A method for improving the plate shape of high-alloy medium plate after quenching and tempering treatment
By precisely controlling the quenching and rolling process parameters, combined with high-pressure water removal of iron oxide scale and heated straightening, the problem of plate shape defects in the production of high alloy medium plates has been solved, and the production of high-performance steel plates has been realized.
Patent Information
- Application Number
- CN202211078388.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-09-05
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2042-09-05
AI Technical Summary
High-alloy steel plates are prone to defects such as warping, edge waviness, and sickle-shaped bends during production, and existing processes are difficult to improve them effectively. In particular, excessive straightening force in high-alloy steel plates can easily cause irreversible defects.
By precisely controlling the water ratio and quenching machine roller speed during the steel plate quenching process, segmented control of the finishing rolling start temperature, and combining high-pressure water removal of iron oxide scale, water-avoiding rolling, and heated straightening, heating uniformity is ensured, and the rolling and straightening processes are optimized.
It effectively reduces the unevenness of steel plates, improves plate shape defects, and has good steel plate performance. The impact performance at -196℃ is ≥100J, the yield strength is 600-630MPa, the tensile strength is 710-740MPa, and the cost is low without the need for additional equipment.
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Figure CN115582426B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of steel metallurgy, and particularly relates to a method for improving the plate shape of high-alloy medium plate after quenching and tempering treatment. BACKGROUND
[0002] In the steel metallurgy industry, the thickness of medium plate is usually 4-20 mm. In the production process of the steel plate, uneven heating or cooling of the upper and lower surfaces and both ends or both sides often occurs, which generates a large internal stress. For the steel plate with a thickness of 4-20 mm, the resistance to the stress generated in the production process is poor due to the thin thickness of the steel plate, and plate shape defects such as head and tail warping, edge wave and sickle bay often occur. The above-mentioned plate shape defects can only be rectified by a straightening machine.
[0003] For high-alloy steel plate, the steel plate is more sensitive to uneven heating and cooling and is prone to generate a larger internal stress in the rolling and heat treatment process due to the high content of alloy elements in the steel plate. In the production process of the steel plate, uneven heating of the billet and the steel plate and uneven cooling of the steel plate are prone to cause plate shape defects of the steel plate. Meanwhile, the steel plate has higher strength and hardness due to the solid solution strengthening, fine-grain strengthening and precipitation strengthening of the alloy elements. If plate shape defects occur in the rolling and heat treatment process of the steel plate, it is difficult to improve the plate shape of the steel plate by cold straightening in the later stage. If the straightening force is increased to forcibly straighten the steel plate, it is likely to generate irreparable plate shape defects. Warm straightening is a straightening method for high-alloy steel, but the performance of the steel plate is prone to be inconsistent after reheating, so the control of warm straightening is difficult. In summary, for high-alloy medium plate, the plate shape of the steel plate is difficult to control at the current process level, and it is very difficult to rescue the treatment after the occurrence of plate shape defects.
[0004] Therefore, for high-alloy medium plate, how to improve the plate shape and reduce the unevenness of the steel plate is extremely important for the smooth production of the steel plate. SUMMARY
[0005] The present application provides a method for improving the plate shape of high-alloy medium plate after quenching and tempering treatment. The present application improves the plate shape of high-alloy medium plate after quenching and tempering treatment and reduces the unevenness of the steel plate by accurately controlling the water ratio in the quenching process of the steel plate and the roller speed of the quenching machine and accurately controlling the rolling temperature in the section.
[0006] To solve the above-mentioned technical problems, the technical scheme adopted by the present application is as follows: a method for improving the plate shape of high-alloy medium plate after quenching and tempering treatment, the method comprising quenching, rolling, straightening and heating processes; the quenching process: the water ratio of the quenching machine is 1.35-1.45 and the roller speed of the quenching machine is 2-7 m / min in the quenching process of the steel plate; the rolling process: the rolling temperature in the finishing mill is 900-960 DEG C.
[0007] The quenching procedure of the application is as follows: 8mm≤T<12mm, roller speed 5-7m / min; 12mm≤T<18mm, roller speed 3-5m / min; 18mm≤T≤20mm, roller speed 2-3m / min, wherein T is the thickness of the steel plate, unit: mm.
[0008] The rolling procedure of the application is as follows: 8mm≤T<12mm, rough rolling temperature 940-960℃; 12mm≤T<18mm, 920-940℃; 18mm≤T≤20mm, 900-920℃, wherein T is the thickness of the steel plate, unit: mm.
