CN102091873A - Method for performing laser welding by filling powder between aluminum sheet and steel sheet - Google Patents

Abstract

A powder-filling laser welding method between an aluminum sheet and a steel sheet belongs to the technical field of laser welding. The arc energy in the existing method is difficult to control. If too much heat is input to one side of the aluminum material, the temperature will be too high, resulting in temper brittleness and reducing the strength of the welded joint. In addition, the welding wire plugging phenomenon will also occur during the welding process. Said technical problem is even more serious for thin sheets with a thickness of less than 4 mm. The welding workpieces of the present invention are aluminum plates and steel plates, which are butt-jointed on the same plane but leave a gap, and each joint is grooved, using Al-Si solder, and adding alloy elements Cu, Mn, Zn, aluminum plates and steel plates They are aluminum thin plate and steel thin plate respectively, and the thickness is determined between 1 and 4mm. Al-Si solder is made into powder. Shaped Al-Si solder, the aluminum sheet and the steel sheet walk together, and at the same time, the laser is used as the welding heat source for welding.

Description

Powder-filled laser welding method between aluminum sheet and steel sheet

technical field

The invention relates to a powder-filled laser welding method between an aluminum thin plate and a steel thin plate to realize good welding of two thin metal workpieces, and belongs to the technical field of laser welding.

Background technique

Dissimilar metal structures such as aluminum-steel structures are obtained by welding. However, due to the large differences in physical properties such as thermal expansion coefficient, thermal conductivity, specific heat, and melting point between dissimilar metals, and because dissimilar metals are easily reacted to form brittle intermetallic compounds, or there are brittle phases in welded joints, resulting in welded joints The mechanical properties deteriorated severely. Especially in the welding of aluminum and steel, the solid solubility between the main alloying elements is very low, and the thermophysical properties are very different. The two are more likely to react to form brittle intermetallic compounds. The mechanical properties of the welded joints, such as tensile strength and shear The strength is poor. A Chinese patent application with the application number 200810063869.5 titled "A Welding Wire and Its Applied Method for Welding Aluminum and Aluminum Alloys to Steel" discloses a scheme. The solder is based on Al and Si, and alloying elements Cu, Mn, Zn and trace elements B, Zr, La are made into welding wire, and the welding heat source is an arc. During the welding process, welding occurs on the aluminum side and brazing occurs on the steel side at the same time, through the interaction of alloy elements To control the generation of brittle intermetallic compounds, and suppress the generation of brittle phases in welded joints from the root. Although this method solves the problem of generating brittle intermetallic compounds during the welding process of dissimilar metals, it is difficult to control the energy of the arc. If too much heat is input to one side of the aluminum material, the temperature will be too high, resulting in temper brittleness. Reduced strength of welded joints. In addition, the welding wire plugging phenomenon will also occur during the welding process. The technical problem is more serious for thin plates with a thickness of less than 4mm, because it is more difficult to apply heat between the thin plates, and the thinner the solder, the easier it is to block the wire.

Contents of the invention

On the premise of avoiding the formation of brittle intermetallic compounds during the welding process of dissimilar metals, it is possible to apply moderate heat on different metals, eliminate the plugging phenomenon, and make the welding process go smoothly. Powder filled laser welding method.

The welding workpiece of the present invention is an aluminum plate and a steel plate, which are butt-jointed on the same plane but leave a gap, each joint is beveled, Al-Si solder is used, and alloy elements Cu, Mn, and Zn are added. It is characterized in that aluminum The plates and steel plates are aluminum thin plates and steel thin plates respectively, and the thickness is determined between 1 and 4mm. Al-Si solder is made into powder. Powdered Al-Si solder is added to the groove, and the aluminum sheet and the steel sheet walk together, and at the same time, the laser is used as the welding heat source for welding.

The technical effect of the present invention is that the laser is used as the welding heat source, and the laser energy is concentrated, and the processing flexibility is good due to many controllable factors, such as laser power, laser defocus amount, welding speed, etc., can be precisely adjusted, so that the welding heat source can be realized Moderate application on workpieces of different materials, thus preventing excessive heating of the aluminum side in particular. Compared with filamentary solder, that is, welding wire, powdery solder is added in a way of falling slowly, and the solder at the solder outlet of the welding head will not melt, so there will be no plugging of the solder outlet. The proportion of the powdered solder can be adjusted flexibly, so that the present invention can also adapt to the welding of small batches and various kinds of workpieces. The technical effect is more prominent in the welding of thin plate workpieces of different materials. In addition, the surface of the welded joint is smooth without obvious deformation.

