CN115369304A - Preparation method of stainless steel material and stainless steel material - Google Patents

Abstract

The application provides a preparation method of stainless steel material and stainless steel material, including the following steps: Step (1): Prepare stainless steel billet by adopting vacuum smelting + vacuum self-consumption double process, and reduce component segregation through solidification parameter control; through solidification parameter Controlling and mitigating composition segregation includes: controlling the maximum molten pool depth in the mushy zone of the self-consumable billet by controlling the current-voltage ratio, thereby reducing composition segregation so that the carbon mass fraction fluctuation in the stainless steel billet is within ±0.015%; step (2): Performing high-temperature diffusion and homogenization treatment on the stainless steel billet to obtain a primary product; step (3): performing forging or rolling deformation treatment on the primary product obtained in step (2) to obtain a stainless steel material. The preparation method of the stainless steel material and the stainless steel material provided by the application can effectively reduce the segregation degree of the stainless steel, reduce the distribution of inclusions, refine the crystal grains, and facilitate the control of defects such as holes and high-temperature ferrite.

Description

Preparation method of stainless steel material and stainless steel material

technical field

This application relates to the technical field of stainless steel materials, and specifically relates to a method for preparing stainless steel materials and stainless steel materials.

Background technique

At present, CSS-42L and Cronidur high-temperature stainless steel are potential materials for the new generation of aerospace bearing steel due to their better high temperature resistance and corrosion resistance.

However, due to the high alloy content of these steel types, during the solidification process, the composition is often uneven due to severe dendrite segregation. defect. Moreover, due to the high content of Cr in these steels, brittle high-temperature ferrite phases are easily formed in the subsequent high-temperature diffusion and forging processes, making the blanks easy to crack during deformation. An unreasonable forging process will not only lead to coarse grains and mixed crystals, which will reduce the strength and toughness of the material, but will also easily cause defects such as flow instability and microcracks. These defects are difficult to eliminate in the subsequent heat treatment process and will be extremely Greatly shorten the service life and reduce the safety of materials.

Therefore, how to provide a method for preparing a stainless steel material and a stainless steel material that can effectively reduce the segregation degree of stainless steel and reduce the distribution of inclusions has become an urgent problem to be solved by those skilled in the art.

Contents of the invention

Therefore, the technical problem to be solved in this application is to provide a preparation method of stainless steel material and stainless steel material, which can effectively reduce the segregation degree of stainless steel and reduce the distribution of inclusions.

In order to solve the above problems, the application proposes a preparation method of stainless steel material, comprising the following steps:

Step (1): Prepare stainless steel blanks by vacuum smelting + vacuum self-consumption duplex process, and reduce composition segregation through solidification parameter control; reduce composition segregation through solidification parameter control includes: control the self-consumption billet paste by controlling the current-voltage ratio The maximum molten pool depth in the shape zone, thereby reducing composition segregation, makes the fluctuation of the carbon mass fraction in the stainless steel billet within ±0.015%;

Step (2): performing high-temperature diffusion and homogenization treatment on the stainless steel billet to obtain primary products;

Step (3): performing forging or rolling deformation treatment on the primary product obtained in step (2) to obtain a stainless steel material.

Further, controlling the maximum molten pool depth in the mushy zone of the consumable billet by controlling the current-voltage ratio includes the following steps:

The current-voltage ratio is controlled between 260-320A/V, so that the maximum molten pool depth in the mushy zone of the consumable billet is less than 250mm, thereby reducing composition segregation.

Further, in the process of step (1), cooling helium gas is introduced, and the pressure of the cooling helium gas is between 0.2-1.5kpa.

