A method for evaluating the welding ability of ultra-high strength steel suitable for narrow lap welding machines

Abstract

The present invention discloses a method for evaluating the welding ability of ultra-high strength steel suitable for a narrow lap welding machine, which relates to the technical field of continuous annealing welding and includes: establishing a welding ability evaluation model for the welding machine to weld ultra-high strength steel based on the influence mechanism of strip specifications on welding heat and weld thickness; calculating the first parameters required when the welding machine welds ultra-high strength steel, and the first parameters include: total heat and effective heat; calculating the second parameters after the welding machine welds ultra-high strength steel, and the second parameters include: estimated thickness, allowable minimum weld thickness, and allowable maximum weld thickness; based on the first parameters and the second parameters, using the welding ability evaluation model to evaluate the welding ability of the welding machine to weld ultra-high strength steel, and obtaining the minimum thickness and maximum thickness of the same specification of ultra-high strength steel welded by the welding machine under the existing parameters. The method for evaluating the welding ability of ultra-high strength steel suitable for a narrow lap welding machine provided by the present invention ensures the continuous production of the continuous annealing unit and improves its production efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of continuous annealing welding, and particularly relates to a method for evaluating the welding ability of ultra-high strength steel suitable for a narrow lap welding machine. Background Art

[0002] The welding machine is an important auxiliary equipment in the field of continuous production of continuous annealing units and plays an important role in the continuous annealing process of strip materials. The narrow lap resistance welding machine mainly consists of a welding main body, a loop picking device, an inlet PAD, inlet and outlet clamping devices, and an outlet PAD. It is mainly used to connect the front and rear strip steels to achieve uninterrupted production of the unit. With the continuous improvement of the automation and mechanization levels of the welding machine, the strip material specifications that the welding machine can weld have been greatly improved. To increase the production capacity of the unit, it is necessary to expand the strip material specifications that the welding machine can weld. However, plate and strip defects such as strip breakage, excessive or insufficient weld thickness often occur due to improper expansion of the strip material specifications, resulting in a serious reduction in the production efficiency of the unit.

[0003] Through research, it is known that the expansion range of strip material specifications is mainly restricted by two aspects: weld thickness and welding heat. Therefore, it is necessary to calculate the weld thickness and welding heat when the welding machine equipment parameters, welding process parameters, and strip material parameters are known, and evaluate the limit specifications of the ultra-high strength steel that the welding machine can weld within the allowable range of its welding heat and weld thickness to determine the maximum specifications that can be welded under certain working parameters, so as to reduce the probability of defects such as excessive or insufficient weld thickness or strip breakage, and improve the working efficiency and stable working ability of the welding machine.

[0004] Currently, the research directions at home and abroad are mainly focused on the research on the causes of defects at the strip weld and preventive measures, the research on the influencing factors of weld quality, and the analysis of the reasons for strip breakage at the weld. There is no relevant content on evaluating the limit specifications of strip materials that the welding machine can weld using the welding heat and weld thickness evaluation models.

[0005] Therefore, considering comprehensively the welding equipment and welding process characteristics of the continuous annealing unit, by studying the influence mechanism of strip material specifications on welding heat and weld thickness, a comprehensive evaluation model for the welding machine to weld ultra-high strength steel is established, and the limit specifications of the welding machine to weld ultra-high strength steel are evaluated through the evaluation model to ensure that the unit production will not be interrupted due to specification expansion, improve the on-site work safety, and has the value of further popularization and application. Summary of the Invention

[0006] In view of this, the present invention discloses a method for evaluating the welding ability of ultra-high strength steel suitable for a narrow lap welding machine, which fully considers the welding process characteristics of the continuous annealing unit and the influence of welding heat and weld thickness on the surface quality of the strip. By studying the influence of strip specifications on welding heat and weld thickness, the ultimate ability of the narrow lap welding machine to weld ultra-high strength steel can be evaluated, thereby ensuring the uninterrupted production of the unit and realizing the specification expansion of the welding machine equipment.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for evaluating the welding ability of ultra-high strength steel suitable for a narrow lap welding machine, including the following steps executed by a computer:

