stainless steel material prepared are significantly improved. And by introducing argon into the heating furnace, the formation of the surface oxide layer is reduced. During the preheating stage, the temperature is raised slowly to preliminarily homogenize the internal structure of the component raw materials of the stainless steel material, reduce the generation of thermal stress, and avoid defects such as internal cracks caused by thermal stress concentration. Moreover, the preheating zone adopts a stepped cyclic temperature rise, and the element diffusion is promoted through thermal oscillation to eliminate dendritic segregation. In the heating zone, the temperature is raised rapidly to endow the material with good plasticity, providing suitable conditions for subsequent rolling. And the alloying elements are fully diffused to form a more stable solid solution, enhancing the matrix strength. In the holding zone, it is ensured that the overall temperature of the material is uniform, so that the internal structure of the material is fully homogenized, and the grain growth is more uniform, avoiding problems of stress concentration caused by the mixture of large and small grains and performance non-uniformity caused by tissue differences.

[0023] 2. Through the multi-stage rolling process, which is divided into three stages: rough rolling, intermediate rolling, and finish rolling, different deformation amounts are set in each stage, combined with different rolling speeds and temperatures, to achieve grain refinement and tissue homogenization, and the mechanical properties of the nickel-containing stainless steel material are significantly improved. In rough rolling, the large grain size of the billet is broken by a large deformation amount of 50% to create conditions for subsequent tissue refinement. Intermediate rolling further refines the grains and improves the rolling speed to enhance production efficiency. Finish rolling ensures the dimensional accuracy and surface quality of the product. In addition, during the rolling process, through the dynamic adjustment of the surface temperature of the rolling rolls and the use of high-lubricity rolling lubricants, surface defects and internal stress concentration are further reduced.

[0024] 3. By combining ultrasonic surface treatment and plasma surface treatment and using rolling lubricants during the rolling process, the corrosion resistance of the nickel-containing stainless steel material is significantly improved. Utilizing the high-frequency vibration and cavitation effect of ultrasonic waves, micro-defects on the surface of the rolled plate, such as micro-cracks and holes, are effectively eliminated, the surface finish is significantly improved, the surface roughness is reduced, and the corrosion resistance of the product is enhanced. Plasma surface treatment is carried out in a vacuum environment, and a mixed gas of argon and nitrogen is introduced. Through the bombardment of the material surface by high-energy particles, the surface atoms are rearranged, and chemical reactions occur with the working gas to form a new dense surface layer, improving the corrosion resistance of the nickel-containing stainless steel.

[0025] 4. Through the gradient cooling technology and the optimized design of microalloying components, the grain structure of the stainless steel material is significantly refined, and the strength and toughness of the finally produced nickel-containing stainless steel are significantly improved. The gradient cooling is divided into high-speed air flow cooling and spray cooling, and the precise control of the cooling rate is achieved through a special air nozzle and a fine atomization nozzle; the high-speed air flow cooling inhibits grain growth, and the spray cooling further refines the grains, finally forming a uniform nano-scale precipitation phase. At the same time, trace amounts of niobium, vanadium, and titanium are added to the material components, and nano-scale carbonitrides precipitate during the hot rolling and cooling processes, effectively inhibiting grain growth and improving the strength and toughness of the material; and when subjected to a large external force impact, the nano-scale precipitation phase can hinder dislocation movement and disperse stress concentration, making the material not easily break. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process flow diagram of a hot rolling production process for a stainless steel material of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. 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.

[0028] Please refer to Figure 1 , the present invention provides a hot rolling production process for a stainless steel material, and the stainless steel material is obtained through segmented heating, multi-stage rolling, surface treatment, gradient cooling, and coiling of the stainless steel material components; the technical solutions are as follows:

[0029] The substance information involved in the present invention is as follows:

[0030] Polyglycerol ricinoleate CAS: 114355-43-0; Sodium stearate CAS: 822-16-2; Nano molybdenum dioxide CAS: 18868-43-4; Absolute ethanol CAS: 64-17-5; Tocopherol CAS: 1406-18-4; Tween 60 CAS: 9005-67-8.