Further, the stainless steel billet is subjected to riser cutting and/or peeling treatment; for steel ingots with a length of 1-1.5m, the diameter of the crucible used is 0.4-0.6m. After the vacuum self-consumption ends, the cutting size of the riser of the stainless steel billet is ≥0.15m; and/or, the peeling thickness of the stainless steel billet is ≥15mm;

And/or, in the process of step (1), adopting vacuum smelting+vacuum self-consumption dual process to prepare stainless steel billet includes the following steps: adopting a self-consumable billet with a weight of 1t-3t in the vacuum self-consumption process; preferably , 1-1.5t high-temperature stainless steel consumable blanks are used in the vacuum self-consumption process;

Further, the primary product is a uniform structure without high-temperature ferrite;

Further, step (2): performing high-temperature diffusion homogenization treatment on the stainless steel blank, and obtaining the primary product includes the following steps:

Add pre-deformation treatment before high-temperature diffusion, the temperature of the pre-deformation treatment is ≥1000°C, and the deformation amount is ≤30%;

And/or, the stainless steel billet is subjected to high temperature insulation at ≥1120°C, preferably, the temperature of high temperature insulation is 1120-1230°C; and/or, the time of high temperature insulation is 10-25h.

Further, the average size of the grains of the stainless steel material is ≤15 μm, the size of the hole defect of the stainless steel material is ≤10 μm; the maximum size of the inclusions in the stainless steel material is ≤5 μm.

Further, in step (3): performing forging or rolling deformation treatment on the primary product obtained in step (2) includes the following steps:

The primary product is subjected to multi-fire forging deformation treatment, and upsetting, drawing and elongation are alternately carried out in the multi-fire forging deformation treatment;

Further, in the multi-fire forging deformation treatment, the initial forging temperature is not lower than 1100°C, preferably, the initial forging temperature is 1100-1200°C.

Further, during the multi-fire forging deformation treatment, the total forging ratio of the billet is ≥7; and/or, the deformation amount of the last fire time is ≥50%;

And/or, during the multiple-fire forging deformation process, the final forging temperature is not lower than 950°C; and/or, during the multiple-fire forging deformation process, the strain rate is not higher than 0.1s ^-1 .

Further, the stainless steel material preparation method also includes the following steps:

After step (4): heating the stainless steel material obtained in step (3) to 780-950° C. for 2-5 hours, and then air cooling to room temperature.

According to another aspect of the present application, a stainless steel material is provided, the stainless steel material is prepared by the above stainless steel material preparation method; the carbon mass fraction of the stainless steel material fluctuates within ±0.015%, and the maximum size of the inclusions of the stainless steel material is ≤5 μm, The grain size at 1/2 radius of the stainless steel material is ≤15 μm, and the size of the hole defect in the stainless steel material is ≤10 μm; the stainless steel material has no high-temperature ferrite.

Further, the carbon content in the stainless steel material is ≤0.15wt%, the chromium element content is >13wt%, and the total alloy content is >30wt%.

The preparation method of the stainless steel material and the stainless steel material provided by this application are coordinated and regulated through a series of technologies such as high-homogeneity self-consumable billet solidification, high-temperature diffusion homogenization, and multi-fire cross-forging. While controlling component segregation and reducing inclusions, It ensures that the crystal grains of the obtained material are fine and uniform, and avoids the appearance of high-temperature ferrite and holes. After the above treatment, the carbon mass fraction of the obtained stainless steel fluctuates within ±0.015%, the maximum size of inclusions is ≤5μm, the number of inclusions per unit area does not exceed 5/mm ² , and the average grain size at 1/2 radius is ≤15μm , the maximum size of the hole defect is ≤10μm, and no high-temperature δ-ferrite is found in the structure. The application can effectively reduce the segregation degree of stainless steel, reduce the distribution of inclusions, and facilitate the control of defects such as holes and high-temperature ferrite.

Description of drawings

Fig. 1 is the solidification front element enrichment and inclusion throwing path of embodiment 1;

Fig. 2 is the high temperature diffusion and forging deformation of embodiment 1;

Fig. 3 is the Φ 60mmCSS-42L steel rod inclusions statistical chart of embodiment 1;

Fig. 4 is the Φ 60mmCSS-42L steel bar grain size figure of embodiment 1;

FIG. 5 is a microstructure and morphology diagram of the Φ60mm CSS-42L steel bar in Example 1. FIG.

