SU1712023A1 - Method of manufacturing electrically weldable articles - Google Patents

Abstract

The invention relates to high-frequency welding of products with deburring with an oxygen jet and, in particular, can be used on electric electric pipe welding units for the production of electric welded pipes with flash removal. The purpose of the invention is to increase the productivity and quality of the welded joint by automating the process and reducing the power input. The method includes the continuous supply of the molded preform, heating by the power source and welding the edges with the formation of burr, removal of the burr by jets of oxygen. During the welding process, the power of the power source is adjusted depending on the height of the bur. When oxygen is supplied, its consumption is defined as a value proportional to the height of the burr and the welding speed. The invention makes it possible to increase the productivity of the process by 15–20% due to the additional heating of the billet during the burning of burrs in oxygen. 3 silos

Description

The invention relates to high-frequency welding with deburring with an oxygen jet and can be used on electric pipe welding units for the production of electric welding tubes with remote flash.

Methods are known for removing internal flash, which consists in supplying an oxygen jet per bur. The disadvantage of these methods is that they take into account the increment of the temperature of the welded joint, resulting from the exothermic reaction of combustion of grats in the oxygen jet. The welding speed, which determines the amount of bur, passing per unit of time through the spot of contact of the bur with the oxygen jet, is also not taken into account.

The closest in technical essence and the achieved result to the invention is a method of manufacturing straight electric welded pipes 3, including continuous feeding of the molded billet, heating and welding edges to form burrs, removing burrs by blowing the edges with oxygen jets supplied from inside the pipe to meet its movement: for the point of convergence of the edges, and the supply of protective gas in the course of the pipe from the outside to the heated edges before they converge during welding.

The disadvantage of this method is that it does not take into account the increment of heat produced by the burning of burrs in oxygen. The change in the height of the burr and the welding speed caused by changes in factors affecting the formation of a welded joint with the flash removed is also not taken into account. Such factors, for example, include the variation and especially the thickness of the workpiece along the length of the coil. Thus, the amount of burr passing per unit of time through the spot of contact of the burr with an oxygen stream varies continuously, which, with constant oxygen consumption, leads to poor quality removal of the burr.

The purpose of the invention is to increase the productivity of the process of manufacturing electrically welded products due to the additional heating of the billet during burning of grats in oxygen, as well as improving the quality of the welded joint due to an exact match at each point in time between the amount of burr and the amount of oxygen needed to burn it completely without splashing .

This is achieved by the fact that in the method including continuous feeding of the molded billet, heating by the power source, welding the edges with forming burr and removing the burr with an oxygen jet during the welding process, correct the power of the power source using burr as a parameter for adjusting the burr oxygen change is proportional to the burr height and welding speed ..

The use of the proposed method of manufacturing welded products allows to increase the productivity of the process by 15-20% due to the additional heating of the billet during the combustion of burrs in oxygen, as well as the quality of the connection by automating the process.

In order to obtain a high-quality surface of the product to be welded in the process of deburring with an oxygen jet, it is necessary that the amount of oxygen and debur be among themselves in strict weight ratios determined by the law of a chemical oxidation reaction. The lack of oxygen leads to incomplete removal of burr from the surface of the product, and a significant excess to the fact that part of the burr is blown out, not having time to react with oxygen, forming splashes sticking to the surface and significantly deteriorating its quality. During the process of pipe welding, the welding speed fluctuates within certain limits, as a result of which the amount of bur formed changes due to the change in the degree of heating of the metal, and the quantity of bur to change also changes

passing in unit time spot of contact of grata with oxygen. The unevenness of the width and especially the thickness of the strip tekzhe cause fluctuations in the height of the burr, which, with a constant flow of oxygen leads to uneven burning of the burr and to the poor surface of the pipe. Thus, when changing welding parameters affecting the bur height or welding speed, it is necessary to adjust the oxygen density, the rate of oxygen outflow from the nozzle, or the angle of inclination of the oxygen jet. It is easiest to change the pressure of oxygen, which, with constant parameters of this system, changes

oxygen flow rate. In the proposed method, at each time point, the burr height and welding speed are determined. The obtained data are processed taking into account the delay and the amount of oxygen necessary for burning the gas in the optimal mode is determined without splashing on the surface of the product, which is supplied per bur. At the same time, taking into account that the reaction of combustion, burr in an oxygen jet occurs with the release of heat, a signal is received at the heat source proportional to the height of the burr, which corrects for the amount of excess heat. A comparative analysis of the proposed and known methods shows that the power of the heating source in the proposed method varies depending on the height of the bur, and the oxygen consumption is determined as an amount proportional to the height of the bur and welding speed.

