CN116551185A - Swing laser-electric arc composite welding method with plate thickness not less than 30mm Ji Pagang - Google Patents

Abstract

The invention relates to a swing laser-electric arc composite welding method with the plate thickness more than or equal to 30mm Ji Pagang, which comprises the following steps: 1) Machining a Y-shaped groove on one side of the Jipa steel plate; 2) The polished Jipa steel plates are placed side by side with a gap of 0.2-1.5 mm; 3) Adjusting the relative position of the laser head and the arc welding gun; 4) Sequentially performing backing welding and cover surface welding during welding; 5) And covering the joint area by adopting a heat insulation material after welding. According to the invention, the Jipa steel plate with the plate thickness of more than or equal to 30mm is used as a base material, and the swinging laser-electric arc composite welding method is adopted to prepare the Ji Pagang welding joint, so that the welding efficiency can be remarkably improved, the weld pore defect can be reduced, the mechanical property of weld metal can be improved, and the method has important significance for developing a key technology for welding a large thickness Ji Pagang.

Description

A method for oscillating laser-arc hybrid welding of gipa steel with plate thickness ≥ 30mm

technical field

The invention relates to the technical field of welding of ultra-high-strength steel plates, in particular to an oscillating laser-arc hybrid welding method for steel plates with yield strength greater than 1 GPa and plate thickness ≥ 30 mm.

Background technique

In recent years, my country's industrial production technology has continued to improve. Due to the needs of environmental protection and energy saving, coupled with the rapid development of new energy vehicles, rail trains, large-scale engineering structures and other fields, not only requires materials to have ultra-high strength to achieve lightweight, but also requires some steel The force-restrained mechanical structural parts have good reliability. In order to meet the requirements of large-scale, lightweight and high-efficiency engineering structures, high-strength steel has received extensive attention, especially the amount of high-strength steel (gippa steel) with a yield strength above 1000 MPa has increased significantly. However, the large-scale application of Jipa steel is limited by the strength of welded joints. This is mainly due to the large carbon equivalent and strong brittleness of Jipa steel, which is prone to cracks and other problems during welding, which leads to certain limitations in its application.

At present, the welding methods of Jipa steel mainly include submerged arc welding, MIG arc welding and laser welding. The Chinese invention patent with the authorized announcement number CN106312372 B discloses "a gas-shielded solid welding wire for welding 1000MPa high-strength steel and its preparation and welding method", and the Chinese invention patent with the authorized announcement number CN106270957 B discloses "a 1000MPa-level engineering Gas-shielded welding method for mechanical high-strength steel thick plate", the Chinese patent application with publication number CN102179606 A discloses "a welding process for 1000MPa non-quenched and tempered high-strength steel", the Chinese patent application with publication number CN112372120 A A Chinese patent application with publication number CN 112453662 A discloses "a welding process for electrode arc welding suitable for 1000MPa high-strength steel" and "a submerged arc welding process suitable for 1000MPa high-strength steel". Both proposed a similar welding process for 1000MPa high-strength steel, that is, welding high-strength steel by means of gas shielded welding, manual arc welding and submerged arc welding. Although submerged arc welding and arc welding methods have the advantages of low equipment investment and simple operation, the disadvantages of this process are also obvious, such as large heat input, shallow penetration, large post-weld deformation, and the groove opening for thick plate welding. If the size is large, the mechanical properties of the joint will decrease significantly.

The Chinese invention patent with the authorized announcement number CN 113399834 B discloses "a preparation method for laser welding joints of high-strength steel plates for automobiles with a level of 1000 MPa and above", which adopts a laser welding process, and laser welding has high welding efficiency and small deformation after welding , The welding process is easy to realize the automation and so on. However, laser welding has high requirements for the assembly of workpiece grooves, cold cracks or hot cracks are likely to occur when welding certain high-performance metal materials without filler materials, and weld collapse is prone to occur when welding thick plates.

