A welding method for a high-strength steel plate

Abstract

The application relates to a welding method of a high-strength steel plate, the thickness of the high-strength steel is <=20mm, the method comprises the following steps: welding at least two high-strength steel test plates by using a current welding material to obtain a high-strength steel welded joint test plate; performing metallographic structure detection on a welded joint of the high-strength steel welded joint test plate to obtain a dilution rate of the welded joint; obtaining the chemical element content of a target welding material according to the chemical element content of the high-strength steel test plate, the chemical element content of the deposited metal of the current welding material and the dilution rate; welding at least two new high-strength steel test plates by using the target welding material to obtain a target high-strength steel welded joint plate. The application obtains the required welding material composition under a high-dilution-rate welding environment, can accurately guarantee that the composition of a weld zone after welding is consistent with a target composition, and improves the low-temperature impact toughness of the high-strength steel welded joint.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-strength steel welding, and particularly relates to a welding method of high-strength steel plate. BACKGROUND

[0002] Compared with the material of ordinary strength level, the component of high-strength steel has small section size and low quality, and is widely used in various fields such as engineering machinery, building structure, ocean engineering, energy and bridge. The submerged arc welding process has the advantages of stable welding quality, high welding productivity, no arc light and little smoke, and is widely used in the welding field of high-strength steel.

[0003] At present, the dilution rate of the double-sided submerged arc welding process of the thin-gauge high-strength steel is higher than that of the multi-layer multi-pass welding. After the double-sided submerged arc welding process is used, the performance of the joint weld zone is greatly different from the mechanical properties of the deposited metal of the matching welding material, and the low-temperature impact toughness of the joint is seriously reduced. SUMMARY

[0004] The present application provides a welding method of high-strength steel plate to solve the technical problem of how to improve the low-temperature impact toughness of the high-strength steel welded joint.

[0005] In the current aspect, the present application provides a welding method of high-strength steel plate, the thickness of the high-strength steel is ≤20mm, and the method comprises the following steps.

[0006] At least two high-strength steel test plates are welded by using the current welding material to obtain high-strength steel welded joint test plates.

[0007] The welded joint of the high-strength steel welded joint test plates is subjected to metallographic structure detection to obtain the dilution rate of the welded joint.

[0008] According to the chemical element content of the high-strength steel test plate, the chemical element content of the deposited metal of the current welding material and the dilution rate, the chemical element content of the target welding material is obtained.

[0009] At least two new high-strength steel test plates are welded by using the target welding material to obtain target high-strength steel welded joint plates.

[0010] Optionally, the chemical element content of the target welding material satisfies the following relationship formula:

[0011] a=(b-η*c) / (1-η)

[0012] In the formula, a represents the chemical element content of the target welding material, b represents the chemical element content of the deposited metal of the current welding material, c represents the chemical element content of the high-strength steel test plate, and η represents the dilution rate.

[0013] Optionally, the chemical element content of the target welding material is obtained according to the chemical element content of the high-strength steel test plate, the chemical element content of the deposited metal of the current welding material, and the dilution rate.

[0014] The chemical element content of the target welding material is obtained according to the chemical element content of the high-strength steel test plate, the chemical element content of the deposited metal of the current welding material, and the dilution rate.

[0015] Optionally, the welding of the at least two high-strength steel test plates by using the current welding material to obtain the high-strength steel welded joint sample plate comprises the following steps.

[0016] The thickness of the high-strength steel test plate is obtained.

[0017] The welding heat input is obtained according to the thickness of the high-strength steel test plate.

[0018] The welding of the at least two high-strength steel test plates by using the current welding material to obtain the high-strength steel welded joint test plate is performed under the welding heat input.

[0019] Optionally, the welding heat input is obtained according to the thickness of the high-strength steel test plate, and the welding heat input is obtained according to the thickness of the high-strength steel test plate.

