阅读说明：本技术 一种超声脉冲mag复合焊接超高强钢的方法 (Method for ultrasonic pulse MAG composite welding of ultrahigh-strength steel ) 是由 郭浩然 王刚 付知易 张闰勃 李静 于 2021-08-13 设计创作，主要内容包括：一种超声脉冲MAG复合焊接超高强钢的方法,本发明涉及超声脉冲MAG复合焊接领域。本发明要解决现有方法焊接高强钢易产生气孔等缺陷,焊缝强度低的技术问题。方法：一、焊接前加工坡口；二、将待焊工件进行预热；三、将超声装置固定；四、调整焊接工艺参数及超声参数；五、采用MAG焊接机器人进行多层多道焊接,同时开启超声装置；六、消氢处理。本发明在MAG焊接过程中引入了超声振动和脉冲搅拌两种利于增加熔池流动性的方法,解决了焊接气孔,裂纹的同时,超声振动还能对熔池中先形成的树枝晶进行破碎,增加熔池形核基地与形核数量,细化焊缝晶粒尺寸,提高铝合金焊接接头力学性能。本发明应用于防弹车辆超高强钢焊接生产领域。(The invention discloses a method for ultrasonic pulse MAG composite welding of ultrahigh-strength steel, and relates to the field of ultrasonic pulse MAG composite welding. The invention aims to solve the technical problems that the high-strength steel welded by the existing method is easy to generate air holes and the like, and the weld joint strength is low. The method comprises the following steps: firstly, processing a groove before welding; secondly, preheating a workpiece to be welded; thirdly, fixing the ultrasonic device; fourthly, adjusting welding process parameters and ultrasonic parameters; fifthly, performing multilayer multi-pass welding by adopting an MAG welding robot, and simultaneously starting an ultrasonic device; sixthly, hydrogen elimination treatment. The ultrasonic vibration and the pulse stirring are introduced into the MAG welding process, so that the method is beneficial to increasing the fluidity of the molten pool, the problem of welding pores and cracks is solved, meanwhile, the ultrasonic vibration can also crush dendrites formed in the molten pool, the nucleation bases and the number of nucleation of the molten pool are increased, the grain size of a welding line is refined, and the mechanical property of an aluminum alloy welding joint is improved. The method is applied to the field of welding production of the bulletproof vehicle ultrahigh-strength steel.)

1. A method for ultrasonic pulse MAG composite welding of ultrahigh-strength steel is characterized by comprising the following steps:

firstly, performing groove processing on a part to be welded of a workpiece to be welded, performing decontamination cleaning on a region to be welded, and then fixing the region to be welded on a welding tool fixture;

secondly, preheating the workpiece to be welded processed in the first step, and controlling the preheating width to be 60-80 mm away from the edge of the groove;

fixing an ultrasonic device along the welding direction, controlling the distance between an ultrasonic vibration tool head and a workpiece to be welded to be 20-50 mm, and controlling the contact pressure between the ultrasonic vibration tool head and the workpiece to be welded to be 0.2-0.6 MPa;

fourthly, adjusting welding process parameters and ultrasonic parameters:

backing welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 50-100A, the peak current is 100-200A, the pulse frequency is 50-200 Hz, the welding speed is 50-500 mm/min, Ar and CO are adopted as shielding gas₂The flow of the protective gas is controlled to be 20-25L/min;

filling and welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 100-150A, the peak current is 200-300A, the pulse frequency is 50-200 Hz, the welding speed is 50-500 mm/min, and Ar and CO are adopted as shielding gas₂The flow of the protective gas is controlled to be 15-20L/min;

the amplitude of the ultrasonic vibration tool head is 5-10 um, and the vibration frequency is 50-200 kHz;

fifthly, welding the workpiece to be welded fixed in the first step by adopting direct current reverse welding to obtain a welding part;

sixthly, hydrogen elimination treatment after welding:

and (4) performing heat preservation and dehydrogenation treatment on the welded part welded in the step five to finish the method.

2. The method for ultrasonically pulsed MAG composite welding of ultra-high strength steel as claimed in claim 1, wherein step one of the workpieces to be welded is PRO500S bullet-proof steel.

3. The method for ultrasonically pulsed MAG hybrid welding of ultra-high strength steel according to claim 1, wherein the groove machined in the first step is a V-groove, a U-groove or a Y-groove.

