A method for predicting deformation of plate butt welding based on inherent strain method

Abstract

The present invention provides a method for predicting deformation of plate butt welds based on an inherent strain method. The method comprises: providing a group of plates of the same material with different thicknesses, establishing a welding deformation prediction model based on the plates; obtaining the plate thicknesses, and using the deformation prediction model to obtain the shrinkage of plates of different thicknesses, thereby establishing a curve relationship diagram of the shrinkage and plate thickness under unit inherent strain and regional width; and calculating the shrinkage angle of the plate butt welds based on the curve relationship diagram to determine the maximum deformation of the plate shrinkage. By calculating the shrinkage angle of the plate butt welds based on the curve relationship diagram to determine the maximum deformation of the plate shrinkage, the present invention enables technicians to approximately calculate and predict the maximum deformation of the plate shrinkage caused by welding deformation through the prediction method of the present invention, thereby quickly guiding work in the design and production stages.

Description

Technical Field

[0001] The present invention relates to the technical field of plate welding, and in particular to a method for predicting deformation of plate butt welding based on an inherent strain method. Background Art

[0002] Welding is a process method for forming and manufacturing parts in the modern machinery manufacturing industry. Welding is widely used in the fields of automobiles, rail transportation, ships, heavy machinery industry, nuclear industry, etc. At present, the numerical simulation methods of welding deformation include the thermo-elastic-plastic finite element method and the inherent strain method. The thermo-elastic-plastic finite element method realizes the thermo-solid coupling simulation of welding by programming the heat source movement subroutine, which can simulate the welding process more accurately, but it has high requirements on computer hardware, so the computing power for large welds is limited. The inherent strain method loads the inherent strain obtained by theoretical calculation to the weld and the near-weld area, and a finite element calculation can simulate the welding deformation. It is suitable for the simulation of large welds.

[0003] General technicians lack basic computer knowledge and professional knowledge of welding simulation. It is difficult to accurately estimate the deformation of the workpiece after welding based on experience. In addition, the experimental cost of large welded parts is high and the cycle is long. Therefore, the existing plate butt welding deformation prediction method has the technical defect of not being able to quickly guide the work in the design and production stages.

[0004] In view of this, it is necessary to improve the existing method for predicting deformation of plate butt welding to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to disclose a method for predicting the deformation of plate butt welding based on the inherent strain method, which is used to solve the many defects of the plate butt welding deformation prediction methods in the prior art, so as to achieve the purpose of quickly guiding the work in the design and production stages.

[0006] To achieve one of the above objectives, the present invention provides a method for predicting plate butt weld deformation based on the inherent strain method, comprising:

[0007] Providing a set of plates of the same material with different thicknesses, and establishing a welding deformation prediction model based on the plates;

[0008] Obtaining the thickness of the plate, and obtaining the shrinkage of the plates of different thicknesses using the deformation prediction model, so as to establish a curve relationship diagram between the shrinkage and the plate thickness under unit inherent strain and area width of the plate;

[0009] The shrinkage angle of the plate butt welding is calculated based on the curve relationship diagram to determine the maximum deformation amount of the plate shrinkage.

[0010] As a further improvement of the present invention, providing a group of plates of the same material with different thicknesses, and establishing a welding deformation prediction model based on the plates includes:

[0011] Based on the welding process required for the plate weld, the size of the inherent strain application area is calculated and the plate edge point is obtained, wherein the plate edge point is located farthest from the vertical weld and has the maximum deformation;

[0012] Obtaining the shrinkage of the inherent strain application region in the state in which the inherent strain is applied based on the shrinkage of the inherent strain application region in a free state, wherein the free state refers to a state in which the height of the inherent strain application region is equal to the thickness of the plate;

[0013] Based on the shrinkage amount, obtaining a shrinkage angle of the weld;

[0014] Based on the shrinkage angle, the displacement of the edge point of the plate is obtained.

[0015] As a further improvement of the present invention, obtaining the thickness of the plate and obtaining the shrinkage of the plate with different thicknesses using the deformation prediction model to establish a curve relationship diagram between the shrinkage and the plate thickness under unit inherent strain and area width includes:

[0016] establishing a three-dimensional model based on the cross-sectional dimensions of the inherent strain application region to divide the inherent strain application region, applying the inherent strain to the inherent strain application region according to the anisotropy of the thermal expansion coefficient of the plate, and performing a finite element analysis on the inherent strain application region to which the inherent strain is applied by setting analysis steps and load constraints and dividing a mesh in the inherent strain application region to which the inherent strain is applied;

[0017] The plate thickness of the plate is obtained, and the shrinkage of the plate with different plate thicknesses is obtained through the finite element analysis, so as to establish a curve relationship diagram between the shrinkage and the plate thickness under unit inherent strain and area width.

