Integrated thickness section gradient performance control steel member and manufacturing method and application thereof

Abstract

The invention discloses an integrated thickness section gradient performance control steel member and a manufacturing method and application thereof, and belongs to the technical field of automobile and mechanical part manufacturing. The technical problems that in the prior art, when the gradient performance control steel component is prepared, hot pressing forming or welding or laser sintering or other modes are needed, the manufacturing process is complex, consumed time is long, and cost is high are solved. The method realizes performance gradient control of the same steel plate, and can be used for manufacturing parts requiring performance gradient such as an automobile anti-collision beam. The manufacturing method comprises the steps that 1, a steel plate is cut according to the unfolding size of a part; 2, the steel plate is subjected to cold machining to form a cambered surface in a bending deformation or roll bending deformation mode, and a tension stress mode and a compression stress mode are generated respectively; and 3, the steel plate is finely machined according to the part size requirement, and part manufacturing is completed. By means of the method, the steel part with the integrated thickness section gradient performance control function can be prepared, and complex processes such as steel plate hot stamping forming, welding and laser sintering are not needed.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical parts manufacturing, and in particular to an integrated thickness-section gradient performance-controlled steel component and a manufacturing method and application thereof. Background Art

[0002] In some service scenarios, people often hope that the two sides of the same material have different properties or functions, and the two sides with different performances are perfectly combined. For example, in a supersonic combustion ramjet engine, the side of the combustion chamber wall that contacts the combustion gas must withstand extremely high temperatures, and the side that contacts liquid hydrogen must withstand extremely low temperatures. People think of using metals and ceramics together, using ceramics to deal with high temperatures and metals to deal with low temperatures. In the automotive field, ThyssenKrupp has developed the "sandwich steel plate material" Litecor. This material consists of two layers of thin steel plates, with fiber-reinforced heat in the middle, and the engine hood outer panel manufactured has excellent stiffness and lightweight effects. There are also existing technologies that use high-strength steel plate hot forming technology to generate a single-thickness B-pillar reinforcement plate with variable yield strength. The optimized hot-formed variable gradient B-pillar reduces the weight of the vehicle body by 0.773kg while better meeting the requirements of side collisions.

[0003] The above-mentioned materials with gradient performance distribution are usually a combination of two or more materials, and the interface processing technology requires high requirements. The single-thickness B-pillar with variable yield strength obtained by hot forming is to obtain different mechanical properties at different positions of the same part, and to obtain different mechanical properties at the same thickness section of the same material. In particular, there are few reports on achieving different performance gradients at the same thickness section of steel parts. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide an integrated thickness-section gradient performance-controlled steel component and a manufacturing method and application, so as to solve the technical problem that the prior art uses bonding, explosion welding and other connection methods to prepare gradient performance-controlled parts, and cannot achieve integrated preparation of gradient performance-controlled steel parts.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] In one aspect, the present invention provides a method for manufacturing a steel component with integrated thickness-section gradient performance control, the method comprising the following steps:

[0007] Step 1: Cut the steel plate according to the unfolded size of the parts;

[0008] Step 2: cold-processing the steel plate into an arc surface by bending deformation or roller bending deformation, thereby generating tension and compression force modes respectively;

[0009] Step 3: Finish the steel plate according to the part size requirements to complete the part manufacturing.

[0010] Furthermore, in step 2, the microstructure of the steel plate before and after bending or roll bending is a completely austenitic structure.

[0011] Furthermore, in step 1, the raw material of the steel part is a plate.

[0012] Furthermore, in step 2, the bending deformation and the roll bending deformation are both performed at room temperature.

[0013] Furthermore, in step 2, when bending deformation is adopted, the bending radius is equal to 2-10 times the thickness of the steel plate, that is, d=2t-10t; wherein d is the bending radius and t is the thickness of the steel plate.

[0014] Furthermore, in step 2, when bending deformation is adopted, the bending radius is equal to four times the thickness of the steel plate, that is, d=2t; wherein d is the bending radius and t is the thickness of the steel plate.

[0015] Furthermore, in step 2, when a roll bending machine is used to perform roll bending deformation on the steel plate, the steel plate is bent and deformed with a certain arc under the cooperation of two supporting rolls and one active roll, and the plate surface on one side of the supporting roll is under tensile stress, and the plate surface on the side of the active roll is under compressive stress.