Laser-arc hybrid welding technology (Laser-arc Hybrid Welding) is a new welding technology that inherits the advantages of laser welding and arc welding. This welding technology has the advantages of large weld penetration, high welding efficiency, stable welding arc, and small welding deformation. , It is easy to realize the advantages of single-sided welding and double-sided forming. The laser-arc hybrid welding technology increases the molten pool by filling the welding wire material, which allows larger assembly tolerances and reduces the precision requirements for the processing and clamping of the joints to be welded. Therefore, laser-arc hybrid welding technology is a method with very good application prospects for welding high-strength steel in medium and thick plates.

The Chinese patent application with the publication number CN102962591 A discloses a "high-strength steel welding method", which uses laser-arc hybrid welding to weld high-strength steel plates. However, its welding method is mainly suitable for welding high-strength steel sheets with a thickness of 6-14 mm, and the alloy composition of the welding wire in the laser-arc hybrid welding method is not specified, and the groove form for welding high-strength steel is not given.

At present, in the welding process of Gippa steel, the problems of poor weld joint formation, high weld porosity, high weld crack sensitivity and weld metal toughness of large thickness (thickness ≥ 30mm) Gippa steel have not been effectively resolved. solve.

Contents of the invention

The invention provides a method for oscillating laser-arc composite welding of Gippa steel with a plate thickness ≥ 30mm, using the Gipa steel plate with a thickness ≥ 30mm as the base material, and adopting the oscillating laser-arc composite welding method to prepare the welded joint of Gipa steel. It can significantly improve welding efficiency, reduce weld porosity defects, and improve the mechanical properties of weld metal, which is of great significance for the development of key technologies for welding large-thickness Gippah steel.

In order to achieve the above object, the present invention adopts the following technical solutions to realize:

A method for oscillating laser-arc hybrid welding of gippah steel with a plate thickness ≥ 30mm, comprising the following steps:

1) Process a symmetrical Y-shaped groove on the joint side of two Gipa steel plates with a thickness ≥ 30mm;

2) Grind the base metal on the periphery of the Y-shaped groove, remove the oxide layer of the steel plate, and then clean the grinding position, place two pieces of Gippa steel plates side by side, and control the gap between the plates at the joint between 0.2 and 1.5 mm;

3) Adjust the relative position of the laser head and the arc welding torch. Along the welding direction, the laser head is in front and the arc welding torch is behind, and ensure that both are at the center of the weld. The angle is 20°～35°, and the distance between light filaments is 2～8mm;

4) During welding, base welding and cover welding are carried out in sequence; among them, the laser power of base welding is 2 to 4 times that of cover welding laser power; the process parameters during welding are: laser power is 1 ~ 8kW, laser separation The focal amount is between -3～+3mm, the laser swing frequency is 10～30Hz, and the laser swing range is 1～3mm; the working current of the arc welding torch is 150～300A, the working voltage is 20～35V, and the pulse frequency is 10～100Hz The dry elongation of the welding wire is 10-20mm; the diameter of the welding wire is 1.2-2.0mm, the wire feeding speed is 2-18m/min, the welding speed is 0.6-1.5m/min; the shielding gas flow rate is 15-35L/min;

5) After the welding of the cover surface is completed, the thermal insulation material is used to cover the welded joints of the Jipa steel and the joint areas on both sides of the weld to reduce the cooling speed of the joints.

Further, in the step 1), the groove surface angle of the Y-shaped groove is 65°-80°, and the size of the blunt edge is 2-8mm.

Further, in the step 1), the parent material on the periphery of the Y-shaped groove refers to the parent material within 10 mm of the periphery of the Y-shaped groove.

Further, in the step 4), the chemical composition of the welding wire is C: 0.1%-0.5%, Mn: 1.5%-2.5%, Si: 0.4%-0.65%, Ni: 2.5%-4.0%. , Cr: 0.5% to 1.5%, Mo: 0.5% to 1.3%, Ti: 0.3% to 0.6%, Nb: 0.3% to 0.7%, S≤0.006%, P≤0.010%, and the balance is Fe.