[0018] As a further improvement of the present invention, the calculation of the shrinkage angle of the plate butt weld based on the curve relationship diagram to determine the maximum deformation of the plate shrinkage includes:

[0019] Obtaining geometric parameters, material parameters, and welding process parameters of the plate, and calculating the single-pass or multi-pass welding heat source bus energy and the eccentricity of the inherent strain application area to determine the cross-sectional size of the inherent strain application area;

[0020] Calculating the inherent strain based on the cross-sectional dimensions of the inherent strain application region, and calculating the inherent strain per unit length;

[0021] Calculating the shrinkage based on the inherent strain per unit length and the curve relationship diagram;

[0022] calculating a contraction angle based on the contraction amount and the height of the inherent strain region;

[0023] Based on the shrinkage angle, the maximum deformation of the edge point of the plate is calculated.

[0024] As a further improvement of the present invention, the analysis step is temperature-displacement coupling, the load constraint includes an environmental constraint at -1°C, and the grid is set as a temperature-displacement coupling grid.

[0025] As a further improvement of the present invention, the geometric parameters include:

[0026] the length, width and thickness of the sheet;

[0027] The material parameters include:

[0028] density, specific heat, thermal conductivity, plasticity, elasticity and thermal expansion coefficient of the sheet material;

[0029] The welding process parameters include:

[0030] The voltage, current, thermal efficiency and welding speed of the plate welding.

[0031] As a further improvement of the present invention, the step of obtaining geometric parameters, material parameters, and welding process parameters of the plate, and calculating the single-pass or multi-pass welding heat source bus energy and the eccentricity of the inherent strain application area to determine the cross-sectional size of the inherent strain application area includes:

[0032] Calculate the total heat source energy for single or multi-pass welding: , where η is the heat source efficiency, U is the voltage, I is the current, and v is the welding speed;

[0033] Calculate the eccentricity of the region where the inherent strain is applied: , where h′ is the height of the inherent strain application area and h is the plate thickness;

[0034] Then the cross-sectional dimensions of the inherent strain application area are: ,in, , a is the width of half of the inherent strain application area, and e is the eccentricity value.

[0035] As a further improvement of the present invention, the calculating the maximum deformation of the edge point of the plate based on the shrinkage angle includes:

[0036] Calculate the maximum deformation of the plate edge point based on the arc length formula and the contraction angle;

[0037] The maximum deformation = θ × π / 180 × (ba), where θ is the contraction angle, b is the width of the plate, and a is the width of half the area where the inherent strain is applied.

[0038] As a further improvement of the present invention, the inherent strain is a transverse inherent strain.

[0039] As a further improvement of the present invention, the thickness of the plate is 4-100 mm.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention provides a method for predicting deformation of plate butt welding based on the inherent strain method. By providing two plates, a welding deformation prediction model is established based on the plates; the plate thickness is obtained, and the shrinkage of the plate thickness with different plate thicknesses is obtained through the deformation prediction model to establish a curve relationship diagram of the shrinkage and the plate thickness under the unit inherent strain and regional width of the plate; the shrinkage angle of the plate butt welding is calculated based on the curve relationship diagram to determine the maximum deformation of the plate shrinkage. Through the prediction method of the present invention, technicians can approximately calculate and predict the maximum deformation of the plate shrinkage caused by welding deformation, thereby quickly guiding the work in the design and production stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a flow chart of a method for predicting deformation of plate butt welding based on the inherent strain method of the present invention;

[0043] Figure 2 The present invention provides a set of plates, and a flow chart of establishing a welding deformation prediction model based on the plates;

[0044] Figure 3 A flowchart for obtaining the thickness of the plate and obtaining the shrinkage of the plate with different thicknesses using the deformation prediction model to establish a curve relationship diagram of the shrinkage and the plate thickness under unit inherent strain and area width;

[0045] Figure 4 This is a flow chart of the present invention for calculating the shrinkage angle of the plate butt welding based on the curve relationship diagram to determine the maximum deformation amount of the plate shrinkage;

[0046] Figure 5 This is a simplified schematic diagram of the transverse inherent strain mechanism of the present invention;

[0047] Figure 6 The simulation results of one embodiment of the present invention are shown in FIG. 1 , where (c) is the deformation result when both the transverse natural strain and the longitudinal natural strain are applied, and (d) is the deformation result when only the transverse natural strain is applied.

