CN120680135A - A laser arc hybrid welding method for high-grade silicon steel - Google Patents

Abstract

The present invention relates to the field of strip steel welding technology and material science and technology, and in particular to a laser arc hybrid welding method for high-grade silicon steel. The method comprises the following steps: clamping two strip steel plates to be welded; shearing the welding ends of the two strip steel plates to be welded respectively; splicing the two sheared strip steel plates to be welded; and preheating, laser arc hybrid welding, and heat treatment of the two strip steel plates to be welded. By adopting the laser arc hybrid welding method for high-grade silicon steel provided by the present invention, hot-rolled high-grade silicon steel is welded through a combined process of laser arc hybrid welding, preheating, and post-weld heat treatment, which can effectively improve the quality of the welded joint, and the welded joint of the product has good toughness and is not easy to break. The method has a simple process, is easy to operate, and has low production cost.

Description

Laser arc hybrid welding method for high-grade silicon steel

Technical Field

The invention relates to the technical field of strip steel welding technology and material science, in particular to a laser arc composite welding method of high-grade silicon steel.

Background

And a silicon steel normalizing pickling line adopts a laser welding machine to weld the head part and the tail part of the strip steel so as to ensure the continuity of the production line. The inlet raw material of the normalizing pickling line is hot rolled silicon steel raw material. The laser welding has three welding processes of laser, laser filler wire welding and laser arc composite welding, but the welding performance of the pure laser and the laser filler wire welding high-grade silicon steel is unstable, the welding success rate is lower, and the requirements of mass, high-efficiency and continuous production cannot be met. In addition, the existing steel mill adopts more carbon dioxide gas lasers, and the defects of high price, complex structure, difficult maintenance, high use cost and the like are gradually replaced by high-power solid lasers represented by optical fiber lasers and disc lasers. Therefore, the original welding process based on the carbon dioxide gas laser cannot meet the application requirements of the solid laser.

The hot-rolled high-grade non-oriented silicon steel has high Si content, the welded weld joint structure is thick, the heat affected zone structure is greatly influenced by welding heat input, the structure uniformity is poor, the toughness of a welded joint is poor, the weld joint of the welded silicon steel by adopting the welding process is full, the weld joint cannot be qualified even if the surface shape is full when a bending experiment is carried out on a weld joint detection bending machine, and the weld joint is easy to crack along the weld joint or the heat affected zone to break when a unit is in operation, so that the production efficiency is reduced.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides a laser arc composite welding method for high-grade silicon steel.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a laser arc composite welding method of high-grade silicon steel comprises the following steps:

Clamping the two strip steel plates to be welded;

Respectively shearing the welding ends of the two strip steel plates to be welded;

splicing the sheared two strip steel plates to be welded;

and preheating, laser arc composite welding and heat treatment are carried out on the two strip steel plates to be welded.

In one embodiment, the plate thicknesses of the two strip steel plates to be welded are h1 and h2 respectively, wherein h1 is less than or equal to h2, h2-h1 is less than or equal to 0.8mm, and h2 is less than or equal to 1.3h1.

In one embodiment, the preheating is an in-line preheating, and the temperature of the preheating is above 300 ℃ and below 400 ℃.

In one embodiment, the heat treatment is an in-line heat treatment, and the temperature of the heat treatment is above 700 ℃ and below 800 ℃.

In one embodiment, the laser-to-wire spacing of the laser arc hybrid welding is above 2mm and below 5mm.

In one embodiment, the gap between the two butt joints of the steel plates to be welded after the steel plates to be welded are cut is more than 0.2mm and less than 0.3 mm.

In one embodiment, the laser arc hybrid welding is a single-sided welding mode, and the inter-plate gap between the two strip steels is welded.

In one embodiment, the laser arc hybrid welding is performed by a laser arc hybrid welding head;

and induction heating coils are respectively arranged in front of and behind the laser arc composite welding head along the extending direction of the welding line for preheating and heat treatment.

In an embodiment, the laser arc hybrid welding adopts a single-sided welding mode to weld the joint gaps of two steel belts to be welded.