[0020] If 5mm≤the thickness of the high-strength steel test plate≤10mm, the welding heat input is 10kJ / cm-15kJ / cm.

[0021] Optionally, the welding heat input is obtained according to the thickness of the high-strength steel test plate, and the welding heat input is obtained according to the thickness of the high-strength steel test plate.

[0022] If 10mm<the thickness of the high-strength steel test plate≤20mm, the welding heat input is 16kJ / cm-35kJ / cm.

[0023] Optionally, the yield strength of the high-strength steel test plate is≥460MPa.

[0024] Optionally, the chemical elements of the high-strength steel test plate include C, Si, Mn, Ni, Mo, Cu, Nb, V, and Ti.

[0025] Optionally, the groove form of the high-strength steel test plate includes one of the following: I type and X type.

[0026] Optionally, the target welding material includes one of the following: flux-cored wire and solid wire; wherein the diameter of the flux-cored wire is 3.2mm-5.0mm.

[0027] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art.

[0028] The welding method of the high-strength steel plate provided by the embodiments of the present application uses the current welding material to weld the high-strength steel test plate, to obtain a high-strength steel welded joint test plate; the welding joint of the high-strength steel welded joint test plate is subjected to metallographic structure detection, to obtain the dilution rate of the welding joint; the chemical element content of the target welding material is obtained according to the chemical element content of the high-strength steel test plate, the chemical element content of the deposited metal of the current welding material, and the dilution rate; the high-strength steel test plate is welded again using the target welding material, to obtain a target high-strength steel welded joint plate. The method takes into account the dilution rate of the high-strength steel base material in the welding bead, can obtain the chemical element content of the required target welding material under a high-dilution-rate welding environment, thereby accurately ensuring that the composition of the weld zone after welding is consistent with the target composition, the performance of the welded joint after welding meets the technical requirements, and finally the low-temperature impact toughness of the high-strength steel welded joint is improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative labor.

[0031] Figure 1 A flowchart of a welding method of a high-strength steel plate according to some embodiments of the present application;

[0032] Figure 2 A schematic diagram of a welding bead with a "T" type welding bead groove form of a high-strength steel plate according to Embodiment 1 of the present application;

[0033] Figure 3 A schematic diagram of a welding bead with an "X" type welding bead groove form of a high-strength steel plate according to Embodiment 2 of the present application. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0035] Various embodiments of the present application can exist in a range of forms; it should be understood that the description in a range form is merely for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application; therefore, it should be considered that the range description has disclosed all possible sub-ranges and single values within the range. For example, it should be considered that the range description from 1 to 6 has disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single values within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in the present application, it refers to any cited number (fraction or integer) within the indicated range.

[0036] In the present application, the terms "include", "contain" and the like refer to "include but not limited to".

[0037] Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment, etc. used in the present application can be purchased on the market or can be prepared by existing methods.

[0038] With the improvement of the strength grade of the material, the composition system of the high-strength steel and the matching welding material is more and more different. When the welding material is used for multi-layer multi-pass welding or surfacing with small dilution rate, the composition of the weld zone is not much different from that of the deposited metal, and the performance meets the welding requirements. However, under the welding condition of large dilution rate, the proportion of the base material composition in the weld zone composition increases, and the obtained weld zone composition is quite different from the composition of the selected welding material, and the performance cannot meet the welding requirements. Therefore, the present application provides a welding method for a high-strength steel plate, Figure 1 A flowchart of a welding method for a high-strength steel plate according to some embodiments of the present application is shown in the figure; please see Figure 1 , the thickness of the high-strength steel is ≤20mm, and the method comprises:

[0039] S1, using the current welding material to weld at least two high-strength steel test plates to obtain high-strength steel welded joint test plates;

[0040] In some embodiments, the step of using the current welding material to weld at least two high-strength steel test plates to obtain high-strength steel welded joint test plates comprises:

[0041] obtaining the thickness of the high-strength steel test plate;

[0042] obtaining the welding heat input according to the thickness of the high-strength steel test plate;

[0043] under the condition of the welding heat input, using the current welding material to weld at least two high-strength steel test plates to obtain high-strength steel welded joint test plates.