4. The method for ultrasonically pulsed MAG composite welding of the ultrahigh-strength steel according to claim 1, wherein in the first step, the angle of the groove is controlled to be 40-60 degrees, the gap of the butt joint is 1-2 mm, and the height of the truncated edge of the groove is 0-2 mm.

5. The method for ultrasonic pulse MAG hybrid welding of the ultrahigh-strength steel according to claim 1, wherein the first step is to polish or clean the surfaces of the two sides of the groove, so that the metallic luster is exposed on the surface of the groove, and the rust and oil stain in the 50mm range of the area to be welded are removed.

6. The method for ultrasonically-pulsed MAG composite welding of the ultrahigh-strength steel as claimed in claim 1, wherein the preheating temperature in the second step is controlled to be 200-300 ℃.

7. The method for ultrasonic pulse MAG composite welding of ultrahigh-strength steel as claimed in claim 1, wherein the welding wire of step four is ER100S-G welding wire or ER120S-G welding wire.

8. The method for ultrasonically pulsed MAG composite welding of ultrahigh-strength steel according to claim 1, wherein in the fourth step, the volume content of argon is 75-95% and the volume content of carbon dioxide is 5-25%.

9. The method for ultrasonically-pulsed MAG composite welding of ultrahigh-strength steel according to claim 1, wherein in the step five, the interlayer temperature is controlled to be 200-250 ℃ during filling control filling welding.

10. The method for ultrasonically-pulsed MAG composite welding of the ultrahigh-strength steel as claimed in claim 1, wherein the temperature of the hexahydrogen treatment is controlled to be higher than 150 ℃ for 4 hours or longer.

Technical Field

The invention relates to the field of ultrasonic pulse MAG composite welding.

Background

The armored vehicle high-strength steel protective steel plate is more and more widely applied, is not only applied to the military field nowadays, but also uses the protective steel plate in succession in each current large automobile brand, and provides a vehicle with high protective performance. At present, more advanced ultrahigh-strength bulletproof steel plates with tensile strength of more than 1500MPa are mostly adopted, and the development is towards high hardness and ultrahigh hardness. When the hardness of the bulletproof steel plate exceeds a certain value, the bullet deforms or breaks when penetrating armor, and the bulletproof performance is greatly improved along with the improvement of the hardness. The VR9 grade protective steel plate researched by the invention can resist three times of shooting at a distance of ten meters for a bullet with the caliber of 7.62 multiplied by 51 mm.

However, since the strength, hardness and carbon equivalent are high, an inevitable problem encountered during the welding heat cycle is the generation of weld cracks including thermal cracks, delayed cracks, coarsening of crystal grains in the weld heat affected zone, thereby causing local softening of the heat affected zone. This phenomenon is increasingly severe with increasing welding heat input. Along with the reduction of the hardness, the bulletproof performance of the armor steel plate is reduced, so that the armor steel plate becomes the weakest link of the bulletproof performance of a protective vehicle, and therefore, the selection of a proper welding method and a proper welding process are very important for improving the performance of the protective steel plate.

At present, welding methods of ultrahigh-strength steel are various and comprise laser welding, laser MAG hybrid welding, TIG welding, K-TIG welding, manual arc welding and CO₂In gas shielded welding and the like, martensite in a tempering area is decomposed during laser welding, a netlike cementite is precipitated among crystal grains, the hardness and the impact toughness of the cementite are obviously reduced compared with those of a base metal and the center of a welding line, and the bulletproof performance is insufficient.

Disclosure of Invention

The invention provides a method for ultrasonically-pulsed MAG composite welding of ultrahigh-strength steel, aiming at solving the technical problems that the high-strength steel welded by the existing method is easy to generate air holes and the like, and the welding seam strength is low.

A method for ultrasonic pulse MAG composite welding of ultrahigh-strength steel specifically comprises the following steps:

firstly, performing groove processing on a part to be welded of a workpiece to be welded, performing decontamination cleaning on a region to be welded, and then fixing the region to be welded on a welding tool fixture;

secondly, preheating the workpiece to be welded processed in the first step, and controlling the preheating width to be 60-80 mm away from the edge of the groove;

fixing an ultrasonic device along the welding direction, controlling the distance between an ultrasonic vibration tool head and a workpiece to be welded to be 20-50 mm, and controlling the contact pressure between the ultrasonic vibration tool head and the workpiece to be welded to be 0.2-0.6 MPa;

