Preparation method of 304 stainless steel cold plate used as clean plate

Abstract

The invention belongs to the technical field of 300 series stainless steel cold plate preparation, and particularly relates to a preparation method of a 304 stainless steel cold plate used as a clean plate, which comprises the following specific steps: (1) rolling mill plate type control: controlling the deformation rate of the first pass to be less than or equal to 23%, and controlling the deformation rate of the last pass to be less than or equal to 10%; the first-pass speed is controlled to be smaller than or equal to 300 m / min, and the last-pass speed is controlled to be smaller than or equal The rolling oil flow is controlled to be larger than or equal to 7000 l / min in the first pass, larger than or equal to 6000 l / min in the middle pass and larger than or equal to 4000 l / min in the last pass; (2) cold line annealing specification: annealing and pickling processes of cold-rolled strip steel are controlled, and the plate temperature is controlled to be 1090-1110 DEG C; (3) leveling parameter specification: 40 rollers are used for an upper roller, and 60 rollers are used for a lower roller; and (4) withdrawal and straightening control is conducted, specifically, a pure tension mode is used, and the withdrawal and straightening elongation is controlled to be 1-1.5%. According to the method, the surface requirement of the clean plate is met by optimizing the rolling mill plate shape, cold line annealing, leveling pressure and withdrawal and straightening elongation parameters, production is stable, and the product percent of pass is increased.

Description

Technical Field

[0001] This invention belongs to the field of 300 series stainless steel cold-rolled sheet preparation technology, and particularly relates to a method for preparing 304 stainless steel cold-rolled sheet for use as a cleanroom plate. Background Technology

[0002] 304 cleanroom panels contain chromium, which forms a dense oxide film on the surface. This film is smooth and dense, with almost no pores, preventing the intrusion of corrosive media. Bloodstains, oil stains, and even microorganisms can be easily wiped away, and it is resistant to strong acid and alkali disinfectants. Because it is usually paired with a Class A fire-retardant core material, it meets overall non-combustible standards and has a high fire resistance rating, theoretically with a lifespan of over 20 years. Due to its outstanding performance, it is widely used in environments with high hygiene requirements, corrosion risks, or high cleanliness needs, primarily including: food processing, pharmaceuticals, electronics, chemical and corrosive environments, and extreme environments.

[0003] As a cleanroom board, its thickness is 0.35~0.6mm. It has very high requirements for the flatness and surface consistency of the board surface. The flatness of the board shape is required to be ≤2mm / m. After processing, there should be no distortion or refraction of light. The surface requirements are strict and there should be no color difference. These requirements pose a challenge to the quality control level of the manufacturing enterprise.

[0004] 300 series stainless steel cold-rolled sheets are rolled using a Sendzimir 20-roll mill, employing multi-pass reversible rolling. The cleanliness of the sheet surface is subject to stringent requirements. Inappropriate control of parameters such as the number of rolling passes, the number of rolls, and the rolling pressure during the rolling process leads to extremely high production difficulty and a low product qualification rate. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing 304 stainless steel cold-rolled plates for use as cleanroom plates, solving the problem of extremely difficult production and low product qualification rate caused by unreasonable control of parameters such as rolling passes, number of rolls, and rolling pressure during the rolling process.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing 304 stainless steel cold-rolled sheet for use as a cleanroom plate, the specific steps of which are as follows: (1) Rolling mill plate shape control Control the deformation rate of the first pass to ≤23% and the deformation rate of the last pass to ≤10%; control the speed of the first pass to ≤300m / min and the speed of the last pass to ≤400m / min; control the rolling oil flow rate to ≥7000l / min for the first pass, ≥6000l / min for the intermediate passes, and ≥4000l / min for the last pass. (2) Cold wire annealing specifications The annealing and pickling processes of cold-rolled strip steel are controlled, and the plate temperature is controlled at 1090~1110℃; (3) Leveling parameter specifications The upper roller uses 40 rollers, and the lower roller uses 60 rollers; (4) Straightening control Using pure tension mode, the elongation rate is controlled at 1-1.5%.

[0007] Preferably, step (2.) further includes a heat preservation time of 2 to 2.8 min / mm per millimeter of strip thickness.

[0008] Preferably, step (3) further includes leveling pressure controlled at 400-500 tons.

[0009] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) By controlling the shape of the rolling mill, a good foundation is laid for the final product shape, and the qualified level of the finished product shape is effectively improved; (2) By using the cold wire annealing specification, the strip steel is effectively dissolved, internal stress is released, and the uniformity of the microstructure is improved, providing room for further improvement of the subsequent plate shape; (3) By standardizing the flatness parameters, the defect of "stiffening" in the middle of the steel strip is minimized, and the plate shape is kept straight and the surface is uniform. (4) By controlling the tension, the plate shape is further improved so that the plate unevenness meets the requirements; (5) By optimizing the parameters of mill plate shape, cold line annealing, leveling pressure and tensile elongation, the requirements for clean plate surface are met, production is stabilized and the product qualification rate is improved. Detailed Implementation

[0010] The technical solution of the present invention will be described in detail below with reference to the embodiments.

[0011] The production process for one roll of 0.4*1219mm 304 stainless steel cold-rolled sheet is as follows: raw material annealing and pickling → rolling → cold annealing → leveling → tension straightening. The specific steps are as follows: The deformation rate of the first rolling pass is 22.5%, and the deformation rate of the last rolling pass is 9%; the speed of the first rolling pass is ≤260m / min, and the speed of the last rolling pass is ≤300m / min; the rolling oil flow rate is 7000l / min for the first rolling pass, 6500l / min for the intermediate rolling passes, and 4500l / min for the last rolling pass; the temperature of the cold wire plate is controlled at 1100℃, and the required heat preservation time per millimeter of cold wire plate thickness is 2.5min / mm; 40 rolls are used for the upper leveling roll and 60 rolls are used for the lower leveling roll, and the leveling pressure is 435 tons; the tension leveling uses pure tension mode, and the tension leveling elongation rate is 1.2%.

[0012] The flatness of this 304 cleanroom panel is 1.5mm / m, which meets the requirement of ≤2mm / m.

[0013] Using the method of this invention, 304 stainless steel cold-rolled plates for cleanroom applications were successfully prepared, with a plate shape qualification rate of 100% and a plate shape flatness of ≤2mm / m.

Claims

1. A method for preparing 304 stainless steel cold-rolled sheet for use as a cleanroom plate, characterized in that, The specific steps are as follows: (1) Rolling mill plate shape control Control the deformation rate of the first pass to ≤23% and the deformation rate of the last pass to ≤10%; control the speed of the first pass to ≤300m / min and the speed of the last pass to ≤400m / min; control the rolling oil flow rate to ≥7000l / min for the first pass, ≥6000l / min for the intermediate passes, and ≥4000l / min for the last pass. (2) Cold wire annealing specifications The annealing and pickling processes of cold-rolled strip steel are controlled, and the plate temperature is controlled at 1090~1110℃; (3) Leveling parameter specifications The upper roller uses 40 rollers, and the lower roller uses 60 rollers; (4) Straightening control Using pure tension mode, the elongation rate is controlled at 1-1.5%.

2. The method for preparing 304 stainless steel cold-rolled sheet for use as a cleanroom plate according to claim 1, characterized in that, The (2.) also includes a heat preservation time of 2 to 2.8 min / mm per millimeter of strip thickness.

3. The method for preparing 304 stainless steel cold-rolled sheet for use as a cleanroom plate according to claim 1, characterized in that, The (3) also includes leveling pressure control at 400-500 tons.