Welding process of high manganese high aluminum steel welded joint

Abstract

The application discloses a welding process of high-manganese high-aluminum steel welded joints, and belongs to the technical field of welding processes.The welding process of high-manganese high-aluminum steel welded joints comprises the following steps: a groove processing step, a fixing tool step, a primer layer welding step, a preliminary welding step of front filling welds, a subsequent welding step of front filling welds, a preliminary welding step of back filling welds, and a subsequent welding step of back filling welds.The welding process of high-manganese high-aluminum steel welded joints effectively solves the problems of high cost and strict welding process of high-manganese steel welding in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel plate welding, in particular to a welding process for high-manganese high-aluminum steel welded joints. BACKGROUND

[0002] High-manganese high-carbon steel has an austenitic structure, and a large number of twins are generated to coordinate deformation in addition to dislocation slip during the deformation process, especially more twins are generated in a low-temperature environment. Therefore, the steel has excellent strength, plasticity and fracture toughness in a wide range, and the cost is lower than that of austenitic stainless steel and 9Ni steel. In recent years, the steel has been rapidly developed and is expected to replace high-cost stainless steel or 9Ni steel used for LNG storage tanks. However, a significant disadvantage of high-manganese high-aluminum steel is that the aluminum content and manganese content are high. Aluminum, as a transition metal, has a strong deoxidizing metallurgical effect, which seriously affects the stability of the electric arc during welding. In addition, high manganese content and carbon content increase the carbon equivalent. According to the empirical formula of the carbon equivalent of low-alloy steel, when the carbon equivalent of steel material is greater than 0.4%, it is considered that the weldability of the material is poor. The alloy element composition of high-manganese high-aluminum steel far exceeds the steel materials widely used in structural steel, stainless steel and 9Ni steel on the market.

[0003] The solid core welding wire and welding process for welding austenitic high-manganese steel in the prior art obtain a welded joint with a tensile strength ≥700 MPa, an elongation ≥25%, and an impact energy AKv ≥41 J at -196 ℃, which has certain low-temperature mechanical properties, by optimizing the welding process parameters and adding different alloy elements, and selecting 80% argon and 20% carbon dioxide as the shielding gas.

[0004] In the welding process of the prior art described above, in order to obtain good welding joint performance when welding high-manganese steel, the welding process needs to be strictly controlled. Although the alloy composition does not contain a large amount of precious alloy elements, it still contains 2.3-3.0% Ni and 1.4-2.0% Mo, and a large number of other trace elements, which increases the cost of the welding wire and makes the welding process costly.

[0005] In summary, the high-manganese steel welding in the prior art has the problems of high cost and strict welding process. SUMMARY

[0006] The embodiment of the present application provides a welding process of a high-manganese high-aluminum steel welded joint to solve the problems of high cost and strict welding process of the high-manganese steel welding in the prior art.

[0007] To achieve the above object, the present application provides a welding process of a high-manganese high-aluminum steel welded joint, comprising the following steps:

[0008] The groove processing step is to process one side of the butt joint of the high-manganese high-aluminum steel plate into a welding groove, and polish the groove and at least a range of 20 mm on both sides to remove surface rust and water;

[0009] The fixed tool step is to increase an auxiliary welding tool at the end of the processed groove, and use the auxiliary welding tool to fix the welding plate;

[0010] The backing layer welding step is to use argon arc self-melting backing, and the welding material does not use welding wire; the backing layer uses a welding power supply connection mode of direct current reverse connection, and the welding mode is argon arc welding;

[0011] The preliminary welding step of the front filling weld is to weld the first layer of filling weld on the front of the plate, wherein the welding parameters are that the protective gas is 99.9% argon, the welding material uses the solid core welding wire with the same composition as the base material, the plate preheating temperature is 200 DEG C, the back of the plate is simultaneously increased with argon protection, the welding current is 110-120 A, the arc voltage is 18-22 V, the cooling mode is air cooling, and the layer temperature is less than or equal to 140 DEG C;

