Cold rolling process of 625 alloy for high-temperature reactor

Abstract

The invention discloses a cold rolling process for a 625 alloy for a high-temperature reactor. The cold rolling process comprises the steps that S1, coping is conducted, specifically, oxide surface defects on the surface of a 625 alloy strip blank are removed; s2, primary rolling is conducted, specifically, the 625 alloy strip blank is fed into a rolling mill to be rolled for the first time, the deformation of a single rolling process ranges from 50% to 80%, and a blooming strip is obtained; s3, cleaning is conducted; s4, annealing is conducted; s5, primary edge cutting; s6, secondary rolling is conducted, specifically, the primarily-rolled strip is fed into the rolling mill to be rolled for the second time, the single-rolling-process deformation is larger than 50%, and a finish-rolled strip is obtained; s7, heat treatment is conducted, specifically, the finish-rolled strip is subjected to continuous annealing treatment at the temperature of 980-1200 DEG C, and rapid cooling is conducted; s8, withdrawal and straightening are conducted, specifically, the finish rolling strip which is not completely cooled after heat treatment is subjected to withdrawal and straightening through withdrawal and straightening equipment; and S9, carrying out secondary trimming to obtain a 625 alloy finished product strip. Compared with the prior art, the problem that the mechanical property of an existing finished strip at high temperature cannot meet the requirement is solved.

Description

Technical Field

[0001] The invention relates to the technical field of cold rolling, and in particular to a cold rolling process of a 625 alloy for high temperature stacking. Background Art

[0002] The process of cold rolling production generally includes raw material preparation, pickling, rolling, degreasing, annealing (heat treatment), finishing, etc. Cold rolled products have high packaging requirements to prevent the surface of the product from being scratched during transportation.

[0003] 625 nickel-based alloy has excellent corrosion resistance and oxidation resistance, good tensile properties and fatigue resistance between -196℃ and 980℃, and is widely used in aviation engine parts, aerospace structural components, chemical equipment, etc.

[0004] In the existing processing of cold-rolled strip of 625 nickel-based alloy, the cold rolling quality is not high, resulting in the mechanical properties of the finished strip at high temperature failing to meet the requirements. Summary of the invention

[0005] The purpose of the present invention is to provide a 625 alloy cold rolling process for high temperature stacking, so as to solve the problem that the mechanical properties of the finished strips obtained by the existing cold rolling process at high temperatures cannot meet the requirements.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme: a cold rolling process of 625 alloy for high temperature stack, comprising the following steps:

[0007] S1. Grinding: Unwinding the 625 alloy hot-rolled coil to obtain a 625 alloy strip, removing 0.1 mm to 0.5 mm of the thickness of the 625 alloy strip by grinding, and removing oxide surface defects on the surface of the 625 alloy strip;

[0008] S2, primary rolling: feeding the 625 alloy strip into the rolling mill for the first rolling, with a single rolling deformation of 50% to 80%, to obtain the initial rolled strip;

[0009] S3, cleaning: remove the lubricating grease coated on the surface of the 625 alloy strip during the first rolling process to avoid contamination of the surface of the initial rolled strip during annealing;

[0010] S4, Annealing: The initial rolled strip is subjected to intermediate annealing to eliminate the work hardening caused by cold deformation through recrystallization, so as to restore the plasticity of the material and reduce the deformation resistance of the metal;

[0011] S5, primary trimming: cutting off the edges on both sides of the initially rolled strip;

[0012] S6, secondary rolling: the primary rolled strip is sent to the rolling mill for secondary rolling, and the deformation amount of a single rolling process is greater than 50%, so as to obtain a more complete organizational structure and obtain a finished rolled strip;

[0013] S7, heat treatment: the finished strip is subjected to continuous annealing treatment at 980°C to 1200°C, and then rapidly cooled;

[0014] S8, straightening: use straightening equipment to straighten the finished strip that has not been completely cooled after heat treatment;

[0015] S9. Secondary trimming: According to the width requirements, the edge of the finished strip is cut off to obtain the 625 alloy finished strip.

[0016] As a further description of the above technical solution:

[0017] In step S1, a surface grinder is used to grind the surface of the 625 hot-rolled strip, and after grinding, the surface of the 625 hot-rolled strip is subjected to wire drawing.

[0018] As a further description of the above technical solution:

[0019] In step S5, the width D1 of the initially rolled strip after the first trimming is smaller than the set width D of the 625 alloy finished strip.