[0031] Example 1

[0032] The hot rolling production process of the stainless steel material is as follows:

[0033] S1 Stepwise Heating: Argon is introduced into the heating furnace. By mass percentage, 12.00% nickel, 0.04% niobium, 0.02% vanadium, 0.01% titanium, 0.06% carbon, 0.80% silicon, 1.60% manganese, 17.00% chromium, ≤0.035% phosphorus, ≤0.030% sulfur, and the balance of iron are added to the preheating zone of the heating furnace. It is heated at 800°C for 25 min, then heated at 1100°C in the heating zone for 45 min, and finally held at 950°C in the holding zone for 20 min to obtain a slab. The preheating zone uses stepwise cyclic temperature increase. First, it is heated to 700°C and held for 5 min, then heated to 750°C and held for 5 min, and finally heated to 800°C.

[0034] S2 Multi-stage Rolling: The slab is rough-rolled with a rough-rolling deformation of 50%, a rolling speed of 0.3 m / s, and a rolling temperature of 1050°C; then it is medium-rolled with the medium-rolling deformation adjusted to 30%, a rolling speed of 0.8 m / s, and a rolling temperature of 1000°C; finally, it is finish-rolled with a finish-rolling deformation of 20%, a rolling speed of 1.3 m / s, and a rolling temperature of 950°C to obtain a rolled plate. During the rolling process, the rolling lubricant is evenly sprayed on the surfaces of the rolls and the slab. The surface temperature of the rolls is controlled by dynamically adjusting the coolant flow rate to make the surface temperature of the rolls 250°C; the coolant flow rate is 5 - 10 L / min.

[0035] S3 Surface Treatment: The rolled plate is subjected to ultrasonic surface treatment for 4 min under the conditions of a power of 100 W and a frequency of 30 kHz; then it is subjected to plasma surface treatment. The rolled plate after ultrasonic surface treatment is placed in a vacuum treatment chamber, evacuated to 10 -3 Pa, then a mixed gas of argon and nitrogen is introduced with a flow rate range of 5 sccm, the radio frequency plasma generator is turned on with a power of 500 W and a working frequency of 13.56 MHz, and it is treated for 8 min to obtain a steel plate; the mixed volume ratio of argon and nitrogen is 1:1.

[0036] S4 Gradient Cooling: The steel plate is subjected to gradient cooling. When the temperature of the steel plate is above 650°C, high-speed air cooling is carried out with a wind speed of 10 m / s; when the temperature drops below 650°C, spray cooling is carried out with a spray pressure of 0.1 MPa, and it is cooled to 400°C to obtain a cooled steel plate.

[0037] S5 Coiling: The cooled steel plate is coiled to obtain a stainless steel material with a coiling temperature of 550°C, a coiling tension of 50 kN, and a coiling speed of 1.2 m / s.

[0038] The preparation method of the rolling lubricant is as follows: By mass, 60 parts of polyglycerol ricinoleate are added to a reaction kettle, stirred at a speed of 130 rpm at 55 °C, and 5 parts of sodium stearate are added while stirring to obtain a first mixed solution; 8 parts of nano-molybdenum dioxide are dispersed in absolute ethanol to obtain a dispersion with a mass fraction of 8%; the dispersion and 1.2 parts of tocopherol are added to the mixed solution, and stirring is continued for 35 min to obtain a second mixed solution; 6.5 parts of Tween 60 are added to 22 parts of deionized water to obtain an emulsion; the emulsion is added to the second mixed solution, the stirring speed is increased to 450 rpm, and after reacting for 60 min, it is passed through a microporous filter with a pore size of 0.3 μm to obtain the rolling lubricant.

[0039] Examples 2 - 4

[0040] Refer to the production process of Example 1, and the specific differences are shown in Table 1.

[0041] Comparative Example 1

[0042] Refer to the production process of Example 1, except that heat preservation is not carried out in the heat preservation zone.

[0043] Comparative Example 2

[0044] Refer to the production process of Example 1, except that the temperature in the heat preservation zone is 1100 °C.

[0045] Comparative Example 3

[0046] Refer to the production process of Example 1, except that preheating is not carried out in the preheating zone.

