A cold-rolled annealing process for semi-hard precision alloy 4J29

Abstract

The application discloses a cold-rolling annealing process of semi-hard precision alloy 4J29, which comprises the following steps: S1, measuring hardening characteristics: the cold rolling work hardening curve of the semi-finished product of 4J29 alloy is measured by gradient rolling of 4J29 alloy samples; S2, front rolling: the semi-finished product of 4J29 alloy is rolled through eight passes, and the single-pass deformation is determined according to the cold rolling work hardening curve; S3, annealing: heating to 1000 DEG C in a protective atmosphere, and passing through a cooling section at a linear speed of 25 m / min; S4, rear rolling: the 4J29 alloy intermediate product cooled to normal temperature is cold-rolled again, and the rolling deformation is 12%, so that the semi-hard precision alloy 4J29 is obtained. Compared with the prior art, the application solves the problem that the current 4J29 precision alloy preparation method cannot prepare the material with a hardness value HV 1.0 higher than 210.

Description

Technical Field

[0001] This invention relates to the field of cold rolling and annealing technology, and in particular to a cold rolling and annealing process for a semi-hard precision alloy 4J29. Background Technology

[0002] 4J29 precision alloy is a high-performance iron-nickel-cobalt alloy with iron, nickel and cobalt as the main components. It has an extremely low coefficient of thermal expansion and is commonly used in precision sealing and electronic equipment.

[0003] The existing processing method for semi-hard precision alloy 4J29 is as follows: first, cold rolling is performed, followed by low-temperature annealing at 1000℃. The resulting semi-hard precision alloy 4J29 has a hardness value of HV. 1.0 Hardness values ​​below 210 cannot be directly obtained by simply adjusting heat treatment parameters. 1.0 Materials with a value higher than 210 cannot meet the user's HV requirements. 1.0 It reaches between 210 and 250. Summary of the Invention

[0004] The purpose of this invention is to provide a cold rolling and annealing process for semi-hard precision alloy 4J29, so as to solve the problem that the current 4J29 precision alloy preparation method cannot obtain a hardness value HV. 1.0 The problem of materials with a value higher than 210.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a cold rolling and annealing process for semi-hard precision alloy 4J29, comprising the following steps: S1. Hardening characteristics: The cold rolling hardening curve of the 4J29 alloy semi-finished product was measured by gradient rolling of the 4J29 alloy sample. S2. Pre-rolling: The 4J29 alloy semi-finished product is rolled in 8 passes to obtain the 4J29 alloy intermediate product. The total deformation amount does not exceed 65%. The deformation amount per pass is determined according to the cold rolling work hardening curve, and the deformation amount per pass is 6%-16%. S3. Annealing: The 4J29 alloy intermediate is fed into an annealing furnace, heated to 1000℃ in a protective atmosphere, and passed through the cooling section at a linear speed of 25m / min. S4. Subsequent rolling: The 4J29 alloy intermediate product, cooled to room temperature, is cold rolled again with a rolling deformation of 12% to obtain semi-hard precision alloy 4J29.

[0006] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In this invention, based on the cold rolling work hardening curve of the 4J29 alloy semi-finished product, the cold rolling parameters for the previous rolling are set. When the total deformation rate of the 4J29 alloy semi-finished product rolled in the previous rolling is close to the upper limit after 8 rolling passes, it is subjected to low-temperature annealing. After being heated to 1000°C in the annealing furnace, it is passed through the cooling section at a linear speed of 25 m / min for rapid cooling in a short time. The recrystallization process is suppressed by the ultra-fast cooling rate, forming fine grains. Rapid cooling hinders dislocation recombination, retains the cold rolling work hardening effect, and improves the surface hardness of the 4J29 alloy intermediate product. The heat-treated 4J29 alloy is rolled again. By combining heat treatment with cold rolling deformation, the hardness of the precision alloy is controlled, improving production efficiency and saving costs.