[0009] The rolling procedure of the application is as follows: during the rolling process of the blank, high-pressure water is used to remove the surface iron oxide scale of the blank in each rough rolling pass, the pressure of the high-pressure water is 18-22MPa, and water-avoiding rolling is used in the finishing rolling.
[0010] The straightening procedure of the application is as follows: during the straightening process after rolling, the steel plate is straightened for 3-7 times, the straightening temperature is 300-400℃, and the straightening force is 2500-3000t.
[0011] The heating procedure of the application is as follows: during the heating process of the blank, the uniformity of the heating of the blank is ensured, the temperature difference between the head and tail is ≤20℃, and the temperature difference between the upper and lower surfaces is ≤10℃.
[0012] The steel plate obtained by the method of the application has good plate shape and no edge wave and head and tail warping plate shape defects, the unevenness of the steel plate is ≤6mm / 1m, and the unevenness of the steel plate is ≤10mm / 2m.
[0013] The steel plate obtained by the method of the application has impact performance ≥100J at -196℃, yield strength 600-630MPa, and tensile strength 710-740MPa.
[0014] The thickness specification of the steel plate obtained by the method of the application is 8-20mm.
[0015] The chemical composition and mass percentage of the steel plate obtained by the method of the application are as follows: C≤0.08%, Si≤0.35%, Mn≤0.8%, P≤0.008%, S≤0.005%, Ni: 8.70-9.50%, and the balance is iron and inevitable impurities.
[0016] The high-alloy medium plate of the application refers to GB / T 24510-2017, and the plate shape of the steel plate refers to GB / T 709-2019.
[0017] This invention improves the plate shape of high-alloy medium plates after quenching and tempering. By strictly controlling the water-to-water ratio and roller speed of the quenching machine during the quenching process, the internal stress generated during phase transformation can be reduced and the plate shape improved while ensuring the pass rate of steel plate performance. During the billet heating process, uniform heating is ensured. During the rolling process, high-pressure water is used in each rolling pass of the roughing mill to remove the iron oxide scale on the surface of the billet. Water-avoiding rolling is adopted for the finishing mill, and the starting temperature of the finishing mill is strictly controlled, which can optimize the rolled plate shape and reduce the plate shape defects generated during the rolling process. After rolling, the steel plate is straightened with a heated strip, which can improve the plate shape defects generated during the rolling process.
[0018] The beneficial effects of adopting the above technical solution are as follows: 1. The alloy steel plate produced by the method of the present invention is free from edge waviness and warping defects, and the flatness of the steel plate is controlled within 6mm / 1m and 10mm / 2m; 2. The steel plate obtained by the present invention has good performance, with an impact performance of ≥100J at -196℃, a yield strength of 600-630MPa, and a tensile strength of 710-740MPa; 3. The method of the present invention only innovates the production process without increasing equipment investment, resulting in lower production costs. Attached Figure Description
[0019] Figure 1 This is a morphological image of the steel plate after heat treatment in Example 1. Detailed Implementation
[0020] The present invention will be further described in detail below with reference to specific embodiments.
[0021] Example 1
[0022] The high-alloy medium plate obtained in this embodiment has the following steel composition as shown in Table 1 and a thickness of 8 mm.
[0023] Methods to improve the plate shape of high-alloy medium plates after quenching and tempering include quenching, rolling, straightening, and heating processes, with specific control parameters as follows:
[0024] 1) Quenching process: During the quenching process of steel plate, the water ratio of the quenching machine is 1.35 and the roller speed of the quenching machine is 7m / min.
[0025] 2) Rolling process: During the steel plate rolling process, high-pressure water is used to remove the iron oxide scale on the surface of the billet in each rolling pass of the rough rolling process. The pressure of the high-pressure water is 18MPa.
[0026] The finishing rolling process adopts water-avoidance rolling, and the starting temperature of the finishing rolling is 960℃.
[0027] 3) Straightening process: During the straightening process after steel plate rolling, straightening is performed 3 times, the straightening temperature is 300℃, and the straightening force is 2500t.
[0028] 4) Heating process: During the billet heating process, ensure that the billet is heated evenly, with a temperature difference of 20℃ between the head and tail and a temperature difference of 10℃ between the upper and lower surfaces.