Further, in the step 4), the protective gas is a mixed gas of 80% Ar+20% CO ₂ .

Further, in the step 5), the Gippa steel welded joint and the joint area on both sides of the weld seam refer to the area within 200mm of the periphery of the joint.

Compared with prior art, the beneficial effect of the present invention is:

(1) The selected welding wire composition ratio of the present invention can ensure the stability of the welding process, excellent weld formation, refine the microstructure of the weld metal, and improve the crack resistance and fracture toughness of the weld metal;

(2) At present, the welding of Jipa steel generally requires preheating before welding to reduce the probability of cracking of the weld metal. And adopt welding wire and welding method described in the present invention, can not do pre-heating treatment before welding, reduce workload, improve work efficiency;

(3) The swing laser-arc hybrid welding method is used to weld large-thickness Gipa steel plates. When the two heat sources, laser and arc, act together in a molten pool, the laser can provide a large penetration depth, and the arc can increase the area of the molten pool. and the filling quantity of weld seam; therefore, compared with the process of adopting arc welding and submerged arc welding alone, the method of the present invention can reduce the welding passes and the filling quantity of weld metal, and effectively suppress the welding caused by multi-pass welding. The performance of the joint is deteriorated due to the influence of thermal cycle; due to the agitation effect of the oscillating laser beam on the molten pool, the flow velocity of the molten pool is increased, the convective behavior of the molten pool is enhanced, which is beneficial to the floating of air bubbles and reduces the pores in the weld defect;

(4) Adopting the welding method of the present invention to weld the large-thickness Gipa steel plate can reduce the assembly accuracy, improve the adaptability of the welding process to the groove gap, the amount of misalignment, and the centering deviation, the process is simple, and the practicability is strong.

Description of drawings

Fig. 1 is a schematic diagram of the double-sided Y-shaped symmetrical groove of the present invention.

Fig. 2 is a schematic diagram of welding sequence of oscillating laser-arc hybrid welding according to the present invention.

Fig. 3 is a schematic diagram of the principle of oscillating laser-arc hybrid welding according to the present invention.

In the figure: 1. Bottom weld bead 2. Cover weld bead 3. Y-shaped groove 4. Laser head 5. Arc welding torch 6. Welding wire

T. Thickness of Jipa steel plate h. Blunt edge size θ. Groove face angle δ. Plate gap

Detailed ways

According to the present invention, a method for oscillating laser-arc hybrid welding of Gippa steel with a plate thickness of ≥30 mm comprises the following steps:

1) Process a symmetrical Y-shaped groove on the joint side of two Gipa steel plates with a thickness ≥ 30mm;

2) Grind the base metal on the periphery of the Y-shaped groove, remove the oxide layer of the steel plate, and then clean the grinding position, place two pieces of Gippa steel plates side by side, and control the gap between the plates at the joint between 0.2 and 1.5mm;

3) Adjust the relative position of the laser head and the arc welding torch. Along the welding direction, the laser head is in front and the arc welding torch is behind, and ensure that both are at the center of the weld. The angle is 20°～35°, and the distance between light filaments is 2～8mm;

4) During welding, base welding and cover welding are carried out in sequence; among them, the laser power of base welding is 2 to 4 times that of cover welding laser power; the process parameters during welding are: laser power is 1 ~ 8kW, laser separation The focal amount is between -3～+3mm, the laser swing frequency is 10～30Hz, and the laser swing range is 1～3mm; the working current of the arc welding torch is 150～300A, the working voltage is 20～35V, and the pulse frequency is 10～100Hz The dry elongation of the welding wire is 10-20mm; the diameter of the welding wire is 1.2-2.0mm, the wire feeding speed is 2-18m/min, the welding speed is 0.6-1.5m/min; the shielding gas flow rate is 15-35L/min;

5) After the welding of the cover surface is completed, the thermal insulation material is used to cover the welded joints of the Jipa steel and the joint areas on both sides of the weld to reduce the cooling speed of the joints.