fourthly, adjusting welding process parameters and ultrasonic parameters:

backing welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 50-100A, the peak current is 100-200A, the pulse frequency is 50-200 Hz, the welding speed is 50-500 mm/min, Ar and CO are adopted as shielding gas₂The flow of the protective gas is controlled to be 20-25L/min;

filling and welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 100-150A, the peak current is 200-300A, the pulse frequency is 50-200 Hz, the welding speed is 50-500 mm/min, and Ar and CO are adopted as shielding gas₂The flow of the protective gas is controlled to be 15-20L/min;

the amplitude of the ultrasonic vibration tool head is 5-10 um, and the vibration frequency is 50-200 kHz;

fifthly, welding the workpiece to be welded fixed in the first step by adopting direct current reverse welding to obtain a welding part;

sixthly, hydrogen elimination treatment after welding:

and (4) performing heat preservation and dehydrogenation treatment on the welded part welded in the step five to finish the method.

And step five, performing multilayer and multi-pass welding by adopting an MAG welding robot, and simultaneously starting the ultrasonic device.

Further, in the step one, the workpiece to be welded is PRO500S bulletproof steel, and the thickness is 6-10 mm.

The PRO500S bulletproof steel comprises, by mass, 0.24-0.38% of C, 0.5% of Si, 1.10-1.70% of Mn, 0.025% of P, 0.035% of S, 1.2% of Ni, 0.30-1.20% of Cr, 0.8% of Mo, 0.002-0.005% of B and the balance Fe, and inevitable impurities are present;

the yield strength of the PRO500S bulletproof steel is 1500MPa, and the tensile strength is 2000 MPa.

Further, the groove processed in the first step is a V-shaped groove, a U-shaped groove or a Y-shaped groove.

Further, in the first step, the angle of the groove is controlled to be 40-60 degrees, the gap of the butt joint is 1-2 mm, and the height of the truncated edge of the groove is 0-2 mm.

Further, the surfaces of two sides of the processed groove are polished or cleaned, the surface of the groove is exposed with metallic luster, and rust and oil stains in a 50mm range of a region to be welded are removed completely.

Further, the preheating temperature in the second step is controlled to be 200-300 ℃.

Further, the welding wire in the fourth step is an ER100S-G welding wire or an ER120S-G welding wire.

The ER100S-G welding wire comprises, by mass, 0.11% of C, 0.50-0.80% of Si, 1.40-1.80% of Mn, 0.025% of P, 0.025% of S, 1.20-1.55% of Ni, 0.3-0.6% of Mo, and the balance Fe, and inevitable impurities are present. The deposited metal has the following mechanical properties: the tensile strength is more than or equal to 745MPa, and the yield strength is more than or equal to 630 MPa.

The ER120S-G welding wire comprises, by mass, 0.1% of C, 0.8% of Si, 1.8% of Mn, 0.025% of P, 0.025% of S, 0.35% of Cr, 2.25% of Ni, 0.6% of Mo, and the balance Fe, and contains inevitable impurities. The deposited metal has the following mechanical properties: the tensile strength is more than or equal to 915MPa, and the yield strength is more than or equal to 960 MPa.

The invention has the beneficial effects that:

the technical problem to be solved by the invention is to provide a method for ultrasonically pulsing MAG composite welding of ultrahigh-strength steel aiming at the defects of the prior art. The method is optimized and improved on the basis of MAG welding with relatively stable current technology, wherein ultrasonic-MAG arc hybrid welding introduces the advantages of ultrasonic into the welding process, and obtains remarkable performance in refining crystal grains. The torch structure resembles a single axis acoustic levitation system, creating an arc in the area between the sound emitting end and the workpiece being welded. After the ultrasonic wave is added, the welding arc is compressed, the splashing is weakened, and air holes are reduced. Therefore, the ultrasonic MAG welding high-strength protective steel plate can overcome the defects of the traditional method and improve the performance of the welding joint.

The invention utilizes the combination of the ultrasonic vibration source with the frequency of 50 kHz-200 kHz and the pulse MAG welding to weld the super-rigid steel plate, namely two methods of ultrasonic vibration and pulse stirring are introduced in the MAG welding process, which are favorable for increasing the fluidity of a molten pool, effectively solves welding air holes and cracks, and simultaneously can crush dendrites formed in the molten pool firstly by the ultrasonic vibration, increase the nucleation base and the number of nucleation of the molten pool, refine the grain size of a welding seam and improve the mechanical property of an aluminum alloy welding joint.