[0047] Comparative Example 4

[0048] Refer to the production process of Example 1, except that the temperature in the preheating zone is 600 °C.

[0049] Comparative Example 5

[0050] Refer to the production process of Example 1, except that the temperature in the preheating zone is 1000 °C.

[0051] Comparative Example 6

[0052] Refer to the production process of Example 1, except that heating is not carried out in the heating zone.

[0053] Comparative Example 7

[0054] Refer to the production process of Example 1, except that it is only heated at 1100 °C for 45 min in the heating zone.

[0055] Experimental Example 1 Mechanical Property Test

[0056] The test is carried out with reference to the standard of GB / T228.1 - 2021, and the obtained results are shown in Table 1.

[0057] Table 1 Mechanical property tests of Examples 1-4 and Comparative Examples 1-7

[0058]

[0059]

[0060] As can be seen from Table 1, in Examples 1-4, segmented heating was adopted in the heating stage, and the strength and toughness of the nickel-containing stainless steel material prepared were significantly improved. By introducing argon into the heating furnace, the formation of the surface oxide layer was reduced. During the preheating stage, the temperature was raised slowly to preliminarily homogenize the internal structure of the component raw materials of the stainless steel material, reduce the generation of thermal stress, and avoid defects such as internal cracks caused by thermal stress concentration. Moreover, a stepped cyclic temperature increase was adopted in the preheating zone to promote element diffusion through thermal oscillation and eliminate dendritic segregation. In the heating zone, the temperature was raised rapidly to endow the material with good plasticity, providing suitable conditions for subsequent rolling. Also, the alloying elements diffused sufficiently to form a more stable solid solution, enhancing the matrix strength. In the holding zone, the overall temperature of the material was ensured to be uniform, enabling the internal structure of the material to be fully homogenized and the grain growth to be more uniform, avoiding problems such as stress concentration caused by the mixture of large and small grains and performance non-uniformity caused by tissue differences. In Example 2, when the preheating time was 35 min, the heating time was 55 min, and the holding time was 30 min, the mechanical properties of the produced nickel-containing stainless steel material were the best, with a tensile strength of 836 MPa and an elongation of 52.6%. In Comparative Example 1, no holding was carried out in the holding zone, resulting in uneven internal temperature and non-uniform structure of the billet, leading to uneven deformation during rolling, stress concentration, and thus reducing the continuity and uniformity of the material and the mechanical properties of the material. In Comparative Example 2, the temperature in the holding zone was 1100 °C. Too high a temperature would cause grain growth and weaken the grain boundary strength. Although the atomic diffusion ability was enhanced, grain coarsening would reduce the strength and toughness of the material. In Comparative Example 3, the billet directly entered the high-temperature heating zone without preheating in the preheating zone. Due to the sudden temperature change, the billet generated a large amount of thermal stress, and the internal structure was non-uniform, making it prone to defects such as cracks during rolling, resulting in a decrease in tensile strength and elongation and a deterioration in material quality. In Comparative Examples 4-5, the temperature in the preheating zone was too low, the billet was insufficiently heated, the degree of internal structure homogenization was insufficient, and the atomic activity was low. During subsequent heating and rolling, the material had poor plasticity and was difficult to deform, thus resulting in internal defects. When the temperature was too high, local grain growth or abnormal tissue changes occurred in the billet during the preheating stage, which would affect the tissue evolution during subsequent heating and rolling processes, leading to a decrease in the mechanical properties of the material and a deterioration in quality. In Comparative Example 6, no heating was carried out in the heating zone, the billet temperature was low, the plasticity was poor, and it was difficult to deform during rolling, resulting in a large number of cracks and defects, and a sharp drop in tensile strength and elongation. In Comparative Example 7, the material was only heated at 1100 °C for 45 min in the heating zone without preheating and holding. There were many tissue defects inside the material, such as uneven grain size, undissolved phases or impurities, etc. These defects would become the positions for crack initiation and propagation when the material was deformed by external forces, thus reducing the mechanical properties of the material.

[0061] Examples 5-7

[0062] Referring to the production process of Example 2, the specific differences are shown in Table 2; in Table 2, the reaction time is the reaction time when adding the emulsion into the second mixed solution during the preparation of the rolling lubricant.

