CN105665933B - A kind of Invar mould steel laser electrical arc complex welding method - Google Patents

Abstract

The invention discloses a kind of Invar mould steel laser electrical arc complex welding method, step is as follows：The selection of welding material；Invar steel thick plate weldments bevel shape is designed and welding preparation；Invar mould steel thick plate hybrid Laser-Arc Welding path plannings；Invar mould steel thick plate hybrid Laser-Arc Welding process parameters designs.The present invention completes the welding of the multiple material special slab Invar mould steel of part of big aircraft by rationally using hybrid Laser-Arc Welding technology.

Description

A laser-arc hybrid welding method for Invar die steel

technical field

The invention belongs to the technical field of nickel-based alloy high-energy beam welding, and in particular refers to a laser-arc composite welding method for Invar die steel.

Background technique

Due to a series of advantages such as small specific gravity, high strength, and good fatigue performance, composite materials can bring comprehensive benefits such as reducing the body structure, extending maintenance intervals, and reducing operating costs when applied to aerospace products, so they become one of the key materials for large aircraft manufacturing. one. Composite parts are compounded and finally formed in the mold, and the outer surface of the formed part does not need any processing, which puts forward certain requirements for the mold material: stability under changing temperatures, compatibility with composite materials Consistent thermal expansion coefficient, good stability in vacuum environment and low manufacturing cost, etc. Invar steel has become one of the important materials for mold manufacturing because of its low expansion coefficient, good temperature stability and low manufacturing cost.

Due to the large size of large aircraft composite materials, the size of the mold is also large, which is difficult to form at one time, and usually requires a welded structure. At present, the welding process of large thick plate Invar mold steel is generally MIG welding, and multi-layer and multi-pass filling. The process is simple to operate and low in cost, but it also has many limitations. For example, the large number of welding passes leads to long teaching and welding time and low efficiency; multiple teachings increase labor intensity, and errors gradually accumulate, which affects welding quality; conventional arc welding has a small depth-to-width ratio, which is likely to cause incomplete penetration and fusion And other welding defects, and the use of higher heat input is easy to cause coarse grains and serious deformation after welding.

In view of the above problems, how to effectively improve the penetration of Invar steel welding, stabilize welding quality, reduce welding deformation, and improve welding efficiency has become an important topic of concern to people in the industry.

When the laser and arc are combined for welding, the arc and the laser will have a synergistic effect. When the current and laser power match, the weld penetration will be more than double that of laser welding. Therefore, when the laser-arc hybrid welding process with appropriate parameters is adopted, a larger weld depth-to-width ratio can be obtained with lower heat input, which can effectively improve the penetration of Invar steel during welding. And greatly shorten the welding time.

Contents of the invention

For above-mentioned deficiencies in the prior art, the object of the present invention is to provide a kind of laser-arc hybrid welding method of Invar mold steel, solves the poor interlayer fusion that exists when the arc welding technology thick plate Invar steel exists in the prior art, crack clamping More slag, poor weld formation, low production efficiency and other problems, the method of the invention can obtain thick plate Invar mold steel butt joints with stable weld quality while greatly improving production efficiency.

In order to achieve the above object, a kind of Invar mold steel laser-arc composite welding method of the present invention comprises the steps:

Selection of welding materials: The weight percentage of the chemical composition of the Invar mold steel plate is: Ni35.5%-36.5%, C<0.01%, Si<0.02%, Mn0.2%-0.4%, P<0.007%, S<0.002%, Cr<0.15%, Co<0.4%, the rest is Fe;

Design the groove shape of Invar mold steel weldment and preparation before welding: perform single-sided welding forming, V-shaped groove is made on the weldment, the groove angle is 30°, the blunt edge is 6mm, and the distance between blunt edges is 0.8mm. 99.9% Ar, the flow rate is controlled at 15L/min, the laser power is 2-6KW, the defocus is 0mm, the laser leading distance is 0mm, the welding current is 240-320A, the arc voltage is 24.3-26.6V, and the welding speed is 0.35- 1m/min, the inclination angle of the arc welding torch is 45°; before welding, finely grind the vicinity of the groove to remove residual impurities on the surface of the sample, and use acetone to wipe and clean the sample to remove residual oil;