[0012] The subsequent welding step of the front filling weld is to weld the second layer of filling weld on the front of the plate, wherein the welding parameters are that the protective gas is 99.9% argon, the welding material uses the solid core welding wire with the same composition as the base material, the plate preheating temperature is 200 DEG C, the back of the plate is simultaneously increased with argon protection, the welding current is 120-140 A, and the arc voltage is 18-22 V; after completing the pass, air cooling is performed to below 150 DEG C, and the next pass welding is performed with the same welding parameters until the weld reinforcement on the front of the plate is not more than 3 mm;

[0013] The preliminary welding step of the back filling weld is to weld the first layer of filling weld on the back of the plate, wherein the welding parameters are that the protective gas is 99.9% argon, the welding material uses the solid core welding wire with the same composition as the base material, the plate preheating temperature is 200 DEG C, the welding current is 110-120 A, the arc voltage is 18-22 V, the cooling mode is air cooling, and the layer temperature is less than or equal to 140 DEG C;

[0014] Subsequent welding step of back filling weld: the second layer of filling weld is welded on the back of the plate, wherein the welding parameters are that the shielding gas is 99.9% argon, the welding material is the solid core welding wire with the same composition as the base material, the preheating temperature of the plate is 200 DEG C, the welding current is 120-140 A, and the arc voltage is 18-22 V; after the step is completed, the air cooling is performed to below 150 DEG C, and the next pass welding is performed with the same welding parameters until the weld reinforcement on the back of the plate is not more than 3 mm.

[0015] Further, the chemical composition of the plate of the high-manganese high-aluminum steel is: C: 0.55-0.85%, Mn: 15.5-19.0%, Al: 0.8-1.4%, Si: 0.3-1.2%, and the rest is Fe and inevitable impurity elements.

[0016] Further, in the machining groove step, the groove is a double-V-shaped groove.

[0017] Further, in the machining groove step, the angle of the groove is 25 DEG -35 DEG.

[0018] In the technical scheme of the present application, the machining groove step can prevent defects from affecting the mechanical properties of the welded part during welding; the auxiliary welding device is used in the fixing tool step, which aims to fix the welded plate to prevent welding heat input deformation. In the subsequent welding step, argon arc self-melting is used to add solid core welding wire for welding, which is combined with small heat input and back protection mode to effectively solve the problems of high carbon equivalent and a large amount of manganese smoke generated during welding, effectively avoid the problem of high carbon equivalent deteriorating the weld quality, and reduce the amount of manganese smoke generated during welding, effectively improving the welding quality. At the same time, no welding wire is used in the backing layer welding step, and the same solid core welding wire as the base material is used in the front filling weld and the back filling weld. Compared with the solid core welding wire selected in the prior art, the cost of the welding wire is greatly reduced, and the cost of the welding process is reduced. Moreover, compared with the welding process in the prior art, only the key steps of welding are needed, and the process steps and parameters do not need to be strictly controlled, the welding process is simpler, and the problem of harsh high-manganese steel welding process in the prior art is solved. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a flowchart of the welding process of the high-manganese high-aluminum steel welded joint of the embodiment of the present application;

[0020] Figure 2 is a structural schematic diagram of the welded joint in the welding process of the high-manganese high-aluminum steel welded joint of the embodiment of the present application;

[0021] Figure 3is a macroscopic physical diagram of a welded joint in a welding process of a high-manganese high-aluminum steel welded joint according to an embodiment of the present application;

[0022] Figure 4 is a metallographic structure of a fusion zone and a heat-affected zone of a welded joint in a welding process of a high-manganese high-aluminum steel welded joint according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments, but is not limited to the embodiments.

[0024] Referring to Figure 1 According to an embodiment of the present application, a welding process of a high-manganese high-aluminum steel welded joint is provided, and the welding process of the high-manganese high-aluminum steel welded joint includes the following steps:

[0025] A groove forming step S10 is performed to form a welding groove on one side of the butt joint of the high-manganese high-aluminum steel plate, and the groove and the range of at least 20 mm on both sides are polished to remove surface rust and water.

[0026] A fixing tool step S20 is performed to add an auxiliary welding tool to the end of the formed groove, and the auxiliary welding tool is used to fix the welding plate.

