Thin-gauge quenched plate as well as preparation method and product thereof

Abstract

The invention provides a thin-gauge quenched plate and a preparation method and a product thereof, and the method for preparing the thin-gauge quenched plate comprises the following steps: S10, providing a to-be-quenched steel plate with the thickness smaller than 4 mm; s20, the to-be-quenched steel plate is subjected to edge cutting treatment, so that the to-be-quenched steel plate obtained after edge cutting is obtained, and the edge cutting treatment comprises the step that the two sides of the to-be-quenched steel plate in the width direction are subjected to edge cutting by 10-30 mm correspondingly; s30, shot blasting treatment is conducted on the to-be-quenched steel plate obtained after edge cutting, so that an oxide layer on the surface of the to-be-quenched steel plate is removed, and the to-be-quenched steel plate obtained after shot blasting is obtained; wherein in the shot blasting treatment, the shot blasting frequency is 2-4 times, the diameter of each shot is 0.6-0.8 mm, the striking angle is 40-50 degrees, and the steel plate conveying speed is 1-3 m / min; and S40, the to-be-quenched steel plate obtained after shot blasting is subjected to quenching and cold straightening treatment, and the thin-specification quenched plate is obtained. The thin-gauge quenched plate has a good plate shape, and further machining and utilization of the thin-gauge quenched plate are facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of steel plate production, and in particular to a thin-gauge quenched plate and a preparation method and product thereof. Background Art

[0002] With the trend of lightweight and ultra-high strengthening of engineering machinery, the demand for ultra-thin quenched plates with a thickness of ≤4mm is increasing. With the automation of customer processing technology, the requirements for plate shape are becoming more and more stringent. At present, the straightness requirement is ≤3mm / m, and some high-end products require ≤2mm / m. Such ultra-thin quenched plates are prone to defects such as edge waves and middle waves during rolling, and the instability of the rolled plate shape and uneven cooling will also affect the thickness and composition of the oxide on the steel plate surface, thereby affecting the quenched plate shape control. Therefore, it is necessary to improve the plate shape of thin quenched plates. Summary of the invention

[0003] The present application provides a thin-gauge quenched plate and a preparation method and product thereof, aiming to obtain a quenched plate with a good plate shape by improving the process of thin-gauge quenched plate.

[0004] In a first aspect, the present application provides a method for preparing a thin gauge quenched plate, comprising the following steps:

[0005] S10: Provide steel plates to be quenched with a thickness of ≤4mm;

[0006] S20: performing edge trimming on the steel plate to be quenched to obtain an edge trimmed steel plate to be quenched, wherein the edge trimming includes trimming 10 to 30 mm on both sides of the steel plate to be quenched in the width direction;

[0007] S30: Shot blasting the trimmed steel plate to be quenched to remove the oxide layer on the surface of the steel plate to be quenched, so as to obtain the steel plate to be quenched after shot blasting; wherein, in the shot blasting, the shot blasting times are 2 to 4 times, the shot diameter is 0.6 to 0.8 mm, the striking angle is 40° to 50°, and the steel plate transmission speed is 1 to 3 m / min;

[0008] S40: quenching and cold straightening the steel plate to be quenched after shot blasting to obtain a thin quenched plate.

[0009] According to the present application, the method is particularly suitable for the production of thin-gauge quenched plates with a thickness of ≤4 mm. The steel plates are trimmed and shot blasted before quenching, so that the plate shape and surface quality of the steel plates before quenching are well controlled, thereby reducing the adverse effects of subsequent quenching treatment on the plate shape. Furthermore, thin-gauge quenched plates with low flatness can be obtained only through simple cold straightening treatment, which has a good plate shape and is conducive to its further processing and utilization.

[0010] In some embodiments of the present application, in S10, the thickness of the steel plate to be quenched is not less than 2 mm.

[0011] In some embodiments of the present application, in S20, the width of the steel plate to be quenched after trimming is less than 2 m.

[0012] In some embodiments of the present application, in S30, the straightness of the steel plate to be quenched after shot blasting does not exceed 8 mm / m.