[0063] Comparative Example 8

[0064] Referring to the production process of Example 2, the difference is that rough rolling is not carried out.

[0065] Comparative Example 9

[0066] Referring to the production process of Example 2, the difference is that intermediate rolling is not carried out.

[0067] Comparative Example 10

[0068] Referring to the production process of Example 2, the difference is that finish rolling is not carried out.

[0069] Comparative Example 11

[0070] Referring to the production process of Example 2, the difference is that no rolling lubricant is added during the rolling process.

[0071] Comparative Example 12

[0072] Referring to the production process of Example 2, the difference is that the rough rolling deformation amount is 70%.

[0073] Comparative Example 13

[0074] Referring to the production process of Example 2, the difference is that the intermediate rolling deformation amount is 40%.

[0075] Comparative Example 14

[0076] Referring to the production process of Example 2, the difference is that the finish rolling deformation amount is 30%.

[0077] Experimental Example 2 Mechanical Property Test

[0078] The test was carried out according to the standard of GB / T228.1 - 2021, and the obtained results are shown in Table 2.

[0079] Table 2 Mechanical Property Tests of Example 2, Examples 5 - 7 and Comparative Examples 8 - 14

[0080]

[0081] As can be seen from Table 2, in Example 2 and Examples 5-7, a multi-stage rolling process is used, which is divided into three stages: rough rolling, intermediate rolling and finishing rolling. Different deformation amounts are set in each stage. In combination with different rolling speeds and temperatures, the grain refinement and uniform organization can be achieved, and the mechanical properties of the nickel-containing stainless steel material are significantly improved. In Example 5, when the rough rolling speed is 0.5 m / s, the intermediate rolling speed is 1.0 m / s, and the finishing speed is 1.6 m / s, when the rolling lubricant is prepared, the reaction time of adding the emulsion to the mixed solution 2 is 75 min, and the obtained nickel-containing stainless steel material has the best mechanical properties, with a yield strength of 400 MPa, a tensile strength of 842 MPa, and an elongation of 54.2%. In Comparative Example 8, rough rolling was not performed, the original billet had coarse grains and uneven internal structure, and it was difficult to obtain uniform and fine grain structure during subsequent intermediate rolling and finishing rolling. The strength and toughness of the material would be reduced due to the coarse grains, and due to the uneven structure, the deformation ability would also deteriorate, resulting in a decrease in elongation and poor overall mechanical properties. In Comparative Example 9, intermediate rolling was not performed, the degree of grain refinement was insufficient, and the strength improvement of the material was limited; at the same time, due to the lack of deformation adjustment in the intermediate rolling stage, the unreasonable distribution of deformation during finishing rolling would lead to stress concentration, affecting the uniform deformation of the material and reducing the elongation. In Comparative Example 10, finishing rolling was not performed, the product dimensional accuracy and surface quality would deteriorate, and the degree of grain refinement was insufficient, and the strength and surface hardness of the material could not be effectively improved; in addition, due to the lack of final deformation adjustment of finishing rolling, the internal residual stress of the material was large, and crack propagation was prone to occur when subjected to force, and the elongation would also be affected and reduced. In comparative example 11, no rolling lubricant is added during the rolling process, the rolling force will increase, resulting in increased energy consumption during the rolling process, and the friction between the roller and the steel plate surface will intensify, resulting in surface scratches, cracks and other defects, which will become stress concentration points, reduce the strength and fatigue performance of the material, and also deteriorate the surface quality, affecting the corrosion resistance of the material, and the elongation will also be reduced due to the presence of internal defects in the material. In comparative example 12, the rough rolling deformation is 70%, resulting in a large number of dislocations and defects inside the material, and due to the excessive deformation, the internal stress concentration of the material is serious, which may cause abnormal growth or crushing of the grains, reducing the toughness of the material; at the same time, excessive stress concentration will also cause the material to be prone to crack expansion during subsequent processing or use, reducing the strength of the material. In comparative example 13, the intermediate rolling deformation is 40%, and a large deformation will increase the internal dislocation density of the material too quickly, making it difficult to effectively control the grain size and uniformity of the organization during subsequent fine rolling, resulting in excessive grain refinement or uneven deformation, and reduced elongation of the material; and due to the excessive deformation, the internal residual stress of the material increases, thereby affecting the strength. In Comparative Example 14, the finishing deformation is 30%. Excessive deformation will increase the residual stress inside the material, making it easy for cracks to propagate when subjected to stress, thereby reducing the strength of the material. In addition, excessive deformation may also lead to excessive grain refinement, causing the elongation of the material to decrease.

