RU1133781C - Method of controlling process of electron-beam welding - Google Patents

Description

This invention relates to electron beam welding technology.

There is a method of controlling the process of electron-beam welding, in which a constant depth of penetration is maintained by changing the focusing current, achieving the minimum value of the plasma torch radiation from the treatment area under the steady state process.

The disadvantage of this method is low accuracy due to the sensitivity to dusting of the sensor by metal vapors and interference from general heat radiation.

The closest to the invention in its technical essence and the achieved effect is a method for controlling the process of electron-beam welding, in which the penetration depth is kept constant at the minimum radiation power of the plasma torch from the welding zone at a steady state of the process.

The disadvantage of this method is the low accuracy of adjusting the depth of penetration in electron beam welding. The aim of the invention is to improve the accuracy when the focus of the electron beam is located at half the required penetration depth.

This goal is achieved by the fact that in the method of controlling the process of electron beam welding, in which the penetration depth is kept constant at the minimum radiation power of the plasma torch from the welding zone under the steady state process. The minimum value of the radiation power of the plasma torch is ensured by setting the zero value of the derivative of the radiation power of the plasma torch by adjusting the electron beam current while simultaneously applying a wobble to the beam focusing current with a frequency of 60-250 Hz and an amplitude equal to 0.3-5% of the focus current amplitude.

FIG. 1 shows a scheme for implementing the method; in fig. 2 shows the dependence of the radiation power of the plasma torch from the welding zone on the focusing current at different values of the electron beam current; in fig. 3- dependence of the position of the focus on the focusing current. Using an electron gun 1 fed from a current source 2, a beam is obtained and directed to welding zone 3 (Fig. 1). By changing the current in the focusing coil 4 with the help of the focus current source 5 to a value of 6 {Fig. 2), set the focus of the beam 7 at half the required depth of penetration Npr, for

What is used is an experimental dependence linking the positions of the focus 7 with the current of the focusing coil 4 (Fig. 3), using a wobble generator 8 to the current

focusings impose a wobble with amplitude 9. In this case, in accordance with dependence 10, oscillations of the radiation power of the plasma torch from the welding zone 3 of size AW occur. Allocated with

using a photoelectric sensor 11 and a selective amplifier 12, the power fluctuations determine the sign of the derivative of the radiation power of the plasma torch in d W

focusing current. Using the synchronic detector 13 and directing the corresponding signal to the source 2 of the beam current to change the magnitude of the beam current to obtain a zero value of the derivative

dW

radiation power. . Fok0 current 1f,

si 1f in accordance with curve 14 (Fig. 2). At the same time, the penetration depth reaches the value of Npr and is constantly maintained at this level.

The wobble frequency is chosen to be at least 60 Hz to eliminate interference associated with the natural vibrations of the weld pool. When using frequency more

250 Hz, a significant phase shift occurs between the wobbles of the focusing current and the oscillations of the plasma torch power, which makes it impossible to determine the sign of the derivative.

The minimum wobble amplitude superimposed on the focusing current is chosen to be at least 0.3% of the amplitude of the focusing current in order to reliably isolate the variations in the power of the plasma torch against the background noise. Increasing the wobble amplitude over 5% of the amplitude of the focusing current leads to a decrease (p is the concentration of the power density in the beam and makes it impossible to obtain a dagger melting.

Thus, by eliminating interference and stable release of the magnitude of the change in the radiation of the plasma torch, it is possible to accurately determine the sign of the derivative and its zero value, and therefore

to ensure accurate adjustment of the energy introduced into the product during electron beam welding.

PRI me R. The method was tested on an electron-beam installation CA-424,

a complete electron beam gun with a pronal tantalum cathode and an extreme focusing current controller CA-424.02.12. The beam current was controlled by changing

filament current, which ensured a stable position of the beam focus in space at a constant current of the focusing lens. Wedw

derivative sign

determined using the extreme controller CA-424.02.12, which provided the imposition of a wobble on the focusing current with an amplitude of 0.3% of the effective value of the focusing current. Welding was carried out on samples from AD1 and 12X18H10T, without splicing. ToK focusing set BVOMA. which ensured a focus depth of 9 mm, after that the welding beam with a 70 mA flux was switched on and gradually increased until it was zero

d W derivative value ... When welding

In the AD1 alloy, the beam current was 92 mA, and the penetration depth was 18–19 mm. When welding 12X18N UT steel, the beam current value was equal to 120 mA, and the penetration depth was 18 mm. The remaining test results are summarized in table.

The method of comparison. With the base object allows improving the quality of the welded

joints due to stabilization of the optimal geometrical parameters of the weld pool (penetration depth within 6% and verticality of the weld fusion line in the middle of the penetration depth in

limits 5). to obtain maximum thermal efficiency and to minimize energy input to the product, as well as significantly reduce the time to select the optimal parameters of the welding process and practically refuse welding of prototypes.

6) V.I. Zharikov. Kinetics of formation of a welded joint in electron-beam welding. Materials of the V All-Union Conference on Electron-beam Welding, 1977, p. 56. Patent of Germany number 2443563. class. In 23 K 15 / 00.28.06.78.

Claims (1)

Invention Formula METHOD OF REGULATING THE PROCESS OF ELECTRON-BEAM WELDING, in which the penetration depth is kept constant at the minimum radiation power of the plasma torch from the welding zone at a steady state of the process, characterized in melting, the minimum value of the radiation power of the plasma torch is ensured by setting the zero value of the derivative of the radiation power of the plasma torch by adjusting the eye of an electron beam with simultaneous imposition of a wobble on the focusing current of a beam with a frequency of 60–250 Hz and amplitude; equal to 0.3 - 5% of the amplitude of the focus current. v X .2