[0048] Figure 7 Schematic diagram of the welding deformation calculation model of the present invention;

[0049] Figure 8 This is a schematic diagram of the transverse contraction of the plate of the present invention in a free state;

[0050] Figure 9 Schematic diagram of the inherent strain application area of ​​the present invention;

[0051] Figure 10 This is a calculation relationship diagram of the eccentricity value of the inherent strain application area of ​​the present invention;

[0052] Figure 11 This is a linear relationship diagram between the width of the inherent strain region and the shrinkage amount of the present invention;

[0053] Figure 12 is a linear relationship diagram between inherent strain and shrinkage of the present invention;

[0054] Figure 13 This is a graph showing the relationship between the thickness of the 316L stainless steel plate and the shrinkage under unit inherent strain and width;

[0055] Figure 14 A welding simulation deformation cloud diagram according to an embodiment of the present invention;

[0056] Figure 15 This is a welding simulation deformation cloud diagram according to another embodiment of the present invention. DETAILED DESCRIPTION

[0057] The present invention is described in detail below with reference to the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in this field based on these embodiments are all within the scope of protection of the present invention.

[0058] The method for predicting deformation of plate butt welding based on the inherent strain method disclosed in the present invention aims to obtain a curve relationship diagram of the shrinkage amount and plate thickness under the unit inherent strain and regional width of the plate to calculate the shrinkage angle of the plate butt welding, so as to determine the maximum deformation of the plate shrinkage, thereby achieving the purpose of quickly guiding the work in the design and production stages.

[0059] It should be noted that the thickness of the plate butt joint in this embodiment is medium-thick plate or thick plate type. Since the thin plate does not meet the assumed model in this embodiment that regards the outside of the inherent strain application area as a "rigid area", it is not suitable for the deformation calculation of thin plates, but only suitable for the welding deformation calculation of medium-thick plates of 4-25mm or thick plates of 25-100mm.

[0060] Ginseng Figure 1As shown, this embodiment discloses a method for predicting deformation of plate butt welding based on the inherent strain method (hereinafter referred to as the "method"), which includes the following steps S1 to S3.

[0061] Step S1: providing a group of plates of the same material with different thicknesses, and establishing a welding deformation prediction model based on the plates;

[0062] Specifically, refer to Figure 1 、 Figure 2 and Figure 5 As shown, two plates are provided, and a welding deformation prediction model is established based on the plates, including the following steps S11 to S14:

[0063] S11. Based on the welding process required for the plate weld, calculate the size of the inherent strain application area and obtain the plate edge point, wherein the plate edge point is located farthest from the vertical weld and has the maximum deformation;

[0064] Specifically, refer to Figure 2 and Figure 5 As shown, the plate includes a first plate 10 and a second plate 20. Two butt joints are formed at the adjacent ends of the first plate 10 and the second plate 20, and a weld is formed at the butt joint structure. According to the inherent strain theory, the weld and the area near the weld are deformed by applying the inherent strain 40. The area where the inherent strain 40 is applied is considered a flexible deformable area, and the other areas are considered rigid areas. Figure 5 This is a schematic diagram of the inherent strain mechanism model used in the welding deformation prediction model of this embodiment. This model is a simplification of the actual deformation state. Because the areas outside the inherent strain application area constrain the area, limiting its displacement, the degree of deformation contraction is uneven. Consequently, the lateral inherent strain causes the flexible area to deform into a trapezoidal region 30, while the "rigid area" outside this region undergoes warping deformation. Welding deformation is also a complex process of mutual influence and superposition.

[0065] S12. Based on the shrinkage of the inherent strain application area in a free state, obtain the shrinkage of the inherent strain application area in a state where the inherent strain is applied, wherein the free state refers to a state where the height of the inherent strain application area is equal to the thickness of the plate.