Detailed ways

Referring to Figures 1-5, a method for preparing a stainless steel material comprises the following steps:

Step (1): Prepare stainless steel blanks by vacuum smelting + vacuum self-consumption duplex process, and reduce composition segregation through solidification parameter control; reduce composition segregation through solidification parameter control includes: control the self-consumption billet paste by controlling the current-voltage ratio The maximum molten pool depth in the shape zone, thereby reducing composition segregation, makes the fluctuation of the carbon mass fraction in the stainless steel billet within ±0.015%;

Step (2): performing high-temperature diffusion and homogenization treatment on the stainless steel billet to obtain primary products;

Step (3): performing forging or rolling deformation treatment on the primary product obtained in step (2) to obtain a stainless steel material.

This application controls the maximum molten pool depth by controlling the current-voltage ratio. The appropriate molten pool depth and full molten pool shape are conducive to the discharge of gas in the molten pool and the feeding of liquid metal, while the smaller mushy zone It is beneficial to reduce the degree of segregation of steel. That is, the present application can control the degree of alloy segregation by controlling the current-voltage ratio.

The present application also discloses some embodiments. Controlling the maximum molten pool depth in the mushy zone of the self-consumable billet by controlling the current-voltage ratio includes the following steps:

The current-voltage ratio is controlled between 260-320A/V, so that the maximum molten pool depth in the mushy zone of the consumable billet is less than 250mm, thereby reducing composition segregation.

This application adopts the current-voltage ratio between 260-320A/V, so that the maximum molten pool depth in the mushy zone of the self-consumable billet is less than 250mm, which can effectively reduce the segregation degree of steel, and is beneficial to the control of defects such as porosity and pores, and It can promote the discharge of gas in the molten pool and the feeding of liquid metal while taking into account low segregation. After the treatment in step (1), the carbon mass fraction fluctuates within ±0.015%.

The present application also discloses some embodiments. During the step (1), cooling helium gas is introduced with a pressure between 0.2-1.5kpa. Introducing cooling helium can reduce the dendrite arms and remove relatively high density inclusions. Specifically, feeding cooling helium can reduce the primary and secondary dendrite arms. After passing helium, the maximum spacing of primary dendrite arms is 980 μm, and the maximum spacing of secondary dendrite arms is 145 μm; at the same time, cooling gas reduces the The composition segregation is shortened and the growth time of inclusions is shortened, which is beneficial to the removal of inclusions with relatively high density. In this application, the purpose of refining dendrites is achieved by feeding cooling helium, and this application can also control and reduce segregation by feeding cooling helium, and remove inclusions with relatively high density.

The application also discloses some embodiments, which are to perform riser cutting and/or peeling treatment on the stainless steel billet; the application can ensure the uniformity of the composition through the riser cutting and skinning treatment, avoid cracking in the forging process, and improve the utilization rate of the material . Peeling treatment can remove the light inclusions on the columnar surface of the ingot, and riser cutting can remove the light inclusions floating on the upper surface of the ingot and the position where the segregation of the ingot is the largest near the upper surface. And after the above treatment, the average inclusion size of the obtained stainless steel billet is 3 μm, the largest inclusion size does not exceed 5 μm, and the number of inclusions per unit area does not exceed 5/mm ² ;

The present application also discloses some embodiments. During the step (1), for a steel ingot with a length of 1-1.5 m, the diameter of the crucible used is 0.4-0.6 m. After the vacuum self-consumption ends, the cutting size of the riser of the stainless steel billet is ≥0.15m, and/or the thickness of the skin is ≥15mm, which can improve the utilization rate while ensuring the uniformity of the material.

And/or, in the process of step (1): adopting vacuum smelting+vacuum self-consumption duplex process to prepare stainless steel billet comprises the following steps: adopting a weight 1t-3t self-consumable billet in the vacuum self-consumption process; preferably, in 1-1.5t high-temperature stainless steel consumable blanks are used in the vacuum self-consumption process. The self-consumption process includes three stages of arc starting, arc stabilization and arc extinguishing. Through the control of solidification parameters, including the control of current-voltage ratio, cooling intensity, riser cutting and peeling, it can effectively reduce the degree of segregation of steel and reduce inclusions. The distribution of matter, and is conducive to the control of defects such as porosity and pores.

In summary, this application uses three aspects to control inclusions and composition segregation. During the solidification process, the degree of alloy segregation is controlled by controlling the current-voltage ratio and strengthening the cooling intensity; and then after the solidification is completed, the segregation is directly removed by cutting the riser The largest position and remove the light inclusions floating on the surface; finally peel off the skin and remove the light inclusions on the side surface.