[0029] The properties of the high-alloy medium plate obtained in this embodiment are shown in Table 2. Figure 1 The image shown is of the morphology of the steel plate after heat treatment in Example 1 (the images for other examples are similar and omitted). Figure 1 It can be seen that the steel plate has a good shape, without defects such as edge waviness, upturned ends, or sickle bends. The flatness of the steel plate is controlled at 6mm / 1m and 10mm / 2m.
[0030] Example 2
[0031] The high-alloy medium plate obtained in this embodiment has the following steel composition as shown in Table 1 and a thickness of 12 mm.
[0032] Methods to improve the plate shape of high-alloy medium plates after quenching and tempering include quenching, rolling, straightening, and heating processes, with specific control parameters as follows:
[0033] 1) Quenching process: During the quenching process of steel plate, the water ratio of the quenching machine is 1.45 and the roller speed of the quenching machine is 5m / min.
[0034] 2) Rolling process: During the steel plate rolling process, high-pressure water is used to remove the iron oxide scale on the surface of the billet in each rolling pass of the rough rolling process. The pressure of the high-pressure water is 22MPa.
[0035] The finishing rolling process adopts water-avoidance rolling, and the starting temperature of the finishing rolling is 940℃.
[0036] 3) Straightening process: During the straightening process after steel plate rolling, straightening is performed 7 times, the straightening temperature is 400℃, and the straightening force is 3000t.
[0037] 4) Heating process: During the billet heating process, ensure that the billet is heated evenly, with a temperature difference of 18℃ between the head and tail and a temperature difference of 9℃ between the upper and lower surfaces.
[0038] The high-alloy medium plate obtained in this embodiment has the following properties as shown in Table 2. It has a good plate shape and is free from defects such as edge waviness, upturned ends, and sickle bends. The flatness of the plate is controlled within 5mm / 1m and 8mm / 2m.
[0039] Example 3
[0040] The high-alloy medium plate obtained in this embodiment has the following steel composition as shown in Table 1 and a thickness of 18 mm.
[0041] Methods to improve the plate shape of high-alloy medium plates after quenching and tempering include quenching, rolling, straightening, and heating processes, with specific control parameters as follows:
[0042] 1) Quenching process: During the quenching process of steel plate, the water ratio of the quenching machine is 1.42 and the roller speed of the quenching machine is 3m / min.
[0043] 2) Rolling process: During the steel plate rolling process, high-pressure water is used to remove the iron oxide scale on the surface of the billet in each rolling pass of the rough rolling. The pressure of the high-pressure water is 21MPa.
[0044] The finishing rolling process adopts water-avoidance rolling, and the starting temperature of the finishing rolling is 920℃.
[0045] 3) Straightening process: During the straightening process after steel plate rolling, straightening is performed 6 times, the straightening temperature is 370℃, and the straightening force is 2680t.
[0046] 4) Heating process: During the billet heating process, ensure that the billet is heated evenly, with a temperature difference of 17℃ between the head and tail and a temperature difference of 7℃ between the upper and lower surfaces.
[0047] The high-alloy medium plate obtained in this embodiment has the following properties as shown in Table 2. It has a good plate shape and is free from defects such as edge waviness, upturned ends, and sickle bends. The flatness of the plate is controlled at 6mm / 1m and 9mm / 2m.
[0048] Example 4
[0049] The high-alloy medium plate obtained in this embodiment has the following steel composition as shown in Table 1 and a thickness of 20 mm.
[0050] Methods to improve the plate shape of high-alloy medium plates after quenching and tempering include quenching, rolling, straightening, and heating processes, with specific control parameters as follows:
[0051] 1) Quenching process: During the quenching process of steel plate, the water ratio of the quenching machine is 1.40 and the roller speed of the quenching machine is 2m / min.
[0052] 2) Rolling process: During the steel plate rolling process, high-pressure water is used to remove the iron oxide scale on the surface of the billet in each rolling pass of the rough rolling. The pressure of the high-pressure water is 19MPa.
[0053] The finishing rolling process adopts water-avoidance rolling, and the starting temperature of the finishing rolling is 900℃.
[0054] 3) Straightening process: During the straightening process after steel plate rolling, straightening is performed 5 times, the straightening temperature is 490℃, and the straightening force is 2706t.
[0055] 4) Heating process: During the billet heating process, ensure that the billet is heated evenly, with a temperature difference of 16℃ between the head and tail and a temperature difference of 6℃ between the upper and lower surfaces.