[0020] In step S2, after the 625 alloy strip is fed into the rolling mill, it is continuously rolled for multiple passes, and the deformation amount of a single rolling pass is 10%-20%.

[0021] In step S6, the initially rolled strip is fed into the rolling mill for the second rolling, and then continuously rolled for multiple passes, with the deformation of a single rolling pass being 5%-10% and the roller surface roughness Ra≤0.2 μm.

[0022] As a further description of the above technical solution:

[0023] In step S8, during the straightening process, the straightening stress is controlled at 180 MPa to 230 MPa, the straightening elongation coefficient is controlled at 0.5% to 1.2%, and the straightening speed is 20 m / min to 40 m / min.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] 1. In the present invention, after the 625 alloy hot-rolled coil raw material is subjected to two rolling and straightening treatments, a 625 alloy finished strip with a high-strength structure is obtained, and the yield strength, tensile strength and elongation are significantly improved, so that the material exhibits good high-temperature comprehensive mechanical properties at a high temperature of 750°C to 950°C, maintains a high-strength structure and excellent thermal stability, and the surface is not easily scratched, which is convenient for transportation.

[0026] 2. In the present invention, the tensioning stress is controlled at 180MPa-230MPa, the tensioning elongation coefficient is controlled at 0.5%-1.2%, and the tensioning speed is 20m / min-40m / min. The finished strip that is not completely cooled after heat treatment is tensioned and straightened by the tensioning equipment to achieve fine shaping and ensure flatness of the plate shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is a flow chart of the cold rolling process of 625 alloy for high temperature stacking. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] See also Figure 1 The present invention provides a technical solution: a cold rolling process of 625 alloy for high temperature stack, comprising the following steps:

[0033] S1. Grinding: Unwinding the 625 alloy hot-rolled coil to obtain a 625 alloy strip, removing 0.1 mm to 0.5 mm of the thickness of the 625 alloy strip by grinding, and removing oxide surface defects on the surface of the 625 alloy strip;

[0034] S2, primary rolling: feeding the 625 alloy strip into the rolling mill for the first rolling, with a single rolling deformation of 50% to 80%, to obtain the initial rolled strip;

[0035] S3, cleaning: remove the lubricating grease coated on the surface of the 625 alloy strip during the first rolling process to avoid contamination of the surface of the initial rolled strip during annealing;

[0036] S4, Annealing: The initial rolled strip is subjected to intermediate annealing to eliminate the work hardening caused by cold deformation through recrystallization, so as to restore the plasticity of the material and reduce the deformation resistance of the metal;

[0037] S5, primary trimming: cutting off the edges on both sides of the initially rolled strip;

[0038] S6, secondary rolling: the primary rolled strip is sent to the rolling mill for secondary rolling, and the deformation amount of a single rolling process is greater than 50%, so as to obtain a more complete organizational structure and obtain a finished rolled strip;

[0039] S7, heat treatment: the finished strip is subjected to continuous annealing treatment at 980°C to 1200°C, and then rapidly cooled;

[0040] S8, straightening: use straightening equipment to straighten the finished strip that has not been completely cooled after heat treatment;

[0041] S9. Secondary trimming: According to the width requirements, the edge of the finished strip is cut off to obtain the 625 alloy finished strip.

[0042] In step S2, after the 625 alloy strip is fed into the rolling mill, it is continuously rolled for multiple passes, and the deformation amount of a single rolling pass is 10%-20%.

[0043] In step S6, the strip is fed into the rolling mill for the second rolling, and then rolled continuously for multiple passes. The deformation of a single rolling pass is 5%-10%, and the roll surface roughness Ra≤0.2μm. The surface of the working roll is fine, ensuring that the surface of the finished product after rolling is uniform.

[0044] Working principle: After two rolling and straightening treatments, the 625 alloy hot-rolled coil raw material is treated to obtain a 625 alloy finished strip with a high-strength structure. The yield strength, tensile strength and elongation are significantly improved, so that the material exhibits good high-temperature comprehensive mechanical properties at high temperatures of 750℃ to 950℃, maintains a high-strength structure and excellent thermal stability, and the surface is not easily scratched, making it easy to transport.

[0045] Example 2

[0046] This embodiment further provides the following improved technical solutions based on the above embodiment: In step S1, a surface grinder is used to grind the surface of the 625 hot-rolled strip, and after grinding, the surface of the 625 hot-rolled strip is subjected to wire drawing. The grinding marks are removed to ensure that the 625 hot-rolled strip is rolled uniformly at all locations during the subsequent rolling process, and the performance of the rolled strip is uniform at all locations.

