Aluminum-lithium alloy sheet production method and aluminum-lithium alloy sheet

Abstract

The present application relates to the technical field of aluminum lithium alloy, in particular to a kind of aluminum lithium alloy plate preparation method and aluminum lithium alloy.The aluminum lithium alloy plate preparation method described in the present application includes the following steps: ingot structure pretreatment: with the flat ingot with side edge being concave as raw material, the side edge of the flat ingot is sandblasted with 0.7~1.0MPa pressure;Then set heat preservation coating on the side edge of the flat ingot;Ingot structure processing: the pretreated ingot structure is heated and then heat preserved;Then rolled, rolled to total deformation of 25~35% with single pass small deformation, and then returned to normal rolling;After rolling, solid solution quenching, pre-stretching and aging treatment are carried out in sequence.The aluminum lithium alloy plate product prepared by the present application has no edge cracking, high yield, excellent comprehensive performance, and can better meet the demand of aerospace for aluminum lithium alloy plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum-lithium alloy, in particular to a preparation method of aluminum-lithium alloy plate and aluminum-lithium alloy. BACKGROUND

[0002] Aluminum-lithium alloy is a light and high-strength material commonly used in aerospace. The aluminum-lithium alloy plate is often used to manufacture straight cylinder segments of rocket storage tanks and aircraft skin parts. However, the existing aluminum-lithium alloy plate is prone to edge cracking during the preparation process. The edge cracking part needs to be completely removed during processing, resulting in low material yield. In addition, the recycling of aluminum-lithium alloy is difficult, which leads to high cost of aluminum-lithium alloy plate and limits its further popularization and application.

[0003] To solve the problem of plate edge cracking, some current improvement methods include cladding rolling, edge sticking rolling and improved rolling mill. The cladding rolling method usually uses a common rectangular flat ingot. Before rolling, the edge of the aluminum-lithium alloy ingot is completely wrapped with a pure aluminum plate or other soft alloy plate, and then rolling is performed. The cladding layer plays a protective role in the edge, reduces the temperature drop and improves the stress state. However, this scheme has significant drawbacks, such as the need for additional cladding materials such as pure aluminum plates, which increases material costs. The cladding operation process is complex and time-consuming, which affects production efficiency. The cladding layer and the base alloy may stick together or be contaminated during rolling, which affects the surface quality of the final plate or requires additional cleaning procedures. The cladding layer needs to be removed after rolling, which produces additional waste and increases the process. The edge sticking rolling method is to weld or attach a high-plasticity material strip to the edge of the ingot. The disadvantages are that special welding or additional equipment is needed, which has high equipment investment and maintenance costs. The welding / adding operation is complex and requires high process control. In addition, the additional material may introduce contamination or affect the rolling stability and also needs to remove the additional material afterwards, which is limited in practical application.

[0004] Therefore, the existing technology has the disadvantages of large special equipment investment and complex operation for plate edge cracking, which is difficult to meet the needs of high-efficiency and low-cost industrial production. Therefore, the present application aims to develop a preparation method of aluminum-lithium alloy plate and aluminum-lithium alloy to effectively solve the edge cracking defect problem of aluminum-lithium alloy plate, reduce production cost and improve production efficiency. SUMMARY

[0005] One of the technical problems solved by the present application is to provide a preparation method of aluminum-lithium alloy plate, which effectively solves the edge cracking defect problem of aluminum-lithium alloy plate, reduces waste generation, reduces production cost and improves production efficiency.

[0006] The second technical problem solved by the present application is to provide an aluminum-lithium alloy plate product with excellent comprehensive performance and no edge cracking.

[0007] The technical problem solved by the present application is implemented by adopting the following technical scheme:

[0008] The present application discloses a preparation method of an aluminum-lithium alloy plate.

[0009] The ingot structure is pre-processed by sand blasting the side edges of the flat ingot at a pressure of 0.7-1.0 MPa, and then a heat-insulating coating is arranged on the side edges of the flat ingot.

[0010] The pre-processed ingot structure is heated and then rolled, and the first 25-35% of the total deformation is rolled by single-pass small deformation.