[0082] Examples 8 - 11

[0083] Referring to the production process of Example 5, the specific differences are shown in Table 3.

[0084] Comparative Example 15

[0085] Referring to the production process of Example 5, except that ultrasonic surface treatment was not carried out.

[0086] Comparative Example 16

[0087] Referring to the production process of Example 5, except that plasma surface treatment was not carried out.

[0088] Comparative Example 17

[0089] Referring to the production process of Example 5, except that the working gas for plasma surface treatment was nitrogen.

[0090] Comparative Example 18

[0091] Referring to the production process of Example 5, except that the working gas for plasma surface treatment was argon.

[0092] Experimental Example 3 Corrosion Resistance Test

[0093] Intergranular corrosion test was carried out according to the standard of GB / T4334 - 2020, and the test time was 16h. The obtained results are shown in Table 3.

[0094] Table 3 Corrosion Resistance Test of Example 5, Examples 8 - 11, Comparative Example 11 and Comparative Examples 15 - 18

[0095] Example Ultrasonic power / W Gas flow rate / sccm Plasma power / W Mass loss / mg Example 5 100 5 500 0.37 Example 8 200 20 800 0.29 Example 9 300 30 1200 0.20 Example 10 400 40 1600 0.28 Example 11 500 50 2000 0.34 Comparative Example 11 100 5 500 0.60 Comparative Example 15 / 5 500 0.58 Comparative Example 16 100 / / 0.66 Comparative Example 17 100 5 500 0.52 Comparative Example 18 100 5 500 0.46

[0096] As can be seen from Table 3, in Examples 5 and 8 - 11, by combining ultrasonic surface treatment and plasma surface treatment and using rolling lubricant during the rolling process, the corrosion resistance of the nickel - containing stainless steel material is significantly improved. Utilizing the high - frequency vibration and cavitation effect of ultrasonic waves, micro - defects on the surface of the rolled plate, such as tiny cracks and pores, are effectively eliminated, significantly improving the surface finish, reducing the surface roughness, and enhancing the corrosion resistance of the product; Plasma surface treatment is carried out in a vacuum environment. A mixed gas of argon and nitrogen is introduced. Through the bombardment of the material surface by high - energy particles, the surface atoms are rearranged, and chemical reactions occur with the working gas to form a new dense surface layer, enhancing the corrosion resistance of the nickel - containing stainless steel. In Example 9, when the ultrasonic power is 300W, the gas flow rate is 30sccm, and the plasma power is 1200W, the nickel - containing stainless steel material prepared has the best corrosion resistance, and the mass loss is 0.20mg. In Comparative Example 11, no rolling lubricant is added, and the friction between the steel plate surface and the roll during the rolling process is aggravated, easily generating micro - defects such as scratches and pits. Electrochemical corrosion micro - cells are easily formed at the defect sites, becoming corrosion sources, making it easier for the corrosion medium to invade and reducing the corrosion resistance of the stainless steel. In Comparative Example 15, no ultrasonic surface treatment is carried out, and the rolled plate will retain surface micro - defects, which will not only reduce the surface density but also become the adsorption points and penetration channels of the corrosion medium, accelerating the corrosion process and causing the corrosion resistance of the stainless steel to decline. In Comparative Example 16, no plasma surface treatment is carried out, and a protective modified layer cannot be formed on the steel plate surface. Compared with the treated material, its surface chemical activity is higher, and it is more likely to undergo chemical reactions in the corrosion environment, thus reducing the corrosion resistance. In Comparative Examples 17 - 18, the working gas for plasma surface treatment is only nitrogen or argon, and the surface layer after treatment is slightly inferior in terms of the uniformity of structure and composition, and its comprehensive corrosion resistance is not as good as that after treatment with the mixed gas.