The application also discloses some embodiments. The primary product is a uniform structure without high-temperature ferrite; the primary product obtained in the above step (1) is a high-temperature stainless steel low-segregation double-vacuum billet, which is further combined with pre-deformation treatment to increase the diffusion of elements channel, reducing the probability of high-temperature ferrite due to local Cr enrichment. At the same time, by precisely controlling the temperature and time of high-temperature diffusion homogenization treatment, the appearance of high-temperature δ-ferrite in a state of thermodynamic equilibrium is avoided, and the probability of cracking in forging is reduced.

The application also discloses some embodiments, step (2): performing high-temperature diffusion homogenization treatment on the stainless steel billet, and obtaining the primary product also includes the following steps:

Add pre-deformation treatment before high-temperature diffusion, the temperature of pre-deformation treatment is ≥1000°C, and the deformation amount is ≤30%;

And/or, the stainless steel billet is kept at high temperature at ≥ 1120° C., so as to achieve the purpose of making the distribution of interdendritic components more uniform.

Preferably, the temperature for high-temperature heat preservation is 1120-1230° C.; avoiding the occurrence of high-temperature ferrite due to excessive temperature.

And/or, the time for high temperature insulation is 10-25h. The billet obtained after the treatment in step (2) is the primary product without high temperature delta ferrite.

The application also discloses some embodiments, the average grain size of the stainless steel material is ≤15 μm, and the stainless steel material has no instability defects such as holes and cracks; the maximum size of inclusions in the stainless steel material is ≤5 μm.

The application also discloses some embodiments. In step (3): performing forging or rolling deformation treatment on the primary product obtained in step (2) includes the following steps:

The primary product is subjected to multi-fire cross-forging deformation treatment; in the multi-fire time forging deformation treatment, upsetting and elongation are alternately carried out; The deformation method is to obtain a high-temperature stainless steel material with fine and uniform grains and no instability defects such as microcracks. After the treatment in step (3), the average grain size of the material is ≤15 μm, and there is no instability defects such as holes and microcracks.

The present application also discloses some embodiments. In the multi-fire cross forging deformation treatment, the initial forging temperature is not lower than 1100° C., preferably, the initial forging temperature is 1100-1200° C. The forging temperature should not be too low. If the forging temperature is too low, microcracks and flow instability will easily form, and dynamic recrystallization will not completely occur. It is easy to form a mixed crystal structure, which is not good for subsequent performance. High-temperature ferrite is easily formed by local overheating, and high-temperature ferrite is easy to crack, which is not good for subsequent use. At the same time, if the forging temperature is too high, the grains after dynamic recrystallization will grow further, reducing its strength and toughness. The above temperature range is the best forging temperature.

The present application also discloses some embodiments. During the multi-fire cross forging deformation process, the total forging ratio of the billet is ≥7, so that the deformation of the entire billet is uniform; and/or, the deformation amount of the last fire time is ≥50%; Dynamic recrystallization needs to reach this critical deformation amount to fully occur, otherwise it is easy to form a mixed crystal structure, which is detrimental to subsequent performance. And/or, during the multi-fire cross forging deformation process, the final forging temperature is not lower than 950°C; and/or, during the multi-fire cross forging deformation process, the strain rate is not higher than 0.1s ^-1 .

The application of the above-mentioned final forging temperature and strain rate can prevent flow instability and microcracks caused by too low final forging temperature and too high strain rate. Through the coordinated control of the deformation temperature, strain rate and deformation amount during the multi-fire forging process, the micro-defects of the micro-holes can be healed while the grains are refined. The elimination of the micro-defects of the holes in this application refers to In the prepared material, the maximum size of hole-type micro-defects is ≤10 μm.

After the above step (3), the average grain size at 1/2 radius of the obtained forged material is ≤15 μm, and the maximum size of hole defects is ≤10 μm. The high-temperature stainless steel has fine and uniform grains and no instability defects such as microcracks.

The application also discloses some embodiments, the stainless steel material preparation method also includes the following steps:

After step (4): heating the stainless steel material obtained in step (3) to 780-950° C. for 2-5 hours, and then cooling to room temperature. It can prevent the precipitation of Cr ₂₃ C ₆ along the grain boundary of stainless steel and increase the tendency of intergranular corrosion. The cooling method can be air cooling.

