CN115070197A - Heat release welding process for cable and steel rail - Google Patents

Abstract

The invention discloses a heat release welding process for cables and steel rails, which comprises the following steps: when the steel rail is heated to the first temperature, the heating area is kept warm, the welding area is continuously heated to the second temperature, and the temperature of any point on the steel rail is not higher than 800 ℃; fixing a heat-releasing welding mould on the heated steel rail, sleeving a sleeve on the end part to be connected of the cable, placing the sleeve into the heat-releasing welding mould for heat-releasing welding, and cooling after the heat-releasing welding; in the cooling process, a heat-insulating material is adopted to cover and wrap the steel rail, and the mold is subjected to heat release welding; the horizontal distance between any point in the welding area and the welding point is not more than a first distance, and the horizontal distance between any point in the heating area and the welding point is more than the first distance and less than or equal to a second distance. The invention controls the temperature of the heating area and the welding area of the steel rail, and is beneficial to keeping the metallographic structure as pearlite at the joint of the cable and the steel rail, thereby obviously improving the connection strength of the cable and the steel rail.

Description

Heat release welding process for cable and steel rail

Technical Field

The invention relates to the field of exothermic welding, in particular to an exothermic welding process for cables and steel rails.

Background

The connecting wire, the jumper wire, the current equalizing wire and the return wire of the steel rail are pure copper cables, and the pure copper cables are connected with the steel rail and provide signals and working current for the railway locomotive according to different use positions. According to the relevant technical specifications of railways, the connection point of the pure copper cable and the steel rail must have good mechanical property and conductivity, and the metallographic structure of the steel rail base material should not be affected.

In the prior art, to connect a cable with a steel rail, a hole is usually formed in the steel rail, and a mechanical connection of bolt expansion nails or brazing is mainly adopted. The bolt expansion nail is easy to have the problem of joint looseness under the condition of long-term vibration of the steel rail, and in an outdoor environment, the bolt and the steel rail are easy to corrode, the contact resistance value is increased, the performance of an electric appliance is reduced, signals formed on a locomotive are easy to misjudge, and the stroke safety is influenced; the brazing connection also causes the increase of contact resistance under the influence of vibration, and the construction process is complicated, the efficiency is low, and the situations of solder overflow, solder joint depression, solder joint looseness and the like are easy to occur.

The heat release welding is a welding technology widely used in the field of electrical grounding, and is matched with the connection of a heat release welding mold at joints between grounding conductors such as carbon structural steel, copper and the like, so that the heat release welding operation can be carried out only by removing surface moisture from the heat release welding mold and a welded wire material by using gas tank flame. The exothermic welding does not belong to mechanical structure connection and non-contact resistance, the resistance value of the joint is stable, and the conformity to the system is good. However, the rail is usually made of U71Mn pearlite steel, and welded by a conventional exothermic welding process in the field of grounding, and the metallurgical structure at the joint of the cable welded joint and the rail is likely to form martensite and bainite, so that the cable and the rail are difficult to weld, and even if the welding is performed only by force, the fusion depth of the fusion zone between the cable and the rail is less than 1mm, and the connection strength is extremely low.

Disclosure of Invention

The invention aims to provide a heat release welding process for cables and steel rails, which enables the metallographic structure of the joint of the cables and the steel rail parent metal to be pearlite by controlling the temperature difference and the temperature gradient of a welding point, a welding area and a heating area of the cables and the steel rails in the heat release welding process, thereby remarkably improving the connection strength of the cables and the steel rails.

The invention is realized by the following technical scheme:

an exothermic welding process for cables and rails comprising the steps of:

heating the steel rail to a heating area on the steel rail, keeping the heating area warm when the temperature of a welding area is higher than a first temperature, and continuously heating the welding area to a second temperature, wherein the temperature of any point on the steel rail is not higher than 800 ℃;

fixing a heat-releasing welding mould on the heated steel rail, sleeving a sleeve on the end part to be connected of the cable, placing the sleeve into the heat-releasing welding mould for heat-releasing welding, and cooling after heat-releasing welding;

in the cooling process, the steel rail is covered and wrapped by a heat insulation material, and the heat release welding mould is used;

the horizontal distance between any point in the welding area and the welding point is not more than a first distance, and the horizontal distance between any point in the heating area and the welding point is more than the first distance and less than or equal to a second distance.

In the technical scheme, the steel rail is heated before heat release welding. The areas to be heated on the rail include a heating area and a welding area. The welding area is located at a point to be connected between the cable and the steel rail along the extension direction of the steel rail, namely a region on two sides of the welding point, and the horizontal distance between any point in the welding area and the welding point is smaller than or equal to a first distance; the heating area is an area which is positioned at two sides of the welding area along the extending direction of the steel rail, and the horizontal distance between any point in the heating area and the welding point is larger than the first distance but not larger than the second distance. The horizontal distance is that a plane where the welding point is located and perpendicular to the horizontal plane and the extending direction of the steel rail is projected on the horizontal plane to form a projection straight line, any point is projected on the horizontal plane to form a projection point, and the shortest distance from the projection point to the projection straight line is the horizontal distance.