[0013] In some embodiments of the present application, in S40, the quenching treatment specifically includes heating the steel plate at 870-910° C. for 20-35 min in a quenching furnace with an oxygen content of less than 100 ppm; and cooling the steel plate after heating.

[0014] In some embodiments of the present application, the cooling treatment specifically includes cooling the heated steel plate in a roller quenching machine, wherein the cooling conditions include: water pressure of 0.8-0.9 MPa, upper and lower water ratio of 1:1-1:1.6, water temperature of 13-17 ° C, roller speed of 0.5-0.6 m / s, water volume of 2400-3500 m 3 / h.

[0015] In some embodiments of the present application, in S40, the number of straightening times in the cold straightening process does not exceed 2 times.

[0016] In a second aspect, the present application provides a thin-gauge quenched plate, which is prepared by the method described in any embodiment of the first aspect.

[0017] In some embodiments of the present application, the straightness of the thin gauge quenched plate does not exceed 15 mm / m.

[0018] In a third aspect, the present application provides a product obtained by processing the thin-gauge quenched plate described in any embodiment of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0020] Figure 1 An external view of the steel plate of Example 1 is shown.

[0021] Figure 2 The appearance of the steel plate of Comparative Example 1 is shown.

[0022] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0023] The various embodiments or implementation schemes in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments.

[0024] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the implementation or examples are included in at least one implementation or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same implementation or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more implementations or examples in a suitable manner.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] As described in the background technology above, the requirements for the flatness of thin-gauge quenched plates are becoming increasingly higher. In the production process of thin-gauge quenched plates, each process has a great influence on the plate shape of the thin-gauge quenched plates. On the one hand, in the early rolling stage, the thinner the steel plate, the more likely it is to have defects such as edge waves and middle waves, and it is easy to cause surface quality differences due to uneven cooling; on the other hand, the plate shape of steel plates with poor flatness and surface quality after rolling will further deteriorate during the quenching process, resulting in poor flatness of the obtained thin-gauge quenched plates, which do not meet the delivery requirements.

[0027] Based on this, the related technologies mainly quench the rolled steel plate in a roller quenching machine after shot blasting, and then manually observe the defects of the plate shape after quenching to adjust the parameters such as the water volume, roller gap, and roller speed of the quenching machine to control the plate shape of the quenched plate, and make the quenched plate have a smaller flatness through multiple strong straightening after quenching to improve the plate shape. However, the problem in these related technologies is that the adverse effects of the quenching treatment on the plate shape are improved only by optimizing the quenching treatment, and multiple strong straightening will cause the internal stress of the quenched plate to increase, affecting the subsequent processing of the quenched plate; on the other hand, the above-mentioned technology has a certain effect on thicker quenched plates (such as >4mm), but for thin quenched plates (thickness ≤4mm), because they are more difficult to control, it is impossible to obtain a quenched plate with a good plate shape by optimizing the quenching process alone.

[0028] In view of this, the present application provides a method for preparing a thin-gauge quenched plate, by optimizing the pre-quenching treatment of the steel plate, so that its plate shape is less adversely affected by the quenching treatment, and a thin-gauge quenched plate with a smaller straightness can be obtained through a small number of cold straightening. A thin-gauge quenched plate provided by the present application, a preparation method thereof, and a product thereof are described in detail below.

[0029] In a first aspect, the present application provides a method for preparing a thin gauge quenched plate, comprising the following steps:

[0030] S10: Provide steel plates to be quenched with a thickness of ≤4mm;

[0031] S20: trimming the steel plate to be quenched to obtain a trimmed steel plate to be quenched, wherein the trimming includes trimming 10 to 30 mm on both sides of the steel plate in the width direction;

[0032] S30: Shot blasting the trimmed steel plate to be quenched to remove the oxide layer on the surface of the steel plate to be quenched, so as to obtain the steel plate to be quenched after shot blasting; wherein, in the shot blasting, the number of shot blasting is 2 to 4 times, the diameter of the shot is 0.6 to 0.8 mm, the striking angle is 40° to 50°, and the steel plate transmission speed is 1 to 3 m / min;

[0033] S40: The steel plate to be quenched after shot blasting is quenched and cold-rectified to obtain a thin-gauge quenched plate.