[0044] In some embodiments, obtaining the welding heat input based on the thickness of the high-strength steel test plate includes:

[0045] If the thickness of the high-strength steel test plate is 5mm ≤ 10mm, then the welding heat input is 10kJ / cm~15kJ / cm.

[0046] In some embodiments, obtaining the welding heat input based on the thickness of the high-strength steel test plate includes:

[0047] If the thickness of the high-strength steel test plate is less than 10mm and less than or equal to 20mm, then the welding heat input is 16kJ / cm to 35kJ / cm.

[0048] In some embodiments, the bevel form of the high-strength steel test plate includes one of the following: type I or type X.

[0049] In some embodiments, the yield strength of the high-strength steel test plate is ≥460MPa.

[0050] In some embodiments, the chemical elements of the high-strength steel test plate include: C, Si, Mn, Ni, Mo, Cu, Nb, V, and Ti.

[0051] In this embodiment, when preparing high-strength steel welding test plates, creating welding bevels, and welding 5-20mm thick high-strength steel butt welds using submerged arc welding (SAW) technology, the selection of welding materials is based on the principle of "equal strength matching," while also considering that the low-temperature impact toughness of the welding materials meets the application requirements. Suitable SAW materials are selected. An "I" or "X" shaped bevel can be used for double-sided SAW welding, with one pass on each side. This welding process has the advantages of high efficiency and stable welding quality. To ensure the welding quality and weld bead formation of the weld joint, SAW process parameters are selected according to the plate thickness, thereby ensuring the mechanical properties of the weld bead. For example, if the thickness of the high-strength steel test plate is 5mm ≤ 10mm, the welding heat input can be 10kJ / cm, 11kJ / cm, 12kJ / cm, 13kJ / cm, 14kJ / cm, 15kJ / cm, etc.; if the thickness of the high-strength steel test plate is 10mm < 20mm, the welding heat input can be 16kJ / cm, 17kJ / cm, 18kJ / cm, 20kJ / cm, 22kJ / cm, 24kJ / cm, 25kJ / cm, 26kJ / cm, 28kJ / cm, 29kJ / cm, 30kJ / cm, 31kJ / cm, 32kJ / cm, 33kJ / cm, 34kJ / cm, 35kJ / cm, etc. The yield strength of the above-mentioned high-strength steel test plate can be ≥460MPa, and further, the yield strength of the high-strength steel test plate can be 460MPa~690MPa. The chemical elements of the high-strength steel test plate can include: C, Si, Mn, Ni, Mo, Cu, Nb, V and Ti, and can also include N, B, Cr, etc.

[0052] S2. Metallographic analysis of the welded joint of the high-strength steel welded joint test plate is performed to obtain the dilution rate of the welded joint;

[0053] In this embodiment of the application, the metallographic image of the weld joint is taken, and the weld morphology is obtained by etching. The area of ​​the weld and the area of ​​high-strength steel material melted into the weld are obtained by image analysis software. The dilution rate of the joint under this welding process is calculated. The dilution rate = area of ​​high-strength steel material melted into the weld / area of ​​the weld, which can be set as the ratio of the area of ​​the base metal melted in a single weld to the area of ​​the molten pool in a single weld.

[0054] S3. Based on the chemical element content of the high-strength steel test plate, the chemical element content of the deposited metal of the current welding material, and the dilution rate, the chemical element content of the target welding material is obtained.

[0055] In some embodiments, the chemical element content of the target welding material satisfies the following relationship (1):

[0056] a = (b - η * c) / (1 - η)

[0057] In the formula, a represents the chemical element content of the target welding material, b represents the chemical element content of the deposited metal of the current welding material, c represents the chemical element content of the high-strength steel test plate, and η represents the dilution rate.