The present application provides some examples, disclosing a stainless steel material, which is prepared by the above-mentioned stainless steel material preparation method; the carbon mass fraction of the stainless steel material fluctuates within ±0.015%; the maximum size of the inclusions of the stainless steel material is ≤5 μm, The number of inclusions per unit area does not exceed 5/mm ² ; the grain size at 1/2 radius of the stainless steel material is ≤15 μm; the size of the hole defect in the stainless steel material is ≤10 μm; and there is no high-temperature ferrite and microcracks, etc. stable defects.

1. The stainless steel material of this application is a high-temperature stainless steel with a carbon content of ≤0.15wt%, a chromium content of >13wt%, and a total alloy content of >30wt%. Due to the existence of ultra-high alloying elements in this type of steel, the viscosity of molten steel is large, the mushy area is large, the local solidification time is long, the dendrites are developed, and the microscopic segregation is serious, which not only makes it easy to produce inclusions that are difficult to remove during the solidification process, but also Segregation-type defects such as freckles often appear. At the same time, the high chromium element makes it easy to form high-temperature δ-ferrite during the high-temperature diffusion process, which is not conducive to subsequent uniform deformation. In order to solve this common problem, this application uses a series of technologies such as solidification of high-homogeneous self-consumable billet, high-temperature diffusion homogenization, and multi-fire forging deformation to achieve the fluctuation of the carbon mass fraction of high-temperature stainless steel within ±0.015%. , the maximum size of inclusions ≤ 5 μm, the number of inclusions per unit area does not exceed 5/mm ² , the average grain size at 1/2 radius ≤ 15 μm, the maximum size of hole defects ≤ 10 μm, and no high temperature δ-ferrite is found in the structure body, which promotes the cleanliness and homogenization of high-temperature stainless steel.

This application controls the reduction of component segregation, refines dendrites, and reduces inclusions by controlling the current-voltage ratio, strengthening cooling intensity, and reasonable riser cutting and peeling. On the one hand, the quality of the billet is guaranteed, and on the other hand, the material utilization rate is improved. , reducing the cost of materials.

The present application eliminates the brittle high-temperature delta-ferrite phase by controlling the parameters of high-temperature diffusion and homogenization of the slab, and reduces the probability of cracking in subsequent deformation.

In this application, through the thermal deformation method based on the coordinated control of deformation temperature, strain rate and deformation amount, it not only ensures that the crystal grains of the obtained material are fine and uniform, but also avoids defects such as flow instability and microcracks.

2. This application can effectively reduce the occurrence of instability defects such as microcracks and improve service life and safety and stability through low segregation of consumable billet, high temperature diffusion uniformity, and multi-fire forging deformation treatment. Among them, reasonable high-temperature homogenization parameters can improve the composition segregation caused by the solidification process and improve the uniformity of the composition. After multiple times of forging, the micro-defects left in the solidification process will be further healed, while ensuring that the grains are fine and uniform.

3. This application is suitable for high-quality preparation of bearing steel, gear steel, mold steel and other pipes and bars. This application improves the purity and homogenization of high-temperature stainless steel, and finally enables the rods or pipes such as bearing steel, gear steel, and mold steel to meet the high-speed, high-temperature, corrosion, heavy-load harsh working conditions and high fatigue life service performance requirements . This application provides an effective method for improving the inner quality of CSS-42L, Cronidur and other high-temperature stainless steels.

It has been verified that the high-temperature stainless steel obtained by the method of the present application has a dense matrix and fine and uniform grains, which can be used in the manufacture of parts in the fields of aviation, aerospace, tools, molds, gears, etc., and has the advantages of long service life, high temperature resistance, and high reliability.