[0034] According to the present application, a steel plate to be quenched with a thickness of ≤4 mm is provided in S10. The present application does not further limit the source of the steel plate to be quenched, and the steel plate can be a steel plate obtained by hot rolling and cold rolling of a slab. Since the shape of a thin-gauge wide-section quenched plate is difficult to control, the method is mainly applicable to a steel plate to be quenched with a thickness of ≤4 mm and a width of ≤1800 mm, and the subsequent process conditions are also controlled accordingly based on this.

[0035] In S20, the steel plate to be quenched is trimmed, and the trimming includes trimming 10 to 30 mm on both sides of the width direction of the steel plate to be quenched. This is because in the preparation process of thin-gauge quenched plates, it was found that in the preparation process of quenched plates with a thickness of ≤4 mm, no matter how the quenching process conditions are controlled, the shape of the quenched plate cannot be effectively improved, and defects such as middle waves and warping are prone to occur. It often requires multiple straightenings to achieve the required straightness. After analysis, although shot blasting to remove surface oxide scale before quenching, or flattening to make it less flat before quenching can improve the adverse effects of quenching on plate shape, the main reason is that thin-gauge steel plates to be quenched are generally obtained by rolling, and rolling will inevitably lead to thinning of the edge thickness. During the quenching process, the inconsistent thickness of the steel plate in the width direction causes deformation. When the steel plate is thicker, the deformation caused by this reason is not obvious and can be improved by optimizing the quenching process. When the thickness is thinner, the deformation caused by this reason is more serious and cannot be effectively improved only by optimizing the quenching process. Based on this, in this application, the steel plate to be quenched is trimmed in the width direction, so that the thickness of the steel plate to be quenched in the width direction is more uniform, thereby effectively reducing the adverse effects of quenching on the plate shape.

[0036] It is worth noting that, after the trimming treatment, the cut steel plate needs to be recycled for further use, which will increase the cost to a certain extent. Therefore, the length of the trimming on both sides is controlled between 10 and 30 mm. While controlling the plate shape, the production cost is taken into account. However, from the perspective of the entire production process, the trimming treatment is conducive to the smooth process, and can reduce the number of straightening times after quenching, improve the quality of thin-gauge quenched plates, and comprehensively consider the cost reduction, which is suitable for industrial production. In addition, this method is also mainly suitable for thin-gauge quenched plates. The quality of the cut steel plate is relatively low, and the cost will not be greatly increased. For example, the length of the trimming on both sides can be 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, or within the range composed of any of the above values.

[0037] In S30, the steel plate to be quenched after trimming is shot blasted, and the specific conditions of the shot blasting are specifically defined. The shot blasting is to remove the iron oxide scale on the surface of the steel plate, so as to effectively reduce the effect of the iron oxide scale on the uniformity of heating and cooling during the quenching process, thereby reducing the adverse effect of the quenching process on the plate shape. In actual production, it is found that it is difficult to obtain a quenched plate with a good plate shape using the shot blasting process in the existing process. After analysis, it is found that since the existing process is aimed at steel plates with thicker thickness, the steel plates are not easy to deform, and even if there is a small amount of iron oxide scale remaining on the thicker steel plates, it will not seriously affect the plate shape of the quenched plate. Therefore, in the existing shot blasting process, in order to improve production efficiency, shot blasting is generally performed using larger particle size pellets to quickly remove the iron oxide scale on the surface of the steel plate. In contrast to the thin-gauge steel plates in this application, the conditions of larger particle size and fast shot blasting are used. The large particle size of the shots will cause the steel plates to deform during the shot blasting process, and fast shot blasting may also lead to incomplete removal of the iron oxide scale, resulting in uneven heating or cooling of the steel plates during the quenching process. Therefore, using the existing shot blasting process, it is impossible to obtain a quenched plate with a good plate shape.

