RU2663759C2 - Rail connection method - Google Patents

Abstract

FIELD: molding.SUBSTANCE: method of rail connection involves cutting the ends of rails at an angle of 45°(±)15° to the longitudinal axis and the connection of the rails by welding or using linings.EFFECT: welded joints and joints using overlays alternate throughout the block-section or railroad track.1 cl, 8 dwg

Description

Е01В - the upper structure of the track, tools for this; devices for laying and repairing rail tracks of all types;

ЕВВ 11/00 - rail butt joints;

ЕВВ 11 / 02-11 / 32 - detachable butt joints, overlays;

Е01В 11 / 44-11 / 46 - one-piece welded joints (welding in general: V23K)

List of documents cited in the application:

RU 2241795, RU 2424092, RU 2430820.

The invention relates to methods for connecting rails of railway, city (tram, metro) and industrial vehicles, as well as rails for crane tracks in ports and at enterprises.

The proposed method consists in the fact that the ends of the rails are welded in a vertical plane at an angle to the longitudinal axis other than 90 °, mainly at an angle of 30-45 °, before welding, the ends of the connected rails are cut at the same angle.

The closest analogue of the invention is the patent RU 2241795, in which the ends of each joint rail are made axisymmetrically at an angle. How and how to accomplish this is not indicated. Actually in the field, with modern technical equipment for track work, the axisymmetric rail joint cannot be performed. Even in the factory, such a preparation of the ends of the rails is very problematic, therefore, the analogue method has no practical application.

Metallurgical plants produce rails for railways, urban rail transport (tram, metro), industrial transport, crane tracks in river and sea ports, etc. a certain length (in accordance with accepted standards): 12.5; 25; 100 and more meters. At the same time, the ends of the rails are cut strictly perpendicularly, at 90 ° to the axis in the vertical plane.

During the construction of the track, the rails are connected in two ways:

1. Link way. Using 2 overlays with 4 or 6 holes, under which holes are drilled coaxially in the necks of the rails to be connected, bolts are inserted into the holes and the plates are tightened with nuts. At the same time, a gap is left between the connected rails to compensate for their temperature elongation (shortening).

2. The jointless path. By welding. Apply: pressure welding (electric, gas press, etc.), electric arc and aluminothermic methods.

The link path has many disadvantages.

In FIG. 1 shows a diagram of rolling a wheel of a rolling stock through a gap between rails in a link path. Despite the fact that the joint is taken into the lining, there is the possibility of a small movement of the rails relative to each other. When the wheel rolls through the gap, the "letting out" rail, under the action of the mass of the rolling stock, sits down, becomes lower than the "receiving" rail. This drawdown (step) can be more than 1 mm, depending on the condition of the track: the rails themselves, sleepers, rail track, etc. When the wheel hits the “receiving” rail, a dynamic impact occurs, as a result of which:

- the surface layer of the “receiving” rail is crushed and crumbled, which after a certain time becomes defective and will need to be replaced;

- the rail track is deformed, the path is frustrated;

- there is intense wear of parts of the carts of the rolling stock;

- there is a vibration of cars and a knock, creating discomfort for passengers;

- more energy is required for the traction of the train in connection with overcoming the "steps";

- High-speed train movement is impossible, since the force of a dynamic shock increases many times and the influence of the above negative processes increases sharply.

To create a weld-free track, rail welding enterprises and machines (technologies) for welding rails on the track are necessary.

The jointless (velvet) path is devoid of the shortcomings of the link path, however, it also has disadvantages:

- the welded joint is a weak point in the rail whip, defects in welded joints (including kinks in welded joints) make up 30-35% of all rail defects detected in operation;

- welded rail lashes must be fixed on the sleepers at the optimum temperature, determined by the average annual air temperature in a particular section of the track (north, middle lane, south);

- to compensate for the temperature elongations (shortenings) of the rail lashes, “equalizing” insert rails are installed between the lashes using overlays. Shortened “leveling” rails are installed before the summer season, and elongated rails before the winter season. This prevents the "emissions" of the path in the summer season (Fig. 2) and ruptures of the lashes in the winter.

The indicated disadvantages of the jointless path are more than compensated by its advantages over the link structure of the path:

- eliminated the defective rails in the ends adjacent to the gap, increases the service life of the rails;

- dramatically reduced wear of the parts of the carts of the rolling stock;

- no less than 10% reduced energy costs for traction trains;

- reduced dressing and maintenance costs;

- the implementation of high-speed train traffic is possible;

- Comfort for passengers rises sharply.

The aim of the invention is to eliminate the disadvantages of both the link structure of the track and the jointless, while achieving a significant reduction in the cost of their construction and maintenance.

The prerequisite for this decision is the increasing production by the metallurgical plants (both abroad and in Russia) of long - 100 or more meters of rails. This already eliminates (at least) 3 welded joints (compared to 25-meter rails), which are a weak point in the rail track and for which certain costs are required.

