SU1537433A1 - Method of arc welding - Google Patents

Abstract

The invention relates to welding and can be used in various parts of the national economy in the manufacture of sheet structures from materials that are welded by arc welding methods and have an increased requirement for the appearance of the joint zone and the accuracy of the product as a whole. The purpose of the invention is to obtain a joint in the joint zone without any defects in the external formation of the seam while completely eliminating welding deformations. To do this, simultaneously with welding, plastic deformation of the seam is carried out with a roller, which is placed in the tail section. Welding and deformation are carried out in two passes from two sides and provide penetration depths with the first pass of 0.66 ÷ 0.8, and with the second one 0.5 ÷ 0.4 of the thickness of the base material. The result is a joint without defects with good geometry. 4 il.

Description

The invention relates to gas-shielded arc welding and can be used in the manufacture of sheet structures that have increased demands on the accuracy and quality of the formation of the welded joint.

The purpose of the invention is to obtain a joint in the joint zone without any defects in the external formation of the seam while completely eliminating welding deformations.

Figure 1 shows the scheme for carrying out the method when performing the first pass; in fig. 2 - the same, when performing the second pass on the reverse side; in fig. 3 - dependence of the deflection f change on the value of the relative penetration depth of the first pass; in fig. 4 shows the dependence of the change in the height of the metal alignment on the reverse side on the value of the relative penetration depth of the second pass.

The method is carried out as follows.

A device for welding and high-temperature rolling of the weld metal, including the welding torch 1 and the cooled roller 2, is set along the axis of the joined edges, excites the arc and creates the necessary force F to smooth the metal of the tail part of the bath 3 flush with the base material. Upon completion of welding, first turn off the current, and then relieve pressure on the roller.

SP

00 1

J

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The welding mode and the magnitude of the applied force are determined experimentally or by calculation. In this case, it is assumed that the parameters I) of the welding period must ensure penetration in the first pass of 0.66-0.8, and in the second 0.5-0 , 4 thickness of the base material (S).

An understating or an overestimation of the depth of penetration of NA from the established range during the first pass causes a noticeable increase in the deformation of the welded assembly, estimated by the magnitude of the protrusion T (FIG. 3). In addition, with Hj / o values of 0.66, the second pass, in order to reliably overlap the rollers, has to be carried out with relative

penetration depths, 5, which leads to an increase in the height of extrusion of metal fr.h from the reverse side (Fig. 4). This phenomenon is explained by a significant softening of the metal under the roller from the back side with a large depth of penetration during the second pass,

These results were obtained on samples of the alloy VT-ZV 4 mm thick over a length of 500 mm. It has been established experimentally that if the exit from the plane does not exceed 1.5 mm, then when welding products having a large number of gaBOBs (5 and 5), the required accuracy of the product can be achieved. Therefore, penetrations in the range of 0.66–0.8 were chosen as limiting values for the first pass. Increasing and decreasing the depth of penetration above this range causes an increase in the specimen deformation estimated by a deflection of 1.5 mm.

In the second pass, an important factor affecting the formation of external defects in the formation of a seam 9 is the possibility of the appearance of a hillock of extruded metal on the reverse side (from the first pass side). It was experimentally found that with increasing depth of penetration from the second pass, the height of the extruded metal increases. Proceeding from the requirements for products, as well as from the specifications for thickness difference, the reinforcement height should not exceed 0.15 mm. This, in turn, determines the range of penetration during the second pass. Increasing the penetration depth above

0

five

0

five

0

five

0

five

(035 leads to unacceptable extrusion of the weld metal, 15 mm. Reduction, 4 is unacceptable due to the fact that it is possible to not overlap the weld from the first pass, which leads to the appearance of such a defect as lack of penetration.

Thus, performing welding and plastic deformation consistently from two sides with ensuring the penetration depth at the first pass of 0.66 - 0.85, and at the second 0.5-0.4 thickness of the base material allows to obtain a joint in the joint zone without external defects weld formation (undercuts, reinforcement, melting) with almost complete elimination of welding deformations,

Example, After welding and high-temperature rolling by the proposed method, on five sheet elements of titanium alloy VT-ZV with a thickness of 4 mm out of the plane on a length of 500 mm no more than 1 mm; undercuts, no melts, metal thickening in the joint zone no more than 0.08 mm0 Welding and high-temperature rolling of the weld metal was carried out in the following modes: first pass 1С8 260 A, VCB 20 m / h, F 2,2 kN, dp 20 mm; second proI, 1.9 kN.

The results of the experiments confirm that the proposed method is effective and useful for production and will find wide application in welding of sheet structures of increased accuracy, improved appearance and products for special purposes.

Claims (1)

Invention Formula The method of arc welding, in which simultaneously with the execution of the weld, a roller is forcibly impacted on the tail part of the bath, characterized in that, in order to obtain a joint in the joint area without defects of the external weld formation while completely eliminating the welding deformations, welding and plastic deformation are carried out sequentially from two sides with ensuring penetration depth at the first pass of 0.66 - 0.8, and at the second - 0.5 - 0.4 thickness of the base material „ stroke 1CB 160 As Vce -20 m / h, F (l U -J l u) 0.25 , / o, & ff, 4 V