[0009] Based on the influence mechanism of strip specifications on welding heat and weld thickness, and the allowable welding heat range and weld thickness range for strip welding, a welding ability evaluation model for the welding machine to weld ultra-high strength steel is established;

[0010] According to the collected welding machine equipment parameters, welding process parameters, and strip parameters, use the heat calculation model to calculate the first parameters required for the welding machine to weld ultra-high strength steel, and the first parameters include: total heat and effective heat;

[0011] Determine the second parameters after the welding machine welds ultra-high strength steel according to on-site tests and theoretical analyses, and the second parameters include: estimated thickness, allowable minimum weld thickness, and allowable maximum weld thickness;

[0012] Based on the first parameters and the second parameters, use the welding ability evaluation model to evaluate the welding ability of the welding machine to weld ultra-high strength steel, and obtain the minimum thickness and maximum thickness of the same specification ultra-high strength steel welded by the welding machine under the existing parameters.

[0013] Furthermore, the welding ability evaluation model for the welding machine to weld ultra-high strength steel is:

[0014]

[0015] Among them, Q rbmin is the minimum value of the heat ratio, Q rbmax is the maximum value of the heat ratio, Q1 is the effective heat, Q is the total heat, H is the weld thickness, H min is the minimum allowable weld thickness of the unit, H max is the maximum allowable weld thickness of the unit.

[0016] Further, based on the first parameter and the second parameter, use the welding ability evaluation model to evaluate the welding ability of the welding machine for welding ultra-high strength steel, and obtain the minimum thickness and maximum thickness of the same specification of ultra-high strength steel welded by the welding machine under the existing parameters, including:

[0017] Substitute the first parameter and the second parameter into the welding ability evaluation model If both equations hold simultaneously, let δ i = δ s , λ = λ + 1, i = i + 1, and recalculate the first parameter required for the welding machine to weld ultra-high strength steel. Among them, δ i is the strip thickness storage value;

[0018] If both equations do not hold simultaneously, determine whether the thickness adjustment coefficient i = 1 holds. If i = 1 holds, let λ = λ + 1 and recalculate the first parameter required for the welding machine to weld ultra-high strength steel. If i = 1 does not hold, determine whether the strip thickness δ jmin ≤ δ s ≤ δ jmax holds. If δ jmin ≤ δ s ≤ δ jmax holds, let λ = λ + 1 and recalculate the first parameter required for the welding machine to weld ultra-high strength steel. If δ jmin ≤ δ s ≤ δ jmax does not hold, assign values to the limit specifications of the welding machine for welding ultra-high strength steel, δ min = δ1, δ max = δ i-1 ;

[0019] Output the minimum thickness δ min and the maximum thickness δ max of the same specification of ultra-high strength steel welded by the welding machine under the existing parameters.

[0020] Further, use the heat calculation model to calculate the total heat required for the welding machine to weld ultra-high strength steel, including:

[0021] According to the formula Q = λ1cA·(ξ s δ s + ξ x δ x )(b djl + b bcl )ρΔT, calculate the total heat Q required for the welding machine to weld ultra-high strength steel;

[0022] Among them, δ s is the thickness of the forward strip steel, δ xThe thickness of the trailing strip steel is δ, the thickness adjustment coefficient of the leading strip is λ, the optimized step of the strip steel thickness is Δδ, jmin The minimum thickness of the strip steel produced by the unit is δ, jmax The maximum thickness of the strip steel produced by the unit is δ, s δ x δ jmin = δ s + λΔδ, where λ1 is the melting coefficient of the nugget, c is the specific heat capacity of the strip, A is the penetration rate, ξ x is the influence coefficient of the welding pressure on the thickness of the leading strip steel, ξ djl is the influence coefficient of the pressure on the thickness of the trailing strip steel, b bcl is the overlap of the strip, b