In one embodiment, during welding, a shielding gas is blown out to the welding part;

the protective gas blown out of the front surface of the welding seam is mixed protective gas;

the protective gas blown out of the back surface of the welding seam is single-component protective gas;

Preferably, the mixed shielding gas consists of argon and 18% carbon dioxide;

preferably, the flow rate of the mixed shielding gas is more than 25L/min and less than 30L/min;

Preferably, the pressure of the mixed shielding gas is above 0.4MPa and below 0.6 MPa;

Preferably, the single component shielding gas is argon;

preferably, the flow rate of the single-component shielding gas is more than 8L/min and less than 15L/min;

Preferably, the pressure of the single-component shielding gas is 0.4MPa or more and 0.6MPa or less.

Based on the above, compared with the prior art, the laser arc hybrid welding method for the high-grade silicon steel provided by the invention adopts the combined process of laser arc hybrid welding, preheating and postweld heat treatment to weld the hot-rolled high-grade silicon steel, can effectively improve the quality of a welded joint, has good toughness of the welded joint of a product, and is not easy to break. The method has the advantages of simple process, convenient operation and low production cost.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained according to the drawings without the need of creative efforts for a person skilled in the art, and the positional relationship shown in the drawings in the following description is based on the directions of components shown in the drawings unless otherwise specified.

FIG. 1 shows a process flow diagram of a laser arc hybrid welding method for high grade silicon steel provided by an embodiment of the invention;

FIG. 2 is a schematic diagram of a welding process according to an embodiment of the present invention;

FIG. 3 shows an image of the tissue at the weld of a product according to an embodiment of the invention;

FIG. 4 is a photograph of a weld after a cupping test of the product of the example of the invention;

FIG. 5 is a photograph of a weld after a cupping test of the comparative example 1 product of the present invention;

FIG. 6 is a photograph of a weld after a cupping test of the comparative example 2 product of the present invention;

FIG. 7 is a photograph of a weld after a cupping test of the product of comparative example 3 of the present invention;

FIG. 8 is a photograph of a weld after a cupping test of the product of comparative example 4 of the present invention.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments, technical features designed in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other, and all other embodiments obtained by those skilled in the art without making creative efforts on the basis of the embodiments of the present invention are all within the scope of protection of the present invention.

In the description of the present invention, it should be noted that all terms used in the present invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs and are not to be construed as limiting the present invention, and it should be further understood that the terms used in the present invention should be construed as having meanings consistent with the meanings of the terms in the context of the present specification and the related art and should not be construed in an idealized or overly formal sense unless expressly so defined herein.

Referring to fig. 1, an embodiment of the present invention provides a laser arc hybrid welding method for high grade silicon steel, which includes the following steps:

step 1, clamping two steel plates to be welded;

In the embodiment, two strip steel plates to be welded are clamped through a clamping device on a welding machine to fix the positions of the strip steel plates to be welded, so that the strip steel plates are prevented from shifting or shaking in the subsequent shearing, splicing and welding processes, and therefore welding precision and quality are ensured, the high-grade silicon steel is silicon steel with the silicon content of 2.7% or more (mass ratio), and the head and tail of the silicon steel strip are welded by a laser welding machine when the grade silicon steel is produced by a standardized pickling unit, a continuous rolling unit and other continuous line management processes, so that the continuity of the production line is ensured. Specific operations include, but are not limited to:

Selecting a proper clamp, namely selecting a clamp with enough clamping force and stability according to the size, shape and thickness of the strip steel to be welded. For example, for thinner strip steel plates, a magnetic clamp may be used that is capable of uniformly applying a clamping force to avoid deformation of the strip steel plate, while for thicker strip steel plates, a mechanical clamp, such as a hydraulic clamp, may be required to provide a greater clamping force;

and determining the clamping position, namely arranging the clamp at a proper position of the strip steel plate, wherein the clamping is ensured to be firm, and the subsequent shearing and welding operations cannot be influenced. Generally, the clamp should be close to the part to be welded, but enough space is left for the operation of the shearing tool and the movement of the welding head;

The clamping force is adjusted to be moderate, the excessive clamping force can possibly lead to the deformation of the steel plate, and the too small clamping force can not ensure the fixation of the steel plate. The clamping force can be adjusted to be proper according to the material and the thickness of the steel plate through the adjusting device of the clamp.