Further, in the step 1), the groove surface angle of the Y-shaped groove is 65°-80°, and the size of the blunt edge is 2-8mm.

Further, in the step 1), the parent material on the periphery of the Y-shaped groove refers to the parent material within 10 mm of the periphery of the Y-shaped groove.

Further, in the step 4), the chemical composition of the welding wire is C: 0.1%-0.5%, Mn: 1.5%-2.5%, Si: 0.4%-0.65%, Ni: 2.5%-4.0%. , Cr: 0.5% to 1.5%, Mo: 0.5% to 1.3%, Ti: 0.3% to 0.6%, Nb: 0.3% to 0.7%, S≤0.006%, P≤0.010%, and the balance is Fe.

Further, in the step 4), the protective gas is a mixed gas of 80% Ar+20% CO ₂ .

Further, in the step 5), the Gippa steel welded joint and the joint area on both sides of the weld seam refer to the area within 200mm of the periphery of the joint.

In the present invention, firstly, the composition of the welding wire alloy used in arc welding must be determined to ensure that the welding seam is formed well and the mechanical properties of the welding seam are excellent. The main alloying elements of welding wire are C, Mn, Si, Ni, and the trace elements are Cr, Mo, Ti, Nb, S, P.

For the main alloying elements, C element is the basic element to ensure the mechanical properties of steel, and can significantly improve the hardness and strength of the weld. Mn element has good deoxidation and desulfurization effects. Mn is soluble in ferrite, which can refine the grain structure and improve the strength of steel. Si element can play the role of solid solution strengthening and deoxidation in steel, and inhibit the generation of welding porosity. Ni element can be infinitely dissolved in steel, which can not only improve the strength and toughness of steel, but also improve its welding performance.

For trace alloy elements, Cr element can significantly improve the strength, hardness and wear resistance of steel, but at the same time reduce its plasticity and toughness. Mo element can refine the grain structure of weld metal, improve the strength of steel without reducing its plasticity and toughness. Ti element is a C and N compound forming element, and can also fix harmful element S, improving the purity and high temperature performance of weld metal. The Nb element can refine the grain structure of the weld metal, improve the mechanical properties of the steel, and can also improve the welding performance of the steel, but it will slightly reduce the plasticity and toughness. P and S elements will seriously deteriorate the mechanical properties of the weld metal, so their content should be strictly controlled.

When welding, root welding uses high-power laser parameters to achieve deep penetration. For cap welding, low-power laser parameters are used to guide the arc to achieve stable filling.

The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing; The following examples are implemented under the premise of the technical solution of the present invention, and detailed implementation and specific operation process are provided, but the protection scope of the present invention is not limited Examples described below.

【Example 1】

As shown in Figures 1-3, in this embodiment, the oscillating laser-arc hybrid welding process is used to weld Gippah steel with a plate thickness T=30mm, and the specific process is as follows:

a. Take two pieces of Gippa steel plates with the same geometric size (300mm×150mm×30mm), and process a symmetrical Y-shaped groove 3 on the joint side of the two steel plates (as shown in Figure 1), the groove Face angle θ=65°, blunt edge size h=3mm;

b. Use sandpaper to grind the base metal within 10mm around the groove, remove the oxide layer of the steel plate, and then clean the grinding position with acetone, place two pieces of Gippa steel plates side by side, and control the plate gap δ at the joint to 0.5mm ;

c. As shown in Figure 3, adjust the relative position of the laser head 4 and the arc welding torch 5. Along the welding direction, the laser head 4 is in front and the arc welding torch 5 is behind, and ensure that both are at the center of the weld. In the way of vertical incidence, the angle between the welding torch and the laser is 25°, and the distance between the light wires is 6mm;