The proposed method consists in the fact that the ends of the rails before the connection are cut in a vertical plane at an angle to the longitudinal axis other than 90 °, mainly at an angle of 30-45 °, the connection of the rails is performed:

a) by welding;

b) using 2 overlays with 4 or 6 holes, under which holes are drilled coaxially in the necks of the rails to be connected, bolts are inserted into the holes and the plates are tightened with nuts.

Both rail connection technologies can be combined over the length of the block section or stage.

A. The advantages of connecting rails with "oblique" ends by welding,

- increase the strength characteristics of welded rails and their reliability.

B. Advantages of connecting rails with "oblique" ends using overlays:

- excludes dynamic impact at the end of the "receiving" rail. The wheel smoothly rolls through the gap, which eliminates or eliminates all the above negative effects of a dynamic impact in the link.

Currently, in all countries, by all welding methods used, rails are welded with ends cut strictly in a vertical plane at an angle of 90 ° to the axis.

In FIG. 3. The scheme of the impact of the wheel of the rolling stock on the welded joint of the rails is shown. The load from the wheel (part of the mass of the car) acts in the plane of the weld, i.e. in the weakest spot of the weld. In this case, the seam of the rail head is in a compressed state, and the seam of the sole is in a stretched state. When a weld is located between two wheels (Fig. 4), the stress state in the weld changes to the opposite: in the rail head in a stretched state, in the sole - in a compressed state. Thus, during the operation of the welded rail, the weld constantly experiences alternating loads that act in the plane of the weld.

The essence of the invention is to create conditions under which the loads from the wheels of the rolling stock did not act in the plane of the weld, which will increase the resistance of the welded joint of the rails to alternating loads and, ultimately, its strength properties.

This is achieved by performing a weld in a vertical plane at an angle to the longitudinal axis of the rail, different from 90 °, as is accepted in all published patents on methods for welding rails.

In FIG. Figures 5 and 6 show the arrangement of the weld at an angle of 45 ° to the axis of the rails, the acting loads and stresses in the head and sole. Only the part of the weld, the length of which together with the heat-affected zone (HAZ), is located in the plane of the external working or test load (load on the head), depends on the angle of inclination of the weld to the longitudinal axis of the rail and the gap between the welded rails (width of the weld) . In the rest of the plane of action of the external load falls on the main metal of the rail.

Thus, in order to increase the strength characteristics of the welded joint, it is necessary to strive to reduce the length of the weld + HAZ in the plane of the external load.

If the gap between the welded rails is 8 mm, the length of the weld along with the HAZ in the plane of the external load will be 14-20 mm, or about 15% of the total length.

If the gap between the welded rails is 18 mm, the length of the weld along with the HAZ in the plane of the external load will be 26-40 mm or about 30% of the total length. In this case, the strength characteristics of the welded joint of the rails will be lower than with a gap of 8 mm.

All these provisions are relevant provided that there are no typical welding defects in the weld: pores, cracks, non-metallic inclusions, quenching structures, etc.

The choice of optimal values of the angle of the weld to the axis of the rails and the gap is also affected by economic factors: the smaller the angle and the larger the gap, the greater the consumption of welding materials and welding time (for electric arc methods).

Some features may also occur depending on the choice of welding method.

For practical confirmation of the stated provisions, several samples of R65 rails were welded by the electric arc method and their standard tests for static bending were carried out.

The ends of the welded rails were cut with a band saw in a vertical plane at an angle of 45 ° to the longitudinal axis of the rails.

Welding was carried out with a gap between the rails of 12 mm, automatic electric arc method according to patent RU 2424092 apparatus according to patent RU 2430820.

After welding and free cooling, abrasive cleaning of the weld and a standard test of the welded joint of the rails for static bending were performed.

Test results: breaking load of 172-186 t, deflection boom - 22-27 mm, which significantly exceeds the test results of welded joints of rails made by the same method and apparatus with a weld at an angle of 90 ° to the longitudinal axis of the rails. The test results satisfy the current requirements for welded rails.

In FIG. 7 (side view) and in FIG. 8 (top view) shows a fracture view of a tested welded rail. The kink occurred in the plane of action of the breaking load, perpendicular to the longitudinal axis of the rail, and not along the weld or heat-affected zone.

The test results confirm the reality of the practical application of the method and the effectiveness of the proposed technical solution for connecting rails. The alternation of “oblique” welded joints and overlays taken over the block section or rail track spacing creates the effect of a “velvet” track, for which there is no need for off-season installation of “leveling” rails, as is required for a continuous joint.

Claims (2)

1. A method of connecting rails, including trimming the ends of the rails at an angle of 45 ° (±) 15 ° to the longitudinal axis and connecting the rails by welding or using overlays, characterized in that the welded joints and the joints using overlays alternate throughout the block section or the run rail track. 2. The method according to claim 1, characterized in that before welding the ends of the connected rails are cut at the same angle.

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