Invar mold steel laser-arc composite welding path planning: Invar mold steel thickness is 19.05mm, three layers are designed, each layer is filled with a single weld seam and a straight line welding path, and the welding direction alternates in turn;

The laser-arc composite welding parameters of Invar mold steel plate are: the laser power used for root welding is 5500W, the welding current is 240A, the welding speed is 1m/min, and the wire feeding speed is 1.2m/min; the laser power used for filling welding is 2000W, and the welding current is 250A , The welding speed is 0.35m/min, the wire feeding speed is 1.2m/min; the laser power used for cover welding is 2000W, the welding current is 300A, the welding speed is 0.35m/min, and the wire feeding speed is 1.2m/min.

Preferably, the welding material used is Invar M93 welding wire with a diameter of 1.2mm, and the chemical composition of the welding wire is the same as that of the base metal.

Beneficial effects of the present invention:

The present invention realizes the welding of large-thickness Invar steel specially used for aircraft composite material mold manufacturing by rationally adopting the laser-arc hybrid welding technology; for the Invar steel with a thickness of 19.05mm, three layers of welds are used, and each layer has one weld. Filling; the welding seam is well formed, without obvious defects such as spatter, undercut, slag inclusion, etc., the total depth-width ratio of the weld seam is large, and the deformation after welding is small; the large laser power of backing welding obtains a large depth-width ratio, It can ensure the penetration of backing welding; when filling welding and cover welding, the laser power can be reduced and the arc power can be increased, so as to properly reduce the depth-width ratio of the weld; through the laser guiding and stabilizing the arc, a better interlayer can be obtained Fusion effect and cover forming.

The invention also overcomes the disadvantages of poor interlayer fusion, more cracks and slag inclusions, poor weld formation and low production efficiency when using traditional arc welding technology for thick plate Invar steel. Post-deformation provides process assurance.

Description of drawings

Fig. 1 is the surface forming figure of Invar steel laser-arc hybrid welding sample in the embodiment of the present invention 1;

Fig. 2 is a sectional view of Fig. 1;

Fig. 3 is the surface forming figure of Invar steel laser-arc hybrid welding sample in the embodiment of the present invention 2;

Fig. 4 is a sectional view of Fig. 3;

Description of drawings: 11 is the first cover layer, 12 is the first filling layer, 13 is the first primer layer, 21 is the second cover layer, 22 is the second filling layer, and 23 is the second primer layer.

detailed description

In order to facilitate the understanding of those skilled in the art, the present invention will be further described below in conjunction with the embodiments and accompanying drawings, and the contents mentioned in the embodiments are not intended to limit the present invention.

A kind of Invar mold steel laser-arc composite welding method of the present invention comprises the steps:

Selection of welding materials: The weight percentage of the chemical composition of the Invar mold steel plate is: Ni35.5%-36.5%, C<0.01%, Si<0.02%, Mn0.2%-0.4%, P<0.007%, S<0.002%, Cr<0.15%, Co<0.4%, and the rest is Fe; the base metal is a nickel-based alloy, and its microstructure at room temperature is a typical austenitic structure; the welding material used is Invar M93 welding wire, and the diameter of the welding wire is 1.2mm, the chemical composition of the welding wire is the same as that of the base metal, and the welding wire with high manganese content can improve the deoxidation ability and crack healing ability of the weld;

Selection of welding equipment: laser-arc hybrid welding device composed of KUKA robot KR30HA, TPS-5000 Fronius welding machine, IPG YLS-6000 fiber laser and manipulator;