d. Carry out root welding on Jipa steel, the laser power is 4kW, the laser defocus is -1mm, the laser swing frequency is 15Hz, and the laser swing amplitude is 1.5mm. The working current of the arc welding torch is 180A, the working voltage is 25V, the pulse frequency is 20Hz, and the dry elongation of the welding wire 6 is 10mm. The diameter of the welding wire 6 is 1.2 mm, the wire feeding speed is 6 m/min, and the welding speed is 1 m/min. The protective gas is a mixed gas of 80% Ar+20% CO ₂ , and the flow rate of the protective gas is 15L/min. The bottoming weld bead 1 is shown in Figure 2.

e. Carry out cover welding on Gippa steel, the laser power is 1.5kW, the laser defocus is -1.5mm, the laser swing frequency is 20Hz, and the laser swing amplitude is 2mm. The working current of the arc welding torch is 230A, the working voltage is 28V, the pulse frequency is 25Hz, and the dry elongation of the welding wire 6 is 10mm. The diameter of the welding wire 6 is 1.2 mm, the wire feeding speed is 10 m/min, and the welding speed is 0.9 m/min. The protective gas is a mixed gas of 80% Ar+20% CO ₂ , and the flow rate of the protective gas is 15L/min. The cover weld bead 2 is shown in Figure 2.

f. After the welding of the cover is completed, use asbestos cloth to cover the welded joints of Gippa steel and the 200mm joint area on both sides of the weld to reduce the cooling speed of the joints.

In this embodiment, the tensile strength of the welded joint is 1150 MPa, and the elongation can reach 8%. The fractured position of the joint is at the weld seam, and no obvious pore defect is found in the weld seam.

Comparative example: 30mm thick Gippa steel is welded by the gas shielded welding method, the tensile strength of the joint is 820MPa, and the elongation is 6%. .

[Example 2]

In this embodiment, the oscillating laser-arc hybrid welding process is used to weld Gippah steel with a plate thickness T=50mm, and the specific process is as follows:

a. Take two Jipa steel plates with the same geometric size (450mm×200mm×50mm), and process a symmetrical Y-shaped groove on the joint side of the two steel plates. The angle of the groove surface is 70°, and the blunt edge The size is 5mm;

b. Use sandpaper to grind the base metal within 10mm around the groove, remove the oxide layer of the steel plate, and then clean the grinding position with acetone, place two pieces of Gippa steel plates side by side, and control the gap between the plates at the joint to 0.8mm;

c. Adjust the relative position of the laser head and the arc welding torch. Along the welding direction, the laser head is in front and the arc welding torch is behind, and ensure that both are at the center of the weld. The laser adopts a vertical incident method, and the angle between the welding torch and the laser is 30°, and the distance between light filaments is 4mm;

d. Carry out root welding on Jipa steel, the laser power is 5kW, the laser defocus is -1mm, the laser swing frequency is 20Hz, and the laser swing amplitude is 1.5mm. The working current of the arc welding torch is 200A, the working voltage is 25V, the pulse frequency is 25Hz, and the dry elongation of the welding wire is 15mm. The wire diameter is 1.5mm, the wire feeding speed is 5m/min, and the welding speed is 0.9m/min. The protective gas is a mixed gas of 80% Ar+20% CO ₂ , and the flow rate of the protective gas is 20L/min.

e. Carry out cover welding on Gippa steel, the laser power is 2kW, the laser defocus is 0mm, the laser swing frequency is 25Hz, and the laser swing amplitude is 1.5mm. The working current of the arc welding torch is 260A, the working voltage is 28V, the pulse frequency is 35Hz, and the dry elongation of the welding wire is 18mm. The wire diameter is 2.0mm, the wire feeding speed is 15m/min, and the welding speed is 0.8m/min. The protective gas is a mixed gas of 80% Ar+20% CO ₂ , and the flow rate of the protective gas is 25L/min.

f. After the welding of the cover is completed, use asbestos cloth to cover the welded joints of Gippa steel and the 200mm joint area on both sides of the weld to reduce the cooling speed of the joints.