[0097] Examples 12 - 14

[0098] Referring to the production process of Example 9, the specific differences are shown in Table 4; the wind speed in Table 4 is the wind speed during high - speed air cooling; the pressure is the spray pressure during spray cooling.

[0099] Comparative Example 19

[0100] Referring to the production process of Example 9, the difference is that high - speed air cooling is not carried out, and spray cooling is directly carried out.

[0101] Comparative Example 20

[0102] Referring to the production process of Example 9, the difference is that spray cooling is not carried out.

[0103] Comparative Example 21

[0104] Refer to the production process of Example 9, except that no niobium component is added to the stainless steel material.

[0105] Comparative Example 22

[0106] Refer to the production process of Example 9, except that no vanadium component is added to the stainless steel material.

[0107] Comparative Example 23

[0108] Refer to the production process of Example 9, except that no titanium component is added to the stainless steel material.

[0109] Experimental Example 4 Mechanical Testing

[0110] The tests were carried out according to the standard of GB / T228.1-2021, and the results are shown in Table 4.

[0111] Table 4 Mechanical Property Tests of Example 9, Examples 12 - 14 and Comparative Examples 19 - 23

[0112]

[0113] As can be seen from Table 4, through gradient cooling technology and optimized design of microalloying components, the grain structure of the stainless steel material has been significantly refined, and the strength and toughness of the finally produced nickel-containing stainless steel have been significantly improved. High-speed air cooling uses a special nozzle to ensure that the air flow evenly blows on the surface of the steel plate, quickly reducing the temperature of the steel plate and inhibiting grain growth; spray cooling uses a fine atomization nozzle to evenly atomize the coolant into tiny droplets, which fully contact the surface of the steel plate to achieve slow cooling, refine the grain structure, and improve the strength and toughness of the product; at the same time, trace amounts of niobium, vanadium, and titanium are added to the material components, and nano-scale carbonitride precipitates are formed during hot rolling and cooling, effectively inhibiting grain growth and improving the strength and toughness of the material; and when subjected to a large external force impact, the nano-scale precipitates can hinder the movement of dislocations, disperse stress concentration, and make the material less likely to break. In Example 12, when the niobium content is 0.08%, the vanadium content is 0.04%, the titanium content is 0.03%, the wind speed during high-speed air cooling is 20 m / s, and the spray cooling pressure is 0.4 MPa, the mechanical properties of the produced nickel-containing stainless steel material are the best, with a yield strength of 864 MPa and an elongation of 55.6%. In Comparative Example 19, high-speed air cooling was not carried out, and spray cooling was directly carried out. The cooling rate of the steel plate was too slow in the high-temperature section, and the grains continued to grow at a higher temperature. The coarse grains would reduce the grain boundary strengthening effect, resulting in a decrease in yield strength; at the same time, the coarse grains made the material deformation uneven, easily causing defects such as cracks, and the elongation would also decrease accordingly. In Comparative Example 20, spray cooling was not carried out, and only high-speed air cooling was relied on. The cooling rate was too fast, which might cause large thermal stresses inside the steel plate, forming an uneven structure and resulting in a reduction in mechanical properties. In Comparative Example 21, no niobium component was added to the stainless steel material. The grains were more likely to grow during heating and rolling. The large grains would reduce the grain boundary area and the hindering effect of the grain boundary on deformation, resulting in a decrease in yield strength; at the same time, due to the lack of nano-scale precipitates formed by niobium, the toughness of the material was poor, and it was prone to brittle fracture during deformation, and the elongation would also decrease. In Comparative Example 22, no vanadium component was added to the stainless steel material. The precipitation strengthening effect of the material was weakened, and the yield strength would decrease; and the lack of vanadium would make the grains relatively coarse, further reducing the strength and plasticity of the material, resulting in a decrease in elongation. In Comparative Example 23, no titanium component was added to the stainless steel material. The carbide at the grain boundary increased, reducing the grain boundary strength and resulting in a decrease in yield strength; in addition, the grain refinement effect became worse, the plasticity and toughness of the material decreased, and the elongation was also affected and decreased.