Groove shape design and pre-weld preparation of Invar mold steel weldment: The thickness of the Invar mold steel is 19.05mm. According to the needs of assembly, a single-sided welding forming process is selected, and the weldment is to be V-shaped groove, and the groove angle is 30. °, the blunt side is 6mm, the distance between the blunt sides is 0.8mm, opening a small-angle groove can prevent the laser beam from irradiating the metal sides, which is equivalent to increasing the heat input, thus increasing the penetration depth, and in general, increasing the slope The opening gap will increase the penetration depth of the weld. When the gap between the blunt edge of the groove is not greater than 0.8mm, the larger the gap, the greater the penetration depth of the weld; the welding process is protected by 99.9% Ar, the flow rate is controlled at 15L/min, The power is 2-5.5kW, the defocus is 0mm, the laser leading distance is 0mm, the welding current is 240-300A, the welding voltage is 24.3-26.6V, the welding speed is 0.35-1m/min, the inclination angle of the arc welding torch is 45°, before welding Finely grind the vicinity of the groove to remove impurities such as rust remaining on the surface of the sample, wipe and clean the sample with acetone, and remove residual oil to ensure that the surface of the sample is clean;

Invar mold steel laser-arc composite welding path planning: the thickness of the Invar mold steel plate is 19.05mm, three layers are designed, each layer is filled with a single weld and a straight line welding path, and the bottom weld is mainly laser power and robot speed Current and robot speed are the leading role in filling and capping welding. Clamp the weldment on the workbench, use the feeler gauge to control the groove gap; when welding, ignite the arc first, and emit the laser beam after the molten pool is formed;

Invar mold steel plate laser-arc composite welding parameters are: the laser power used for root welding is 5500-6000W, the welding current is 240A, the welding speed is 1m/min, and the wire feeding speed is 1.2m/min; the laser power used for filling welding is 2000W, and the welding current is 240A. Current 220-280A, welding speed 0.35m/min, wire feeding speed 1.2m/min; laser power used for cover welding is 2000W, welding current 280-320A, welding speed 0.35m/min, wire feeding speed 1.2m/min min.

Specific description is given below by two examples:

Example 1

The welding base material is Invar steel with a Ni content of 35.87%, with a size of 100mm×50mm×19.05mm, a 30° groove, a blunt edge thickness of 6mm, and a spacing of 0.8mm; the welding wire is Invar M93, with a Ni content of 35.87%, and a diameter of 1.2mm ; 99.9% Ar atmosphere flow rate is 15L/min; welding equipment is KUKA robot KR30HA, TPS-5000 Fronius welding machine, IPG YLS-6000 fiber laser; before welding, finely grind the vicinity of the groove to remove residual residue on the surface of the sample Rust and other impurities, use acetone to wipe and clean the sample to remove residual oil to ensure that the surface of the sample is clean; then teach the welding trajectory and set the parameters. The specific parameters are as follows:

The first layer (first layer 13): straight line trajectory, laser power 5500W, welding current 240A, welding voltage 24.3V, speed 1m/min;

The second layer (first filling layer 12): straight track, laser power 2000W, welding current 250A, welding voltage 24.6V, speed 0.35m/min;

The third layer (the first cover layer 11): straight track, laser power 2200W, welding current 300A, welding voltage 26.6V, speed 0.35m/min;

The macroscopic and joint morphology of Invar steel after welding is shown in Figure 1 and Figure 2. It can be seen that the macroscopic appearance of the weld is well formed, without defects such as spatter, undercut, and slag inclusions, and the cross-section of the welded joint shows a typical laser- The morphology of the hybrid arc welding joint has obvious equiaxed lines in the center of the weld, and there are also obvious columnar lines near the center of the weld, and the width of the weld and the height of the weld are small, which is a good welded joint. The laser power is 5500W during backing welding, there will be no penetration or incomplete penetration, the welding current is 250A during filling welding, and the arc can be welded stably and efficiently under the guidance of the laser, while the cover welding The 300A current ensures that the weld seam is well formed, and common welding defects will not appear on the surface of the sample.