The method is applied to the field of welding production of the bulletproof vehicle ultrahigh-strength steel.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of an ultrasonically assisted pulsed MAG welding apparatus;

FIG. 2 is a diagram of an embodiment ultrasonic assisted pulsed MAG welding apparatus installation profile;

FIG. 3 is a metallographic photograph of a weld of the first embodiment;

FIG. 4 is a photograph of a weld seam of the embodiment without destructive inspection.

Detailed Description

The technical solution of the present invention is not limited to the specific embodiments listed below, and includes any combination of the specific embodiments.

The first embodiment is as follows: the embodiment of the invention relates to a method for ultrasonic pulse MAG composite welding of ultrahigh-strength steel, which comprises the following steps:

firstly, performing groove processing on a part to be welded of a workpiece to be welded, performing decontamination cleaning on a region to be welded, and then fixing the region to be welded on a welding tool fixture;

secondly, preheating the workpiece to be welded processed in the first step, and controlling the preheating width to be 60-80 mm away from the edge of the groove;

fixing an ultrasonic device along the welding direction, controlling the distance between an ultrasonic vibration tool head and a workpiece to be welded to be 20-50 mm, and controlling the contact pressure between the ultrasonic vibration tool head and the workpiece to be welded to be 0.2-0.6 MPa;

fourthly, adjusting welding process parameters and ultrasonic parameters:

backing welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 50-100A, the peak current is 100-200A, the pulse frequency is 50-200 Hz, the welding speed is 50-500 mm/min, Ar and CO are adopted as shielding gas₂The flow of the protective gas is controlled to be 20-25L/min;

filling and welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 100-150A, the peak current is 200-300A, the pulse frequency is 50-200 Hz, the welding speed is 50-500 mm/min, and Ar and CO are adopted as shielding gas₂The flow of the protective gas is controlled to be 15-20L/min;

the amplitude of the ultrasonic vibration tool head is 5-10 um, and the vibration frequency is 50-200 kHz;

fifthly, welding the workpiece to be welded fixed in the first step by adopting direct current reverse welding to obtain a welding part;

sixthly, hydrogen elimination treatment after welding:

and (4) performing heat preservation and dehydrogenation treatment on the welded part welded in the step five to finish the method.

The second embodiment is as follows: the first difference between the present embodiment and the specific embodiment is: step one, the workpiece to be welded is PRO500S bulletproof steel. The rest is the same as the first embodiment.

The third concrete implementation mode: the present embodiment differs from the first or second embodiment in that: the groove processed in the first step is a V-shaped groove, a U-shaped groove or a Y-shaped groove. The other is the same as in the first or second embodiment.

The fourth concrete implementation mode: the difference between this embodiment mode and one of the first to third embodiment modes is: in the first step, the angle of the groove is controlled to be 40-60 degrees, the gap of the butt joint is 1-2 mm, and the height of the truncated edge of the groove is 0-2 mm. The others are the same as in one of the first to third embodiments.

The fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: polishing or cleaning the surfaces of two sides of the processed groove, exposing metallic luster on the surface of the groove, and cleaning rust and oil stain in a 50mm range of a region to be welded. The other is the same as one of the first to fourth embodiments.

The sixth specific implementation mode: the difference between this embodiment and one of the first to fifth embodiments is: and step two, controlling the preheating temperature to be 200-300 ℃. The other is the same as one of the first to fifth embodiments.

The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is: step four, adjustment:

backing welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 70-100A, the peak current is 120-200A, the pulse frequency is 100-200 Hz, the welding speed is 100-500 mm/min, Ar and CO are adopted as shielding gas₂The flow rate of the protective gas is controlled to be 20-25L/min. The other is the same as one of the first to sixth embodiments.

The specific implementation mode is eight: the present embodiment differs from one of the first to seventh embodiments in that: step four, adjustment:

backing welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 80-100A, the peak current is 160-200A, the pulse frequency is 150-200 Hz, the welding speed is 300-500 mm/min, Ar and CO are adopted as a protective gas₂The flow of the protective gas is controlled to be 20-25L/min;

filling and welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 120-150A, the peak current is 250-300A, the pulse frequency is 150-200 Hz, the welding speed is 300-500 mm/min, Ar and CO are adopted as a protective gas₂The flow of the protective gas is controlled to be 15-20L/min;

the amplitude of the ultrasonic vibration tool head is 5-10 um, and the vibration frequency is 150-200 kHz. The rest is the same as one of the first to third embodiments.

