SU1660921A1 - Method of repair of articles having cracks - Google Patents

Abstract

The invention relates to methods for repairing cracked products and may find application in the repair of machine parts in various fields of mechanical engineering. The purpose of the invention is to increase the efficiency of repairing products with inclined cracks. When repairing in a weakened area, the shaped grooves are made on both sides of the product in the direction perpendicular to the direction of the crack. They are pressed into them towards each other by the main and additional figured inserts with spikes. At the ends of the spikes there are conical protrusions and apertures mating with each other during counter-pressing. The hole is on the end of one, and the protrusion is on the end of the other spike of the same insert. Using a unified asymmetric spike insert with a protrusion on one end and a hole on the other end of the spike creates uneven residual stresses around the inclined crack of the product, generating a useful torque that contributes to the reliable closure of the edges of the crack faces, which leads to an increase in repair efficiency. 5 il.

Description

The invention relates to technological processes and equipment for the repair of machine parts, in particular to methods of dealing with cracks in products, and will find application in mechanical engineering.

The purpose of the invention is to increase the efficiency of repairing products with inclined cracks.

FIG. 1 shows the product after repair, section; in fig. 2-joint node of the shaped inserts for carrying out the method in the open state; in fig. 3 - a product with a crack and figured inserts for the implementation of the method of repairing products with oblique cracks: in Figures 4 and 5 - plots

stress distribution along the crack between the inserts.

The method of repairing products with inclined cracks is carried out with the help of the main and additional uniform unified figure insert. The main and additional figure inserts have a jumper 1 and conical spikes 2, ending with a protrusion 3, with notch 4 on the end of one and a hole 5 on the end of another spike 7, having notch 6.

For the implementation of the method in article 8 having a crack 9 of thickness d, figured grooves 10 are made on both sides to accommodate figured inserts. Oiaef 01 ic (through) are drilled in the extreme sections of the grooves

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11 and 12 for the entire thickness of the product 8. The holes are positioned relative to each other at a distance S. This distance is chosen from the ratio I S 21,

This ratio provides an acceptable uniform compression of the crack 9 along its entire length. After that, from the opposite sides of the product, the main and additional figure inserts of uniform size and material are pressed in. With this, a conical spike 2 with a protrusion 3 enters the hole 11 on one side of the product 8, and the spike 7 e enters the other hole 12 with an opening 5 in it.

The same holes 11 and 12 on the opposite side of the product 8 include a conical spike 7 with a hole 5 and a conic spike 2 with a protrusion 3 that mate with the listed spikes.

At the beginning of the press-in, due to the action of the conic studs 2 and 7 of the figured inserts, the initial distribution of the holes and their secure fastening are made by the external notch b. The resulting uneven residual stress of the hedgehog and the torque of Mcr, characterized by plots 13m 14, effectively ensure a reliable closure of the edges of the cracks 9.

At the end of the pressing-in, the holes 11 and 12 are additionally distributed, when entering the end grooves in the form of the holes 5, of conical protrusions 3 with a relief on the surface for reliable engagement (Fig. 2). In the case of the part (tractor gearbox) with an edge crack 50–56 mm long and a tip thickness of 0.17 mm, in the middle b is 0.254 mm, four figured inserts are pressed at a distance of mm, s distance I 12 mm, with

1 taper of thorns 2 in - Tet, protrusions 3

eleven

b - -a, spikes 7 in TJ, and a notch on the spikes

and end tabs, made in the form of a torn thread. When pressed in, the tension in the joint is provided by up to A 5 0.03–0.04 mm.

The shaped inserts provide, during pressing, the tensile forces at a level of 3 to 3.5 kN and are made of a steel strip by stamping. During the operation of the tractor during the season of agricultural field work, the opening of the edge crack and its further propagation was not observed.

The bench tests carried out under loading plates with perpendicular and inclined slots, cyclic loads showed an increase in the efficiency of the proposed method by 1.2–1.3 times as compared with the base one.

Conducted bench tests showed the effectiveness of the proposed method and in the presence of small branches from the main crack.

Claims (1)

Invention Formula The method of repairing cracked products, in which figured passes are made on both sides of the product in the weakened zone in a direction perpendicular to the direction of the crack, and they are pressed against one another by the main and additional figured inserts with spikes, at the ends of which during counter-pressing, conical protrusions and holes, characterized in that, in order to increase the efficiency of repairing products with cracks, are inclined 1 toward the surface of the product, by creating unequal residual stresses zhenii, insertion is performed with asymmetric studs, wherein the opening is at tootse one protrusion and - on the other end of the cleat, NO sa ate 00 o Ri.5 FIG. C