[0066] Specifically, refer to Figure 2 、 Figures 5 and 6 As shown in Figure 3, the welding deformation prediction model only considers the deformation caused by the transverse inherent strain, but ignores the influence of the longitudinal inherent strain. Figure 2 Shown is a set of welding simulation results. Figure 2 (c) Deformation result when both transverse and longitudinal natural strains are applied. The deformation is 0.1924 mm. Figure 2(d) is the deformation result when only the transverse inherent strain acts, and the deformation amount is 0.1907 mm. It can be seen that the transverse inherent strain plays a dominant role in welding deformation. Therefore, the welding deformation prediction model of the present invention only considers the deformation caused by the transverse inherent strain 40, while ignoring the slight effect brought by the longitudinal inherent strain. This also simplifies the subsequent theoretical calculation method of welding deformation.

[0067] S13. Obtain the shrinkage angle of the weld based on the shrinkage amount.

[0068] Specifically, refer to Figure 2 、 Figures 5 to 8 As shown, the transverse inherent strain application area 40 is a rectangular area, the upper boundary of the rectangular area is regarded as the maximum deformation, and the lower boundary is regarded as the rigid non-deformation displacement; Figure 5 The upper edge of the natural strain application region (a) exhibits the greatest deformation due to its distance from the constraint region, while the lower edge, connected to the rigid region, is considered to be undeformed. Considering the upper boundary point's distance from the rigid constraint region, its contraction in the free state is used to approximate its contraction in the constrained state. To more conveniently determine the deformation of the upper edge of the transverse natural strain application region, its lower contraction in the free state is used as an approximation.

[0069] S14. Based on the shrinkage angle, obtain the displacement of the edge point of the plate.

[0070] Specifically, refer to Figure 7 As shown, the weld shrinkage angle is obtained by using inverse trigonometric functions; see Figure 7 As shown, the contraction angle can be expressed as: , where: θ is the contraction angle, x is the maximum lateral contraction, and h′ is the height of the inherent strain application area;

[0071] The displacement of the plate edge point is approximately calculated using the arc length formula. The displacement can be expressed as:

[0072]

[0073] Where: θ is the shrinkage angle, l is the distance from the edge of the plate to the area where the inherent strain is applied.

[0074] S2. Obtaining the thickness of the plate, and obtaining the shrinkage of different plate thicknesses through a deformation prediction model, so as to establish a curve relationship diagram between the shrinkage and the plate thickness under unit inherent strain and area width of the plate;

[0075] Specifically, refer to Figure 2 、 Figures 5 to 9 As shown, the plate thickness is obtained, and the shrinkage of different plate thicknesses is obtained through a deformation prediction model to establish a curve relationship diagram of shrinkage and plate thickness under unit inherent strain and area width, including the following steps S21 to S22:

[0076] S21. Establish a three-dimensional model based on the cross-sectional dimensions of the inherent strain application area to divide the inherent strain application area, apply inherent strain to the inherent strain application area according to the anisotropy of the thermal expansion coefficient of the plate, and perform finite element analysis on the inherent strain application area by setting analysis steps and load constraints and dividing the mesh in the inherent strain application area to which the inherent strain is applied.

[0077] Specifically, refer to Figure 3 、 Figure 6 and Figure 10 As shown, a set of butt joint geometry, material parameters, and welding process parameters are obtained. The transverse inherent strain is calculated based on inherent strain theory, and the cross-sectional dimensions of the area where the inherent strain is applied are determined. As one embodiment of the present invention, the base material geometry is selected as length × width × thickness = 100 mm × 50 mm × 4 mm. The welding process parameters are voltage 10 V, current 70 A, thermal efficiency 0.8, welding speed 0.3 cm / s, and single-pass welding. The material type is 316L stainless steel, and the material parameters at room temperature are shown in Table 1 below.

[0078] It should be noted that the welding process parameters in the above examples are all for the welding method of the workpiece, and the specific welding process parameters can be determined by those skilled in the art.

[0079] Table 13 Material parameters of 16L stainless steel at room temperature

[0080]

[0081] The inherent strain theory is a technology known to those skilled in the art, and is briefly introduced in the present invention to clearly describe the embodiments.

[0082] According to the inherent strain theory, the welding line energy Q can be expressed as:

[0083]

[0084] Where: η is the heat source efficiency, U is the voltage, I is the current, and v is the welding speed.

[0085] Transverse and longitudinal inherent strains W of single-pass welds y 、W x It can be expressed as:

[0086]

[0087]

[0088] The sum of the transverse and longitudinal inherent strains of multi-pass welding W y 、W x It can be expressed as:

[0089]

[0090]

[0091] Where: ξ and K are the transverse and longitudinal inherent strain coefficients respectively. Generally, ξ can be taken as 1.8×10 -6 cm 3 / J, K can be 8.6×10 -7 cm 3 / J;F w is the cross-sectional area of ​​the weld; σ s is the yield strength; E is the elastic modulus.