[0027] A backing layer welding step S30 is performed to use argon arc self-melting backing, and no welding wire is used for the welding material. The backing layer uses a welding power supply connection mode of direct current reverse connection, and the welding mode is argon arc welding.

[0028] A preliminary welding step S40 of front filling weld is performed to weld the first layer of filling weld on the front of the plate, wherein the welding parameters are that the shielding gas is 99.9% argon, the welding material uses a solid core welding wire with the same composition as the base material, the plate preheating temperature is 200°C, the back of the plate is simultaneously provided with argon protection, the welding current is 110-120 A, the arc voltage is 18-22 V, the cooling mode is air cooling, and the layer temperature is ≤140°C.

[0029] A subsequent welding step S50 of front filling weld is performed to weld the second layer of filling weld on the front of the plate, wherein the welding parameters are that the shielding gas is 99.9% argon, the welding material uses a solid core welding wire with the same composition as the base material, the plate preheating temperature is 200°C, the back of the plate is simultaneously provided with argon protection, the welding current is 120-140 A, and the arc voltage is 18-22 V. After this pass, air cooling is performed to below 150°C, and the next pass is welded with the same welding parameters until the weld reinforcement on the front of the plate is not more than 3 mm.

[0030] The back filling weld preliminary welding step S60: the first layer of filling weld welding is performed on the back of the plate, wherein the welding parameters are that the shielding gas is 99.9% argon, the welding material uses the solid core welding wire with the same composition as the base material, the plate preheating temperature is 200℃, the welding current is 110-120A, the arc voltage is 18-22V, the cooling mode is air cooling, and the layer temperature is ≤140℃;

[0031] The back filling weld subsequent welding step S70: the second layer of filling weld welding is performed on the back of the plate, wherein the welding parameters are that the shielding gas is 99.9% argon, the welding material uses the solid core welding wire with the same composition as the base material, the plate preheating temperature is 200℃, the welding current is 120-140A, and the arc voltage is 18-22V; after the pass is completed, air cooling is performed to below 150℃, and the next pass welding is performed with the same welding parameters until the weld reinforcement of the back of the plate is not more than 3mm.

[0032] In the technical scheme of the present application, the groove machining step can prevent defects from affecting the mechanical properties of the welded part during welding; the fixing tool step uses an auxiliary welding device, which aims to fix the welded plate to prevent welding heat input deformation. In the subsequent welding step, argon arc self-melting is used to add solid core welding wire for welding, which is combined with small heat input and back protection mode to effectively solve the problems of high carbon equivalent and a large amount of manganese smoke generated during welding, effectively avoid the problem of high carbon equivalent deteriorating weld quality, and reduce the amount of manganese smoke generated during welding, effectively improving the welding quality. At the same time, no welding wire is used in the backing layer welding step, and the same solid core welding wire as the base material is used in the front filling weld and the back filling weld. Compared with the solid core welding wire selected in the prior art, the cost of the welding wire is greatly reduced, and the cost of the welding process is reduced. Moreover, compared with the welding process in the prior art, the welding process only needs to perform key steps, does not need to strictly control the process steps and parameters, and the welding process is simpler, solving the problem of harsh high manganese steel welding process in the prior art.

[0033] Preferably, the chemical composition of the high manganese high aluminum steel plate in the embodiment is: C: 0.55-0.85%, Mn: 15.5-19.0%, Al: 0.8-1.4%, Si: 0.3-1.2%, and the rest is Fe and inevitable impurity elements.

[0034] Preferably, in the groove machining step, the groove is a double-V groove.

[0035] In the groove machining step, the angle of the groove is 25°-35°.

[0036] In this embodiment, using 10mm thick new high manganese high aluminum steel butt welding as an example, a 35° double V type welding groove is processed, and the joint schematic diagram is shown in Figure 2

[0037] The argon arc welding is used for self-melting backing, the argon arc welding is used for filling layer welding by using Φ2.4mm solid core welding wire, the argon gas is used as back protection gas at the same time, the gas flow is 15-20L / min, and the specific welding parameters are shown in Table 1.