Description of drawings

Fig. 1 is a schematic diagram of the powder-filled laser welding method between an aluminum thin plate and a steel thin plate according to the present invention, and this figure is also used as a summary drawing. Fig. 2 is a schematic diagram of the shape, size and mutual position of the welded workpieces in the powder-filled laser welding method between the aluminum sheet and the steel sheet according to the present invention.

Detailed ways

Embodiment 1: As shown in Figure 1 and Figure 2, a welding workpiece aluminum thin plate 1 is made of A6111-T4 aluminum alloy, the thickness a is 1mm, and the groove angle α is 30±5°; another welding workpiece steel thin plate 2 The material is JSC270CC low carbon steel, the thickness b is 1mm, and the groove angle β is 45±5°. Cleaning of the welding area: Use fine sandpaper and acetone to clean and clean the grooves of the two welding workpieces successively to remove the scale and oil on the surface of the groove. The two welding workpieces are butted on the same plane copper heat sink 3, but a gap h of 0.8 mm is left. Using Al-Si solder, its weight ratio is: Al: 86.46-89.83%, Si: 7.0%-8.5%, Cu: 2.2%-3.5%, Mn: 0.8%-1.2%, Zn: 0.1%-0.2% , B: 0.08%-0.14%, Zr: 0.06%-0.12%, La: 0.03%-0.08%; the Al-Si solder is made into powder to obtain powdered Al-Si solder 4 . During the welding process, powdered Al-Si solder 4 is added to the grooves sandwiched by the respective grooves of the aluminum sheet 1 and the steel sheet 2, the aluminum sheet 1 and the steel sheet 2 walk together, and the laser 5 is used as the welding heat source to apply Soldering, the shielding gas 6 surrounds the powdery Al-Si solder 4. The protective gas 6 is a mixed gas of He with a flow rate of 10 l/min and Ar with a flow rate of 15 l/min. The three-channel coaxial welding head 7 central cone hole passes through the laser 5, the second annular cone hole passes through the powdered Al-Si solder 4, and the third annular cone hole passes through the shielding gas 6, and the shielding gas 6 is in the slowly falling powdered Al-Si A protective air curtain is formed outside the powder flow of solder 4 to protect the welding area and gather the powder flow.

Embodiment 2: As shown in Fig. 1 and Fig. 2, a welding workpiece aluminum thin plate 1 is made of 5052-H34 aluminum alloy, the thickness a is 4.0mm, and the groove angle α is 30±10°; another welding workpiece steel thin plate 2 The material is SUS301L austenitic stainless steel, the thickness b is 4mm, and the groove angle β is 45±10°. In the weight ratio of Al-Si solder, the added amount of Zn is 0.8%-1.0%. The two welding workpieces are butted on the same plane copper heat sink 3, but a gap h of 1.2 mm is left. Other process conditions and steps are identical with embodiment one.

Claims (3)

1. between aluminium sheet and steel sheet, fill out the powder method for laser welding for one kind, welding work pieces is aluminium plate and steel board, at grade the butt joint but leave the gap, each bevel of seam crossing, adopt the Al-Si scolder, and adding alloying element cu, Mn, Zn, it is characterized in that, aluminium plate and steel board are respectively aluminium sheet and steel sheet, and thickness is all determined between 1～4mm, the Al-Si scolder is made powder, in welding process, add Powdered Al-Si scolder in by aluminium sheet and the steel sheet groove that groove presss from both sides separately, aluminium sheet and steel sheet are together walked, and are the welding heat source welding simultaneously with laser.

2. the powder method for laser welding of filling out according to claim 1 is characterized in that, described two kinds of welding work pieces are gone up butt joint in same plane copper heat sink (3).

3. the powder method for laser welding of filling out according to claim 1, it is characterized in that, its weight proportion of Al-Si scolder that is adopted is: Al:86.46～89.83%, Si:7.0%～8.5%, Cu:2.2%～3.5%, Mn:0.8%～1.2%, Zn:0.1%～1.0%, B:0.08%～0.14%, Zr:0.06%～0.12%, La:0.03%～0.08%.

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