RU2288085C1 - Foot member restoring method - Google Patents

Abstract

FIELD: repairing of railway road rolling stock, namely restoration of foot members of cargo and passenger cars.

SUBSTANCE: method comprise steps of making covering for worked thrust cylindrical and supporting surfaces of foot member by placing heated blank of disc-like covering on supporting surface of foot member and upsetting it while squeezing bulged portions around thrust cylindrical surface of said member. After unloading surfaces of foot member, covering is subjected to self-tempering. Covering is formed according to shape of said surfaces of foot member and it has thickness equal to depth of working foot member. Thrust cylindrical and supporting surfaces of foot member are worked by turning them by depth no less than their maximum wear degree at roughness 16 ≤ Rz ≤ 50. Height of thrust cylindrical surface is to be no less than depth of center plate of over-spring beam of truck minus covering wall thickness value. Blank of covering is heated till temperature more than point Ac₃ of phase diagram "iron-carbon" and it is placed on supporting surface of foot member in heated state at temperature of said surface no more than 550°C. Covering blank is upset by means of spinner with cooled surface. Bulged portions are squeezed at process of cooling blank in temperature range Ac₃ -Ar₁ of phase diagram "iron-carbon".

EFFECT: enhanced operational reliability and capability for repairing foot member.

1 ex, 2 dwg

Description

The invention relates to the field of repair of railway rolling stock, in particular to the repair of Fridays of freight and passenger cars. It can also be used in car building and in other areas of technology in the manufacture of similar parts.

A known method of restoring friars, including installing on a machined thrust cylindrical and abutment surface of the firing patches of sheet steel with wear-resistant properties, made in the form of the mentioned surfaces of the friday and with a thickness equal to the depth of machining of the friday (RU 2223166 C2, 23 P 6/00, 02/10/2004). The disadvantage of this technical solution is the difficulty of ensuring a snug fit of the lining to the Friday at the places of the radius joints of their supporting and thrust surfaces.

The aim of the invention is to increase the operational reliability of Fridays and improve their maintainability.

This goal is achieved by the fact that on a mechanically machined supporting and abutting surface of the Friday, the disk-shaped blanks of sheet steel are pressed in hot condition with wear-resistant properties with a thickness equal to the depth of turning of the Friday, made in the form of the mentioned surfaces of the Friday and heated to a temperature above point Ac _{3 of the} diagram the state of "iron-carbon", which is placed on the supporting surface of the Friday at a temperature of the latter not higher than 550 ° C, while the supporting-resistant surfaces are Friday Before installing the pads, they grind it to a depth of at least maximum wear with a roughness within 16≤Rz≤50 to obtain a height of the thrust cylindrical surface of at least the depth of the thrust bearing of the trolley’s tension beam, minus the thickness of the lining wall, and pressing the blanks onto the lining is carried out with the latter pressed down with a cooled surface and squeezing the inlets during the cooling of the lining in the temperature range Ac ₃ ÷ Ar ₁ state diagrams "iron-carbon", and after unloading carry out self-release lining due to heat transfer with the associated walls of the Friday.

Salient features of the invention are:

- turning the support-resistant surfaces of the Friday with a roughness of 16≤Rz≤50 to a depth of not less than their maximum wear;

- pressing on the turned surfaces of the Friday in the hot state of the blank billets made of sheet steel with wear-resistant properties, at a temperature of the Friday not higher than 550 ° C;

- the temperature of the heating of the workpiece linings before hot pressing above the point Ac ₃ phase diagrams of the "iron-carbon";

- deposition of the lining on the supporting surface of the Friday through the cooled surface of the press and squeezing its inlets around the cylindrical surface of the Friday in the process of cooling the lining below the point Ar ₁ state diagram "iron-carbon";

- self-release pads after unloading due to heat transfer with the associated walls of the Friday.

The significance of the distinguishing features is confirmed by the following:

1. Grinding of support-abutting surfaces of a Friday with a roughness of 16≤Rz≤50 is necessary to increase the adhesion of the contact surfaces of the joint of the patch and the Friday to prevent slipping of the patch from the latter during operation. At the same time, the turning depth should be not less than the maximum wear of the supporting and abutting surfaces of the Friday to ensure a snug fit of the lining walls to them.