[0023] Calculate the effective heat during the welding of ultra-high strength steel by the welder using the heat calculation model, including:

[0024] According to the formula Calculate the effective heat during the welding of ultra-high strength steel by the welder;

[0025] Among them, γ is the effective heat calculation coefficient during the welding of ultra-high strength steel by the welder, α is the influence coefficient of the strip steel thickness on the effective heat, Ce1 is the welding carbon equivalent of the leading strip steel, Ce2 is the carbon equivalent of the trailing strip steel, β is the influence coefficient of the carbon equivalent on the effective heat, I is the current during the strip welding, V is the strip welding speed, and R is the total resistance during the welding of ultra-high strength steel.

[0026] Furthermore, calculate the total resistance R during the welding of ultra-high strength steel, including:

[0027] According to the formula Calculate the total resistance R during the welding of ultra-high strength steel;

[0028] Among them, R w is the total resistance of the leading strip steel and the trailing strip steel, R c is the contact resistance between the strips, m is the strip contact coefficient, K c is the coefficient related to the contact material, surface condition, and contact form, ρ0 is the resistivity value of the strip steel at 0°, ρ0 = 9.78×10 -8 Ωm, α1 is the influence coefficient of temperature on resistivity; T is the temperature during the strip welding, b hls is the thickness of the upper welding wheel, b hlx is the thickness of the lower welding wheel, R hls is the radius of the upper welding wheel, R hlx is the radius of the lower welding wheel, E1 is the elastic modulus of the welding wheel, v1 is the Poisson's ratio, E2 is the elastic modulus of the strip steel, v2 is the Poisson's ratio, and P is the welding wheel pressure.

[0029] Further, calculate the estimated thickness, the minimum allowable weld thickness, and the maximum allowable weld thickness after the welder welds ultra-high strength steel, including:

[0030] According to the formula calculate the estimated thickness H, the minimum allowable weld thickness H min , and the maximum allowable weld thickness H max ;

[0031] wherein, S is the safety factor, determined through experiments, φ1 and φ2 are thickness coefficients determined by the strip steel type; B p is the influence coefficient of pressure on the weld thickness, B Q is the influence coefficient of heat on the weld thickness, B L is the influence coefficient of the overlap amount on the weld thickness, P N is the pressure of the rolling wheel, b djl is the strip overlap amount.

[0032] Advantages and positive effects of the present invention: By studying the influence of the thickness of the strip on the heat of the welder and the weld thickness, the present invention establishes a corresponding evaluation model of welding heat and weld thickness. Through the evaluation of the ultimate ability of the narrow lap welder to weld ultra-high strength steel, the continuous production of the unit is ensured, the specification expansion of the welding equipment is realized, the actual production efficiency and quality are improved, and economic benefits are brought to the unit. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 is a flowchart of a method for evaluating the welding ability of ultra-high strength steel suitable for a narrow lap welder in an embodiment of the present invention. Detailed Embodiments