[0058] In some embodiments, the chemical element content of the target welding material is obtained according to the chemical element content of the high-strength steel test plate, the chemical element content of the deposited metal of the current welding material, and the dilution rate, and includes:

[0059] The chemical element content of the target welding material is obtained according to the chemical element content of the high-strength steel test plate, the chemical element content of the deposited metal of the current welding material, and the dilution rate, wherein the chemical element content of the high-strength steel test plate and the chemical element content of the deposited metal of the current welding material are obtained by direct-reading optical spectrum analysis.

[0060] In the embodiments of the present application, the composition of the deposited metal refers to the composition of the welding material required by the high-strength steel, without considering the diluted welding material. The welding material itself meets the performance requirements, the composition of the base material is the chemical composition of the high-strength steel itself, and since the composition of the welding bead under this process is diluted by the base material, a new welding material composition is redesigned. The chemical element content of the target welding material*(1-dilution rate)+the chemical element content of the high-strength steel*dilution rate = the chemical element content of the deposited metal of the current welding material, so after conversion, the chemical element content of the target welding material = (the chemical element content of the deposited metal of the current welding material-dilution rate*the chemical element content of the high-strength steel) / (1-dilution rate). Therefore, the chemical element content of the high-strength steel test plate and the chemical element content of the deposited metal of the current welding material are obtained by using a spectral composition detection device, and the chemical element content of the target welding material is obtained according to the calculation formula (1). In addition, if the element content is negative after calculation, the element content is set to 0.

[0061] S4, using the target welding material to weld at least two new high-strength steel test plates to obtain a target high-strength steel welded joint plate.

[0062] In some embodiments, the target welding material includes one of a flux-cored wire and a solid wire, wherein the diameter of the flux-cored wire is 3.2mm-5.0mm.

[0063] In the embodiments of the present application, the above target welding material can be one of a flux-cored wire and a solid wire. The flux-cored wire is manufactured by wrapping a carbon steel strip with flux powder and drawing. The diameter of the flux-cored wire can be 3.2mm, 3.5mm, 3.8mm, 4.0mm, 4.5mm, 5.0mm, etc. The method obtains the required welding material composition under a high-dilution-rate welding environment through the calculation of the dilution rate, accurately ensures that the composition of the weld zone after welding is consistent with the target composition, can control the composition of the welding wire through the flux-cored wire manufacturing process, and the performance of the welded joint after welding meets the technical requirements.

[0064] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not used to limit the scope of the present application. The experimental methods in the following examples, if no specific conditions are noted, are generally determined according to national standards. If there is no corresponding national standard, the general international standards, conventional conditions, or the conditions suggested by the manufacturer are used.

[0065] Example 1

[0066] Step one, prepare the EH550 marine steel welding test plate with the size of 200*150*13mm, welding current 650A, welding voltage 30V, welding heat input 30kJ / cm, the welding groove form is "I" type, and the double-sided submerged arc welding of the welding test plate is completed after the assembly.

[0067] Step two, take the welding joint metallograph, use 4% nitric acid alcohol etchant to detect the cross section of the welding joint, calculate the dilution rate of the joint under the welding process, and the dilution rate of the welding joint is 62%. Figure 2 For the welding groove form "T" type of the welding bead of the high-strength steel plate provided in Example 1 of the present application, please refer to Figure 2 , the image area calculation software is used to obtain the area B of the welding seam, the area A1 and A2 of the base material melted on both sides of the welding groove, and the joint dilution rate = (A1+A2) / B.

[0068] Step three, obtain the main chemical element content of the EH550 material and the deposited metal of the matching welding material by the direct-reading spectrum analyzer, calculate the chemical element content of the target welding material = (the chemical element content of the deposited metal of the current welding material - the dilution rate * the chemical element content of the high-strength steel test plate) / (1-dilution rate); please refer to Table 1 for the chemical element content of the target welding material, the chemical element content of the deposited metal of the current welding material, and the chemical element content of the high-strength steel test plate provided in Example 1.