The specific implementation method nine: the present embodiment differs from the first to eighth embodiments in that: step four, adjustment:

backing welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 90-100A, the peak current is 180-200A, the pulse frequency is 180-200 Hz, the welding speed is 400-500 mm/min, and Ar and CO are adopted as shielding gas₂The flow of the protective gas is controlled to be 20-25L/min;

filling and welding: the diameter of a welding wire is 1.2mm, the pulse MAG base value current is 140-150A, the peak current is 280-300A, the pulse frequency is 180-200 Hz, the welding speed is 400-500 mm/min, Ar and CO are adopted as a protective gas₂The flow of the protective gas is controlled to be 15-20L/min;

the amplitude of the ultrasonic vibration tool head is 5-10 um, and the vibration frequency is 180-200 kHz. The rest is the same as the first to eighth embodiments.

The detailed implementation mode is ten: the present embodiment differs from one of the first to ninth embodiments in that: and fourthly, the welding wire is an ER100S-G welding wire or an ER120S-G welding wire. The other is the same as one of the first to ninth embodiments.

The concrete implementation mode eleven: the present embodiment differs from one of the first to tenth embodiments in that: fourthly, the volume content of argon in the protective gas is 75-95%, and the volume content of carbon dioxide is 5-25%. The rest is the same as one of the first to tenth embodiments.

The specific implementation mode twelve: this embodiment is different from one of the first to eleventh embodiments in that: and fifthly, controlling the interlayer temperature to be 200-250 ℃ during filling control filling welding. The rest is the same as in one of the first to eleventh embodiments.

The specific implementation mode is thirteen: the present embodiment differs from the first to twelfth embodiments in that: the temperature of the sixth dehydrogenation treatment is controlled to be higher than 150 ℃ and the time is more than or equal to 4 h. The rest is the same as the first to twelfth embodiments.

The following examples were used to demonstrate the beneficial effects of the present invention:

example ultrasound assisted pulsed MAG welding apparatus: two steel sheets 2 to be welded are fixed on a numerical control workbench 9 in a butt joint mode, an MIG welding gun 3 is fixed on a traveling mechanism 13 and is perpendicular to the front surface of the steel sheets 2 to be welded, and a welding wire 4 is installed in the MIG welding gun 3: the ultrasonic vibration tool head 5 is arranged on the front surface of the steel plate 2 to be welded and the side surface of the welding seam 1, the ultrasonic vibration tool head 5 is connected with an amplitude transformer 6, the amplitude transformer 6 is connected with a transducer 7, and the transducer 7 is connected with an ultrasonic generator 1l through a transmission line 8.

The MIG gun 3 is connected to an arc welder 14, which arc welder 14 is connected to a welding gas 15 via a pipe.

The ultrasonic generator 11 is connected with an external control system 12 of the ultrasonic generator, the ultrasonic generator 11 is connected with an external power supply 17 of the ultrasonic generator through a power line 10, and the numerical control workbench 9 and the travelling mechanism 13 are connected with a numerical control operation cabinet 16.

The first embodiment is as follows:

the method for ultrasonic pulse MAG composite welding of the ultrahigh-strength steel specifically comprises the following steps:

firstly, processing a groove at a part to be welded of a workpiece to be welded, wherein the groove is a V-shaped groove, controlling the angle of the groove to be 60 degrees, controlling the gap of a butt joint to be 1mm, and controlling the height of the truncated edge of the groove to be 1mm, performing decontamination cleaning on an area to be welded, polishing or cleaning the surfaces of two sides of the processed groove, exposing metal luster on the surface of the groove, completely removing rust and oil stain in the range of 50mm of the area to be welded, and then fixing the area to be welded on a welding tool clamp; the workpieces to be welded are two PRO500S bulletproof steel plates with the thickness of 8.2 mm;

secondly, preheating the workpiece to be welded processed in the first step to 250 ℃, and controlling the preheating width to be within a range of 80mm away from the edge of the groove;

fixing an ultrasonic device along the welding direction, controlling the distance between the ultrasonic vibration tool head and the workpiece to be welded to be 20mm, and controlling the contact pressure between the ultrasonic vibration tool head and the workpiece to be welded to be 0.6 MPa;