[0035] In order to enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0037] The narrow lap welding machine mainly welds the strip steel through welding heat, and the weld seam is the direct result of the welding of the welding machine. Excessive welding heat will cause the strip steel to be welded through, and too little welding heat is likely to result in incomplete penetration. Moreover, too large a weld seam thickness is likely to cause weld mark defects, and too thin a weld seam thickness is likely to cause the strip to break. Therefore, in the present invention, based on the influence mechanism of strip specifications on welding heat and weld seam thickness, as well as the allowable welding heat range and weld seam thickness range for strip steel welding, an evaluation model for the welding ability of the narrow lap welding machine to weld ultra-high strength steel is established, and the welding ability of the narrow lap welding machine is evaluated based on this welding ability evaluation model. Among them, the heat required to form the fusion core at the weld seam is the heat required for the strip steel covering the volume of the fusion core to melt. According to the heat calculation formula, a calculation model for the total heat of the fusion core can be obtained. The heat used to form the fusion core in the total heat of the fusion core is the effective heat, which mainly depends on the total welding resistance and the carbon equivalent of the strip steel. Based on Joule's law, a calculation model for the effective heat can be obtained; according to the heat calculation model and the relevant parameters collected, the total heat and effective heat required when the welding machine welds ultra-high strength steel can be calculated. The weld seam thickness is mainly determined by the pressure of the rolling wheel, the effective welding heat and the overlap amount of the strip steel, and there are clear positive and negative correlation relationships. Too thick a weld seam is likely to cause weld mark defects, and too thin a weld seam is likely to cause the strip to break. Through on-site tests and theoretical analysis, a model for the weld seam thickness, the allowable minimum weld seam thickness and the allowable maximum weld seam thickness are established. According to the model of the weld seam thickness and the relevant parameters collected, the estimated thickness, the allowable minimum weld seam thickness and the allowable maximum weld seam thickness after the welding machine welds ultra-high strength steel can be calculated.

[0038] Taking the narrow lap welding machine of a certain continuous annealing unit as an example, a method for evaluating the welding ability of ultra-high strength steel suitable for the narrow lap welding machine in the embodiments of the present invention will be described in detail below.

[0039] Example 1:

[0040] Taking the product of ultra-high strength steel 980DP with a thickness range of 0.3 mm to 2.5 mm and a width of 1300 mm as an example, the method for evaluating the welding ability of ultra-high strength steel suitable for narrow lap welding machines described in the present invention will be described in detail.

[0041] Step (A1), collect the welding machine equipment parameters and welding process parameters, mainly including the effective heat calculation coefficient γ = 0.2 when the welding machine welds ultra-high strength steel, the minimum thickness δ of the strip produced by the unit jmin = 0.3 mm, the maximum thickness δ of the strip produced by the unit jmax = 2.5 mm, the penetration rate A = 80%, the current I = 19.7 KA during strip welding, the set value V = 10.9 m / min of the strip welding speed, the strip overlap amount b djl = 1.5 mm, the strip compensation amount b bcl = 1 mm, the thickness b of the upper welding wheel hls = 15 mm, the thickness b of the lower welding wheel hlx = 15 mm, the radius R of the upper welding wheel hls = 160 mm, the radius R of the lower welding wheel hlx = 160 mm, the elastic modulus E1 of the welding wheel = 118 kN / mm 2 、Poisson's ratio v1 = 0.35, the pressure P of the rolling wheel N = 2 kN, the pressure P of the welding wheel = 15.9 kN, the minimum value Q of the heat ratio rbmin = 0, the maximum value Q of the heat ratio rbmax = 10%;

[0042] Step (B1), collect the relevant parameters of the strip, mainly including the influence coefficient δ of the welding pressure on the thickness of the forward strip s = 20%, the influence coefficient δ of the pressure on the thickness of the backward strip x = 20%, the carbon equivalent Ce1 of the forward strip during welding = 0.5212, the carbon equivalent Ce2 of the backward strip = 0.5212, the specific heat capacity c of the strip = 0.46 J / (g·°C), the density ρ of the strip = 7.85 g / cm 3 , the temperature difference ΔT between the normal temperature and the nugget state of the strip = 1515 °C, the influence coefficient α of the strip thickness on the effective heat = 0.25, the influence coefficient β of the carbon equivalent on the effective heat = 0.2, the nugget melting coefficient λ1 = 1.3, the temperature T during strip welding = 1120 °C, the elastic modulus E2 of the strip = 206 kN / mm 2 、Poisson's ratio v2 = 0.3, the influence coefficient B of the pressure on the weld thickness p = 0.03, the influence coefficient B of the heat on the weld thickness Q = 0.012, the influence coefficient B of the overlap amount on the weld thickness L = 0.08;

