SU774855A1 - High-frequency welding process automatic control method - Google Patents

Description

one

The invention relates to the field of high-frequency welding and can be used in the manufacture of electric welded pipes and profiles.

There is a known method for automatically regulating the process of high-frequency welding, in which one of the main process parameters is controlled depending on the signal characterizing the heating of the arms of the product being welded U.

However, this method leads in some cases to a decrease in the stability of the quality of the seam due to the formation of hot cracks in it under the action. 15 tensile stresses.

There is a known method for automatically controlling the high-frequency welding process, in which the power supplied to the heating device 20 is changed, depending on changes in the heating of the edges at the melting point 2.

In order to improve the stability of the quality of the weld by eliminating the formation of hot cracks in it, as a regulating parameter in the method of automatic regulation of the high-frequency welding process, a signal proportional to

the temperature deviation of the welded edges beyond the output cross section of the welding caliber rolls from the set,

As a result of this adjustment, the setpoint temperature of the welded edges at the weld center outlet is stabilized, and the formation of the welded joint always ends by the moment of removing the compressive forces on the seam and eye.) The suture zone improves the stability of the quality of the seam by eliminating the formation there are hot cracks in it.

In order to preserve the constant conditions for the formation of the structure of the welded joint in the weld, it is also necessary to maintain the temperature of the edges at a constant level when entering them in the weld. This requirement is fulfilled when the weld center length, strip width and thickness do not change.

The drawing shows a diagram of a variant of the method for automatically controlling the process of high-frequency welding.

The power of the power source of the heating device is controlled depending on the signal that characterizes the heating of the edges of the tubular billet in the physiological area of the melting center. Speed

The welds are adjusted depending on the signal characterizing the change in the temperature of the weld in the immediate vicinity of the exit section of the welding caliber rolls. For this, the continuously measured value of the enter. grazing radiation from a local source of molten metal formed at the convergence of the edges of the pipe being welded is converted by the photosensor 1 into an electrical signal and compared in the comparator 2 with the optimal, predetermined reference signal set by the setter 3, and the result of the comparison is used as an adjusting signal by means of a regulator 4 on a high-frequency geerator 5 with an inductor 6, with a corresponding change in the heating power of the edges of the billet.

The welding speed is varied according to the signal spacing, which characterizes the integral radiation of the weld in the immediate vicinity of the output section of the welding gauge rolls, and the reference signal. The permissible value of the reference signal is established experimentally and characterizes the integral radiation of the seam, corresponding to the optimal conditions for the formation of a welded joint in the weld, at which the strength of the seam metal against the springing of the billet will be necessary. All deviations from this value are eliminated by the control system by a corresponding change in the welding speed. To do this, the continuously measured value of the integral radiation of the weld in the immediate vicinity of the output, cross section of the welding gauge rolls is converted by the photosensor 7 into an electrical signal and compared in the comparison device 8 with the reference signal set by the setting device 9, the difference signal is converted in the controller 10 and controlled The speed of welding affects the drive of the billet transfer mechanism 11. As a result of this adjustment, the set temperatures of the weld edges at the inlet and outlet of the weld center are stabilized and, at the same time, the process of formation of the welded joint always ends at the moment of removing the compressive forces on the seam and heat-affected zone, which increases the stability of the quality of the seam.

Using the proposed method of automatic control of the process of high-frequency welding

S provides an increase in the yield of suitable pipes by eliminating fractures of the weld or the formation of hot cracks in it, stability of the strength properties of the welded joint.

(and maintenance of welding processes at high (maximum allowable) welding speeds.

Claims (2)

1. USSR author's certificate No. 453263, cl. B 23 K 13/00, 1972. 2. Authors certificate of the USSR 200060, cl. 23 K 13/02, 1966.