[0016] Furthermore, in step 2, when a roll bending machine is used to roll bend the steel plate, the roll bending radius is 30-100 times the thickness of the steel plate, that is, d=30t-100t; wherein d is the roll bending radius and t is the thickness of the steel plate.

[0017] On the other hand, the present invention also provides an integrated thickness-section gradient performance-controlled steel component, which is prepared by the above-mentioned integrated thickness-section gradient performance-controlled steel component manufacturing method.

[0018] Furthermore, the present invention also provides an application of an integrated steel component with thickness-section gradient performance control, and the integrated steel component with thickness-section gradient performance control can be applied to automobile parts.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] (1) The prior art uses hot stamping or welding or nanoparticles plus laser sintering to prepare steel parts with gradient performance control, and the preparation conditions are complex, the preparation process is time-consuming, and the preparation cost is high. Compared with the prior art, the present invention can obtain an integrated thickness section gradient performance controlled steel component by bending deformation or roll bending deformation. It is prepared at room temperature, and the preparation conditions and preparation process are simple. It does not require heat treatment, thermal deformation, etc. to achieve performance gradient control, so it can save preparation costs. The present invention provides a new technical path for preparing steel components with cross-sectional gradient performance control, and provides technical support for the manufacture of high-performance parts.

[0021] (2) The method for manufacturing a steel component with integrated thickness-section gradient performance control provided by the present invention does not require areas with different performance to be connected by bonding or welding, and has the continuity of homogeneous materials;

[0022] (3) When the roll bending machine used in the present invention is used to roll bend the steel plate, only two supporting rolls and one active roll are needed to cooperate to achieve the bending deformation of the steel plate. The roll bending deformation device has a simple structure, is easy to operate, and has a low roll bending deformation cost. The thickness cross-sectional gradient performance of the steel component can be controlled by controlling the rolling radius and the thickness of the steel plate, and has a good prospect for large-scale application.

[0023] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings are only for the purpose of illustrating specific embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0025] Figure 1 Schematic diagram of roll bending process;

[0026] Figure 2 Schematic diagram of steel plate after roller bending;

[0027] Reference numerals:

[0028] 1- steel plate; 2- driving roller; 3- supporting roller; 4- pressure surface; 5- tension surface. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0030] The present invention provides an integrated thickness-section gradient performance-controlled steel component and a manufacturing method and application thereof, comprising the following steps:

[0031] In one aspect, the present invention provides a method for manufacturing an integrated thickness-section gradient performance-controlled steel part, the manufacturing method comprising the following steps:

[0032] Step 1: Cut the steel plate according to the unfolded size of the parts;

[0033] Step 2: cold-processing the steel plate into an arc surface by bending deformation or roller bending deformation, thereby generating tension and compression force modes respectively;

[0034] Step 3: Finish the steel plate according to the part size requirements to complete the part manufacturing.

[0035] The prior art uses hot stamping or welding or nanoparticles plus laser sintering to prepare steel parts with gradient performance control, and the preparation conditions are complex, the preparation process is time-consuming, and the preparation cost is high. Compared with the prior art, the present invention can obtain an integrated thickness section gradient performance controlled steel component by bending deformation or roll bending deformation. It is prepared at room temperature, and the preparation conditions and preparation process are simple. It does not require heat treatment, thermal deformation, etc. to achieve performance gradient control, so it can save preparation costs. The present invention provides a new technical path for preparing steel components with cross-sectional gradient performance control, and provides technical support for the manufacture of high-performance parts.

[0036] In the above step 2, the microstructure of the steel plate before and after bending or roll bending is a complete austenite structure. The austenite structure does not undergo phase transformation during bending deformation or roll bending deformation. This is because austenite crystals have more slip systems, which easily generate a large number of dislocations during deformation and can form a higher dislocation density.

[0037] Specifically, austenitic steel has many slip systems and mainly dislocation strengthening. A large number of dislocations are generated during bending or roll bending deformation. As the deformation increases, the dislocation density continues to increase, the internal stress continues to increase, and the outer arc surface is subjected to tensile stress. When the tensile test is carried out, the internal strength level is continuously strengthened, resulting in an increase in the strength level. The inner arc surface is subjected to compressive stress. When the tensile test is carried out, the dislocation is easily activated, resulting in a decrease in yield strength, thereby forming a gradient distribution of mechanical properties on the same thickness section. In addition, since welding is not required, the performance gradient transition of the steel parts of the present invention is more uniform.