[0043] Step (C1): Define the relevant parameters when the welding machine welds ultra-high strength steel, mainly including the effective heat Q1, the total heat Q, the strip welding resistance R, the weld thickness H, the minimum allowable weld thickness H of the unit, min the maximum allowable weld thickness H of the unit, max the thickness δ of the forward strip, s the thickness δ of the rear strip, x the forward strip thickness adjustment coefficient λ, the strip thickness optimization step Δδ, the strip thickness storage value δ i ;

[0044] Step (D1): Initialize the welding parameters and intermediate process variables, mainly including the strip thickness adjustment coefficient λ = 0, the strip thickness update times i = 1, and the strip thickness optimization step Δδ = 0.1;

[0045] Step (E1): According to the formula Calculate the strip thickness to be δ s = δ x = 1.9mm, and the total heat required when the welding machine welds ultra-high strength steel is Q = 56212J;

[0046] Step (F1): According to the formula Calculate the total resistance of the forward strip and the rear strip to be R w = 5.16×10 -5 , the contact resistance is R c = 1.24×10 -5 Ω, and the total resistance is R = 6.4×10 -5 Ω;

[0047] Step (G1): According to the formula Calculate the effective heat of the welding machine when welding ultra-high strength steel to be Q1 = 56210J;

[0048] Step (H1): According to the formula Calculate the estimated thickness H = 2.104mm, the minimum allowable weld thickness H min = 1.86mm, and the maximum allowable weld thickness H max = 2.09mm after the welding machine welds ultra-high strength steel;

[0049] Step (I1): After judging that the strip specification comprehensive evaluation model cannot hold simultaneously, enter Step (J1);

[0050] Step (J1): After judging that the thickness adjustment coefficient i = 1 does not hold, enter Step (K1);

[0051] Step (K1): After judging that the strip thickness δ jmin ≤ δs ≤δ jmax If it holds, then enter step (E1). Through loop calculation, it can be known that when the thickness is 2 mm to 2.4 mm, it does not meet step (I1), so enter step (L1);

[0052] Step (L1): Assign values to the limit specifications of the butt welder for welding ultra-high-strength steel, where δ min = 0.6 mm and δ max = 1.8 mm;

[0053] Step (M1): Output the minimum thickness δ min = 0.6 mm and the maximum thickness δ max = 1.8 mm of the same specification of ultra-high-strength steel welded by the welder under the existing parameters.

[0054] In this embodiment, the limit specifications of the ultra-high-strength steel 980DP that the welder can weld are evaluated through the welding heat evaluation model and the weld thickness evaluation model, and the thickness specification range of the ultra-high-strength steel 980DP that the welder can weld is obtained, reducing the occurrence probability of weld mark defects and the frequency of strip breakage during the production of ultra-high-strength steel 980DP, greatly improving the production efficiency of the unit. The change in the strip thickness range that the welder can weld before and after the evaluation is shown in Table 1.

[0055] Table 1

[0056] Steel grade Welding specifications before evaluation Welding specifications after evaluation 980DP 0.3 - 2.5 mm 0.6 - 1.8 mm

[0057] Example 2:

[0058] Taking a product of ultra-high-strength steel 780Y with a thickness range of 0.3 mm to 2.5 mm and a width of 1300 mm as an example, the method for evaluating the welding ability of ultra-high-strength steel suitable for narrow lap welders described in the present invention is described in detail.