[0038] Based on this, the present application adopts a small-size shot, slow speed, and multiple shot blasting processes, which is more conducive to removing the iron oxide scale on the surface of the steel plate and reducing the deformation degree of the thin-gauge steel plate, thereby being more conducive to reducing the adverse effects of quenching treatment on the plate shape.

[0039] In S40, the steel plate is quenched and cold-straightened to obtain a thin-gauge quenched plate. Since the thin-gauge steel plate is trimmed and shot blasted, the adverse effects of the quenching treatment on the plate shape can be reduced. After a simple cold-straightening treatment, a thin-gauge quenched plate with reduced flatness can be obtained, which has a good plate shape and is conducive to its further processing and utilization.

[0040] In the present application, the type of thin-gauge quenched plate is not further limited. It can be a quenched plate commonly used in the art, such as wear-resistant steel plate, high-strength steel plate, etc., with a yield strength of 500 to 1300 MPa, which can be prepared using the above method.

[0041] In some embodiments of the present application, in S10, the thickness of the steel plate to be quenched is not less than 2 mm.

[0042] In some of the above embodiments, the thickness of the steel plate to be quenched is further optimized, and the steel plate to be quenched is not less than 2 mm. A steel plate with too small a thickness generally cannot meet the use requirements in strength. At the same time, too small a thickness may further increase the cost and the plate shape is more difficult to control. Therefore, the thickness of the steel plate to be quenched should not be less than 2 mm.

[0043] In some embodiments of the present application, in S20, the width of the steel plate to be quenched after trimming is ≤1800 m.

[0044] In some of the above embodiments, the width of the steel plate to be quenched after trimming is further limited. This is because it was further found in the experiment that the width of the thin-gauge steel plate also has a great influence on the control of the plate shape during the quenching process. In addition, the thin-gauge steel plate is relatively sensitive to the heating and cooling processes, and uneven heating or cooling will cause large internal tissue stress, thereby deteriorating the plate shape of the thin-gauge quenched plate. Therefore, when the width of the steel plate to be quenched after trimming is ≤1800m, the adverse effect of the quenching process on the plate shape is smaller, which is more conducive to obtaining a thin-gauge quenched plate with a good plate shape. Furthermore, the width of the steel plate to be quenched after trimming is ≤1800m and ≥900mm. Too small a width will lead to excessively high production costs.

[0045] In some embodiments of the present application, in S30, the straightness of the steel plate to be quenched after shot blasting is ≤8 mm / m.

[0046] In some of the above embodiments, the straightness of the steel plate to be quenched after shot blasting is further limited, because the straightness of the steel plate before quenching will affect the uniformity of the heating and cooling process during the quenching treatment, thereby affecting the plate shape of the quenched plate. In addition, the wave and warping of the steel plate before quenching will further increase its yield strength after quenching, which increases the difficulty of subsequent cold straightening work. Therefore, the straightness of the steel plate to be quenched after shot blasting may not exceed 8 mm / m, and a thin-gauge quenched plate with better straightness can be obtained.

[0047] It should be noted that if the straightness of the steel plate to be quenched after shot blasting is greater than 8mm / m, the steel plate can be straightened by cold straightening to meet the flatness requirements.

[0048] In some embodiments of the present application, in S30, the shots in the shot blasting process may be steel shots.

[0049] In some embodiments of the present application, in S40, the quenching treatment specifically includes heating the steel plate at 850-950° C. for 20-35 min in a quenching furnace with an oxygen content of less than 100 ppm; and cooling the steel plate after heating.

[0050] In some of the above-mentioned embodiments, the heating conditions in the quenching treatment are further limited, and the oxygen content in the quenching furnace needs to be strictly controlled to reduce the oxidation of the steel plate during the heating process, which is beneficial to the control of the shape of the steel plate. In addition, by controlling the heating temperature and heating time, the steel plate is fully austenitized, and then cooled to complete the quenching.

[0051] In some embodiments of the present application, the cooling treatment specifically includes cooling the heated steel plate in a roller quenching machine, wherein the cooling conditions include: water pressure of 0.8-1.0 MPa, upper and lower water ratio of 1:1-1:1.6, water temperature of 13-17°C, roller speed of 0.5-0.6 m / s, water volume of 2400-3500 m 3 / h.