[0011] Further, the side edges of the flat ingot are concave arc surfaces, and the concave depth of the side edges of the flat ingot is 10-20% of the thickness of the side edges of the flat ingot.

[0012] Further, in the pre-processing of the ingot structure, 24-45 mesh brown corundum is used for sand blasting the side edges of the flat ingot.

[0013] Further, in the pre-processing of the ingot structure, the heat-insulating coating includes a corundum-based coating or a boron nitride coating, and the thickness of the heat-insulating coating is 0.5-1.5 mm.

[0014] Further, in the processing of the ingot structure, the pre-processed ingot structure is heated to 450-500 DEG C and kept for 10-15 h.

[0015] Further, in the processing of the ingot structure, at the beginning of rolling, the ingot structure is rolled by single-pass deformation of 5-15 mm to achieve a thickness deformation of 25-35% of the total deformation, and then rolled by deformation of 20-25 mm per pass to achieve a thickness deformation of 75-90% of the total deformation, and finally rolled by deformation of 6-8 mm per pass to achieve the final thickness.

[0016] Further, in the processing of the ingot structure, during the solution quenching, the plate is heated to 510-520 DEG C and kept for 1.5-2.5 h, and then quenched at room temperature.

[0017] Further, in the processing of the ingot structure, the stretching amount of the pre-stretching is 3-4%.

[0018] Further, in the processing of the ingot structure, the aging temperature is 140-160 DEG C, and the aging time is 30-35 h.

[0019] An aluminum-lithium alloy plate prepared by the method, the aluminum-lithium alloy plate is free of edge cracks, has a tensile strength greater than 585 MPa, an elongation greater than 12.5%, and a yield greater than 80%.

[0020] Beneficial effects: the aluminum-lithium alloy plate preparation method changes the metal flow and stress state of the edge at the initial stage of rolling, actively creates a beneficial compressive stress layer on the edge surface layer to offset the subsequent rolling tensile stress, and effectively slows down the heat loss of the edge during heating and transfer by coating a heat preservation coating on the side surface of the ingot, thereby maintaining the plasticity of the edge. The three work together and are indispensable, and in combination with other processes, effectively solve the edge crack defect problem of the aluminum-lithium alloy plate without complex production equipment, simple operation, reduced production cost, and improved production efficiency.

[0021] The aluminum-lithium alloy plate preparation method does not rely on complex coating materials and special additional equipment, is simple to operate, can effectively control the stress state and temperature field of the edge of the plate during rolling, significantly suppresses the generation of edge cracks, significantly improves the yield of the aluminum-lithium alloy plate, and the yield is greater than 80%, meeting the needs of industrialized production of aluminum-lithium alloy plates for simplicity, high quality and low cost.

[0022] The aluminum-lithium alloy plate product prepared by the method is free of edge cracks, has high yield, and excellent comprehensive performance, and can better meet the needs of aerospace for aluminum-lithium alloy plates. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is an edge structure schematic diagram of the aluminum-lithium alloy plate in Example 1.

[0024] Figure 2 It is an edge structure schematic diagram of the aluminum-lithium alloy plate in Example 2.

[0025] Figure 3 It is an edge structure schematic diagram of the aluminum-lithium alloy plate in Comparative Example 1.

[0026] Figure 4 It is an edge structure schematic diagram of the aluminum-lithium alloy plate in Comparative Example 1.

[0027] Figure 5 It is an edge structure schematic diagram of the aluminum-lithium alloy plate in Comparative Example 1.

[0028] Figure 6 It is an edge structure schematic diagram of the aluminum-lithium alloy plate in Comparative Example 1.

[0029] Figure 7 It is a structure schematic diagram of the flat ingot with the side edge being concave. DETAILED DESCRIPTION

[0030] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in combination with specific examples. EMBODIMENT

[0031] The aluminum-lithium alloy plate preparation method described in this embodiment includes the following steps:

[0032] Ingot structure pretreatment:

[0033] The flat ingot with a concave side is used as the raw material. In this embodiment, the side of the flat ingot raw material is in the form of a concave arc surface, and the concave depth of the side of the flat ingot raw material accounts for 12% of the thickness of the side of the flat ingot. The structure is as shown in Figure 7 The thickness H of the side of the flat ingot is 380 mm, and the concave depth L of the side of the flat ingot raw material is 45.6 mm.