[0059] Step (A2): Collect the welder equipment parameters and welding process parameters, mainly including the effective heat calculation coefficient γ = 0.2 when the welder welds ultra-high-strength steel, the minimum thickness δ jmin = 0.3 mm of the strip produced by the unit, the maximum thickness δ jmax = 2.5 mm of the strip produced by the unit, the penetration rate A = 80%, the current I = 20.5 KA during strip welding, the set value V = 10 m / min of the strip welding speed, the strip overlap b djl = 1.5 mm, the strip compensation b bcl = 1 mm, the thickness b hls = 15 mm of the upper welding wheel, the thickness b hlx = 15 mm of the lower welding wheel, the radius R hls = 160 mm of the upper welding wheel, the radius R hlx= 160 mm, the elastic modulus E1 of the welding wheel = 118 kN / mm 2 , the Poisson's ratio v1 = 0.35, the rolling wheel pressure P N = 2 kN, the welding wheel pressure P = 21.8 kN, the minimum value Q of the heat ratio rbmin = 0, the maximum value Q of the heat ratio rbmax = 10%;

[0060] Step (B2), collect the relevant parameters of the strip, mainly including the influence coefficient ξ of the welding pressure on the thickness of the advancing strip steel s = 20%, the influence coefficient ξ of the pressure on the thickness of the following strip steel x = 20%, the welding carbon equivalent Ce1 of the advancing strip steel = 0.4987, the carbon equivalent Ce2 of the following strip steel = 0.4987, the specific heat capacity c of the strip = 0.46 J / (g·°C), the density ρ of the strip = 7.85 g / cm 3 , the temperature difference ΔT between the normal temperature and the nugget state of the strip steel = 1515 °C, the influence coefficient α of the strip steel thickness on the effective heat = 0.25, the influence coefficient β of the carbon equivalent on the effective heat = 0.2, the nugget melting coefficient λ1 = 1.3, the temperature T during strip steel welding = 1120 °C, the elastic modulus E2 of the strip steel = 206 kN / mm 2 , the Poisson's ratio v2 = 0.3, the influence coefficient B of the pressure on the weld thickness p = 0.03, the influence coefficient B of the heat on the weld thickness Q = 0.012, the influence coefficient B of the overlap amount on the weld thickness L = 0.08;

[0061] Step (C2), define the relevant parameters when the welding machine welds ultra-high strength steel, mainly including the effective heat Q1, the total heat Q, the welding resistance R of the strip, the weld thickness H, the minimum allowable weld thickness H of the unit min , the maximum allowable weld thickness H of the unit max , the thickness δ of the advancing strip steel s , the thickness δ of the following strip steel x , the thickness adjustment coefficient λ of the advancing strip, the strip thickness optimization step Δδ, the strip thickness storage value δ i ;

[0062] Step (D2), initialize the welding parameters and intermediate process variables, mainly including the strip thickness adjustment coefficient λ = 0, the strip thickness update times i = 1, the strip thickness optimization step Δδ = 0.1;

[0063] Step (E2), according to the formula Calculate the strip thickness to be δ s = δ x = 2.2 mm, the total heat required when the welding machine welds ultra-high strength steel is Q = 65087 J;

[0064] Step (F2), according to the formula calculate the total resistance of the front strip and the rear strip as R w = 5.21×10 -5 , the contact resistance is R c = 0.9×10 -5 Ω, and the total resistance is R = 6.11×10 -5 Ω;

[0065] Step (G2), according to the formula calculate the effective heat during welding of ultra-high strength steel by the welder as Q1 = 65085 J;

[0066] Step (H2), according to the formula calculate the estimated thickness H = 2.14 mm, the minimum allowable weld thickness H min = 2.15 mm, and the maximum allowable weld thickness H max = 2.42 mm after welding ultra-high strength steel by the welder;

[0067] Step (I2), after judging that the strip specification comprehensive evaluation model cannot hold simultaneously, then enter Step (J2);

[0068] Step (J2), after judging that the thickness adjustment coefficient i = 1 does not hold, then enter Step (K2);

[0069] Step (K2), after judging that the strip thickness δ jmin ≤δ s ≤δ jmax holds, then enter Step (E2). Through iterative calculation, it can be known that when the thickness is 2.3 mm or 2.4 mm, Step (I2) is not satisfied, then enter Step (L2);

[0070] Step (L2), assign values to the limit specifications of welding ultra-high strength steel by the welder as δ min = 0.5 mm, δ max = 2.1 mm;

[0071] Step (M2), output the minimum thickness δ min = 0.5 mm and the maximum thickness δ max = 2.1 mm of welding ultra-high strength steel of the same specification by the welder under the existing parameters.