[0052] In some of the above-mentioned embodiments, the cooling treatment method is further limited, and cooling conditions of high water pressure, large water volume and high roller speed are adopted to ensure that thin-gauge steel plates can quickly pass through the high-pressure cooling area. In addition, since thin-gauge steel plates have greater cooling sensitivity and faster cooling speeds, they will quickly pass through the phase change point during cooling and form greater phase change stress. Therefore, using rapid and large water volumes to maintain coordinated phase change transformation in all directions can reduce adverse effects on the plate shape and obtain thin-gauge quenched plates with better plate shape.

[0053] In some embodiments of the present application, an online flatness meter is used to detect the shape of the steel plate and automatically determine defects. On the one hand, the subsequent cold straightening process can be determined according to the nature of the defects. On the other hand, the quenching conditions can be adjusted according to the defects to further obtain a thin-gauge quenched plate with a good plate shape.

[0054] In some embodiments of the present application, in S40, the number of straightening times in the cold straightening process does not exceed 2 times.

[0055] In some of the above-mentioned embodiments, the number of straightening times in the cold straightening process is further limited to no more than 2 times. Reducing the number of straightening times can effectively reduce the internal stress generated by cold straightening, thereby reducing the deformation of the steel plate during the cutting and processing process of the customer and improving the quality of thin-gauge quenched plates.

[0056] Furthermore, in order to further reduce the straightness of the thin-gauge quenched plate and obtain a thin-gauge quenched plate with a good plate shape, the straightening times can be twice. The first straightening eliminates edge waves, and the second straightening eliminates defects such as middle waves, turtle backs, and head and tail warping.

[0057] In a second aspect, the present application provides a thin-gauge quenched plate, which is prepared by the method of any embodiment of the first aspect.

[0058] According to the present application, since the thin-gauge quenched plate provided in the present application is prepared according to the method of any embodiment of the first aspect, it has the beneficial effect of the first aspect. The thin-gauge quenched plate with good plate shape can meet the needs of subsequent automated processing.

[0059] In some embodiments of the present application, the straightness of the thin gauge quenched plate does not exceed 15 mm / m.

[0060] In some of the above embodiments, the straightness of the thin-gauge quenched plate may not exceed 15 mm / m, indicating that the thin-gauge quenched plate has a good plate shape. After subsequent straightening, the straightness is ≤3 mm / m, which can meet the needs of customers for automated processing and promote the application of thin-gauge quenched plates in different fields.

[0061] In a third aspect, the present application provides a product obtained by processing the thin-gauge quenched plate according to any embodiment of the second aspect.

[0062] According to the present application, the product is obtained by processing the thin-gauge quenched plate according to any embodiment of the second aspect, and thus has the beneficial effects of the second aspect. Since the quenched plate generally has good strength and wear resistance, it can be widely used in the fields of metallurgy, power engineering, construction, etc. As an example, the thin-gauge quenched plate can be further processed to obtain mining equipment, cement casting and molding equipment, excavation equipment or conveyors, etc. The thin-gauge quenched plate with good plate shape is conducive to the automated production of equipment, and the thinner quenched plate is conducive to the preparation of lightweight products.

[0063] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0064] Example 1

[0065] Preparation of thin gauge quenched plate:

[0067] The steel type is Lian Steel NM450 wear-resistant steel, with a thickness of 3mm and a width of 1550mm.

[0068] The rolled steel coil is flattened and trimmed, with 25mm trimmed on both sides of the width direction. The width of the steel plate after trimming is 1500mm;

[0069] The steel plate was shot blasted 4 times to make the surface present a silvery white metallic luster. The shot material was steel shot, the shot diameter was 0.8mm, the impact angle was 45°, and the steel plate transportation speed was 2.8m / min.