[0034] The side of the flat ingot is sandblasted at a pressure of 0.8 MPa using 30-mesh brown corundum;

[0035] A heat preservation coating is arranged on the side of the flat ingot. The heat preservation coating is formed by spraying boron nitride paint, and the thickness of the heat preservation coating is 0.8 mm;

[0036] Ingot structure processing:

[0037] The pretreated ingot structure is heated to 470℃ in a heating furnace and kept for 10 h. Then, rolling is performed on a rolling mill, and the single-pass deformation amount is controlled to be 8 mm. When the rolling deformation amount reaches 30% of the total deformation amount, the single-pass deformation amount of 20 mm is used to continue rolling to a rolling plate thickness of 60 mm, and then the deformation amount of 6 mm per pass is used to roll to a final thickness of 12 mm.

[0038] After rolling is completed, the plate is heated to 510℃ and kept for 2 h. After keeping, room temperature water quenching is used.

[0039] After solid solution quenching is completed, pre-stretching is performed, and the stretching amount is controlled to be 3.5%.

[0040] After pre-stretching is completed, aging treatment is performed, the aging temperature is 150℃, and the aging time is 32 h.

[0041] The product prepared in this embodiment is as shown in Figure 1 . EMBODIMENT

[0042] The aluminum-lithium alloy plate preparation method described in this embodiment includes the following steps:

[0043] Ingot structure pretreatment:

[0044] The flat ingot is used as the raw material, and in this embodiment, the side of the flat ingot is concave arc-shaped, and the concave depth of the side of the flat ingot is 20% of the thickness of the side of the flat ingot; the thickness H of the side of the flat ingot is 380 mm, and the concave depth L of the side of the flat ingot is 76 mm;

[0045] The side of the flat ingot is sandblasted by 30-mesh brown corundum at a pressure of 1.0 MPa;

[0046] A heat preservation coating is arranged on the side of the flat ingot; the heat preservation coating is formed by spraying boron nitride coating, and the thickness of the heat preservation coating is 1.2 mm;

[0047] Ingot structure processing:

[0048] The pre-processed ingot structure is heated to 450 DEG C in a heating furnace and kept for 15 h; then, rolling is performed on a rolling mill, and the single-pass deformation amount is controlled to be 6 mm; when the rolling deformation amount reaches 35% of the total deformation amount, the single-pass deformation amount of 20 mm is used to continue rolling to a rolling plate thickness of 60 mm, and then the deformation amount of 6 mm per pass is used to roll to a final thickness of 12 mm;

[0049] After rolling is completed, the plate is heated to 510 DEG C and kept for 2 h; after keeping, room temperature water quenching is used;

[0050] After solid solution quenching is completed, pre-stretching is performed, and the stretching amount is controlled to be 3.5%;

[0051] After pre-stretching is completed, aging treatment is performed, the aging temperature is 150 DEG C, and the aging time is 32 h.

[0052] The product prepared in this embodiment is as shown in Figure 2 .

[0053] Comparative Example 1

[0054] The aluminum-lithium alloy plate preparation method described in this comparative example comprises the following steps:

[0055] Ingot structure pretreatment:

[0056] The flat ingot raw material is a conventional ingot without concave side;

[0057] The side of the flat ingot is sandblasted by 30-mesh brown corundum at a pressure of 0.8 MPa;

[0058] A heat preservation coating is arranged on the side of the flat ingot; the heat preservation coating is formed by spraying boron nitride coating, and the thickness of the heat preservation coating is 0.8 mm;

[0059] Ingot structure processing:

[0060] The pretreated ingot structure is heated to 470 DEG C in a heating furnace and kept for 10 h, then rolled on a rolling mill, with single pass deformation controlled at 8 mm, when the rolling deformation reaches 30% of the total deformation, single pass deformation of 20 mm is used to continue rolling to a rolled plate thickness of 60 mm, then rolled to a final thickness of 12 mm with deformation of 6 mm per pass;

[0061] After rolling, the plate is heated to 510 DEG C and kept for 2 h, after keeping, quenched with room temperature water;

[0062] After solid solution quenching, pre-stretching is carried out, with stretching controlled at 3.5%;

[0063] After pre-stretching, aging treatment is carried out, with aging temperature of 150 DEG C and aging time of 32 h.