[0072] In Example 1, the specification range of the butt welder for welding ultra-high strength steel 980DP was evaluated. In this example, the limit specifications of ultra-high strength steel 780Y that the welder can weld were evaluated using a welding heat evaluation model and a weld thickness evaluation model, and the thickness specification range of ultra-high strength steel 780Y that the welder can weld was obtained. The strip steel within this specification range can be used for the production of the unit, and welding defects will not occur due to excessive thickness, resulting in the shutdown and renovation of the unit. This reduces the damage to the welder caused by overloading and improves the production efficiency of the unit. The change in the strip steel thickness range that the welder can weld before and after the evaluation is shown in Table 2.

[0073] Table 2

[0074] Steel grade Welding specifications before evaluation Welding specifications after evaluation 780Y 0.3 - 2.5 mm 0.5 - 2.1 mm

[0075] In several embodiments provided in the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are merely illustrative. For example, the division of the units can be a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the units or modules can be in an electrical or other form.

[0076] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0077] In addition, in each embodiment of the present invention, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0078] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs that can store program codes.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for evaluating the welding ability of ultra-high strength steel suitable for narrow lap welding machines, characterized in that, Including the following steps executed by a computer: Based on the influence mechanisms of strip specifications on welding heat and weld thickness, as well as the allowable welding heat range and weld thickness range for strip welding, establish a welding ability evaluation model for the welder to weld ultra-high strength steel; According to the collected welder equipment parameters, welding process parameters, and strip parameters, use the heat calculation model to calculate the first parameters required when the welder welds ultra-high strength steel, where the first parameters include: total heat and effective heat; Determine the second parameters after the welder welds ultra-high strength steel based on on-site tests and theoretical analysis, where the second parameters include: predicted thickness, allowable minimum weld thickness, and allowable maximum weld thickness; Based on the first parameters and the second parameters, use the welding ability evaluation model to evaluate the welding ability of the welder to weld ultra-high strength steel, and obtain the minimum thickness and maximum thickness of the ultra-high strength steel of the same specification welded by the welder under the existing parameters; Among them, calculating the total heat required when the welder welds ultra-high strength steel using the heat calculation model includes: According to the formula Q = λ1cA·(ξ s δ s + ξ x δ x )(b djl + b bcl ), calculate the total heat Q required when the welding machine welds ultra-high strength steel; Among them, δ s is the thickness of the forward strip steel, δ x is the thickness of the rear strip steel, λ is the thickness adjustment coefficient of the forward strip, Δδ is the optimized step of the strip thickness, δ jmin is the minimum thickness of the strip produced by the unit, δ jmax is the maximum thickness of the strip produced by the unit, δ s = δ x = δ jmin + λΔδ, λ1 is the melting coefficient of the nugget, c is the specific heat capacity of the strip, A is the penetration rate, ξ s is the influence coefficient of the welding pressure on the thickness of the forward strip steel, ξ x is the influence coefficient of the pressure on the thickness of the rear strip steel, b djl is the overlap of the strip, b bcl is the compensation of the strip, ρ is the density of the strip, ΔT is the temperature difference between the normal temperature of the strip and the state of the nugget; Calculating the effective heat required when the welder welds ultra-high strength steel using the heat calculation model includes: According to the formula calculate the effective heat during the welding of ultra-high strength steel by the welding machine; Among them, γ is the effective heat calculation coefficient when the welder welds ultra-high strength steel, α is the influence coefficient of strip thickness on effective heat, Ce1 is the welding carbon equivalent of the forward strip, Ce2 is the carbon equivalent of the rear strip, β is the influence coefficient of carbon equivalent on effective heat, I is the current during strip welding, V is the strip welding speed, and R is the total resistance when welding ultra-high strength steel; Calculating the total resistance R when welding ultra-high strength steel includes: According to the formula calculate the total resistance R when welding ultra-high strength steel; Among them, R w is the total resistance of the forward strip and the rear strip, R c is the contact resistance between the strips, m is the strip contact coefficient, K c is the coefficient related to the contact material, surface condition, and contact form, ρ0 is the resistivity value of the strip at 0°, ρ0 = 9.78×10 -8 Ωm, α1 is the influence coefficient of temperature on resistivity; T is the temperature during strip welding, b hls is the thickness of the upper welding wheel, b hlx is the thickness of the lower welding wheel, R hls is the radius of the upper welding wheel, R hlx is the radius of the lower welding wheel, E1 is the elastic modulus of the welding wheel, v1 is the Poisson's ratio, E2 is the elastic modulus of the strip steel, v2 is the Poisson's ratio, and P is the welding wheel pressure.