[0070] After shot blasting, two passes of straightening are carried out, and the straightness of the steel plate is within 8mm / m;

[0071] The steel plate was heated at 900°C for 30 min in a quenching furnace with an oxygen content of less than 100 ppm; after heating, the steel plate was cooled in a roller quenching machine, wherein the cooling conditions included: water pressure of 0.85 MPa, upper and lower water ratio of 1:1.4, water temperature of 15°C, roller speed of 0.55 m / s, water volume of 3000 m 3 / h;

[0072] The steel plates after rolling off the production line are cold straightened in two passes to obtain thin-gauge quenched plates.

[0073] The straightness of the thin-gauge quenched plate is tested using a straightness meter, and the thin-gauge quenched plate is 5 mm / m.

[0074] Generally, the straightness of thin-gauge quenched plates is controlled not to exceed 15mm / m. Subsequently, it is straightened to less than 3mm through one or two subsequent straightening operations, and finally steel products that meet the requirements are produced for subsequent processing by customers.

[0075] Example 2

[0076] Preparation of thin gauge quenched plate:

[0077] The steel type is Lian Steel NM450 wear-resistant steel, with a thickness of 2mm and a width of 1550mm.

[0078] The rolled steel coil is flattened and trimmed, with 25mm trimmed on both sides of the width direction. The width of the steel plate after trimming is 1500mm;

[0079] The steel plate was shot blasted 4 times to make the surface present a silvery white metallic luster. The shot material was steel shot, the shot diameter was 0.8mm, the impact angle was 45°, and the steel plate transportation speed was 3m / min.

[0080] After shot blasting, two passes of straightening are carried out, and the straightness of the steel plate is within 8mm / m;

[0081] The steel plate was heated at 900°C for 28 min in a quenching furnace with an oxygen content of less than 100 ppm; after heating, the steel plate was cooled in a roller quenching machine, wherein the cooling conditions included: water pressure of 0.85 MPa, upper and lower water ratio of 1:1.4, water temperature of 17°C, roller speed of 0.58 m / s, water volume of 2800 m 3 / h;

[0082] The steel plates after rolling off the production line are cold straightened in two passes to obtain thin-gauge quenched plates.

[0083] The straightness of the thin-gauge quenched plate is tested using a straightness meter, and the thin-gauge quenched plate is 8 mm / m.

[0084] Example 3

[0085] Preparation of thin gauge quenched plate:

[0086] The steel type is Lian Steel NM450 wear-resistant steel, with a thickness of 2.5mm and a width of 1550mm.

[0087] The rolled steel coil is flattened and trimmed, with 25mm trimmed on both sides of the width direction. The width of the steel plate after trimming is 1500mm;

[0088] The steel plate was shot blasted 4 times to make the surface present a silvery white metallic luster. The shot material was steel shot, the shot diameter was 0.8mm, the impact angle was 45°, and the steel plate transportation speed was 2.8m / min.

[0089] After shot blasting, two passes of straightening are carried out, and the straightness of the steel plate is within 8mm / m;

[0090] The steel plate was heated at 900°C for 30 min in a quenching furnace with an oxygen content of less than 100 ppm; after heating, the steel plate was cooled in a roller quenching machine, wherein the cooling conditions included: water pressure of 0.85 MPa, upper and lower water ratio of 1:1.4, water temperature of 15°C, roller speed of 0.55 m / s, water volume of 3000 m 3 / h;

[0091] The steel plates after rolling off the production line are cold straightened in two passes to obtain thin-gauge quenched plates.

[0092] The straightness of the thin-gauge quenched plate was tested using a straightness meter, and the straightness of the thin-gauge quenched plate was within 8 mm / m.

[0093] Example 4

[0094] Preparation of thin gauge quenched plate:

[0095] The steel type is Liangang NM450 wear-resistant steel, with a thickness of 4mm and a width of 1840mm.

[0096] The rolled steel coil is flattened and trimmed, with 20mm trimmed on both sides of the width direction. The width of the steel plate after trimming is 1800mm;

[0097] The steel plate was shot blasted 4 times to make the surface present a silvery white metallic luster. The shot material was steel shot, the shot diameter was 0.8mm, the impact angle was 45°, and the steel plate transportation speed was 3m / min.