[0114] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hot rolling production process for stainless steel material, characterized in that: The production process is as follows: S1 segmented heating: argon gas is introduced into the heating furnace, the component raw materials of the stainless steel material are added into the preheating zone of the heating furnace and heated for 25-50 minutes, then heated in the heating zone for 45-65 minutes, and finally heated in the insulation zone for 20-40 minutes to obtain a slab; the preheating zone adopts a step-by-step cycle heating method; S2 multi-stage rolling: the slab is subjected to rough rolling at a rolling speed of 0.3-0.8 m / s; then intermediate rolling at a rolling speed of 0.8-1.3 m / s; finally, finish rolling at a rolling speed of 1.3-1.9 m / s to obtain a rolled plate; during the rolling process, a rolling lubricant is evenly sprayed on the rollers and the surface of the slab; S3 surface treatment: subjecting the rolled plate to ultrasonic surface treatment and plasma surface treatment to obtain a steel plate; S4 gradient cooling: performing gradient cooling on the steel plate, when the temperature of the steel plate is above 650°C, performing high-speed airflow cooling; when the temperature drops below 650°C, performing spray cooling, cooling to 400°C to obtain a cooled steel plate; S5 Coiling: Coiling the cooled steel plate to obtain the stainless steel material.

2. A hot rolling production process for stainless steel material according to claim 1, characterized in that: The temperature of the preheating zone in S1 is 800°C; the temperature of the heating zone is 1100°C; the temperature of the insulation zone is 950°C; the step-by-step cyclic heating is as follows: the preheating zone is heated to 700°C, then kept warm for 5 minutes, then heated to 750°C, then kept warm for 5 minutes, and finally heated to 800°C.

3. The hot rolling production process of stainless steel material according to claim 1, characterized in that: S2 In the multi-stage rolling, the surface temperature of the roll is controlled by dynamically adjusting the coolant flow rate so that the surface temperature of the roll is 250°C.

4. The hot rolling production process of stainless steel material according to claim 1, characterized in that: The preparation method of the rolling lubricant is as follows: 60 parts of polyglycerol ricinoleate are added to a reaction kettle by mass, stirred at a speed of 130 rpm at 55° C., and 5 parts of sodium stearate are added while stirring to obtain a mixed solution 1; 8 parts of nano molybdenum dioxide are dispersed in anhydrous ethanol to obtain a dispersion with a mass fraction of 8%; the dispersion and 1.2 parts of tocopherol are added to the mixed solution, and stirring is continued for 35 minutes to obtain a mixed solution 2; 6.5 parts of Tween 60 are added to 22 parts of deionized water to obtain an emulsion; the emulsion is added to the mixed solution 2, the stirring speed is increased to 450 rpm, and after reacting for 60-90 minutes, the mixture is passed through a 0.3 μm microporous filter to obtain the rolling lubricant.

5. The hot rolling production process of stainless steel material according to claim 1, characterized in that: The ultrasonic surface treatment power in S3 is 100-500W, the frequency is 30kHz, and the treatment time is 4min.

6. A hot rolling production process for stainless steel material according to claim 1, characterized in that: The plasma surface treatment process in S3 is as follows: the rolled plate subjected to the ultrasonic surface treatment is placed in a vacuum treatment chamber and evacuated to 10 -3 Pa, then a mixed gas of argon and nitrogen is introduced with a flow rate range of 5-50 sccm, a radio frequency plasma generator is turned on with a power of 500-2000 W and an operating frequency of 13.56 MHz, and the treatment is carried out for 8 minutes to obtain the steel plate.

7. A hot rolling production process for stainless steel material according to claim 1, characterized in that: The wind speed of the high-speed airflow cooling in S4 is 10-30 m / s; the spray pressure of the spray cooling is 0.1-0.6 MPa.

8. The hot rolling production process of stainless steel material according to claim 1, characterized in that: The raw materials of the stainless steel material described in S1 include the following components by mass percentage: 12.00% nickel; 0.04%-0.10% niobium; 0.02%-0.06% vanadium; 0.01%-0.06% titanium.

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