[0069] Table 1 Chemical element content of target welding material, chemical element content of deposited metal of current welding material, and chemical element content of high-strength steel test plate (wt%)

[0070] Element C[％] Si [%] Mn [%] Cr[％] Cu [%] Mo [%] Nb [%] Ni [%] Ti [%] V[％] Deposited metal 0.090 0.22 1.37 0.15 0.16 0.46 0.006 0.76 0.005 0.007 High-strength steel test plate 0.135 0.25 1.2 0 0.15 0.2 0.012 0.15 0.015 0.04 Welding material required 0.02 0.17 1.65 0.39 0.17 0.88 0 1.76 0 0

[0071] Step four, according to the required chemical element content of the target welding material obtained in step three, the flux-cored wire is made, and the wire diameter is 4.0mm;

[0072] Step five, the self-developed welding wire is used for the double-sided submerged arc welding of the EH550 material, and the impact value of the joint welding seam area is excellent, please refer to Table 2 for the KV2 impact value test results of the welding seam area of the high-strength steel plate provided in Example 1.

[0073] Table 2 Test results of KV2 impact value of the welded joint of the high-strength steel plate

[0074]

[0075] Example 2

[0076] Step one, prepare the EH690 marine steel welding test plate with the size of 200*150*20mm, welding current 700A, welding voltage 33V, welding heat input 35kJ / cm, the welding groove form is "X" type, and the double-sided submerged arc welding of the welding test plate is completed after the assembly.

[0077] Step two, take the welding joint metallograph, use 4% nitric acid alcohol etchant to detect the cross section of the welding joint, calculate the dilution rate of the joint under the welding process, and the dilution rate of the welding joint is 43%. Figure 3 For the welding groove form "X" type of the high-strength steel plate provided in Example 2 of the present application, please refer to Figure 3 , the area B of the weld, the area A1 and A2 of the base material melted on both sides of the welding groove are obtained by using image area calculation software, and the joint dilution rate = (A1+A2) / B.

[0078] Step three, obtain the main chemical element content of EH690 material and the deposited metal of the matching welding material by using a direct-reading spectrum analyzer, calculate the chemical element content of the target welding material = (the chemical element content of the deposited metal of the current welding material - the dilution rate * the chemical element content of the high-strength steel test plate) / (1-dilution rate); please refer to the chemical element content of the target welding material, the chemical element content of the deposited metal of the current welding material and the chemical element content of the high-strength steel test plate provided in Example 2 shown in Table 3.

[0079] Table 3 Chemical element content of the target welding material, chemical element content of the deposited metal of the current welding material and chemical element content of the high-strength steel test plate (wt%)

[0080] Element C[％] Si [%] Mn [%] Cr[％] Cu [%] Mo [%] Nb [%] Ni [%] Ti [%] V[％] Deposited metal 0.058 0.20 1.80 0.45 0.05 0.51 0.006 2.65 0.005 0.005 High-strength steel test plate 0.10 0.25 1.20 0.5 0.25 0.45 0.02 1.00 0.015 0.05 Welding material required 0.03 0.16 2.25 0.41 0 0.55 0 3.89 0 0

[0081] Step four, according to the chemical element content of the required target welding material obtained in step three, the flux-cored wire is made, and the wire diameter is 4.0mm;

[0082] Step five, the self-developed welding wire is used for the double-sided submerged arc welding of EH690 material, and the impact value of the joint weld zone is excellent, please refer to the test results of KV2 impact value of the welded joint of the high-strength steel plate provided in Example 2 shown in Table 4.