[0064] The product prepared in the example is shown in Figure 3 .

[0065] Example 2

[0066] The aluminum-lithium alloy plate preparation method comprises the following steps:

[0067] Pretreatment of ingot structure:

[0068] The flat ingot with concave side is used as raw material, in the example, the flat ingot raw material has concave arc side, the concave depth of the flat ingot raw material side is 12% of the thickness of the flat ingot side;

[0069] The flat ingot side is sandblasted with 60 mesh brown corundum at a pressure of 1.2 MPa;

[0070] A heat preservation coating is arranged on the flat ingot side, the heat preservation coating is formed by spraying boron nitride coating, and the thickness of the heat preservation coating is 0.8 mm;

[0071] Processing of ingot structure:

[0072] The pretreated ingot structure is heated to 470 DEG C in a heating furnace and kept for 10 h, then rolled on a rolling mill, with single pass deformation controlled at 8 mm, when the rolling deformation reaches 30% of the total deformation, single pass deformation of 20 mm is used to continue rolling to a rolled plate thickness of 60 mm, then rolled to a final thickness of 12 mm with deformation of 6 mm per pass;

[0073] After rolling, the plate is heated to 510 DEG C and kept for 2 h, after keeping, quenched with room temperature water;

[0074] After solid solution quenching, pre-stretching is carried out, with stretching controlled at 3.5%;

[0075] After the pre-stretching is completed, aging treatment is performed, the aging temperature is 150 DEG C, and the aging time is 32h.

[0076] The product prepared in the present example is shown in Figure 4 .

[0077] Example 3

[0078] The method for preparing the aluminum-lithium alloy plate comprises the following steps:

[0079] Pre-treatment of the ingot structure:

[0080] The flat ingot with the inwardly concave side is used as the raw material, in the present example, the side of the flat ingot raw material is in the form of inwardly concave arc surface, and the depth of the inward concave of the side of the flat ingot raw material accounts for 12% of the thickness of the side of the flat ingot;

[0081] The side of the flat ingot is subjected to sand blasting treatment at a pressure of 0.8 MPa by using 30-mesh brown corundum;

[0082] Processing of the ingot structure:

[0083] After the pre-treated ingot structure is heated to 470 DEG C in a heating furnace and is kept for 10h, rolling is performed on a rolling mill, the single-pass deformation amount is controlled to be 8mm, when the rolling deformation amount reaches 30% of the total deformation amount, the single-pass deformation amount of 20mm is used to continue rolling to the thickness of the rolled plate of 60mm, and then the deformation amount of 6mm per pass is used to roll to the final thickness of 12mm;

[0084] After the rolling is completed, the plate is heated to 510 DEG C and is kept for 2h, after the keeping is completed, room-temperature water quenching is performed;

[0085] After the solution quenching is completed, pre-stretching is performed, and the stretching amount is controlled to be 3.5%;

[0086] After the pre-stretching is completed, aging treatment is performed, the aging temperature is 150 DEG C, and the aging time is 32h.

[0087] The product prepared in the present example is shown in Figure 5 .