Example 2

The welding base material is Invar steel with a Ni content of 35.87%, with a size of 100mm×50mm×19.05mm, a 30° groove, a blunt edge thickness of 6mm, and a spacing of 0.8mm; the welding wire is Invar M93, with a Ni content of 35.87%, and a diameter of 1.2mm ; 99.9% Ar atmosphere flow rate is 15L/min; welding equipment is KUKA robot KR30HA, TPS-5000 Fronius welding machine, IPG YLS-6000 fiber laser; before welding, finely grind the vicinity of the groove to remove residual residue on the surface of the sample Rust and other impurities, use acetone to wipe and clean the sample to remove residual oil to ensure that the surface of the sample is clean; then teach the welding trajectory and set the parameters. The specific parameters are as follows:

The first layer (second layer 23): laser power 5500W, welding current 240A, welding voltage 24.3V, speed 1m/min;

The second layer (second filling layer 22): laser power 2400W, welding current 250A, welding voltage 24.6V, speed 0.35m/min;

The third layer ((second cover layer 21): laser power 2200W, welding current 300A, welding voltage 26.6V, speed 0.35m/min;

The macroscopic and joint morphology of Invar steel after welding is shown in Figure 3 and Figure 4. Generally speaking, the macroscopic appearance of the weld is well formed, without obvious spatter, undercut, slag inclusion and macroscopic crack defects. It is a typical morphology of laser-arc hybrid welding joints. The equiaxed line in the center of the weld and the columnar line near the center of the weld are obvious. In addition, there is a narrow area at the edge of the weld, which is relatively to the center of the weld and the The mother color is darker, but this phenomenon was not observed near the root pass. In laser-arc hybrid welding, arc welding is the main method for covering and filling layer, supplemented by laser welding, and the process of material filling and cladding is mainly carried out; while laser welding is the main heat input method for backing welding to realize deep penetration welding , to ensure that the bottom of the blunt edge can be welded through.

There are many specific application approaches of the present invention, and the above description is only a preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements can also be made without departing from the principles of the present invention. Improvements should also be regarded as the protection scope of the present invention.

Claims (2)

1. a kind of Invar mould steel laser-arc hybrid welding in industry method, it is characterised in that comprise the following steps：

The selection of welding material：The percentage by weight of the Invar moulds steel board chemical composition is：Ni35.5%-36.5%, C<0.01%th, Si<0.02%th, Mn0.2%-0.4%, P<0.007%th, S<0.002%th, Cr<0.15%th, Co<0.4%th, remaining It is Fe；

Design Invar moulds steel plate weldment bevel shape and welding preparation：Single-sided welding shaping is carried out, part to be welded opens double V-groove, Bevel angle is 30 °, root face 6mm, root face spacing 0.8mm, and welding process protection uses 99.9%Ar, flow to control in 15L/ Min, laser power is 2-6KW, and defocusing amount is 0mm, and the leading distance of laser is 0mm, and welding current is 240-320A, arc voltage It is 24.3-26.6V, speed of welding is 0.35-1m/min, 45 ° of arc welding gun inclination angle；To finely being beaten near groove before weldering Mill, the impurity of removal specimen surface residual, using acetone wiping, washed samples, removes oil residues；

Invar mould steel plate laser-arc hybrid welding in industry path plannings：Invar mould steel thickness is 19.05mm, designs three layers, Every layer is filled using single-pass welding, straight line path of welding, and welding direction replaces successively；

Invar mould steel plate laser-arc hybrid welding in industry parameters are：Laser power used by backing welding is 5500W, welding current 240A, speed of welding 1m/min, wire feed rate is 1.2m/min；Filling weldering laser power used is 2000W, welding current 250A, speed of welding 0.35m/min, wire feed rate is 1.2m/min；Laser power used by cosmetic welding is 2200W, welding current 300A, speed of welding 0.35m/min, wire feed rate is 1.2m/min.

2. Invar mould steel laser-arc hybrid welding in industry method according to claim 1, it is characterised in that welding used Material is Invar M93 welding wires, and gage of wire 1.2mm, welding wire chemical composition is identical with mother metal chemical composition.