[0056] The high-alloy medium plate obtained in this embodiment has the following properties as shown in Table 2. It has a good plate shape and is free from defects such as edge waviness, upturned ends, and sickle bends. The flatness of the plate is controlled at 3mm / 1m and 8mm / 2m.
[0057] Example 5
[0058] The high-alloy medium plate obtained in this embodiment has the following steel composition as shown in Table 1 and a thickness of 16 mm.
[0059] Methods to improve the plate shape of high-alloy medium plates after quenching and tempering include quenching, rolling, straightening, and heating processes, with specific control parameters as follows:
[0060] 1) Quenching process: During the quenching process of steel plate, the water ratio between the bottom and top of the quenching machine is 1.36, and the roller speed of the quenching machine is 4.4m / min.
[0061] 2) Rolling process: During the steel plate rolling process, high-pressure water is used to remove the iron oxide scale on the surface of the billet in each rolling pass of the rough rolling mill. The pressure of the high-pressure water is 19.6 MPa.
[0062] The finishing rolling process adopts water-avoidance rolling, and the starting temperature of the finishing rolling is 934℃.
[0063] 3) Straightening process: During the straightening process after steel plate rolling, straightening is performed 6 times, the straightening temperature is 318℃, and the straightening force is 2670t.
[0064] 4) Heating process: During the billet heating process, ensure that the billet is heated evenly, with a temperature difference of 17℃ between the head and tail and a temperature difference of 4℃ between the upper and lower surfaces.
[0065] The high-alloy medium plate obtained in this embodiment has the following properties as shown in Table 2. It has a good plate shape and is free from defects such as edge waviness, upturned ends, and sickle bends. The flatness of the plate is controlled at 3mm / 1m and 8mm / 2m.
[0066] Example 6
[0067] The high-alloy medium plate obtained in this embodiment has the following steel composition as shown in Table 1 and a thickness of 11 mm.
[0068] Methods to improve the plate shape of high-alloy medium plates after quenching and tempering include quenching, rolling, straightening, and heating processes, with specific control parameters as follows:
[0069] 1) Quenching process: During the quenching process of steel plate, the water ratio between the bottom and top of the quenching machine is 1.41, and the roller speed of the quenching machine is 5.9m / min.
[0070] 2) Rolling process: During the steel plate rolling process, high-pressure water is used to remove the iron oxide scale on the surface of the billet in each rolling pass of the rough rolling mill. The pressure of the high-pressure water is 21.6 MPa.
[0071] The finishing rolling process adopts water-avoidance rolling, and the starting temperature of the finishing rolling is 951℃.
[0072] 3) Straightening process: During the straightening process after steel plate rolling, straightening is performed 5 times, the straightening temperature is 387℃, and the straightening force is 2930t.
[0073] 4) Heating process: During the billet heating process, ensure that the billet is heated evenly, with a temperature difference of 15℃ between the head and tail and a temperature difference of 8℃ between the upper and lower surfaces.
[0074] The high-alloy medium plate obtained in this embodiment has the following properties as shown in Table 2. It has a good plate shape and is free from defects such as edge waviness, upturned ends, and sickle bends. The flatness of the plate is controlled within 5mm / 1m and 9mm / 2m.
[0075] Example 7
[0076] The high-alloy medium plate obtained in this embodiment has the following steel composition as shown in Table 1 and a thickness of 19 mm.
[0077] Methods to improve the plate shape of high-alloy medium plates after quenching and tempering include quenching, rolling, straightening, and heating processes, with specific control parameters as follows:
[0078] 1) Quenching process: During the quenching process of steel plate, the water ratio between the bottom and top of the quenching machine is 1.44, and the roller speed of the quenching machine is 2.3m / min.
[0079] 2) Rolling process: During the steel plate rolling process, high-pressure water is used to remove the iron oxide scale on the surface of the billet in each rolling pass of the rough rolling mill. The pressure of the high-pressure water is 20.9 MPa.
[0080] The finishing rolling process adopts water-avoidance rolling, and the starting temperature of the finishing rolling is 913℃.
[0081] 3) Straightening process: During the straightening process after steel plate rolling, the straightening is carried out 4 times, the straightening temperature is 391℃, and the straightening force is 2590t.
[0082] 4) Heating process: During the billet heating process, ensure that the billet is heated evenly, with a temperature difference of 16℃ between the head and tail and a temperature difference of 8℃ between the upper and lower surfaces.
[0083] The high-alloy medium plate obtained in this embodiment has the following properties as shown in Table 2. It has a good plate shape and is free from defects such as edge waviness, upturned ends, and sickle bends. The flatness of the plate is controlled within 5mm / 1m and 9mm / 2m.