[0038] It should be noted that in the above step 1, the raw material of the steel part is a plate, and therefore, the raw material of the steel part of the present invention is easy to obtain.

[0039] In the above step 2, the bending deformation and the roll bending deformation are both performed at room temperature. Compared with the prior art, the preparation conditions of the present invention are simple, low-cost, easy to operate and easy to obtain.

[0040] In the above step 2, the method of cold working the steel plate into an arc surface includes bending deformation or roll bending deformation. The steel plate is cold worked into an arc surface by bending deformation or roll bending deformation, which respectively generates tensile and compressive force modes.

[0041] When the roll bending machine used in the present invention is used to roll bend the steel plate, only two supporting rolls and one active roll are needed to cooperate to achieve the bending deformation of the steel plate. The roll bending deformation device has a simple structure, is easy to operate, and has a low roll bending deformation cost. The thickness cross-sectional gradient performance of the steel component can be controlled by controlling the rolling radius and the thickness of the steel plate, and has a good prospect for large-scale application.

[0042] Further, in step 2, when bending deformation is adopted, the bending radius is equal to 2-6 times the thickness of the steel plate, that is, d=2t-10t; wherein d is the bending radius and t is the thickness of the steel plate; such as the bending radius is equal to 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times or 10 times the thickness of the steel plate.

[0043] For example, the steel plate is subjected to a bending process of d=2t by a bending machine, wherein d is the bending radius and t is the thickness of the steel plate; or, the steel plate is subjected to a bending process of d=4t by a bending machine, wherein d is the bending radius and t is the thickness of the steel plate; the steel plate is subjected to a bending process of d=8t by a bending machine, wherein d is the bending radius and t is the thickness of the steel plate.

[0044] In step 2, when a roll bending machine is used to perform roll bending deformation on the steel plate, the steel plate is bent and deformed to a certain arc with the cooperation of two supporting rolls and one active roll, and the plate surface on one side of the supporting roll is under tensile stress, while the plate surface on the other side of the active roll is under compressive stress.

[0045] In the above step 2, it should be pointed out that the steel (made) parts are deformed by bending or rolling to form a stress state in which the inner arc surface is compressed and the outer arc surface is tensile. After processing, the strength of the tensile surface of the steel parts is improved, the elongation after fracture of the plastic index is reduced, the yield strength of the compressive surface is reduced and the plastic index is improved, thereby achieving a gradient distribution of mechanical properties on the same thickness section of the steel plate.

[0046] In step 2, when a roll bending machine is used to roll bend the steel plate, the roll bending radius is 30-100 times the thickness of the steel plate, that is, d=30t-100t; wherein d is the roll bending radius and t is the thickness of the steel plate; for example, d=30t; d=50t; d=80t, wherein d is the roll bending radius and t is the thickness of the steel plate. For example, the roll bending radius is 30 times, 40 times, 50 times, 60 times, 70 times, 80 times, and 90 times the thickness of the steel plate.

[0047] Compared with the prior art, the present invention provides an integrated thickness-section gradient performance-controlled steel component and a manufacturing method and application, which, through bending or roll bending, forms a stress state in which the inner arc surface is compressed and the outer arc surface is tensile, thereby forming a gradient performance in which the outer arc surface strength is increased, the middle strength remains unchanged, and the inner arc surface is softened relative to the original steel plate, forming a uniform gradient distribution of mechanical properties on the same thickness section.

[0048] On the other hand, the present invention also provides an integrated thickness-section gradient performance-controlled steel component, which is prepared by the above-mentioned integrated thickness-section gradient performance-controlled steel component manufacturing method.

[0049] Furthermore, the present invention also provides an application of an integrated thickness-section gradient performance-controlled steel component, which can be applied to a combustion chamber of a supersonic combustion ramjet engine and automotive parts.

[0050] The method for manufacturing a steel component with integrated thickness-section gradient performance control provided by the present invention does not require areas with different performance to be connected by bonding or welding, and has the continuity of homogeneous materials.

[0051] Test Example 1

[0052] The steel plate (the microstructure of the steel plate is austenite) was bent by a bending machine at d=2t, d=4t, d=8t and d=10t respectively, where d is the bending radius and t is the thickness of the steel plate. After bending, tensile samples were taken from the tensile and compressive surfaces, and the measured changes in mechanical properties are shown in Table 1.

