RU2631043C1 - Permanent connection of closed circuit components and method for its implementation - Google Patents

Abstract

FIELD: machine engineering.

SUBSTANCE: invention is intended for permanent connection of closed circuit components made of dissimilar metals which cannot be joined together by welding due to fatigue failure of the weld during operation. The connection comprises male and female metal parts in which at least two holes are formed, wherein a through hole is made in the female part and a recess one is made in the male part. Metal cylindrical pins with a through inner hole, made of the same material as the male part, and well welded together and fused along the inside diameter of the pin with the material of the male part are installed in the holes by the press fit.

EFFECT: increased reliability of the connection of closed circuit components made of dissimilar materials.

2 cl, 2 dwg

Description

The invention relates to the field of instrumentation and mechanical engineering and is intended for one-piece connection of parts of a closed loop (cylindrical parts of the type "shaft-sleeve", parts of rectangular and other sections) made of dissimilar metals.

A one-piece connection is known, consisting of conjugated parts of a closed loop and a method for producing such a connection. The conjugated parts of the closed loop are connected by flowing material into the grooves of one of them, and the grooves are made along the entire perimeter of the pairing at a distance from each other. A smaller section is introduced into a larger part. Flanges can be made on the second part at a distance equal to the distance between the grooves of the first, and whose cross-sectional area is equal to the cross-sectional area of the grooves. Patent for invention RU 2120846, IPC В23Р 11/02, F16L 13/00, 10.27.1998. This method of connection does not protect against turning parts of a larger section relative to a part of a smaller section when applying radial loads, does not allow connecting thin-walled parts due to thermal deformation, is not suitable for the manufacture of connecting parts of rectangular and other sections, and is also quite difficult to implement.

Known electro-riveting compound and method thereof. The electro-rivet joint is intended for joining thin plates to parts consisting mainly of homogeneous materials. An electro-rivet joint is obtained by welding a metal of a filler wire previously made in one of the joined parts of a cylindrical hole to form an electro-rivet rod. In this case, the electric rivet rod has lateral one-piece contact with the surface of the hole wall obtained by the interaction of the additive metal melt with the solid phase of the metal of the part. Patent for invention RU 2375161, IPC В23K 9/173, 12/10/2009. This decision was made as a prototype. This method does not allow a reliable connection of dissimilar materials, for example, stainless steel 12X18H10T and steels of the type HVG, U8, alloy steels 65G, 40X13 and similar.

The problem to which the invention is directed, is the creation of an integral connection of parts of a closed circuit (for example, type "shaft-sleeve") made of dissimilar metals that cannot be joined together by welding due to fatigue damage of the weld during operation (exposure to elevated temperature vibration, shock loads, exposure to aggressive working environments, etc.).

The technical result achieved by using the invention is to increase the reliability of the connection of parts of a closed loop of dissimilar metals.

The technical result is achieved due to the fact that at least two holes are made in an integral connection made of dissimilar metals of closed circuit parts containing the male and female parts, moreover, in the female part and through, and in the male part deaf, in which metal fittings are installed according to the press fit cylindrical pins with a through inner hole, made of the same material from which the male part is made, and fused along the inner diameter of the pin with material of the part covered.

The connection of the pins with the male and female parts on the press fit eliminates the spontaneous loss of the pins during the manufacturing process of the proposed connection.

The implementation of the pins of the same material from which the male part is made, allows to obtain a high-quality welded joint, while a welded joint between the pin and the female part will not be formed.

The ratio of the wall thickness of the pin and the wall thickness of the covered part should be from 1: 1 to 1: 2, which ensures the optimal distribution of temperature fields when welding the pin with the covered part. A decrease in the ratio can lead to a change in the geometric dimensions of the covered part and its burn through, an increase in the ratio can lead to defects in the welded joint of the pin with the covered part.

The outer diameter of the pin is determined by the shear strength requirements for the materials from which the pin and the workpiece are made.

The proposed one-piece connection for parts of the type "shaft-sleeve" is illustrated by drawings, which depict:

in FIG. 1 - one-piece connection, a longitudinal section;

in FIG. 2 - one-piece connection, cross section.

One-piece connection is used to connect part 2 with through holes with part 1 with blind holes using a cylindrical pin with a through inner hole 3 made of the same material from which the covered part 1 is made and well welded with the material of part 1 inserted through coaxial the holes of parts 1 and 2 and connected by welding through a central through hole of the pin with part 1.

Thus, the pin 3 connecting the parts 1 and 2 inseparably to one another performs the function of a rivet having a rod and a welded joint having fusion of the rivet material with the part 1. Moreover, there is no welded joint between the parts 1 and 2, 2 and 3, which may fatigue damage during operation, and the mechanical properties of part 2 are not changed.

One-piece connection is obtained as follows: part 2 with pre-made holes are installed on part 1 with pre-made holes and the holes are combined with each other. The pins 3 are pressed into the holes in the parts 1 and 2, then welding is carried out with filler wire between the part 1 and the pin 3, filling the internal hole of the pin 3 with molten metal. As a result, a strong connection is formed between the part 1 and the pin 3.

Similarly, one-piece connection can be made for parts of square, rectangular, triangular and other sections.

The proposed one-piece connection was performed as follows. They took a pipe made of steel 12X18H10T with an outer diameter of 90 mm and a wall thickness of 6.5 mm and a length of 2500 mm. Two groups of four blind holes with a diameter of 14 mm and a tolerance field of C12 were made in the pipe. Two bushings made of steel 20X17H2 with a bore diameter of 90 mm, an outer diameter of 96 mm, a length of 55 mm, and four holes made in advance with a diameter of 14 mm were installed on the pipe, then the holes on the pipe and the sleeve were combined. Tubular cylindrical pins made of 12X18H10T steel with an outer diameter of 14 mm and a tolerance field of u8, an inner diameter of 8 mm and a length of 4 mm were pressed into each hole. Then, using argon arc welding in a shielding gas medium with a filler wire with a diameter of 1 mm from steel 12X18H10T, a welded joint was made between the pipe and the pin through an internal through hole in the pin.

To test the operability of the proposed one-piece connection, the casings were made of steel 12X18H10T, on which the bushings were made of steel 20X17H2 by the proposed method and field tests were carried out under conditions of elevated temperature up to 150 ° C, vibration frequency up to 300 Hz with a maximum acceleration of 100 m / s ² , mechanical shocks lasting up to 12 ms with a maximum acceleration of 150 m / s and a quantity of up to 50 per minute and exposure to an alkaline environment. The test results showed that the case worked out the installed resource, the connection was not destroyed. Thus, the tests confirmed the performance of the proposed one-piece connection.

Claims (2)

1. An inextricable connection of closed loop parts, characterized in that at least two holes are made in the male and female parts made of dissimilar metals, the parts are aligned with each other, and cylindrical pins with a through hole made of the same holes are installed in the holes by pressing fit material from which the covered part is made, and connected to the covered part by welding with filler metal. 2. A method of performing an inseparable connection of closed loop parts, characterized in that at least two cylindrical holes are made in advance in the male and female parts made of dissimilar metals, the blind ones are male and the through, male and female parts covering the holes are aligned in holes are pressed into cylindrical pins with an internal cylindrical hole made of the same material from which the covered part is made, then the pins are welded feet with filler material on the inner diameter of the male part, while the female part and the pins are not welded together.

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