SU1683933A1 - Method for controlling the single-pass electron-beam penetration welding process - Google Patents

Abstract

The invention relates to welding, in particular, to controlling the processes of electron beam welding of thicker products with penetration, the purpose of the invention is to improve the quality of welded joints of thicknesses by ensuring uniform formation of the weld over its entire height. During the welding process, the height hi of reinforcement 7 and the height h2 of the root bead 8 of the weld are measured. The ratio of heights is calculated. The position of the electron beam focus on the height of the weld is established in accordance with condition 0, §5 hi / h2 1.05. The invention allows to stabilize hydrodynamic processes in the weld pool, which ensures obtaining high-quality welds from a dense cast zone. 1 il.

Description

The invention relates to welding, in particular to the control of processes of electron beam welding of products of large thicknesses with through penetration.

The purpose of the invention is to improve the quality of welded joints of products of large thicknesses by ensuring uniform formation of the weld along its entire height.

The drawing shows a diagram of a device 10 for implementing the method.

To control the process of single-pass electron beam welding with through penetration, the position of the focus of the electron beam along the height of the weld is used as a regulatory parameter. As a controlled parameter of the welding process, characterizing the formation of the weld, the ratio of reinforcement heights and root weld bead is used.

When refocusing the electron beam, the resulting weld has a root bead height greater than the height of the root bead of the weld with a technologically optimal cross section. During underfocusing, the resulting weld has an undercut in the root part. In both cases, the quality of the weld does not meet the technological requirements. 30 By adjusting the position of the focus of the electron beam along the height of the weld according to the ratio of the amplification heights and the root bead of the weld, metal is prevented from flowing from both sides of the weld joint 35 and guarantee a high-quality weld.

The focus position of the electron beam along the height of the weld is set by the ratio of 40

0.95 <ir <1.05.

h ₂ where hi is the height of the reinforcement of the weld. mm; h ₂ - the height of the root bead of the weld, mm. 45

The range of boundaries of the ratio of heights hi / h ₂ in the range of 0.95-1.05 is optimal from the point of view of automatic control and obtaining the guaranteed quality of the cast zone of the weld. For 50 well-weldable materials, deviations from it even within + 10% do not cause internal defects of the cast zone, but entail additional work on welding undercuts on the one hand, and on eliminating excessive forces on the other. Hard-to-weld materials are very sensitive to the shape of the cast zone of a single-pass weld because of the tendency to hot and cold cracks with unfavorable geometry of the cast zone. In this case, the range of 0.95 <hi / h ₂ <1.05 is limited by a tolerance of ± 1%.

Maintaining the focus position of the electron beam in accordance with the relation 0.95 <- * 7 <1.05, provide ravnomerp ₂ NOSTA forming a weld over its entire height, and therefore, high quality and,

A device for implementing the method includes a sensor 1 for recording signals from the weld formation zone, which is connected to the actuator 4 through the signal processing unit 2 of the sensor 1 and the control signal comparison and output unit 3. The output of the output device 4 is connected to the focusing system of the electron beam gun 5 Mirrors 6 are used to transmit images from the welding zone.

The method for controlling the process of single-pass electron beam welding with through penetration includes the following operations: setting the parameters of the welding mode; registration of signals by the sensor 1 from the molten metal of reinforcement 7 and the root roller 8 of the weld: calculation in the signal processing unit 2 of the height 1 sensor hi gain 7 and the height h _{2 of the} root roller 8; determination of the ratio of heights hi m - and comparison of the obtained value n _{2 of the} ratio with the given limits hi

0.95 <- <1.05 in block 3 comparison and h ₂ issuing control action.

At <0.95, the focus of the electron beam ₂ · ka is deepened into the root part of the weld. When -> 1.05, the focus of the electron

P2 beam rises to the front surface of the welded product.

As a result of the comparison, an appropriate control signal is generated in block 3, which is processed by the actuator 4 in the focusing system of the electron beam gun 5.

The radiation from the molten metal of reinforcement 7 and the root bead 8 of the weld from the undigested part of the joint is fixed by the sensor 1 using sensing mirrors 6. As a sensor 1, a television camera equipped with a neutral light filter can be used. Information from the welding zone enters block 2, in which the height hi of reinforcement 7 and the height h2 of the root roller 8 are determined and conversion to electrical signals is performed. In block 3, the ratio of electric signals proportional to the heights hi and h2 is calculated. The result of the ratio is compared with predetermined limits and an effect is produced on the actuator 4, which adjusts the focus position of the electron beam along the height of the weld.

The device adjusts the position of the focus of the electron beam, which ensures uniform formation of the weld 15 along its entire height.

The method was tested during welding with a horizontal electron beam of steel IXI8H9T 60 mm thick using a KTP-65 television camera as a sensor. Welding mode: 11 _usc = 60 kV: 1 _C = 350 mA; 1ph = 890 mA; V _CB = 2.5 mm / s; L = 180 mm. The beam was scanned around the circle ^! ^ Mm with a frequency f = 240 Hz. The formation of the reinforcement and the root bead 25 of the weld occurred smoothly without sharp transitions in height within 1.6-2.0 mm, without splashing and leakage of molten metal. The change in the focusing current Ιφ during the welding process was maintained at a level of ± 4 mA. Inspection of the seams with the help of translucency, ultrasound and metallographic studies of transverse sections did not reveal any defects.

Elimination of weld undercuts, guaranteed by automatic adjustment of the focus position of the electron beam, prevents the risk of delayed destruction from surface concentrators during welding and aging before heat treatment of hardened steels. In addition, active optimization of the focus level stabilizes the hydrodynamic processes in the penetration channel, providing a seal of the cast zone of the weld.

Claims (1)

Claim A method of controlling the process of single-pass electron beam welding with through penetration, in which the parameters of the welding process are controlled by the measured geometric parameters of the weld, characterized in that, in order to improve the quality of the welded joints of products of large thicknesses by ensuring uniform formation of the weld along the entire height of the weld connections, as the geometric parameter of the weld, use the ratio of the height of reinforcement to the height of the root bead of the weld, and as an adjustable parameter of the welding process using the focus position of the electron beam across the thickness of the welded connections .in accordance with the condition of 0.95 <<1.05, P2 where hi is the height of the reinforcement of the weld, mm; Bg is the height of the root bead of the welded 35 seam, mm.