In some preferred embodiments, the thicknesses of the two steel plates to be welded are h1 and h2 respectively, wherein h1 is less than or equal to h2, h2-h1 is less than or equal to 0.8mm, and h2 is less than or equal to 1.3h1, and it is noted that the steel plates to be welded adopt a welding splice welding mode with the lower surfaces being flush. When the thickness difference of the strip steel to be welded is larger, the section stress difference born by the two sides of the thin thick plate is larger. Compared with the thick plate material, the thin plate has small deformation resistance, larger deformation amount is born in the deformation process, and the tensile stress of the thin plate in the area near the welding line is larger. And (3) referring to a metal cup test standard (GB/T4156-2020), performing a cup test on the weld joint, and ensuring that the crack at the break part is not torn along the weld joint when the cup is used for the weld joint, so that the strength of the weld joint is higher than that of a base material. In combination with the practical cupping test effect, the preferable thickness difference and thickness ratio can obtain good cupping effect.

Step 2, shearing welding ends of the two strip steel plates to be welded respectively;

In this embodiment, the welding ends of the two steel plates to be welded are sheared respectively to make the welding ends of the steel plates to be welded have a flat and vertical shearing surface, so as to remove possible defects such as burrs and oxide layers and ensure the quality of the welded joint and the stability of welding, and the specific operations include but are not limited to:

and selecting shearing equipment, namely selecting proper shearing equipment according to the thickness and the material of the steel plate. For thinner strip plates, double shearing can be used, which is fast and accurate, and for thicker strip plates, hydraulic plate shears may be required to provide sufficient shear force.

And adjusting shearing parameters including shearing clearance, shearing speed and the like. The shearing clearance is required to be accurately adjusted according to the thickness of the steel plate, the cutter is possibly worn and aggravated due to the too small clearance, and the shearing surface is uneven due to the too large clearance. The shearing speed is moderate, the shearing surface can be torn when the shearing speed is too high, and the production efficiency can be affected when the shearing speed is too low.

And (3) performing shearing operation, namely ensuring the position fixation of the steel plate and ensuring the accurate movement track of the cutter in the shearing process. Meanwhile, the shearing surface is checked, and if the shearing surface has defects such as burrs, cracks and the like, the shearing surface should be cleaned and repaired in time.

Step 3, splicing the sheared two strip steel plates to be welded;

in this embodiment, the two sheared strip steel plates to be welded are spliced, so that the welding ends of the strip steel plates to be welded are tightly attached to form a good welding joint, welding defects are reduced, and welding quality is improved. Specific operations include, but are not limited to:

Checking the seam clearance, namely controlling the seam clearance in a smaller range, and generally requiring a certain proportion (such as 0.1-0.2 times) of the thickness of the steel plate. If the gap between the welding seams is too large, the welding seams are formed poorly during welding, and the defects of incomplete filling, welding leakage and the like are likely to occur, and if the gap between the welding seams is too small, the filling metal melted by the welding wires at the welding seams during welding cannot be fully fused with the base metal in the molten pool, and the filling part of the filling metal is accumulated on the upper surface of the welding seams, so that the residual height of the welding seams is too high.

And (3) adjusting the positions of the strip steel plates, namely aligning welding ends of the two strip steel plates through a fine adjustment device, and ensuring straightness and verticality of the splice. And a displacement sensor or other instruments and equipment can be used for assisting adjustment, so that the accuracy of the joint is improved.

And fixing the positions of the joints, namely fixing the strip steel plates by using a temporary fixing device (such as a clamp and the like) after the joints are adjusted, so as to prevent the positions of the joints from changing in the welding process.

It should be noted that, the above "clamping two strip steel plates to be welded" in step 1, "shearing the welding ends of the two strip steel plates to be welded" in step 2, and "splicing the sheared two strip steel plates to be welded" in step 3, and those skilled in the art may refer to other related operation procedures of welding the existing hot rolled high-grade non-oriented silicon steel, which are not repeated herein.