Example

Example 1

This embodiment prepares a high-temperature stainless steel rod, and the specific preparation steps are as follows:

1) Preparation of high-temperature stainless steel low segregation double-vacuum self-consumption billets: double-vacuum preparation of cast billets, steel ingot material is CSS-42L steel, self-consumption ingot is 1.5t, steel ingot length is 1.5m, crucible diameter is 0.4m, and the control is stable. The current-voltage ratio in the arc phase is 320A/V and the cooling helium gas is introduced, the pressure is 0.2kpa, the riser is cut 0.25m, and the skin is peeled 15mm. The average inclusion size of the obtained slab is 3μm, and the maximum inclusion size is 5μm. Carbon The mass fraction fluctuates within ±0.008%.

2) Billet high-temperature diffusion and homogenization treatment: pre-deform the cast billet at a deformation temperature of 1000°C and a deformation amount of 10%, and then conduct heat preservation at a high temperature of 1120°C for 25 hours to make the interdendritic composition distribution more uniform.

3) Multi-firing cross-forging deformation billet opening treatment: In the forging process, the cross-deformation is realized by the two-upsetting and two-drawing process, the initial forging temperature is 1100°C, the forging ratio of the whole billet is 7, and the forging ratio of the last fire is 2 , the final forging temperature is 950°C, the forging strain rate is 0.1s ^-1 , the stainless steel material is heated to 950°C for 2 hours, and then air-cooled to room temperature. The average grain size at the 1/2 radius of the bar is 8 μm, the size of the hole defect is less than 10 μm, and there is no high-temperature ferrite and microcracks.

Example 2

This embodiment prepares a high-temperature stainless steel rod, and the specific preparation steps are as follows:

1) Preparation of high-temperature stainless steel low-segregation double-vacuum consumable billet: double-vacuum is used to prepare the cast billet. The material of the ingot is CSS-42L steel, the consumable ingot is 1.6t, the length of the ingot is 1m, and the diameter of the crucible is 0.5m. The phase current-voltage ratio is about 280A/V and cooling helium is introduced, the pressure is 1.5kpa, the riser is cut 0.18m, and the skin is peeled 18mm. The average inclusion size of the obtained slab is 2μm, and the maximum inclusion size is 5μm. The mass fraction fluctuates within ±0.009%.

2) Billet high-temperature diffusion and homogenization treatment: pre-deform the cast billet at a deformation temperature of 1000°C and a deformation amount of 10%, and then heat-preserve at a high temperature of 1170°C for 16 hours to make the distribution of interdendritic components more uniform.

3) Multi-firing cross-forging deformation billet opening treatment: In the forging process, two upsetting and two drawing processes are used to realize cross deformation, the initial forging temperature is 1150°C, the forging ratio of the whole billet is 8, and the forging ratio of the last fire is 3 , the final forging temperature is 950°C, the forging strain rate is 0.1s ^-1 , the stainless steel material is heated to 780°C for 5 hours, and then air-cooled to room temperature. The average grain size at the 1/2 radius of the bar is 12 μm, the size of the hole defect is less than 10 μm, and there is no high-temperature ferrite and microcracks.

Example 3

This embodiment prepares a high-temperature stainless steel rod, and the specific preparation steps are as follows:

1) Preparation of high temperature stainless steel low segregation double vacuum self-consumption billet: adopt double vacuum to prepare cast billet, steel ingot material is CSS-42L steel, self-consumption ingot is 1t, steel ingot length is 1m, crucible diameter is 0.4m, controlled arc stabilization stage The current-voltage ratio is about 260A/V and the cooling helium gas is passed through, and its pressure is 1.33kpa. The riser was cut 0.15m, and the skin was peeled 15mm. The average inclusion size of the obtained slab was 2 μm, the maximum inclusion size was 4 μm, and the carbon mass fraction fluctuated within ±0.012%.

2) Billet high-temperature diffusion homogenization treatment: pre-deform the casting billet at a deformation temperature of 1000°C and a deformation amount of 8%, and then heat-preserve at a high temperature of 1230°C for 10 hours to make the distribution of interdendritic components more uniform.

3) Multi-firing cross-forging deformation billet opening treatment: In the forging process, two upsetting and two drawing processes are used to realize cross deformation, the initial forging temperature is 1200°C, the forging ratio of the whole billet is 9, and the forging ratio of the last fire is 4 , the final forging temperature is 950°C, the forging strain rate is 0.1s ^-1 , the stainless steel material is heated to 900°C for 3 hours, and then air-cooled to room temperature. The average grain size at the 1/2 radius of the bar is 14 μm, the size of the hole defect is less than 10 μm, and there is no high-temperature ferrite and microcracks.