FIG. 1 shows a scheme for carrying out the method; in fig. 2 - section AA on

FIG. one; in fig. 3 is a diagram with the help of which due to the process automation they realize the method.

The method is carried out as follows. The molded workpiece 1 is continuously fed to the welding zone, where the edges 2 are heated and welded to form burr 3. Oxygen is blown onto the weld 3 from the inside of the workpiece 1. Using sensor 4 (Fig. 3), the height is measured

a burr, while the sensor 5 measures the feed rate of the workpiece. Signals proportional to the burr height and the feed rate of the workpiece are fed to block 6 of delay, in which the signals are delayed by

r-.

where r is the signal delay time, s;

I — distance from the grata height sensor to the spot of grata contact with the oxygen jet, m;

V - feed rate of the workpiece, m / s ..

From the output of block 6, the signals are fed to the adder 7, in which the realization of the function Q F (h, V) takes place. After the adder 7, the signal enters the block 8 of the amplifier. After amplification, the signal is fed to control unit 8, then to the actuator 10, acting on the gearbox 11, which regulates the amount of oxygen entering through it to the rotameter 12, then to the electromagnetic valve 13 and through the nozzle 14 per tong. From sensor 4, a signal proportional to the height of the bur, is also fed to the kop-, rector .15, where a coefficient is entered that takes into account the amount of heat produced by the burning of grats in oxygen. Next, the signal enters the actuator 16, with the help of which an amendment is made in the heating source 17 to this amount of heat. The block 18 controls the height of the grata residues and, when the height deviates from the nominal, a signal is given to the block 9, which regulates the change in oxygen supply, until the height of the grata residues becomes equal to the nominal one.

PRI me R. In the mill 300, pipes of 299x4.0 mm in size from STZkp steel were welded. The welding speed is 22 m / min. The dimensions of the internal flash: width 3.8 mm, height 2.7 mm. The nozzle cross-section is made in the form of a circle with a diameter of Ps of 4.0 mm, which ensures overlapping of the burr width, DC Sd а, since 4.0 is 3.8 mm. When oxygen is supplied in the weld zone, the power source power is reduced from 180 to 150 KW, which is 17%. The oxygen pressure is 0.02 MPa (0.2 kg / s). Oxygen consumption 2.80 m / h. Quality of deburring

satisfactory. The height of the grata remains does not exceed 0.08 mm. With a rated power source of 180 KW, the speed rises to 25 m / min. Dimensions Grata: width 3.6 mm, height 2.6 mm. The oxygen pressure is 0.03 MPa (0.3 kg / cm). Oxygen consumption 0.75. The quality of deburring is satisfactory. The height of the residue does not exceed 0.06 mm. So

In the case of high-quality grating with an increase in speed from 22 to 25 m / min, the oxygen consumption changes from 0.70 to 0.75 with a change in the height of the grata from 2.7 to 2.6 mm caused by a change in speed.

Substituting the data obtained into the formula, showing the relationship between the change in oxygen consumption, the height of the bur and welding speed, get

QI 0.70 mW

20 g

 - - and, ui

Q2 0.75 MV4

Vl hi 22 m / min 2.7 u

V2 h2 25 m / min 2,6

The error does not exceed

   2.2%, which is due to inaccuracy in the resulting instruments.

Formula A

A method of manufacturing welded products, mainly pipes, including the continuous supply of a molded billet, heating with a power source, welding edges to form burrs and removing flakes with an oxygen jet, characterized in that, in order to improve the performance and quality of the welded joint by automating the process and reducing energy costs , in the process

welds adjust the power of the power source using the burr height as a correction parameter, and when the burr is removed, the oxygen supply changes directly proportional to the burr height and speed

welding.

Claims (1)

Claim A method of manufacturing electric-welded products, mainly pipes, including continuous feeding of the molded billet, heating by a power source, welding edges with the formation of a burr and removing the burr with an oxygen stream, characterized in that, in order to increase the productivity and quality of the welded joint by automating the process and reducing energy costs, during welding, the power of the power source is adjusted using the height of the burr as a correction parameter, and when the burr is removed, the oxygen supply is changed directly proportional to the height of burr and welding speed. At