And 4, preheating the two steel plates to be welded, performing laser arc hybrid welding and performing heat treatment.

In the embodiment, an electric arc welder for implementing electric arc welding by the laser arc composite welding process adopts a push-pull wire system CMT process, a laser welder for implementing laser welding adopts a solid laser, an induction heater for implementing induction heating is driven by a travelling trolley to move and ensure to cooperatively move with the electric arc welder and the laser welder, the laser arc composite welding process can adopt laser arc paraxial composite welding, a molten pool for laser guided arc composite welding is stable, and when an electric arc acts at the rear, heat input carried by the electric arc is matched with preheating before welding, so that the cooling speed of the molten pool can be effectively reduced, air hole overflow is facilitated, and the probability of generating air hole defects is reduced. In laser-guided arc hybrid welding, the laser mainly acts to attract and stabilize the arc in front, reducing the arc deflection during the welding process to obtain better weld formation.

The preheating is on-line preheating, the heat treatment is on-line heat treatment, and the laser arc composite welding is performed while the unwelded joint part is preheated and the formed welding seam is subjected to post-welding heat treatment. And performing laser arc composite welding operation through a laser arc composite welding head, arranging an electromagnetic induction coil in front of the laser arc composite welding head along the extending direction of a welding line for performing on-line preheating treatment, and arranging an induction heating coil in the rear of the laser arc composite welding head for performing on-line post-welding heat treatment.

The preheating before welding can raise the temperature of the welding area and preheat the steel plate to be welded in advance, so that the laser absorptivity is raised, the required heat input of the laser and the subsequent welding of the electric arc is reduced, and more importantly, the influence of abrupt temperature change caused by the laser-electric arc composite welding heat input of the welding area during actual welding is reduced by preheating before welding, and the welding stress of the welding area is reduced, thereby avoiding the generation of hardening structure. And furthermore, the CMT technology adopted by the electric arc during welding greatly reduces the heat input during welding to reduce the heat influence of the structure of the welding part, and can better ensure the structure performance of the welding joint.

Referring to FIG. 2, in the present embodiment, the preheating and the heat treatment may be achieved by a structure in which the laser arc hybrid welding performs a welding operation by a laser arc hybrid welding head, and induction heating coils are respectively provided in front of and behind the laser arc welding head in the extending direction of the welding seam to perform an on-line preheating and a post-welding heat treatment operation. It will be appreciated that the laser arc hybrid welding head is forward of the unwelded seam side and rearward of the formed seam side. The laser arc composite welding head, the on-line preheating and on-line post-welding heat treatment device are all arranged on a welding trolley, driven by the trolley and moving along the welding line direction along with the trolley, the laser arc composite welding head is arranged above the strip steel, the induction heating coil is arranged on the lower surface of the strip steel, the running speed and the welding speed of the on-line preheating and post-welding heat treatment device are the same, and the three are in synergistic effect, so that the welding line quality is ensured.

According to the embodiment of the invention, the pre-welding preheating induction coil, the laser welding head, the arc welding gun composite welding device and the post-welding heat treatment induction coil are all arranged on the welding trolley, and the pre-welding preheating, the intermediate laser arc composite welding and the post-welding heat treatment are performed simultaneously without waiting time, the pre-welding preheating, the intermediate welding, the post-welding heat treatment and the heat treatment are completed immediately after the welding is completed. In the embodiment of the invention, the heating temperature of the preheating induction coil used for preheating is higher than 300 ℃ and lower than 400 ℃, the heating temperature of the preheating induction coil is 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃, 350 ℃, 360 ℃, 370 ℃, 380 ℃, 390 ℃, 400 ℃ and the like, but the preheating induction coil is not limited to the listed values, other non-listed values in the numerical range are also applicable, the heating temperature of the post-welding heat treatment is higher than 700 ℃ and lower than 800 ℃, the heating temperature of the post-welding heat treatment is, for example, 700 ℃, 710 ℃, 720 ℃, 730 ℃, 740 ℃, 750 ℃, 760 ℃, 770 ℃, 780 ℃, 790 ℃, 800 ℃ or any value between the two, and by preheating before welding, on one hand, the preheating can slow down the cooling speed after welding, reduce the welding stress of a welding area, on the other hand, increase the laser input power, increase the depth, maintain the heat input pool, facilitate the improvement of the welding pool, improve the welding pool quality, reduce the welding pool quality, improve the welding pool quality, and the like. And after the postweld heat treatment, the welding stress is further released, the formation of a hardening structure is reduced, the weld joint structure performance is improved, the weld joint toughness and the cold crack resistance are improved, and the production line belt breakage risk is reduced. In addition, the cooling of the postweld heat treatment can be directly carried out in the air without specially controlling the cooling speed, thereby greatly simplifying the heat treatment process.