[0038] Table 1:

[0039]

[0040] The welding joint section macroscopic photo is shown in Figure 3 The results show that the welding joint is well fused, and no welding defects such as cracks, pores and slag are found.

[0041] According to the standard GB / T2651-2008 welding joint tensile test method, the tensile property detection is carried out on the above welding joint, and the results are shown in Table 2.

[0042] Table 2:

[0043] Gauge length / mm Tensile strength / MPa Elongation at break / % Fracture location 75×12.5×10 750 50 Base material

[0044] From the above data and in combination with Figure 4 It can be seen that the welding process of the high manganese high aluminum steel welding joint adopts the argon arc self-melting backing and then adds the solid core welding wire for welding, cooperates with the small heat input and the back protection mode, effectively solves the influence of the too high carbon equivalent and a large amount of manganese smoke generated during welding, so that the weld quality and performance achieve the expected target.

[0045] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should also be understood that, when the terms "comprise" and / or "include" are used in the specification, they indicate the presence of the features, steps, operations, devices, components and / or combinations thereof.

[0046] Of course, the above is the preferred embodiment of the present application. It should be noted that for those skilled in the art, without departing from the basic principles of the present application, a number of improvements and refinements can also be made, which are also considered within the protection scope of the present application.​

Claims

1. A welding process for a high manganese high aluminum steel welded joint, characterized in that, The method comprises the following steps: A groove processing step: one side of the butt joint of the high manganese high aluminum steel plate is processed into a welding groove, and the groove and at least 20 mm range on both sides are polished to remove surface rust and water, the chemical composition of the high manganese high aluminum steel plate is: C: 0.55~0.85%, Mn: 15.5~19.0%, Al: 0.8~1.4%, Si: 0.3~1.2%, and the rest is Fe and inevitable impurity elements; A fixing tool step: an auxiliary welding tool is added to the end of the processed groove to fix the welding plate; A backing layer welding step: argon arc self-melting backing is adopted, and welding material does not use welding wire; the backing layer adopts a welding power connection mode of direct current reverse connection, and the welding mode is argon arc welding; A preliminary welding step of front filling weld: the first layer of filling weld on the front of the plate is welded, wherein the welding parameters are that the protective gas is 99.9% argon, the welding material uses the same solid core welding wire as the base material, the plate preheating temperature is 200 DEG C, the back of the plate is simultaneously increased with argon protection, the welding current is 110~120A, the arc voltage is 18~22V, the cooling mode is air cooling, and the layer temperature is less than or equal to 140 DEG C; A subsequent welding step of front filling weld: the second layer of filling weld on the front of the plate is welded, wherein the welding parameters are that the protective gas is 99.9% argon, the welding material uses the same solid core welding wire as the base material, the plate preheating temperature is 200 DEG C, the back of the plate is simultaneously increased with argon protection, the welding current is 120~140A, the arc voltage is 18~22V; after completing this pass, air cooling is carried out to below 150 DEG C, and the next pass welding is carried out with the same welding parameters until the weld reinforcement on the front of the plate is not more than 3mm; A preliminary welding step of back filling weld: the first layer of filling weld on the back of the plate is welded, wherein the welding parameters are that the protective gas is 99.9% argon, the welding material uses the same solid core welding wire as the base material, the plate preheating temperature is 200 DEG C, the welding current is 110~120A, the arc voltage is 18~22V, the cooling mode is air cooling, and the layer temperature is less than or equal to 140 DEG C; A subsequent welding step of back filling weld: the second layer of filling weld on the back of the plate is welded, wherein the welding parameters are that the protective gas is 99.9% argon, the welding material uses the same solid core welding wire as the base material, the plate preheating temperature is 200 DEG C, the welding current is 120~140A, and the arc voltage is 18~22V; after completing this pass, air cooling is carried out to below 150 DEG C, and the next pass welding is carried out with the same welding parameters until the weld reinforcement on the back of the plate is not more than 3mm.

2. The welding process of claim 1, wherein, In the groove processing step, the groove is a double V-shaped groove.

3. The welding process of claim 2, wherein, In the groove processing step, the angle of the groove is 25 DEG ~ 35 DEG.

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