[0098] After shot blasting, two passes of straightening are carried out, and the straightness of the steel plate is within 8mm / m;

[0099] The steel plate was heated at 900°C for 33 min in a quenching furnace with an oxygen content of less than 100 ppm; after heating, the steel plate was cooled in a roller quenching machine, wherein the cooling conditions included: water pressure of 0.85 MPa, upper and lower water ratio of 1:1.4, water temperature of 15°C, roller speed of 0.52 m / s, water volume of 3300 m 3 / h;

[0100] The steel plates after rolling off the production line are cold straightened in two passes to obtain thin-gauge quenched plates.

[0101] The straightness of the thin-gauge quenched plate was tested using a straightness meter, and the straightness of the thin-gauge quenched plate was within 5.4 mm / m.

[0102] Example 5

[0103] Preparation of thin gauge quenched plate:

[0104] The steel type is Lian Steel NM450 wear-resistant steel, with a thickness of 3mm and a width of 2050mm.

[0105] The rolled steel coil is flattened and trimmed, with 25mm trimmed on both sides of the width direction. The width of the steel plate after trimming is 2000mm;

[0106] The steel plate was shot blasted 4 times to make the surface present a silvery white metallic luster. The shot material was steel shot, the shot diameter was 0.8mm, the impact angle was 45°, and the steel plate transportation speed was 2.8m / min.

[0107] After shot blasting, two passes of straightening are carried out, and the straightness of the steel plate is within 8mm / m;

[0108] The steel plate was heated at 900°C for 30 min in a quenching furnace with an oxygen content of less than 100 ppm; after heating, the steel plate was cooled in a roller quenching machine, wherein the cooling conditions included: water pressure of 0.85 MPa, upper and lower water ratio of 1:1.4, water temperature of 15°C, roller speed of 0.55 m / s, water volume of 3000 m 3 / h;

[0109] The steel plates after rolling off the production line are cold straightened in two passes to obtain thin-gauge quenched plates.

[0110] The straightness of the thin-gauge quenched plate was tested using a straightness meter. The straightness of the thin-gauge quenched plate was 33 mm / m.

[0111] Comparative Example 1

[0112] Preparation of thin gauge quenched plate:

[0113] The steel type is Lian Steel NM450 wear-resistant steel, with a thickness of 3mm and a width of 1500mm.

[0114] After rolling, the steel coil is flattened without trimming;

[0115] The steel plate was shot blasted 4 times to make the surface present a silvery white metallic luster. The shot material was steel shot, the shot diameter was 0.8mm, the impact angle was 45°, and the steel plate transportation speed was 2.8m / min.

[0116] After shot blasting, two passes of straightening are carried out, and the straightness of the steel plate is within 8mm / m;

[0117] The steel plate was heated at 900°C for 30 min in a quenching furnace with an oxygen content of less than 100 ppm; after heating, the steel plate was cooled in a roller quenching machine, wherein the cooling conditions included: water pressure of 0.85 MPa, upper and lower water ratio of 1:1.4, water temperature of 15°C, roller speed of 0.55 m / s, water volume of 3000 m 3 / h;

[0118] The steel plates after rolling off the production line are cold straightened in two passes to obtain thin-gauge quenched plates.

[0119] The straightness of the thin-gauge quenched plate was tested using a straightness meter. The maximum straightness of the middle wave of the thin-gauge quenched plate was 43 mm / m, and the maximum straightness of the side wave was 5 mm / m.

[0120] Comparative Example 1 has no trimming and has a relatively high straightness. The thin quenched plate is straightened to about 12 mm / m through one or two subsequent straightenings, and the final steel product does not meet customer requirements.

[0121] Comparative Example 2

[0122] Preparation of thin gauge quenched plate:

[0123] The steel type is Lian Steel NM450 wear-resistant steel with a thickness of 3mm and a width of 1550m.

[0124] The rolled steel coil is flattened and trimmed, with 25mm trimmed on both sides of the width direction. The width of the steel plate after trimming is 1500mm;

[0125] The steel plate was shot blasted 5 times to make the surface present a silvery white metallic luster. The shot material was steel shot, the shot diameter was 0.85mm, the impact angle was 45°, and the steel plate transportation speed was 3.5m / min.