[0007] 2. In this invention, the deformation rate of a single pass during the preceding rolling process does not exceed 15.63%, which is strictly controlled within the safety threshold to avoid the risk of microcracks caused by a sudden increase in dislocation density, thus ensuring the integrity of the strip. The final rolling deformation rate is reduced to 6.72%, which improves the uniformity of the microstructure and reduces residual stress. Attached Figure Description

[0008] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a cold rolling work hardening curve of a semi-hard precision alloy 4J29 during the cold rolling annealing process.

[0010] Figure 2 The image shows the hardness test results of semi-hard precision alloy 4J29 obtained by cold rolling and annealing process. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0012] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. Example 1

[0013] Please see Figure 1-2 This invention provides a technical solution: a cold rolling and annealing process for semi-hard precision alloy 4J29, comprising the following steps: S1. Hardening characteristics measurement: By gradient rolling of 4J29 alloy samples, the cold rolling work hardening curve of 4J29 alloy semi-finished products was measured to clarify the critical deformation threshold and the strength-plasticity balance point. S2. Pre-rolling: The 0.35mm thick 4J29 alloy semi-finished product is rolled in 8 passes, with single-pass deformation rates of 8.57%, 15.63%, 14.81%, 14.35%, 13.71%, 12.35%, 10.07%, and 6.72% respectively. The material thickness changes from 0.35mm to 0.32mm, 0.27mm, 0.23mm, 0.197mm, 0.170mm, 0.149mm, 0.134mm, and 0.125mm. Finally, a 0.125mm thick 4J29 alloy intermediate product is obtained, with the total deformation not exceeding 65%. The single-pass deformation is determined based on the cold rolling work hardening curve, and the single-pass deformation is 6%-16%. S3. Annealing: The 4J29 alloy intermediate is fed into an annealing furnace, heated to 1000℃ in a protective atmosphere, and passed through the cooling section at a linear speed of 25m / min. S4. Subsequent rolling: The 4J29 alloy intermediate product cooled to room temperature is cold rolled again with a rolling deformation of 12%. After one rolling, a semi-hard precision alloy 4J29 with a thickness of 0.11 mm is obtained.

[0014] During the process of machining the 4J29 alloy semi-finished product from 0.35mm to 0.11mm, the annealed 4J29 alloy intermediate product with a thickness of 0.125mm is rolled with a single high deformation rate to introduce high dislocation density and grain refinement, which further improves the hardness of the 4J29 alloy.

[0015] Working Principle: Based on the cold rolling work hardening curve of 4J29 alloy semi-finished products, the cold rolling parameters for the preceding rolling process are set. After eight rolling passes, when the total deformation rate of the 4J29 alloy semi-finished product in the preceding rolling process approaches the upper limit, low-temperature annealing is performed. The product is heated to 1000℃ in the annealing furnace and then passed through the cooling section at a linear speed of 25m / min for rapid cooling in a short time. This ultra-fast cooling rate suppresses recrystallization, forming fine grains. Rapid cooling also hinders dislocation recombination, preserving the work hardening effect of cold rolling and improving the surface hardness of the 4J29 alloy intermediate product. The heat-treated 4J29 alloy is rolled again. By combining heat treatment with cold rolling deformation, the hardness of the precision alloy is controlled, improving production efficiency and saving costs. The deformation rate of a single pass in the preceding rolling process does not exceed 15.63%, strictly controlled within the safety threshold to avoid the risk of microcracks caused by a sudden increase in dislocation density, ensuring the integrity of the strip. The final rolling deformation rate decreases to 6.72%, improving the uniformity of the microstructure and reducing residual stress. Example 2

[0016] This embodiment further improves upon the above embodiment by making the following technical solution: In step S1, when the 4J29 alloy sample undergoes gradient rolling experiment and the cold rolling work hardening curve is measured, the hardness is measured after each rolling pass. A Vickers hardness tester (HV) is used to uniformly sample points on the rolling surface to test the hardness, and the average of 5 effective values ​​is taken for each group of deformation. This establishes a cold rolling work hardening curve plotted with deformation as the abscissa and hardness as the ordinate, accurately quantifying the work hardening law of the 4J29 alloy during the cold rolling process. Example 3