Example 4

This embodiment prepares a high-temperature stainless steel rod, and the specific preparation steps are as follows:

1) Preparation of high-temperature stainless steel low segregation double-vacuum consumable billet: double-vacuum is used to prepare cast billet, the steel ingot is made of CSS-42L steel, the consumable ingot is 3t, the length of the steel ingot is 1.3m, the diameter of the crucible is 0.6m, and the arc is controlled and stabilized The current-voltage ratio of the stage is 320A/V and cooling helium is introduced, the pressure is 1.33kpa, the riser is cut 0.25m, and the skin is peeled 21mm. The average inclusion size of the obtained slab is 3μm, the maximum inclusion size is 5μm, and the carbon mass Score fluctuations are within ±0.008%.

2) Billet high-temperature diffusion homogenization treatment: pre-deform the cast billet at a deformation temperature of 1050°C and a deformation amount of 30%, and then heat-preserve at a high temperature of 1150°C for 25 hours to make the distribution of components between dendrites more uniform.

3) Multi-firing cross-forging deformation billet opening treatment: In the forging process, two upsetting and two drawing processes are used to realize cross deformation, the initial forging temperature is 1100°C, the forging ratio of the whole billet is 9, and the forging ratio of the last fire is 4 , the final forging temperature is 980°C, the forging strain rate is 0.05s ^-1 , the stainless steel material is heated to 800°C for 5 hours, and then air-cooled to room temperature. The average grain size at the 1/2 radius of the bar is 8 μm, the size of the hole defect is less than 10 μm, and there is no high-temperature ferrite and microcracks.

Comparative example 1

The preparation method is basically the same as in Example 1, except that the current-voltage ratio in the arc stabilization stage is 220A/V. After testing the final bearing steel bar, it is found that the fluctuation of carbon content exceeds ±0.025%, and it is found that the carbon content exceeds ±0.025%. Inclusions, but the average grain size at 1/2 radius of the bar is 13 μm, the size of hole defects is less than 10 μm, and no high-temperature ferrite and microcracks are found.

Comparative example 2

The preparation method is basically the same as in Example 2, the difference is that before forging, the slab is kept at a high temperature of 1270°C for 16 hours. After testing the final bearing steel bar, the carbon content fluctuates around ±0.01%, and the average inclusion The size is 2μm, the largest inclusion size is 5μm, but the average grain size at 1/2 radius of the bar is 28μm, and 15μm microcracks and high-temperature ferrite are found.

Comparative example 3

The preparation method is basically the same as that of Example 3, except that the final forging temperature is 850°C, the last fire forging ratio is 4, the final bearing steel bar is tested, and the carbon content fluctuation is about ±0.013%, and the average inclusion The size is 3 μm, the largest inclusion size is 5 μm, and no high-temperature ferrite is found. The average grain size at 1/2 radius of the bar is 15 μm, but microcracks of 20 μm are found.

According to an embodiment of the present application, a stainless steel material is provided, and the stainless steel material is produced by the above-mentioned stainless steel material preparation method.

Those skilled in the art can easily understand that, on the premise of no conflict, the above-mentioned advantageous modes can be freely combined and superimposed.

The above are only preferred embodiments of the application, and are not intended to limit the application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the application should be included in the protection scope of the application. Inside. The above are only the preferred embodiments of the present application. It should be pointed out that for those of ordinary skill in the art, some improvements and modifications can be made without departing from the technical principle of the application. These improvements and modifications should also be It is regarded as the scope of protection of this application.

Claims (10)

1. The preparation method of the stainless steel material is characterized by comprising the following steps:

step (1): preparing a stainless steel blank by adopting a duplex process of vacuum smelting and vacuum self-consumption, and reducing component segregation by controlling solidification parameters; the mitigating compositional segregation via solidification parameter control comprises: controlling the maximum molten pool depth of a pasty zone of the consumable blank by controlling a current-voltage ratio so as to further reduce component segregation, so that the fluctuation of the carbon content fraction in the stainless steel blank is within +/-0.015 percent;

step (2): carrying out high-temperature diffusion homogenization treatment on the stainless steel blank to obtain a primary product;

and (3): and (3) forging or rolling deformation treatment is carried out on the primary product obtained in the step (2) to obtain the stainless steel material.