2. The method for evaluating the welding ability of ultra-high strength steel suitable for a narrow lap welding machine according to claim 1, wherein The welding ability evaluation model for the welder to weld ultra-high strength steel is: Among them, Q rbmin is the minimum value of the heat ratio, Q rbmax is the maximum value of the heat ratio, Q1 is the effective heat, Q is the total heat, H is the weld thickness, H min is the minimum weld thickness allowed by the unit, H max is the maximum weld thickness allowed by the unit.

3. The method for evaluating the welding ability of ultra-high strength steel suitable for a narrow lap welding machine according to claim 2, wherein, Based on the first parameters and the second parameters, using the welding ability evaluation model to evaluate the welding ability of the welder to weld ultra-high strength steel, and obtaining the minimum thickness and maximum thickness of the ultra-high strength steel of the same specification welded by the welder under the existing parameters includes: Substitute the first parameter and the second parameter into the welding ability evaluation model If both equations hold simultaneously, then let δ i = δ s , λ = λ + 1, i = i + 1, and recalculate the first parameter required for the welding machine to weld ultra-high strength steel. Among them, δ i is the strip thickness storage value; If the two expressions do not hold simultaneously, then determine whether the thickness adjustment coefficient i = 1 holds. If i = 1 holds, then let λ = λ + 1 and recalculate the first parameter required for the welding machine to weld ultra-high strength steel. If i = 1 does not hold, then determine whether the strip thickness δ jmin ≤δ s ≤δ jmax holds. If δ jmin ≤δ s ≤δ jmax holds, then let λ = λ + 1 and recalculate the first parameter required for the welding machine to weld ultra-high strength steel. If δ jmin ≤δ s ≤δ jmax does not hold, then assign the limit specification for the welding machine to weld ultra-high strength steel as δ min = δ1, δ max = δ i-1 ; The minimum thickness δ and the maximum thickness δ of the super high-strength steel of the same specification welded by the output welding machine under the existing parameters min , max .

4. A method for evaluating the welding ability of ultra-high strength steel suitable for a narrow lap welding machine according to claim 1, characterized in that Calculating the predicted thickness, allowable minimum weld thickness, and allowable maximum weld thickness after the welder welds ultra-high strength steel includes: According to the formula calculate the estimated thickness H of the welded joint after the welder welds the ultra-high strength steel, the minimum allowable weld thickness H min , and the maximum allowable weld thickness H max ; Among them, S is the safety factor, determined through experiments, φ1 and φ2 are the thickness coefficients determined by the steel type of the strip; B p is the influence coefficient of pressure on the weld thickness, B Q is the influence coefficient of heat on the weld thickness, B L is the influence coefficient of the overlap amount on the weld thickness, P N is the pressure of the rolling wheel, b djl is the overlap amount of the strip.

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