[0083] Table 4 Test results of KV2 impact value of the welded joint of the high-strength steel plate

[0084]

[0085] Comparative Example 1

[0086] Step one, prepare the EH550 marine steel welding test plate with the size of 200*150*13mm, welding current 650A, welding voltage 30V, welding heat input 30kJ / cm, the welding groove form is“I”type, after the group, the current welding material is used to complete the double-sided submerged arc welding of the welding test plate;

[0087] Step two, the composition of the weld zone after welding is diluted by the base material composition, the impact performance of the weld center is as follows in Table 5, the impact value of the weld zone is greatly reduced. Please refer to the test results of the KV2 impact value of the welded weld zone of the high-strength steel plate provided by Comparative Example 1 shown in Table 5.

[0088] Table 5 Test results of KV2 impact value of the welded weld zone of the high-strength steel plate

[0089]

[0090] In summary, from Examples 1-2 and Comparative Example 1, the welding method of the high-strength steel plate provided by the present application combines the dilution rate of the high-strength steel base material in the welding bead, and can obtain the required chemical element content of the target welding material under the high dilution rate welding environment, thereby accurately ensuring that the composition of the weld zone after welding is consistent with the target composition, the joint performance after welding meets the technical requirements, and finally improves the low temperature impact toughness of the high-strength steel welded joint.

[0091] The above only describes specific embodiments of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A welding method for high-strength steel plates, characterized in that, The high-strength steel plate has a thickness of ≤20mm and is manufactured using a double-sided submerged arc welding process. The method includes: At least two high-strength steel test plates are welded using the current welding materials to obtain high-strength steel welded joint test plates. Metallographic analysis was performed on the welded joint of the high-strength steel welded joint test plate to calculate the dilution rate of the welded joint under the double-sided submerged arc welding process. The dilution rate = area of ​​high-strength steel material melted into the weld bead / area of ​​weld bead. The chemical element content of the target welding material is obtained based on the chemical element content of the high-strength steel test plate, the chemical element content of the weld metal of the current welding material, and the dilution rate. At least two new high-strength steel test plates are welded together using the target welding material to obtain a target high-strength steel welded joint plate. The chemical element content of the target welding material satisfies the following relationship: a = (b - η * c) / (1 - η) In the formula, a represents the chemical element content of the target welding material, b represents the chemical element content of the deposited metal of the current welding material, c represents the chemical element content of the high-strength steel test plate, and η represents the dilution rate. The step of welding at least two high-strength steel test plates with the current welding material to obtain a high-strength steel welded joint test plate includes: obtaining the thickness of the high-strength steel test plate; obtaining the welding heat input based on the thickness of the high-strength steel test plate; and, under the condition of the welding heat input, welding at least two of the high-strength steel test plates with the current welding material to obtain a high-strength steel welded joint test plate. The step of obtaining the welding heat input based on the thickness of the high-strength steel test plate includes: If 5mm ≤ the thickness of the high-strength steel test plate ≤ 10mm, then the welding heat input is 10kJ / cm~15kJ / cm; If the thickness of the high-strength steel test plate is less than 10mm and less than or equal to 20mm, then the welding heat input is 16kJ / cm to 35kJ / cm.

2. The method according to claim 1, characterized in that, The chemical element content of the target welding material is obtained based on the chemical element content of the high-strength steel test plate, the chemical element content of the weld metal of the current welding material, and the dilution rate. The chemical element content of the high-strength steel test plate and the chemical element content of the weld metal of the current welding material are detected by direct-reading spectral analysis.

3. The method according to claim 1, characterized in that, The yield strength of the high-strength steel test plate is ≥ 460MPa.

4. The method according to claim 1, characterized in that, The chemical elements of the high-strength steel test plate include: C, Si, Mn, Ni, Mo, Cu, Nb, V, and Ti.

5. The method according to claim 1, characterized in that, The bevel types of the high-strength steel test plates include the following: Type I and Type X.

6. The method according to claim 1, characterized in that, The target welding material includes one of the following: flux-cored welding wire and solid welding wire; wherein the diameter of the flux-cored welding wire is 3.2mm~5.0mm.

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