[0092] In the finite element calculation software, after dividing the inherent strain application area, the anisotropy of the thermal expansion coefficient of the material in the inherent strain area is defined and the unit temperature load is applied to achieve the loading of the inherent strain in the longitudinal and transverse directions of the weld. The thermal expansion coefficient α of the longitudinal and transverse inherent strains x , α y The following formula can be obtained:

[0093]

[0094]

[0095] Where: A is the cross-sectional area of ​​the inherent strain application area; ΔT is the unit temperature load; ε x , ε y are the longitudinal and transverse natural strains per unit length, respectively.

[0096] See Figure 6 , the inherent strain application area A of the butt joint can be expressed as:

[0097]

[0098]

[0099] Where: a is the width of half of the inherent strain application area, its value depends on the welding process, generally the weld and near-weld area; e is the eccentricity value.

[0100] S22. Obtain the plate thickness of the plate, and obtain the shrinkage of different plate thicknesses through finite element analysis to establish a curve relationship diagram between the shrinkage and the plate thickness under unit inherent strain and area width.

[0101] Specifically, refer to Figure 2 、 Figures 6 to 10As shown, a three-dimensional model is established in the finite element software, the inherent strain application area is divided, the transverse inherent strain value is applied to the area using the anisotropy of the thermal expansion coefficient, the material properties are assigned, the analysis steps and load constraints are set, the mesh is divided, and the finite element analysis is performed; the present invention approximates the shrinkage of the upper edge of the trapezoid with the shrinkage of the free state, and the simulation obtains the transverse shrinkage x=0.0145mm of the above embodiment. The influence of the geometric parameters of the base material on the transverse shrinkage is shown in Table 2.

[0102] Table 2 Effect of base material geometric parameters on transverse shrinkage

[0103] Parameter Type Original size Present value Transverse shrinkage length 100mm 50mm 0.01447mm thickness 4mm 3mm 0.01554mm width 50mm 40mm 0.01452mm

[0104] As can be seen from Table 2, the shrinkage is highly correlated with the thickness and is negatively correlated. If a graphical relationship between plate thickness and shrinkage is established, the maximum deformation of welding can be directly calculated using a simplified formula.

[0105] By changing the thickness of the butt joint, the transverse shrinkage under different plate thicknesses is simulated and a curve relationship between the shrinkage and plate thickness under unit inherent strain and area width is established. In addition to thickness, the value and width of the applied transverse inherent strain also affect the shrinkage. Figure 11 and Figure 12 As shown, it can be found that the two have a good linear relationship with the shrinkage. The shrinkage under unit inherent strain and width is defined as shrinkage / inherent strain value / area width, so that the influencing factors of the two can be eliminated. The unit inherent strain and shrinkage under width of 316L stainless steel material with different plate thicknesses are as follows Figure 13 shown.

[0106] S3. Calculate the shrinkage angle of the plate seam welding based on the curve relationship diagram to determine the maximum deformation of the plate shrinkage;

[0107] Specifically, refer to Figure 1 、 Figures 4 to 15 As shown, the shrinkage angle of the plate butt welding is calculated based on the curve relationship diagram to determine the maximum deformation of the plate shrinkage, including the following steps S31 to S35.

[0108] S31. Obtain geometric parameters, material parameters, and welding process parameters of the plate, and calculate the single-pass or multi-pass welding heat source bus energy and the eccentricity value of the inherent strain application area to determine the cross-sectional size of the inherent strain application area.

[0109] S32. Calculate the inherent strain based on the cross-sectional dimensions of the inherent strain application region, and calculate the inherent strain per unit length.

[0110] S33. Calculate the shrinkage based on the inherent strain per unit length and the curve relationship diagram.

[0111] S34. Calculate the shrinkage angle based on the shrinkage amount and the height of the inherent strain area.

[0112] S35. Based on the shrinkage angle, the maximum deformation of the edge point of the plate is calculated.

[0113] In order to verify the effectiveness of the method for predicting the transverse bending deformation of butt-welded medium and thick plates based on the inherent strain method disclosed in the present invention, two examples are disclosed to prove it.