[0088] Example 4

[0089] The method for preparing the aluminum-lithium alloy plate comprises the following steps:

[0090] Pre-treatment of the ingot structure:

[0091] The flat ingot with the inwardly concave side is used as the raw material, in the present example, the side of the flat ingot raw material is in the form of inwardly concave arc surface, and the depth of the inward concave of the side of the flat ingot raw material accounts for 12% of the thickness of the side of the flat ingot;

[0092] The side edge of the flat cast ingot is sandblasted at a pressure of 0.8 MPa by using 30-mesh brown corundum;

[0093] A heat preservation coating is arranged on the side edge of the flat cast ingot, the heat preservation coating is formed by spraying boron nitride coating, and the thickness of the heat preservation coating is 0.8 mm;

[0094] Ingot structure processing:

[0095] The pretreated ingot structure is heated to 470 DEG C in a heating furnace and kept for 10 h, then is rolled on a rolling mill, and is continuously rolled to a rolling plate thickness of 60 mm by using single pass 20 mm deformation, and is rolled to a final thickness of 12 mm by 6 mm deformation per pass;

[0096] After rolling, the plate is heated to 510 DEG C and kept for 2 h, and after keeping, room temperature water quenching is adopted;

[0097] After solid solution quenching, pre-stretching is performed, and the stretching amount is controlled to be 3.5%;

[0098] After pre-stretching, aging treatment is performed, the aging temperature is 150 DEG C, and the aging time is 32 h.

[0099] The product prepared in the present comparative example is shown in Figure 6 .

[0100] The products of each example and the comparative example are subjected to performance detection, wherein the detection of tensile strength and elongation is based on GB / T 228.1-2021 metal material, edge crack visual inspection, and the yield rate = finished plate weight / ingot weight x 100%.

[0101] As shown in Table 1, the results show that the product obtained by using the technology of the present application has improved mechanical properties, effectively prevents the generation of product edge crack defects, and the yield rate is increased by more than 20%. Each comparative example shows that the unique flat ingot raw material setting, sandblasting and heat preservation coating setting, rolling process adjustment and the combination of other processes in the present application are extremely critical.

[0102]

[0103] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, the above examples and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method of producing an aluminum-lithium alloy sheet material, characterized by, It comprises the following steps: Ingot structure pretreatment: using a flat ingot with a concave side as raw material, the side of the flat ingot raw material is in a concave arc surface shape, the depth of the concave side of the flat ingot raw material accounts for 10-20% of the thickness of the side of the flat ingot; the side of the flat ingot is sandblasted at a pressure of 0.7-1.0 MPa using 24-45 mesh brown corundum; then a heat preservation coating is arranged on the side of the flat ingot; Ingot structure processing: the pretreated ingot structure is heated and then kept warm; Then rolling is carried out, at the beginning of rolling, single pass deformation of 5-15 mm is used to roll the ingot structure to make the thickness deformation of the ingot structure account for 25-35% of the total deformation; the deformation of 20-25 mm per pass is used to continue rolling to make the thickness deformation of the ingot structure account for 75-90% of the total deformation, and the deformation of 6-8 mm per pass is used to continue rolling to the final thickness; after rolling, solid solution quenching, pre-stretching and aging treatment are carried out in sequence.

2. The method of producing an aluminum-lithium alloy sheet according to claim 1, wherein In the ingot structure pretreatment, the heat preservation coating comprises a corundum coating or a boron nitride coating, and the thickness of the heat preservation coating is 0.5-1.5 mm.

3. The method of producing an aluminum-lithium alloy sheet according to claim 1, wherein In the ingot structure processing, the pretreated ingot structure is heated to 450-500℃ and kept warm for 10-15 h.

4. The method of producing an aluminum-lithium alloy sheet according to claim 1, wherein In the ingot structure processing, during solid solution quenching, the plate is heated to 510-520℃ and kept warm for 1.5-2.5 h, and then quenched at room temperature.

5. The method of producing an aluminum-lithium alloy sheet according to claim 1, wherein In the ingot structure processing, the stretching amount of pre-stretching ranges from 3% to 4%.

6. The method of producing an aluminum-lithium alloy sheet according to claim 1, wherein In the ingot structure processing, the aging temperature is 140-160℃ and the aging time is 30-35 h.

7. An aluminum-lithium alloy sheet material, characterized by, The aluminum-lithium alloy plate prepared by the method of any one of claims 1-6 has no edge crack, the tensile strength is greater than 585 MPa, the elongation is greater than 12.5%, and the yield is greater than 80%.

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