In this embodiment, the tensile strength of the welded joint is 1050 MPa, and the elongation can reach 7.5%. The fracture position of the joint is at the weld seam, and no obvious air hole defect is found in the weld seam.

Comparative example: Submerged arc welding is used to weld 50mm thick Gippa steel, the tensile strength of the joint is 770MPa, the elongation is 5.6%, and the joint breaks at the weld.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (6)

1. A swing laser-electric arc composite welding method with the plate thickness more than or equal to 30mm Ji Pagang is characterized by comprising the following steps:

1) Machining symmetrical Y-shaped grooves on one side of a joint of two Jipa steel plates with the plate thickness of more than or equal to 30 mm;

2) Polishing a parent metal at the periphery of the Y-shaped groove, removing an oxide layer of the steel plate, cleaning a polishing position, placing two GPa steel plates side by side, and controlling a plate gap at a butt joint position to be 0.2-1.5 mm;

3) The relative positions of a laser head and an arc welding gun are adjusted, the laser head is arranged in front of the arc welding gun and behind the arc welding gun along the welding direction, the laser head and the arc welding gun are ensured to be arranged in the center of a welding seam, the laser adopts a vertical incidence mode, the included angle between the welding gun and the laser is 20-35 degrees, and the distance between optical wires is 2-8 mm;

4) Sequentially performing backing welding and cover surface welding during welding; wherein, the prime welding laser power is 2-4 times of the cover surface welding laser power; the technological parameters during welding are as follows: the laser power is 1-8 kW, the defocusing amount of the laser is between-3 mm and +3mm, the laser swing frequency is 10-30 Hz, and the laser swing amplitude is 1-3 mm; the working current of the arc welding gun is 150-300A, the working voltage is 20-35V, and the pulse frequency is 10-100 Hz; the dry extension of the welding wire is 10-20 mm; the diameter of the welding wire is 1.2-2.0 mm, the wire feeding speed is 2-18 m/min, and the welding speed is 0.6-1.5 m/min; the flow rate of the protective gas is 15-35L/min;

5) After the cover surface welding is finished, the Ji Pagang welding joint and joint areas on two sides of the welding line are covered by adopting a heat insulation material, so that the cooling speed of the joint is reduced.

2. The swing laser-arc hybrid welding method according to claim 1, wherein in the step 1), the bevel angle of the Y-shaped bevel is 65-80 degrees, and the blunt edge size is 2-8 mm.

3. The swing laser-arc hybrid welding method according to claim 1, wherein in the step 1), the base material around the Y-groove is the base material within 10mm of the periphery of the Y-groove.

4. The swing laser-arc hybrid welding method with the plate thickness not less than 30mm Ji Pagang as claimed in claim 1, wherein in the step 4), the chemical components of the welding wire are as follows by weight percentage: 0.1 to 0.5 percent of Mn:1.5 to 2.5 percent, si:0.4 to 0.65 percent of Ni:2.5 to 4.0 percent, cr:0.5 to 1.5 percent, mo:0.5 to 1.3 percent of Ti:0.3 to 0.6 percent, nb:0.3 to 0.7 percent, S is less than or equal to 0.006 percent, P is less than or equal to 0.010 percent, and the balance is Fe.

5. The swing laser-arc welding method according to claim 1, wherein in said step 4), the shielding gas is 80% Ar+20% CO ₂ Is a mixed gas of (a) and (b).

6. The swing laser-arc hybrid welding method according to claim 1, wherein in step 5), ji Pagang welding joints and joint regions on both sides of the weld joint refer to regions within 200mm of the outer periphery of the joint.