[0114] Calculation example 1:

[0115] See Figure 12 The plate geometry for the two butt joints is 60 mm × 70 mm × 25 mm in length × width × thickness. The welding heat source parameters are 10 V, 70 A, 0.7 thermal efficiency, 0.2 cm / s welding speed, and 20 multi-pass welds. The material type is 316L stainless steel, and the material parameters are the same as above and will not be repeated here. (Note that for ease of calculation, the multi-pass weld parameters in this example are assumed to be the same; in practice, they may differ.)

[0116] refer to Figure 11 , the prediction process is as follows:

[0117] A. Calculate the single-channel heat source line energy Q = 2450 J / cm

[0118] B. Check Figure 7 , calculate the eccentricity of the inherent strain application area e = 3.75mm

[0119] C. According to the welding process, determine the inherent strain application area A = (1.75×2) cm 2

[0120] D. According to the inherent strain theory, the total transverse inherent strain = 0.0882cm 2

[0121] E. Calculate the thermal expansion coefficient applied to the transverse inherent strain = 0.0252

[0122] F. Check Figure 10 And calculate the lateral shrinkage = 0.0676mm

[0123] G. Calculate the contraction angle θ = arctan (0.0676 / 17.5) = 0.221°

[0124] H. Calculated maximum deformation = 0.221 × π / 180 × (70-10) = 0.231 mm

[0125] I. See Figure 14The welding simulation result of applying both transverse and longitudinal inherent strains is 0.2275, with an error of 1.5%, which verifies the effectiveness of the method of the present invention.

[0126] Calculation example 2:

[0127] See Figure 14 The plate geometry for the two butt joints is 1000 mm × 100 mm × 12 mm in length × width × thickness. The welding heat source parameters are 12 V, 60 A, 0.7 thermal efficiency, 0.3 cm / s welding speed, and 6 multi-pass welds. The material type is 316L stainless steel, and the material parameters are the same as above and will not be repeated here.

[0128] refer to Figure 11 , the prediction process is as follows:

[0129] A. Calculate the single-channel heat source line energy Q = 1680 J / cm

[0130] B. Calculate the eccentricity of the inherent strain application area e = 1.8mm

[0131] C. Determine the inherent strain application area A = (0.84 × 1) cm 2

[0132] D. Intrinsic strain theory calculation total transverse intrinsic strain = 0.01814cm 2

[0133] E. Calculate the inherent strain per unit length = 0.0216

[0134] F. Check Figure 10 And calculate the lateral shrinkage = 0.02903mm

[0135] G. Calculate the contraction angle θ = arctan (0.02903 / 8.4) = 0.198°

[0136] H. Calculated maximum deformation = 0.198 × π / 180 × (1000-5) = 3.4387 mm

[0137] I. See Figure 15 ,The welding simulation result of applying both transverse and longitudinal inherent strains is 3.184mm, with an error of 8%, which verifies the effectiveness of the ,method of the present invention.

[0138] In summary, the embodiment of the present invention first obtains the curve relationship diagram of the unit inherent strain and the shrinkage under the regional width and the plate thickness of 316L stainless steel through simulation, and then the maximum deformation can be directly calculated through a simplified model and calculation method. The effectiveness verification example of the present invention includes 1 large size and 1 small size, which is intended to prove that the method described in the present invention has strong applicability. It should be noted that each material has a specific unit inherent strain and the curve relationship diagram of the shrinkage under the regional width and the plate thickness. This embodiment studies 316L stainless steel. Other materials such as aluminum alloys can also be obtained according to the method of the present invention. If the material type is improved, the method described in the present invention will be able to quickly and effectively help technicians predict whether the size of the welding deformation is within the allowable range.

[0139] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

[0140] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0141] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for predicting deformation of plate butt welding based on inherent strain method, characterized in that: include: Providing a set of plates of the same material with different thicknesses, and establishing a welding deformation prediction model based on the plates; Obtaining the thickness of the plate, and obtaining the shrinkage of the plates of different thicknesses using the deformation prediction model, so as to establish a curve relationship diagram between the shrinkage and the plate thickness under unit inherent strain and area width of the plate; Calculating the shrinkage angle of the plate butt weld based on the curve relationship diagram to determine the maximum deformation of the plate shrinkage; Providing a group of plates of the same material with different thicknesses and establishing a welding deformation prediction model based on the plates includes: Based on the welding process of the plate weld, the size of the inherent strain application area is calculated and the plate edge point is obtained, wherein the plate edge point is located farthest from the vertical weld and has the maximum deformation; Obtaining the shrinkage of the inherent strain application region in the state in which the inherent strain is applied based on the shrinkage of the inherent strain application region in a free state, wherein the free state refers to a state in which the height of the inherent strain application region is equal to the thickness of the plate; Based on the shrinkage amount, obtaining a shrinkage angle of the weld; Based on the shrinkage angle, the displacement of the edge point of the plate is obtained.