fourthly, adjusting welding process parameters and ultrasonic parameters:

backing welding: the diameter of the ER-100S welding wire is 1.2mm, the pulse MAG base value current is 100A, the peak current is 150A, the pulse frequency is 50Hz, the welding speed is 500mm/min, and Ar and CO are adopted as the protective gas₂The flow of the protective gas is controlled to be 20L/min;

filling and welding: the diameter of an ER-100S welding wire is 1.2mm, the pulse MAG base value current is 150A, the peak current is 250A, the pulse frequency is 50Hz, the welding speed is 500mm/min, and Ar and CO are adopted as protective gas₂The flow of the protective gas is controlled to be 15L/min;

the amplitude of the ultrasonic vibration tool head is 10um, and the vibration frequency is 200 kHz;

the volume content of argon in the protective gas is 95%, and the volume content of carbon dioxide is 5%;

fifthly, welding the workpiece to be welded fixed in the first step by adopting direct current reverse welding to obtain a welding part; and step four, controlling the interlayer temperature to be 200 ℃ during filling control filling welding.

Sixthly, hydrogen elimination treatment after welding:

performing heat preservation and dehydrogenation treatment on the welded part welded in the fifth step, controlling the temperature to be 160 ℃, and preserving the heat for 4 hours; the method is completed.

Fig. 3 is a metallographic photograph of a weld of the present embodiment.

FIG. 4 is a photograph showing the non-destructive testing of the weld joint of the present embodiment.

As can be seen from the figure, the welding seam is uniform in whole, has no coarse grain defects, achieves the effect of grain refinement, and has high welding seam quality, no surface cracks and no air holes.

Example two:

the method for ultrasonic pulse MAG composite welding of the ultrahigh-strength steel specifically comprises the following steps:

firstly, processing a groove at a part to be welded of a workpiece to be welded, wherein the groove is a V-shaped groove, controlling the angle of the groove to be 60 degrees, controlling the gap of a butt joint to be 1mm, and controlling the height of the truncated edge of the groove to be 1mm, performing decontamination cleaning on an area to be welded, polishing or cleaning the surfaces of two sides of the processed groove, exposing metal luster on the surface of the groove, completely removing rust and oil stain in the range of 50mm of the area to be welded, and then fixing the area to be welded on a welding tool clamp; the workpieces to be welded are two PRO500S bulletproof steel plates with the thickness of 8.2 mm;

secondly, preheating the workpiece to be welded processed in the first step to 300 ℃, and controlling the preheating width to be within a range of 80mm away from the edge of the groove;

fixing an ultrasonic device along the welding direction, controlling the distance between the ultrasonic vibration tool head and the workpiece to be welded to be 20mm, and controlling the contact pressure between the ultrasonic vibration tool head and the workpiece to be welded to be 0.6 MPa;

fourthly, adjusting welding process parameters and ultrasonic parameters:

backing welding: the diameter of the ER-120S welding wire is 1.2mm, the pulse MAG base value current is 150A, the peak current is 200A, the pulse frequency is 100Hz, the welding speed is 500mm/min, and Ar and CO are adopted as the protective gas₂The flow of the protective gas is controlled to be 20L/min;

filling and welding: the diameter of the ER-120S welding wire is 1.2mm, the pulse MAG base value current is 180A, the peak current is 280A, the pulse frequency is 100Hz, the welding speed is 500mm/min, and Ar and CO are adopted as the protective gas₂The flow of the protective gas is controlled to be 15L/min;

the amplitude of the ultrasonic vibration tool head is 10um, and the vibration frequency is 200 kHz;

the volume content of argon in the protective gas is 95%, and the volume content of carbon dioxide is 5%;

fifthly, welding the workpiece to be welded fixed in the first step by adopting direct current reverse welding to obtain a welding part; and step four, controlling the interlayer temperature to be 200 ℃ during filling control filling welding.

Sixthly, hydrogen elimination treatment after welding:

performing heat preservation and dehydrogenation treatment on the welded part welded in the fifth step, controlling the temperature to be 160 ℃, and preserving the heat for 4 hours; the method is completed.

Tensile strength of the welded steel plates in the first embodiment and the second embodiment can reach 1400-1600MPa, which both reach 70% of tensile strength of base metal, and can meet the use requirement of the weld joint of the bulletproof steel.