[0047] In addition, in step S1, the 625 alloy strip is dephosphorized before grinding. When cleaning the surface of the 625 alloy strip, dust attached to the surface is first removed by an air gun, and then dephosphorization is performed to effectively ensure the grinding quality.

[0048] Example 3

[0049] This embodiment further provides the following improved technical solutions based on the above embodiment: in step S5, the width D1 of the initially rolled strip after the first trimming is smaller than the set width D of the 625 alloy finished strip, so that the strip has sufficient deformation space during the second rolling, the thickness after the second rolling is effectively controlled, the organizational structure strength is improved, and the rolling effect is improved.

[0050] Example 4

[0051] This embodiment further provides the following improved technical solutions based on the above embodiment: In step S7, the finished strip is cooled to 80° C. by air cooling or water cooling. The cooling speed is controlled and the strip is not completely cooled to room temperature to facilitate subsequent straightening.

[0052] Example 5

[0053] This embodiment further provides the following improved technical solutions based on the above embodiment: in step S8, the tensioning stress is controlled at 180MPa-230MPa, the tensioning elongation coefficient is controlled at 0.5%-1.2%, and the tensioning speed is 20m / min-40m / min. The finished strip that has not been completely cooled after heat treatment is tensioned and straightened by the tensioning equipment to achieve fine shaping and ensure flatness of the plate shape.

[0054] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A cold rolling process of 625 alloy for high temperature stack, characterized in that: The following steps are involved: S1. Grinding: Unwinding the 625 alloy hot-rolled coil to obtain a 625 alloy strip, and removing oxide surface defects on the surface of the 625 alloy strip; S2, primary rolling: feeding the 625 alloy strip into the rolling mill for the first rolling, with a single rolling deformation of 50% to 80%, to obtain the initial rolled strip; S3, cleaning: removing the lubricating grease coated on the surface of the 625 alloy strip during the first rolling process; S4, Annealing: The initial rolled strip is subjected to intermediate annealing to eliminate the work hardening caused by cold deformation through recrystallization; S5, primary trimming: cutting off the edges on both sides of the initially rolled strip; S6, secondary rolling: the primary rolled strip is sent to the rolling mill for secondary rolling, and the deformation amount of a single rolling process is greater than 50%, so as to obtain a finished rolled strip; S7, heat treatment: the finished strip is subjected to continuous annealing at 980℃~1200℃ and rapid cooling: S8, straightening: use straightening equipment to straighten the finished strip that has not been completely cooled after heat treatment; S9. Secondary trimming: According to the width requirements, the edge of the finished strip is cut off to obtain the 625 alloy finished strip.

2. The cold rolling process of 625 alloy for high temperature reactor according to claim 1, characterized in that: In the step S1, a surface grinder is used to grind the surface of the 625 hot-rolled strip, and after grinding, the surface of the 625 hot-rolled strip is subjected to wire drawing.

3. The cold rolling process of 625 alloy for high temperature reactor according to claim 2, characterized in that: In the step S1, the 625 alloy strip is dephosphorized before grinding.

4. The cold rolling process of 625 alloy for high temperature reactor according to claim 1, characterized in that: In the step S5, the width D1 of the initially rolled strip after the first trimming is smaller than the set width D of the 625 alloy finished strip.

5. The cold rolling process of 625 alloy for high temperature reactor according to claim 1, characterized in that: In step S2, after the 625 alloy strip is fed into the rolling mill, it is continuously rolled for multiple passes, and the deformation amount of a single rolling pass is 10%-20%.

6. The cold rolling process of 625 alloy for high temperature reactor according to claim 1, characterized in that: In step S6, the initially rolled strip is fed into the rolling mill for the second rolling, and then continuously rolled for multiple passes, with the deformation of a single rolling pass being 5%-10% and the roller surface roughness Ra≤0.2 μm.

7. The cold rolling process of 625 alloy for high temperature reactor according to claim 1, characterized in that: In step S7, the finished strip is cooled to 80° C. by air cooling or water cooling.

8. The cold rolling process of 625 alloy for high temperature reactor according to claim 1, characterized in that: In the step S8, during the straightening process, the straightening stress is controlled at 180 MPa to 230 MPa, the straightening elongation coefficient is controlled at 0.5% to 1.2%, and the straightening speed is 20 m / min to 40 m / min.

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