The laser arc composite welding adopted by the invention has the following advantages compared with the laser filler wire welding process and the like:

(1) The light plasma provides sufficient charged particles for stable combustion of the electric arc, so that the electric arc is stable in combustion and attracted, and the phenomenon of arc drift or stretch-breaking is not easy to occur during high-speed welding. Meanwhile, the filling material enters a molten pool in a molten drop mode, and the laser beam has a strong traction effect on an electric arc and molten drops, so that the defect that the relative position accuracy requirement on the laser beam and a welding wire is high in solid laser-filler wire welding is effectively overcome;

(2) Better weld joint forming and joint quality, namely, the solidification speed of molten pool metal can be effectively slowed down during the welding of a composite heat source, so that phase transformation can be fully carried out, the escape of gas in a welding molten pool is facilitated, and the weld joint quality is improved. And defects such as air holes, cracks, undercut and the like are reduced. The welding seam is full, the melting width is increased by 50%, and the welding seam is matched with the melting of welding wire molten drops, so that the structural performance of the welding seam is effectively improved and improved, the better welding seam quality is obtained, and the welding requirement of high-grade silicon steel and other difficult-to-weld materials is met.

(3) The welding efficiency is higher, the welding cost is lower, the electric arc provides preheating, the welding wire is directly melted, the energy of laser is not required to be consumed, the penetrating capacity of a laser small hole is enhanced, the welding penetration and the welding speed are improved, the welding efficiency is improved by 20-30%, and the welding thickness can reach 10mm. While the reflectivity of the molten metal surface is lower than that of the solid metal surface. When the laser irradiates the liquid molten pool of the base material, the base material can absorb more laser energy, and the melting depth is increased. Compared with single laser welding with the same power, the composite heat source welding improves the penetration by more than 50 percent on average, and ensures that the welding speed can be improved by 1-2 times under the same penetration condition. This means that the power level of the laser is reduced, improving efficiency and thus reducing welding costs.

(4) The addition of the electric arc increases the width of the fusion zone on the surface of the workpiece, so that the sensitivity of laser-electric arc hybrid welding to assembly gaps, centering and misalignment is reduced. Compared with laser welding or laser filler wire welding, the method has higher seam gap and misalignment tolerance, and can tolerate seam gap of 0.5mm and misalignment by 50%.

The welding process parameters were selected as follows:

The thickness of the two strip steels to be welded is h1 and h2 respectively, and preset conditions that h1 is less than or equal to h2, h2-h1 is less than or equal to 0.8mm and h2 is less than or equal to 1.3h1 are required to be met. Obtaining corresponding welding process parameters including welding speed, laser power, laser defocusing amount, seam gap, electric welding voltage, electric welding current, preheating power and postweld heat treatment power in a welding database according to the total thickness of two strip steels to be welded;

The specific welding parameters are as follows:

TABLE 1

In this embodiment, the laser arc hybrid welding speed is 3m/min. The laser is a fiber laser. The defocusing amount of the laser is 5+/-0.5 mm, the distance between the light (laser) -wires (welding wires) of the laser arc composite welding is more than 3mm and less than 5mm, such as 3mm, 4mm and 5mm or any value between the light and the laser-wires, the gap between the abutted seams of the two steel plates to be welded after shearing is more than 0.2mm and less than 0.3mm, such as 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm and 0.30mm or any value between the light (laser) -wires, the welding wires are carbon steel welding wires (50C 6) with the diameter of 1.0mm. The dry elongation of the welding wire is 10-15mm, for example 10mm, 11mm, 12mm, 13mm, 14mm, 15mm or any value in between.