[0053] Table 1 Mechanical properties of steel plates after bending at different amplitudes

[0054]

[0055] It can be seen from Table 1 above that the tensile strength (Rm) and yield strength (Rp0.2) of each tension surface are increased by more than 200MPa, and the elongation after fracture (A) is reduced to less than 20%; while the tensile strength of the compression surface is not much different from the performance of the original steel plate, but the yield strength is reduced by more than 100MPa, and the elongation after fracture is slightly improved.

[0056] Test Example 2

[0057] In this embodiment, a roll bending machine is used to roll bend the steel plate (microstructure austenite of the steel plate), and the roll bending radius is 30-100 times the thickness of the steel plate, for example, d=30t, d=50t, d=80t, d=100t, where d is the roll bending radius and t is the thickness of the steel plate; when d=50t, the processing schematic diagram is as shown in Figure 1 , the schematic diagram after roller bending is as follows Figure 2 .

[0058] Table 2 Mechanical properties of steel parts when roll bending radius d = 30t steel plate thickness

[0059] Roller bending radius d = 30t Rm(MPa) Rp0.2(MPa) A(％) Roller bending tension surface 1020 870 37.5 Roll bending pressure surface 1010 608 43.5 Original Face 980 800 40.5

[0060] Table 3 Mechanical properties of steel parts when roll bending radius d = 50t steel plate thickness

[0061] Roller bending radius d = 50t Rm(MPa) Rp0.2(MPa) A(％) Roller bending tension surface 1010 850 39.5 Roll bending pressure surface 1007 615 42.3 Original Face 980 800 40.5

[0062] Table 4 Mechanical properties of steel parts when roll bending radius d = 80t steel plate thickness

[0063] Roller bending radius d = 80t Rm(MPa) Rp0.2(MPa) A(％) Roller bending tension surface 1008 845 38.5 Roll bending pressure surface 998 675 43.3 Original Face 980 800 40.5

[0064] Table 5 Mechanical properties of steel parts when roll bending radius d = 100t steel plate thickness

[0065]

[0066]

[0067] Samples were taken on the tensile and compressive surfaces, and the tensile properties are shown in Tables 2 to 5. The tensile strength of the steel plate on the tensile and compressive surfaces did not change much, but the yield strength of the tensile surface increased by 50 MPa, and the plasticity did not change much but slightly decreased, while the yield strength of the compressive surface decreased by 185 MPa, and the elongation after fracture increased.

[0068] The effect of bending deformation on the formation of gradient mechanical properties can be verified through the above-mentioned test examples 1 and 2. When the bending radius is small (such as roller bending), the tensile surface of the steel is slightly strengthened, the elongation after forging does not change much, the yield strength of the compressive surface is significantly reduced, and the elongation after fracture is significantly increased; when the bending radius is large (such as bending), the tensile strength and yield strength of the tensile surface are significantly increased, the elongation at fracture is significantly reduced, the tensile strength of the compressive surface does not change much, the yield strength is significantly reduced, and the elongation after fracture is significantly increased.

[0069] Example 1

[0070] This embodiment provides a method for manufacturing an integrated thickness-section gradient performance-controlled steel component, wherein the steel plate is made of austenitic steel, and the manufacturing method comprises the following steps:

[0071] Step 1: Cut the steel plate according to the unfolded size of the parts;

[0072] The dimensions of the austenitic steel plate of this embodiment are: 2m×2m×0.005m (length×width×height);

[0073] Step 2: cold-processing the austenitic steel plate of the above-mentioned size into a curved surface by means of roll bending deformation, thereby generating tension and compression force modes respectively;

[0074] In the above step 2, during the roll bending process, the austenitic steel plate is subjected to roll bending deformation, wherein the roll bending process is performed according to d=100t, wherein d is the roll bending radius, and t is the thickness of the steel plate; since it is known that the thickness of the austenitic steel plate is 0.005m, the roll bending radius is 0.5m; during the roll bending process, two support rollers are placed in parallel on a workbench, and the austenitic steel plate is placed on the two support rollers, and then, the active roller is used to press down from above the austenitic steel plate, that is, the steel plate is subjected to bending deformation with a roll bending radius of 0.5m under the cooperation of the two support rollers and one active roller. For the austenitic steel plate after roll bending, its plate surface is under tensile stress on one side of the two support rollers, and its plate surface is under compressive stress on the side of the active roller.