2. Pressing the blanks of the patch should be done on the dry surface of the turned Friday, preferably when it is heated to the tempering temperature of the steel, to prevent through-hardening of the patch and the formation of cracks in it when it shrinks during cooling. However, it is more efficient to heat the Friday before pressing the lining in the tempering range to relieve residual stresses in the Friday that occurred during previous repairs by surfacing, as well as during operation. The maximum temperature for heating the Friday should be no more than 550 ° C, regulated for tempering the Friday after restoration by surfacing.

3. The heating temperature of the liner preform before hot pressing should exceed the Ac ₃ point of the “iron-carbon” state diagram necessary to obtain quenching structures in the layer located at its working surface with subsequent accelerated cooling provided by heat exchange through the contact surface of the presser.

4. The deposition of the lining on the supporting surface of the Friday through the cooled surface of the press is necessary to combine the operations of hot pressing of the lining and its surface hardening.

5. Self-release of the lining after unloading the Friday is necessary to improve the steel structure and increase the lining resistance to brittle fracture, in particular in operating conditions at low temperatures.

An example implementation of the method.

The restoration of the worn surfaces of the Fridays of freight cars according to the developed technical solution is as follows (figure 1).

The worn out abutment 1 and abutment 2 of the surface of the heel are machined with a roughness of Rz 16 to the same depth, measured from their nominal dimensions and equal to the thickness h _{1 of the} walls of the insert, which has the shape of a plate with an abutting annular wall 3 and a supporting wall 4, which has a central hole for the pin. In this case, the thrust surface 1 is cylindrical to a height of hh ₁ (in the example of the method 30 mm). The blank preparation (Fig. 2) in the form of a disk is made of sheet metal of hardened steel grades (in the example, steel 45) with a thickness of not less than the maximum wear allowed when restoring the spruce plates by surfacing (in the example h ₁ = 8 mm). Then, induction heating of the Friday to a temperature of 300 ° C is carried out and on its supporting surface 2 is placed a disk-shaped blank of a lining heated to steel quenching temperature (in the example up to 850 ° C), which is deposited on the last normally applied static load with simultaneous compression of its inlets protruding beyond the contour of the supporting surface (figure 2 shows a dashed circle), designed to perform an annular contact surface of the Friday. Compression of the inlets is carried out with the implementation of the thrust surface of the annular wall of the insert with a taper of 12.5, which is ensured by the pressure device. To obtain the necessary wear resistance of the metal lining through contact with the lining of the surface of the presser is accelerated heat removal, which is also provided by the device of the latter.

Using the claimed method of recovery provides a reduction in energy and labor costs and increase maintainability, as well as a reduction in jobs associated with harmful working conditions (welding and surfacing).

Claims (1)

A method for recovering Friday shoes, including pressing in hot condition on mechanically machined thrust cylindrical and abutment surfaces of a Friday of an overlay made of sheet steel with wear-resistant properties, made in the form of the mentioned surfaces of the Friday and with a thickness equal to the depth of machining of the Friday, characterized in that when restoring the Friday, pressing the overlays carried out by placing the blanks of the lining, having a disk-like shape, on the supporting surface of the Friday, upsetting the blanks of the lining on the said supporting surface and compressing its inlets around the persistent cylindrical surface of the Friday, while the machining of the resistant cylindrical and supporting surfaces of the Friday is carried out by turning to a depth of not less than their maximum wear with a roughness of 16≤Rz≤50, to obtain a height of the persistent cylindrical surface of the Friday of not less than depth bogie bolster center plate minus the thickness of the wall lining, lining preform is heated to a temperature above the Ac ₃ point of the phase diagram "iron-uglero "And placed on the support surface Pyatnikov in the hot condition at a temperature not higher than the last 550 ° C, squat preform laths davilnikom produce a cooled surface, an overlap crimping is performed during cooling the preform in the temperature range laths Ac ₃ -Ar ₁ state diagram" iron-carbon ", and after unloading the Friday carry out the self-release of the lining due to heat exchange with the associated walls of the Friday.

Images