SU1683926A1 - Method for arc welding in carbon dioxide at open site - Google Patents

Abstract

The invention relates to welding in carbon dioxide and can be used in the construction and installation of industrial buildings and structures, as well as in other branches of the national economy when welding steel structures in open areas under the influence of wind on the welding zone. The purpose of the invention is to improve the quality of welded joints made in open areas by forming a protective gas jet resistant to wind. In the process of welding, the value of the flow of protective gas is established depending on the diameter of the filler wire, the distance from the torch nozzle cut to the diameter of the gas jet at the nozzle section, welding current and wind speed. Welding maintains the ratio given in the description of the invention. The invention makes it possible to reduce the tendency of the weld metal to form pores, to increase its toughness. 1 dw., 2 tab. SL C

Description

The invention relates to gas-shielded arc welding, in particular to carbon dioxide gas welding, and can be used in the construction and installation of industrial buildings and structures, as well as in other branches of the national economy, when welding in open areas under wind conditions. on a welding zone.

The purpose of the invention is to improve the quality of welded joints made in open areas by forming a protective gas jet resistant to wind.

The drawing shows a scheme for implementing the method.

The essence of the method is as follows.

The product 1 is welded. The protective gas is supplied through a nozzle 2 with a diameter of dc. Welding is carried out with the filing of filler wire 3 with a diameter of dnp. The distance between the nozzle section and the product h. The shielding gas 4 is supplied at a flow rate of Qr. The weld zone is affected by wind 5 at a speed of Vb.

The welding process maintains the following relationship between the process parameters.

n n -dnp - (15-0.5VB) Uf0.18-0-C- & 34

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where Or - shielding gas consumption, l / min

h is the distance from the nozzle section to the product, mm;

dnp - diameter of the filler wire, mm;

VB - wind speed, m / s;

dc - nozzle diameter, mm;

ICB - welding current, A.

The proposed relationship allows the determination of the flow of shielding gas depending on the wind speed, taking into account the welding mode. The mode parameters (Icn.dnp.h.dc) are selected depending on the type of steel being welded, the thickness of the products, etc. When the wind speed changes, the protective gas flow is adjusted. The adjustment may affect other parameters of the mode. Wind speeds can vary widely. The maximum wind speed at which the method will be carried out is 12 m / s. The proposed method provides reliable protection of the welding and heat-affected zone by changing the flow of protective gas, taking into account the influence on the protection quality of other parameters of the welding process.

Approx. Welded in the open area. Welding is performed with the following process parameters.

Flow rate qr 5 - 110 l / min;

Welding current 1Sv 100-350 A; The voltage across the arc is 11D 16-32 V;

The diameter of the wire, 8-2.0 mm;

The diameter of the nozzle dc 12-20 mm;

The distance from the nozzle to the product h 5-30 mm;

Wind speed VB 30-12 m / s.

The resistance of the weld metal to pore formation is determined by the presence of pores in the metal and the results of gas analysis. The formation of seams, the stability of the arc and the splashing of the metal is assessed visually. The porosity of the seams is determined by visual inspection and by ultrasound and radiographic control,

In tab. 1 presents the results showing that the proposed method of welding in carbon dioxide in the wind (options

1-3, 8-10, 15-17, 22-24) provides a high resistance of the metal against the formation of pores with good formation of seams, steady arc burning and moderate spattering of the electronic metal. The deviation from this ratio hx xdnp / dc in the direction of increase or decrease leads to the appearance of pores in the weld metal, deterioration of its formation and an increase in the sputtering of the metal. When welding in carbon dioxide in the wind of steel of 09G2S brand with a Sv-08G2S wire of small diameter (1.0-1.4 mm / slight deviation of the welding modes from those proposed, not always

leads to the formation of pores in the seam. However, there is a significant increase in the gas content in the weld metal of Table 2) and, as a result, a decrease in toughness.

Claims (1)

The method of welding in carbon dioxide in open areas improves the quality of welded joints and makes them possible to perform at an air speed of up to 12 m / s. The use of the welding method in construction allows an increase in the level of mechanization of welding operations, the quality of welded joints and labor productivity. Invention Formula The method of arc welding in carbon dioxide in open areas, in which the process is conducted by a melting electrode, is characterized in that, in order to improve the quality of welded joints by forming a wind-resistant protective gas jet, the magnitude of the protective gas consumption is selected by their ratios n -h -dnp (15 + 0.5VB) 0.18 dc I0 34 where Qr is the flow rate of protective gas, l / min; h is the distance from the cutting edge of the welding torch to the product, mm; dnp - diameter of the filler wire, mm; dc is the diameter of the jet of protective gas in the arc of the burner nozzle, mm; I - welding current, A; VB - wind speed, m / s. 0 00 00 (O Yu 05 Effect table 2 the parameters of the process of welding in carbon dioxide in the wind for the content of gases in the weld metal and its impact strength 10 and 18.5 21 15 40 53 thirty 57 72 45 180 200 240 130 220 150 230 250 200 35 18 14 29 16 11 28 10 8 cn 00 with (ABOUT to Oj