And the laser arc composite welding is a single-sided welding mode, and the inter-plate gap between the two strip steels is welded. The distance between the preheating and postweld heat treatment stations and the welding stations is 3+/-0.5 mm. In the laser arc hybrid welding process, shielding gas is blown out to a welding part, wherein the shielding gas blown out to the front surface of the welding line is mixed shielding gas, the shielding gas blown out to the back surface of the welding line is single-component shielding gas, the shielding gas blown out to the back surface of the welding line is mixed gas (argon+18% carbon dioxide) by an electric welding gun, the flow rate is more than 25L/min and less than 30L/min, such as 25L/min, 26L/min, 27L/min, 28L/min, 29L/min, 30L/min or any value between the two, the pressure is more than 0.4MPa and less than 0.6MPa, such as 0.4MPa, 0.5MPa, 0.6MPa or any value between the two, the shielding gas on the back surface of the welding line is argon (purity 99.99%), the flow rate is more than 8L/min and less than 15L/min, such as 8L/min, 9L/min, 10L/min, 11L/min, 12L/min, 13L/min, 14L/min, 15L/min or any value between the two, and 0.4MPa or less than 0.5MPa or any value between the two, such as 0.4MPa and 0.6MPa or any value between the two.

Experimental results showing technical advantages of the present invention will be described below using examples and comparative examples.

Examples

The laser welding is carried out by adopting an optical fiber solid laser, wherein two strip steels to be welded are respectively W250 and W300, the Si content is respectively 3.25% and 2.95%, the thicknesses h1 and h2 are respectively 2.2mm and 2.5mm, and the total thickness is 4.7mm;

Clamping two strip steels, shearing the strip steels, splicing the strip steels, and carrying out laser arc hybrid welding on the splicing positions. The upper and lower surfaces of the welding part are protected by blowing out the shielding gas in the welding process, the welding mode is single-sided welding, and the functions of on-line preheating and on-line post-welding heat treatment are put into the welding process.

The welding process parameters are as follows:

the laser arc composite welding speed is 3m/min, the laser power is 2.5kW, the defocusing amount of the laser is 5mm, the electric welding voltage is 15.4V, the electric welding current is 127A, the online preheating temperature is about 350 ℃, the matched online preheating power is 7+/-0.5 kW, the online post-heating temperature is about 750 ℃, and the online post-welding heat treatment power is 12+/-0.5 kW.

The welding line has no crack, the welding line is not cracked, the welding line and the heat affected zone are uniform in structure, the welding line performance is good, and the welding line is not broken in the product operation process.

As shown in FIG. 3, the structure image of the weld joint is shown, and the structure grain sizes of the weld joint fusion zone and the heat affected zone are relatively uniform.

The performance test at the weld joint is mainly tested and evaluated by a cup test and a weld joint bending test, and the cup test rupture is not along the weld joint according to the metal cup test standard (GB/T4156-2020). The method is widely applied to weld quality assessment in plate and strip production, and redundant description is omitted here.

Referring to FIG. 4, when the on-line preheating power is 7kW and the on-line post-welding annealing power is 12kW, the cracks are not torn along the welding line when the welding line is subjected to a cupping test, and the welding line performance is qualified.

Comparative example 1

The comparative example differs from the example in that the preheating temperature is 250 ℃, where the preheating temperature corresponds to a preheating power of 5kW.

Referring to fig. 5, when the preheating power is reduced to 5kW, the weld morphology is poor and cracks are likely to occur along the weld during the cupping test.

Comparative example 2

The comparative example differs from the example in that the preheating temperature is 450 ℃, where the preheating temperature corresponds to a preheating power of 9kW.

Referring to fig. 6, when the preheating power is increased to 9kW, the shape of the weld is poor, and cracks are likely to occur along the weld during the cupping test.

Comparative example 3

The difference between this comparative example and the example is that the post-weld heat treatment temperature is 650 ℃, where the post-weld heat treatment temperature corresponds to a post-weld heat treatment power of 10kW.