2. The method for predicting deformation of plate butt welding based on the inherent strain method according to claim 1 is characterized in that: The obtaining of the plate thickness and obtaining the shrinkage of the plate with different plate thicknesses by the deformation prediction model to establish a curve relationship diagram between the shrinkage and the plate thickness under unit inherent strain and area width includes: establishing a three-dimensional model based on the cross-sectional dimensions of the inherent strain application region to divide the inherent strain application region, applying the inherent strain to the inherent strain application region according to the anisotropy of the thermal expansion coefficient of the plate, and performing a finite element analysis on the inherent strain application region to which the inherent strain is applied by setting analysis steps and load constraints and dividing a mesh in the inherent strain application region to which the inherent strain is applied; The plate thickness of the plate is obtained, and the shrinkage of the plate with different plate thicknesses is obtained through the finite element analysis, so as to establish a curve relationship diagram between the shrinkage and the plate thickness under unit inherent strain and area width.

3. The method for predicting deformation of plate butt welding based on the inherent strain method according to claim 2 is characterized in that: Calculating the shrinkage angle of the plate butt weld based on the curve relationship diagram to determine the maximum deformation of the plate shrinkage includes: Obtaining geometric parameters, material parameters, and welding process parameters of the plate, and calculating the single-pass or multi-pass welding heat source bus energy and the eccentricity of the inherent strain application area to determine the cross-sectional size of the inherent strain application area; Calculating the inherent strain based on the cross-sectional dimensions of the inherent strain application region, and calculating the inherent strain per unit length; Calculating the shrinkage based on the inherent strain per unit length and the curve relationship diagram; calculating a contraction angle based on the contraction amount and the height of the inherent strain region; Based on the shrinkage angle, the maximum deformation of the edge point of the plate is calculated.

4. The method for predicting deformation of plate butt welding based on the inherent strain method according to claim 2 is characterized in that: The analysis step is temperature-displacement coupling, the load constraint includes an environmental constraint at -1°C, and the grid is set as a temperature-displacement coupling grid.

5. The method for predicting deformation of plate butt welding based on the inherent strain method according to claim 3 is characterized in that: The geometric parameters include: the length, width and thickness of the sheet; The material parameters include: density, specific heat, thermal conductivity, plasticity, elasticity and thermal expansion coefficient of the sheet material; The welding process parameters include: The voltage, current, thermal efficiency and welding speed of the plate welding.

6. The method for predicting deformation of plate butt welding based on the inherent strain method according to claim 3 is characterized in that: The obtaining of geometric parameters, material parameters, and welding process parameters of the plate, and calculating the single-pass or multi-pass welding heat source bus energy and the eccentricity of the inherent strain application area to determine the cross-sectional size of the inherent strain application area includes: Calculate the total heat source energy for single or multi-pass welding: , where η is the heat source efficiency, U is the voltage, I is the current, and v is the welding speed; Calculate the eccentricity of the region where the inherent strain is applied: , where h′ is the height of the inherent strain application area and h is the plate thickness; Then the cross-sectional dimensions of the inherent strain application area are: ,in, , a is the width of half of the inherent strain application area, and e is the eccentricity value.

7. The method for predicting deformation of plate butt welding based on the inherent strain method according to claim 3 is characterized in that: Calculating the maximum deformation of the plate edge point based on the shrinkage angle includes: Calculate the maximum deformation of the plate edge point based on the arc length formula and the contraction angle; The maximum deformation = θ × π / 180 × (ba), where θ is the contraction angle, b is the width of the plate, and a is the width of half the area where the inherent strain is applied.

8. The method for predicting deformation of plate butt welding based on the inherent strain method according to any one of claim 1, characterized in that: The inherent strain is a transverse inherent strain.

9. The method for predicting deformation of plate butt welding based on the inherent strain method according to any one of claims 1 to 6, characterized in that: The thickness of the plate is 4-100 mm.

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