[0017] This embodiment further improves upon the above embodiment by making the following technical solution: In step S2, the 4J29 alloy semi-finished product undergoes pretreatment before rolling. The pretreatment includes removing oxide scale from the surface of the 4J29 alloy semi-finished product and surface cleaning. Specifically, the oxide scale of the 4J29 alloy semi-finished product is removed by surface shot blasting. The shot diameter is 0.2–0.6 mm, and the coverage is ≥98%, avoiding over-blasting while effectively removing the oxide scale and preventing surface defects caused by oxide scale being pressed into the matrix during cold rolling.

[0018] Furthermore, after shot blasting, the 4J29 alloy semi-finished product is passed into an ultrasonic cleaning tank. The ultrasonic cleaning tank contains a chlorine-free hydrocarbon solvent, and ultrasonic cleaning is performed for 2-5 minutes, so that the metal dust and oxide debris remaining from the shot blasting are removed through chemical cleaning.

[0019] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A cold rolling and annealing process for semi-hard precision alloy 4J29, characterized in that, Includes the following steps: S1. Hardening characteristics: The cold rolling hardening curve of the 4J29 alloy semi-finished product was measured by gradient rolling of the 4J29 alloy sample. S2. Pre-rolling: The 4J29 alloy semi-finished product is rolled in 8 passes to obtain the 4J29 alloy intermediate product. The total deformation amount does not exceed 65%. The deformation amount per pass is determined according to the cold rolling work hardening curve, and the deformation amount per pass is 6%-16%. S3. Annealing: The 4J29 alloy intermediate is fed into an annealing furnace, heated to 1000℃ in a protective atmosphere, and passed through the cooling section at a linear speed of 25m / min. S4. Subsequent rolling: The 4J29 alloy intermediate product, cooled to room temperature, is cold rolled again with a rolling deformation of 12% to obtain semi-hard precision alloy 4J29.

2. The cold rolling and annealing process for a semi-hard precision alloy 4J29 according to claim 1, characterized in that, In step S1, when the 4J29 alloy sample is subjected to gradient rolling experiment and the cold rolling work hardening curve is measured, the hardness is measured after each rolling pass. The Vickers hardness tester is used to uniformly sample points on the rolling surface to test the hardness, and the average of 5 effective values ​​is taken for each group of deformation.

3. The cold rolling and annealing process for a semi-hard precision alloy 4J29 according to claim 1, characterized in that, In step S2, during the eight rolling passes of the preceding rolling process, the single-pass deformation rates are 8.57%, 15.63%, 14.81%, 14.35%, 13.71%, 12.35%, 10.07%, and 6.72%, respectively.

4. The cold rolling and annealing process for a semi-hard precision alloy 4J29 according to claim 1, characterized in that, In step S4, the 4J29 alloy intermediate is rolled once to obtain semi-hard precision alloy 4J29.

5. The cold rolling and annealing process for a semi-hard precision alloy 4J29 according to claim 1, characterized in that, In step S2, the 4J29 alloy semi-finished product is pretreated before rolling. The pretreatment includes removing oxide scale from the surface of the 4J29 alloy semi-finished product and surface cleaning.

6. The cold rolling and annealing process for a semi-hard precision alloy 4J29 according to claim 5, characterized in that, In step S2, the oxide scale of the 4J29 alloy semi-finished product is removed by surface shot blasting. The diameter of the shot is 0.2–0.6 mm and the coverage is ≥98%.

7. The cold rolling and annealing process for a semi-hard precision alloy 4J29 according to claim 1, characterized in that, In step S2, after shot blasting, the 4J29 alloy semi-finished product is introduced into an ultrasonic cleaning tank containing a chlorine-free hydrocarbon solvent, and ultrasonic cleaning is performed for 2-5 minutes.

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