SU725836A1 - Arc length regulating method - Google Patents

Description

The goal is achieved by the fact that in the method of controlling the length of an arc over a voltage at which the voltage across an arc is compared to a reference one, the voltage across an arc is measured at the time the arc is formed, which is formed by an arc pulsed longitudinal magnetic field with a pulse duration ( 2–4) and a period of a trace of pulses (1–2) 10 s. Under the action of a pulsed longitudinal magnetic field, the welding arc at the moment of impulse acquires the shape of a hollow cone, the base of which lies outside the weld pool. The comparison of the voltage drop across the arc with the reference voltage is made at the time of the formation of the arc cone. Therefore, this method allows you to control the distance from the end of the electrode to the surface of the material to be welded. . Pulse duration ranges. The magnetic field and the pulse following period are based on the formation of an arc cone under the action of a longitudinal magnetic field and minimal change in the welding process mode due to the formation of a hollow arc cone, the base of which is outside the weld pool. The duration of the pulses of the longitudinal magnetic field is chosen from the condition of stable formation of the arc cone. Since the formation of the arc cone under the action of the longitudinal magnetic field is preceded by the arc rotation stage, the upper limit of the pulse duration of the magnetic field (2-10 s) is chosen taking into account that the arc has time to pass the stage rotation and a stable cone of the arc is formed, the base of which lies beyond the welding. baths. The lower limit (4 10) of the length of the pulse length of the longitudinal magnetic field and the follow-up period (1-2), respectively, is chosen taking into account the minimal change in the welding process mode (i.e. the minimum change in the weld width, melting point). The measurements of the influence of the welding level fluctuations on the process of adjusting the distance of the end of the electrode to the surface of the material to be welded are carried out. Weldable material X18H9 tungsten electrode. Fluctuations in the level of the weld pool are created by alternately switching the welding process from the cooled substrate to the welding on the nose. Thus, when welding Hia to weight, the reverse side of the seam is formed freely, which causes the welding bath to lower, and when transitioning to the cooled substrate, the level of the welding pool rises, as the cooled substrate forcibly forms the reverse side of the seam. To obtain comparative data, measurements of a known method for adjusting the arc length are carried out in parallel. The arc burning time when welding on weight is 2-3 s, when welding on a cooled substrate, 2-3 s, the duration of the pulsed longitudinal magnetic field of the S-s, following the period of 1.5-10 s. The results are shown in the table. As can be seen from the table, in the known method, the difference in stresses measured when the arc burns on a cooled substrate and has a weight of 0.5 V (because when the arc burns on a product without a substrate, welding on weight - the weld pool is lowered, with the arc voltage increasing). Since the field voltage in the arc column without applying a magnetic field is about 1 V / mm, and the difference in voltage is 0.5 V, the arc length increases by 0.5 mm, i.e. the electrode must be lowered to maintain a constant arc length. In the proposed method, the control of the arc length is carried out at the moment of imposing a pulsed longitudinal magnetic field. Since the comparison of the methods is carried out under the same conditions of formation of the weld (alternate transition: welding on the substrate, welding on weight), the variation of the level of the weld pool is 0.5 mm. The resulting voltage difference across the arc at the time of applying a pulsed longitudinal magnetic field is 16.0-15.7 - 0.3 V. The intensity of the arc field at the time of applying a pulsed magnetic field is about 2-2 V / mm, and the value by which the controller must lower the electrode, is if / U. The proposed method for controlling the arc does not practically affect the adjustment process of the level of the weld pool, since the distance is controlled from the end of the electrode to the surface of the product to be welded. The duration of the pulsed longitudinal MarHrfTHoro field is chosen from the condition of stable formation of the arc cone with a minimum pulse duration, i.e., a further decrease in the duration of the pulsed magnetic field leads to an unstable formation of the arc cone. At low welding speeds, it is possible to increase the duration of the magnetic field pulse to 410 s, but it is necessary to increase the pulse time to 210 s. The ratio of the period of the following duration of the longitudinal magnetic field is chosen taking into account the minimal effect of the arc cone on the technology.

welding modes (arc current and voltage, weld width, etc.).

The method of adjusting the length of the arc provides a constant and high accuracy of maintaining the desired distance from the end of the electrode to the top. The installation distance from

The speed of the end of the electrode to the surface of the welded material, mm

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Claims (2)

1. Authors certificate of the USSR 382488, cl. At 23 K 9/10, 1970. 2.Paton B.Ye., Lebedev V.K. Electric equipment for arc and slag welding. M., Mechanical Engineering, 1966, p. 82-89 (prototype).