Referring to FIG. 7, when the post-weld heat treatment power was reduced to 10kW, cracks were observed along the weld during the cupping test, as shown.

Comparative example 4

The difference between this comparative example and the example is that the post-weld heat treatment temperature is 850 ℃, where the post-weld heat treatment temperature corresponds to a post-weld heat treatment power of 15kW.

Referring to fig. 8, when the post-weld heat treatment power was raised to 15kW, cracks were likely to occur along the weld during the cupping test.

In conclusion, the hot-rolled high-grade silicon steel is welded by adopting the combined process of laser arc hybrid welding, preheating and postweld heat treatment, so that the quality of a welded joint can be effectively improved, and the welded joint of the product has good toughness and is not easy to break. The method has the advantages of simple process, convenient operation and low production cost.

In addition, it should be understood by those skilled in the art that although there are many problems in the prior art, each embodiment or technical solution of the present invention may be modified in only one or several respects, without having to solve all technical problems listed in the prior art or the background art at the same time. Those skilled in the art will understand that nothing in one claim should be taken as a limitation on that claim.

It should be noted that the above embodiments are merely for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solution described in the above embodiments may be modified or some or all of the technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present invention.

Claims (10)

1. A laser arc composite welding method for high-grade silicon steel is characterized in that,

The method comprises the following steps:

Clamping the two strip steel plates to be welded;

Respectively shearing the welding ends of the two strip steel plates to be welded;

splicing the sheared two strip steel plates to be welded;

and preheating, laser arc composite welding and heat treatment are carried out on the two strip steel plates to be welded.

2. The laser arc composite welding method of high-grade silicon steel according to claim 1, wherein the plate thicknesses of the two strip steel plates to be welded are h1 and h2 respectively, wherein h1 is less than or equal to h2, h2-h1 is less than or equal to 0.8mm, and h2 is less than or equal to 1.3h1.

3. The laser arc hybrid welding method of high grade silicon steel according to claim 1, wherein the preheating is an on-line preheating, and the preheating temperature is 300 ℃ or more and 400 ℃ or less.

4. The laser arc hybrid welding method of high grade silicon steel according to claim 1, wherein the heat treatment is an on-line heat treatment, and the temperature of the heat treatment is above 700 ℃ and below 800 ℃.

5. The laser arc hybrid welding method of high grade silicon steel according to claim 1, wherein the distance between the laser and the welding wire of the laser arc hybrid welding is more than 2mm and less than 5mm.

6. The laser arc hybrid welding method of high-grade silicon steel according to claim 1, wherein the gap between the two butt joints of the steel plates to be welded after the steel plates to be welded are sheared is more than 0.2mm and less than 0.3 mm.

7. The method for laser arc hybrid welding of high grade silicon steel according to claim 1, wherein the laser arc hybrid welding is a single-sided welding, and the inter-plate gap between the two strip steels is welded.

8. The laser arc hybrid welding method of high grade silicon steel of claim 1, wherein the laser arc hybrid welding is performed by a laser arc hybrid welding head;

and induction heating coils are respectively arranged in front of and behind the laser arc composite welding head along the extending direction of the welding line for preheating and heat treatment.

9. The laser arc hybrid welding method of high-grade silicon steel according to claim 1, wherein the laser arc hybrid welding adopts a single-sided welding mode to weld the joint gaps of two steel belts to be welded.

10. The laser arc hybrid welding method of high grade silicon steel according to claim 1, wherein a shielding gas is blown to the welding portion at the time of welding;

the protective gas blown out of the front surface of the welding seam is mixed protective gas;

the protective gas blown out of the back surface of the welding seam is single-component protective gas;

Preferably, the mixed shielding gas consists of argon and 18% carbon dioxide;

preferably, the flow rate of the mixed shielding gas is more than 25L/min and less than 30L/min;

Preferably, the pressure of the mixed protective gas is above 0.4MPa and below 0.6 MPa;

Preferably, the single component shielding gas is argon;

preferably, the flow rate of the single-component shielding gas is more than 8L/min and less than 15L/min;

Preferably, the pressure of the single-component shielding gas is 0.4MPa or more and 0.6MPa or less.