[0075] Step 3: Finish the steel plate according to the part size requirements to complete the part manufacturing. The mechanical properties of the obtained steel part are shown in Table 6 below.

[0076] Table 6 Mechanical properties of steel parts when roll bending radius d = 100t steel plate thickness

[0077] Roll bending radius d = 100t Rm(MPa) Rp0.2(MPa) A(％) Roller bending tension surface 995 830 39.2 Roll bending pressure surface 992 715 41.2 Original Face 980 800 40.5

[0078] Samples were taken on the tensile and compressive surfaces of the roll bends. The tensile properties are shown in Table 6. The tensile strength of the steel plate on both the tensile and compressive surfaces increased, but the yield strength of the tensile surface increased by 115 MPa, and the plasticity changed slightly, while the yield strength of the compressive surface decreased by 85 MPa, and the elongation after fracture increased.

[0079] In summary, the present invention can obtain an integrated steel component with thickness-section gradient performance control through bending deformation or roll bending deformation. It is prepared at room temperature, and the preparation conditions and process are simple. It does not require heat treatment, thermal deformation, etc. to achieve performance gradient control, thereby saving preparation costs. The present invention provides a new technical path for preparing steel components with cross-section gradient performance control, and provides technical support for the manufacture of high-performance parts.

[0080] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for manufacturing a steel component with integrated thickness-section gradient performance control, characterized in that: The following steps are involved: Step 1: Cut the steel plate according to the unfolded size of the parts; Step 2: cold-processing the steel plate into an arc surface by bending deformation or roller bending deformation, thereby generating tension and compression force modes respectively; Step 3: Finish the steel plate according to the part size requirements to complete the part manufacturing.

2. The method for manufacturing a steel component with integrated thickness-section gradient performance control according to claim 1, characterized in that: In step 2, the microstructure of the steel plate before and after bending or rolling is a completely austenitic structure.

3. The method for manufacturing a steel component with integrated thickness-section gradient performance control according to claim 2, characterized in that: In step 1, the raw material of the steel part is a plate.

4. The method for manufacturing a steel component with integrated thickness-section gradient performance control according to claim 3, characterized in that: In the step 2, the bending deformation and the roll bending deformation are both performed at room temperature.

5. The method for manufacturing a steel component with integrated thickness-section gradient performance control according to claim 4, characterized in that: In step 2, when bending deformation is adopted, the bending radius is equal to 2-10 times the thickness of the steel plate, that is, d=2t-10t; wherein d is the bending radius and t is the thickness of the steel plate.

6. The method for manufacturing a steel component with integrated thickness-section gradient performance control according to claim 5, characterized in that: In step 2, when bending deformation is adopted, the bending radius is equal to four times the thickness of the steel plate, that is, d=2t; wherein d is the bending radius and t is the thickness of the steel plate.

7. The method for manufacturing a steel component with integrated thickness-section gradient performance control according to claim 4, characterized in that: In step 2, when a roll bending machine is used to perform roll bending deformation on the steel plate, the steel plate is bent and deformed to a certain arc with the cooperation of two supporting rolls and one active roll, and the plate surface on one side of the supporting roll is under tensile stress, and the plate surface on the side of the active roll is under compressive stress.

8. The method for manufacturing a steel component with integrated thickness-section gradient performance control according to claim 7, characterized in that: In step 2, when a roll bending machine is used to roll bend the steel plate, the roll bending radius is 30-100 times the thickness of the steel plate, that is, d=30t-100t; wherein d is the roll bending radius and t is the thickness of the steel plate.

9. An integrated thickness section gradient performance controlled steel component, characterized in that: The steel structure is prepared by the method for manufacturing a steel structure with integrated thickness-section gradient performance control as described in any one of claims 1 to 8.

10. Application of an integrated thickness section gradient performance controlled steel component, characterized in that: A steel member with integrated thickness-section gradient performance control as claimed in claim 9; or, prepared by the method for manufacturing a steel member with integrated thickness-section gradient performance control as claimed in any one of claims 1 to 8; The integrated thickness-section gradient performance-controlled steel component is applied to automobile parts.

Images