2. A method of manufacturing a stainless steel material according to claim 1, wherein said controlling a current to voltage ratio to control a consumable billet mush zone maximum weld puddle depth comprises the steps of:

the current-voltage ratio is controlled between 260-320A/V, so that the maximum molten pool depth of the consumable blank mushy zone is less than 250mm.

3. The method for preparing a stainless steel material according to claim 1, wherein during step (1), cooling helium gas is fed, and the pressure of the cooling helium gas is between 0.2 and 1.5 kpa.

4. The method for preparing a stainless steel material according to claim 1, wherein the stainless steel blank is subjected to riser cutting and/or skinning;

further, in the step (1), for the steel ingot with the length of 1-1.5m, the diameter of the crucible is 0.4-0.6m; after the vacuum self-consumption is finished, cutting a dead head of the stainless steel blank to a size of more than or equal to 0.15m; and/or the peeling thickness of the stainless steel blank is more than or equal to 15mm;

and/or, a consumable blank with the weight of 1t-3t is adopted in the vacuum consumable process; preferably, 1-1.5t of high-temperature stainless steel consumable blank is adopted in the vacuum consumable process.

5. A method of manufacturing a stainless steel material according to claim 1, wherein the primary product is a homogeneous structure without high temperature ferrite;

and/or, the step (2): the method comprises the following steps of carrying out high-temperature diffusion homogenization treatment on the stainless steel blank to obtain a primary product:

adding pre-deformation treatment before high-temperature diffusion, wherein the temperature of the pre-deformation treatment is more than or equal to 1000 ℃, and the deformation is less than or equal to 30%;

and/or, carrying out high-temperature heat preservation on the stainless steel blank at the temperature of more than or equal to 1120 ℃, preferably, the high-temperature heat preservation temperature is 1120-1230 ℃; and/or the high-temperature heat preservation time is 10-25h.

6. A method of producing a stainless steel material according to claim 1, characterized in that the average size of the grains of the stainless steel material is ≤ 15 μ ι η; the size of the holes of the stainless steel material is less than or equal to 10 mu m; the maximum size of inclusions in the stainless steel material is less than or equal to 5 mu m.

7. The method for preparing a stainless steel material according to claim 1, wherein in the step (3): the forging or rolling deformation treatment of the primary product obtained in the step (2) comprises the following steps:

performing multiple-fire forging deformation treatment on the primary product, wherein upsetting and lengthening are performed alternately in the multiple-fire forging deformation treatment;

further, in the multiple-fire forging deformation treatment, the initial forging temperature is not lower than 1100 ℃, and preferably, the initial forging temperature is 1100-1200 ℃.

8. The method for preparing a stainless steel material according to claim 7, wherein during the multiple-fire forging deformation treatment, the total forging ratio of the blank is not less than 7; and/or the deformation of the last fire is more than or equal to 50 percent;

and/or in the process of the multiple-fire forging deformation treatment, the temperature of finish forging is not lower than 950 ℃; and/or, during the multiple-fire forging deformation treatment, the strain rate is not higher than 0.1s ^-1 。

9. The method for preparing a stainless steel material according to claim 1, further comprising the steps of:

after the step (4): heating the stainless steel material obtained in the step (3) to 780-950 ℃, preserving heat for 2-5 hours, and then air-cooling to room temperature.

10. A stainless steel material, characterized in that it is produced by the method of manufacturing a stainless steel material according to any one of claims 1-8; the fluctuation of the carbon content fraction of the stainless steel material is within +/-0.015 percent, the maximum size of inclusions in the stainless steel material is less than or equal to 5 mu m, the size of crystal grains at the 1/2 radius part of the stainless steel material is less than or equal to 15 mu m, and the size of hole defects of the stainless steel material is less than or equal to 10 mu m; the stainless steel material is free of high-temperature ferrite;

and/or the stainless steel material contains less than or equal to 0.15wt% of carbon, more than 13wt% of chromium element and more than 30wt% of total alloy.

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