SU1558612A1 - Method and apparatus for laser beam welding - Google Patents

Abstract

The invention relates to the technology of beam welding and equipment for its implementation. The purpose of the invention is to increase productivity by reducing the time to select the optimum welding speed. The welding process is carried out at given values of the spot diameter of heating α of the focused beam, its power and speed of the relative movement of the beam and the product being welded, corresponding to the formation of a seam without root defects. The process is carried out at a rate of relative movement of the product and the beam, equal to _Vc = λ / Α. Here, the value of the thermal diffusivity λ is continuously measured. The device is equipped with automatic express analysis of thermal diffusivity and welding speed calculation. As a result, preparatory stages for experimental selection of the speed of defect-free welding, which depends on the material of the product being welded and on the degree of focusing of the beam, are eliminated, which ensures an increase in productivity. 2 sec. f-ly, 2 ill.

Description

The invention relates to the technology of beam welding and equipment for its implementation.

The purpose of the invention is to increase productivity by reducing the time to select the optimum welding speed.

FIG. 1 shows a diagram of the device; in fig. 2 shows the dependence of the film thickness of the melt, the total pore volume and frequency of pore formation on the welding speed.

The welding process is carried out at specified values of the spot diameter for heating the focused beam 1, its power

and the speed of the relative movement of the beam and the welded product 2, corresponding to the formation of a seam without root defects. The process is carried out at (speeds of relative movement of the product 2 and beam 1 vc8 fl / d, where A is the thermal diffusivity of the material of the article; d is the diameter of the heating point of the focused beam, and the thermal diffusivity coefficient is continuously measured.

A device for carrying out the method comprises a source 3 of the power supply of the beam 1, the focusing system 4,

table 5 and a control system consisting of control blocks 6 to 8, respectively, by the degree of beam focusing 1, its power and the speed of movement of the work table 5.

The device is also equipped with blocks.

9 and 10 automatic express analysis of thermal diffusivity and calculation of the welding speed, with the input of the control unit 6 for the degree of focusing of the beam connected to the input of the unit

10 calculating the speed of movement of the desktop 5, the output of the latter is connected to the inputs of the beam power control unit 7 and the desktop speed control unit 8 of the output of the beam power control unit 7 connected to the input of the beam power source, and the output of the express diffusion thermal analysis unit 9 connected to block 10 for calculating the speed of movement of the desktop.

The device works as follows.

The product 2 is installed on the work table 5. With the help of the block 9, the measured value of the thermal diffusivity of the material of the product 2 is entered into the block 10 for storage. The value required for welding of the diameter of the beam 1 in the focusing plane is set using block 6, the corresponding signal is fed to block 10 and is remembered. Block 6 calculates the welding speed and through block 8 starts moving the table 5 with the resulting speed value. At the same time, unit 7 includes the generation of beam 1 with the power required to penetrate the material of product 2 to a predetermined depth. After welding, blocks 8 and 10 stop moving the process table and turn off the beam.

As a result, automatic welding is carried out. The preparatory stage of the experimental selection, the speed of defect-free welding, depending both on the material of the product 2 and on the degree of focusing of the beam 1, is excluded. The effect of the beam power on the value of the speed of defect-free welding is insignificant, only the penetration depth depends on it.

This allows you to create an automated system of beam welding,

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providing a flexible change in the composition of processed publications, and, consequently, increase the productivity of the process.

Example. The dependence of the total pore volume on the welding speed v (vtfc) is obtained when welding zirconium alloy ZrNb 1 with an electron beam. For the characteristic thermal diffusivity A 0.1 cm / s and the beam diameter in the focusing plane d 0.02 cm, the corresponding value of the defect-free welding speed vce b / d 3 cm / s coincides with the selected value. The position of the maxima of the experimental dependence v (voe) and the dependence proportional to it also coincide (Fig. 2). The dependence of the frequency of pore formation on the welding speed f (vce) was obtained when welding SVS 304 stainless steel with a 3 kW laser beam. In this case, as in the experiment, the speed of defect-free welding is 5 cm / s. The positions of the maxima of the experimental and calculated dependences f (v, .. 6) coincide.

Claims (2)

1. A method of beam welding, in which the process is carried out at specified values of the spot diameter for heating a focused beam, its power and speed of relative movement of the beam and the product to be welded, corresponding to the formation of a weld without root defects, characterized in the time of selection of the optimal value of the welding speed, the process is carried out at a speed of relative movement of the product and the beam vce fl / d, where 1 is the coefficient of thermal diffusivity of the product material; d is the diameter of the spot of heating the focused beam, while the value of the coefficient of thermal diffusivity is continuously measured. 2. A device for beam welding, containing a beam power source, a focusing system, a work table and a control system consisting of control units for the degree of beam focusing, its power and speed of the work table movement, characterized in that, in order to increase productivity by reducing the time selection of optimal h, Vnop, fnop rel about 0, 5- M0, 2 O 1 OL0.5 FIG. 2 0.8 Uc8i onw-eff