[0126] After shot blasting, two passes of straightening are carried out, and the straightness of the steel plate is within 8mm / m;

[0127] The steel plate was heated at 900°C for 30 min in a quenching furnace with an oxygen content of less than 100 ppm; after heating, the steel plate was cooled in a roller quenching machine, wherein the cooling conditions included: water pressure of 0.85 MPa, upper and lower water ratio of 1:1.4, water temperature of 15°C, roller speed of 0.55 m / s, water volume of 3000 m 3 / h;

[0128] The steel plates after rolling off the production line are cold straightened in two passes to obtain thin-gauge quenched plates.

[0129] The straightness of the thin quenched plate was tested using a straightness meter. The maximum straightness of the middle wave of the thin quenched plate was 45 mm / m, and the maximum straightness of the edge wave was 8 mm / m. The thin quenched plate was straightened to about 12 mm / m through one or two subsequent straightenings. The final steel product did not meet customer requirements.

[0130] The shot blasting conditions of Comparative Example 2 are larger particle size, faster speed, fewer times, etc., so the resulting flatness is larger and the effect is not good.

[0131] Figure 1 The appearance diagram of the steel plate of Example 1 is shown. From the diagram, it can be observed that the steel plate is relatively straight. The straightness thereof is 5 mm / m after testing.

[0132] Figure 2 The appearance diagram of the steel plate of comparative example 1 is shown. From the diagram, it can be observed that the steel plate has a certain curvature. After testing, the maximum straightness of the waves is 43 mm / m, and the maximum straightness of the edge waves is 5 mm / m.

[0133] For example, the side wave can be detected at 200 cm from the side. The middle wave can be detected at the middle position of the area except the side wave.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a thin gauge quenched plate, characterized in that: The following steps are involved: S10: Provide steel plates to be quenched with a thickness of ≤4mm; S20: performing edge trimming on the steel plate to be quenched to obtain an edge trimmed steel plate to be quenched, wherein the edge trimming includes trimming 10 to 30 mm on both sides of the steel plate to be quenched in the width direction; S30: Shot blasting the trimmed steel plate to be quenched to remove the oxide layer on the surface of the steel plate to be quenched, so as to obtain the steel plate to be quenched after shot blasting; wherein, in the shot blasting, the shot blasting times are 2 to 4 times, the shot diameter is 0.6 to 0.8 mm, the striking angle is 40° to 50°, and the steel plate transmission speed is 1 to 3 m / min; S40: quenching and cold straightening the steel plate to be quenched after shot blasting to obtain a thin quenched plate.

2. The method according to claim 1, characterized in that In the step S10, the thickness of the steel plate to be quenched is not less than 2 mm.

3. The method according to claim 1, characterized in that In the S20, the width of the steel plate to be quenched after trimming is ≤1800 mm.

4. The method according to claim 1 or 2, characterized in that: In the S30, the straightness of the steel plate to be quenched after shot blasting does not exceed 8 mm / m.

5. The method according to claim 1 or 2, characterized in that: In the S40, the quenching treatment specifically includes heating the steel plate at 850-950°C for 20-35 minutes in a quenching furnace with an oxygen content of less than 100 ppm; and cooling the steel plate after heating.

6. The method according to claim 5, characterized in that The cooling treatment specifically includes cooling the heated steel plate in a roller quenching machine, wherein the cooling conditions include: water pressure of 0.8-1.0 MPa, upper and lower water ratio of 1:1-1:1.6, water temperature of 13-17°C, roller speed of 0.5-0.6 m / s, water volume of 2400-3500 m 3 / h.

7. The method according to claim 1 or 2, characterized in that: In the S40, the number of straightening times in the cold straightening process is no more than 2 times.

8. A thin gauge quenched plate, characterized in that: A thin gauge quenched plate is prepared according to the method according to any one of claims 1 to 7.

9. The thin gauge quenched plate according to claim 8, characterized in that The straightness of the thin gauge quenched plate does not exceed 15 mm / m.

10. A product, characterized in that The thin-gauge quenched plate according to claim 8 or 9 is processed to obtain a product.

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