[0084] Example 8
[0085] The high-alloy medium plate obtained in this embodiment has the following steel composition as shown in Table 1 and a thickness of 13 mm.
[0086] Methods to improve the plate shape of high-alloy medium plates after quenching and tempering include quenching, rolling, straightening, and heating processes, with specific control parameters as follows:
[0087] 1) Quenching process: During the quenching process of steel plate, the water ratio between the bottom and top of the quenching machine is 1.44, and the roller speed of the quenching machine is 3.9m / min.
[0088] 2) Rolling process: During the steel plate rolling process, high-pressure water is used to remove the iron oxide scale on the surface of the billet in each rolling pass of the rough rolling mill. The pressure of the high-pressure water is 21.2 MPa.
[0089] The finishing rolling process adopts water-avoidance rolling, and the starting temperature of the finishing rolling is 929℃.
[0090] 3) Straightening process: During the straightening process after steel plate rolling, straightening is performed 4 times, the straightening temperature is 324℃, and the straightening force is 2780t.
[0091] 4) Heating process: During the billet heating process, ensure that the billet is heated evenly, with a temperature difference of 9℃ between the head and tail and a temperature difference of 6℃ between the upper and lower surfaces.
[0092] The high-alloy medium plate obtained in this embodiment has the following properties as shown in Table 2. It has a good plate shape and is free from defects such as edge waviness, upturned ends, and sickle bends. The flatness of the plate is controlled at 4mm / 1m and 7mm / 2m.
[0093] Table 1. Steel plate composition (wt / %) in Examples 1-8
[0094]
[0095] Table 2 Performance of steel plates in Examples 1-8
[0096]
[0097] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for improving the plate shape of high-alloy medium plate after quenching and tempering treatment, characterized in that: The method comprises quenching, rolling, straightening, and heating processes; In the quenching process, the ratio of water flow rate to the speed of the quenching machine is 1.35-1.45, and the speed of the quenching machine is 2-7 m / min. In the rolling process, the rough rolling temperature is 900-960℃. In the quenching process, the speed of the quenching machine is controlled as follows: 8mm≤T<12mm, 5-7 m / min; 12mm≤T<18mm, 3-5 m / min; 18mm≤T≤20mm, 2-3 m / min, wherein T is the thickness of the steel plate in mm. In the rolling process, the rough rolling temperature is controlled as follows: 8mm≤T<12mm, 940-960℃; 12mm≤T<18mm, 920-940℃; 18mm≤T≤20mm, 900-920℃, wherein T is the thickness of the steel plate in mm. The steel plate obtained by the method has good plate shape, no edge wave and head and tail warping defects, and the unevenness of the steel plate is ≤6mm / 1m and ≤10mm / 2m. The steel plate obtained by the method has impact performance of ≥100J at -196℃, yield strength of 600-630MPa, and tensile strength of 710-740MPa. The steel plate obtained by the method has the following chemical composition and mass percentage: C≤0.08%, Si:≤0.35%, Mn≤0.8%, P≤0.008%, S≤0.005%, Ni: 8.70-9.50%, and the balance being iron and inevitable impurities.
2. The method for improving the plate shape after the quenching and tempering treatment of high-alloy medium plates according to claim 1, characterized in that: In the rolling process, high-pressure water with a pressure of 18-22MPa is sprayed on the surface of the blank to remove the iron oxide scale during rough rolling, and water is avoided during finish rolling.
3. The method for improving the plate shape after the quenching and tempering treatment of high-alloy medium plates according to claim 1 or 2, characterized in that: In the straightening process, the steel plate is straightened for 3-7 times at a temperature of 300-400℃ and a force of 2500-3000t.
4. The method for improving the plate shape after the quenching and tempering treatment of high-alloy medium plates according to claim 1 or 2, characterized in that: In the heating process, the temperature difference between the head and tail is ≤20℃, and the temperature difference between the upper and lower surfaces is ≤10℃.
5. The method for improving the plate shape after the quenching and tempering treatment of high-alloy medium plates according to claim 1 or 2, characterized in that: The steel plate obtained by the method has a thickness of 8-20mm.
Citation Information
Patent Citations
On-line quenching and plate shape controlling technology for 12MnNiVR steel plate
CN103555914A
Manufacturing method for low-cost, high-toughness and thin-specification 9Ni steel plate
CN106191661A