In the technical scheme, in the heating process, the heating area and the welding area of the steel rail are integrally heated to a first temperature, and then the heating area is subjected to heat preservation. The heat preservation mode can adopt any one of the existing heat preservation modes, and preferably, asbestos heat preservation cotton with the thickness of 20-100 mm can be adopted to cover the steel rail of the heating area section. Meanwhile, heating the welding area is continued until the temperature of the welding area reaches the second temperature. Through the intensification to heating region and welding area, heat preservation control, can treat the welded point to the rail fast and heat up near the region on the one hand, and avoid the rail local overheat that the local heating rail caused in the intensification process, temperature gradient is big, cause the condition that the rail is easy brittle failure, and on the other hand, the heating region is little with the temperature difference in welding area, the temperature field is continuous, the holistic temperature variation of rail is little, be favorable to keeping the metallographic structure at track connection position, pearlite promptly, unfavorable metallography such as martensite has been avoided forming. In addition, the temperature of any point on the steel rail is not higher than 800 ℃ in the heating process of the steel rail, otherwise, martensite is easily formed at the joint.

In the technical scheme, any one of the existing exothermic welding dies can be adopted for carrying out exothermic welding on the cable and the steel rail. Specifically, the exothermic welding mold is fixed to the rail. After the end of the cable to be connected to the steel rail is sleeved with the sleeve, the end is placed into a wiring groove and a welding cavity of the heat-releasing welding mold. And opening the die cover, putting the welding flux into the melting cavity, igniting the welding flux and then carrying out heat release welding operation.

In the technical scheme, before the cable is placed into the heat-releasing welding mould, the sleeve is sleeved at the end part of the connecting end of the cable, so that the situation that a plurality of wires of the cable are loose in the welding process and are easily broken due to heat loss in the welding process and an effective joint is difficult to form is avoided. Preferably, the sleeve is made of copper or a copper alloy.

In the technical scheme, the steel rail and the heat-release welding die are cooled after heat-release welding, and in the cooling process, the steel rail and the heat-release welding die are covered and wrapped by adopting a heat-insulating material so as to avoid the steel rail and the heat-release welding die from forming martensite and bainite due to too fast temperature drop. Preferably, the exothermic welding mould, the heating area and the welding area of the steel rail are covered and wrapped by asbestos heat-insulating cotton with the thickness of 20-100 mm. And (4) removing the heat preservation cotton and the heat release welding mould when the highest temperature of the welding area of the steel rail is cooled to be below 200 ℃, and obtaining a finished product connecting joint after removal.

This exothermic welding technology is through the heating region to the rail, welding area's temperature control, not only can avoid the rail overheated, the rail brittle failure that temperature gradient caused greatly, can be faster and keep heating the rail to appointed temperature with reasonable temperature gradient, and the heating region is little with welding area's the difference in temperature, the temperature field is continuous, be favorable to keeping the metallographic structure at the junction of cable and rail to be pearlite, avoid forming unfavorable metallography such as Ma's, thereby the joint strength of cable and rail has been showing to be improved, compare in traditional adoption bolt expansion nail or brazed mechanical connection mode, from the root under the long-term vibration condition solved the joint easily become flexible, corrode, contact resistance grow scheduling problem. In addition, in the cooling process, the steel rail and the heat release die are wrapped and covered, so that the formation of martensite and bainite caused by too fast temperature drop can be avoided, and the joint connection strength is further improved. Moreover, the copper sleeve can avoid the dispersion of the wires of the cable in the heat release welding process, and is favorable for forming an effective joint.

Further, the first distance is 15-25 cm, and the second distance is 80-120 cm. In consideration of the loss of energy consumption and the change of the temperature gradient, the second distance is preferably 4.8 to 5.5 times the first distance. Preferably, the first distance is 15-20 cm, the second distance is 90-105 cm, further preferably, the first distance is 20cm, the second distance is 100cm, namely 40cm is the welding area around the welding point, 200cm is around the welding point, and the area excluding the welding area is the heating area.

Further, the first temperature is 380-420 ℃. Preferably, the first temperature is 395-410 ℃, and further preferably, the first temperature is 398-405 ℃.

Further, the second temperature is 600-800 ℃. Preferably, the second temperature is 750-800 ℃, and further preferably, the second temperature is 790-800 ℃.

In a preferred embodiment of the temperature control of the present invention, the heating rate of the heating region and the welding region to the first temperature is 90 to 110 ℃/min, and the heating rate of the welding region to the second temperature is 15 to 25 ℃/min. Too fast temperature rise easily causes local too high temperature, temperature gradient too big, and too slow temperature rise easily causes the loss of energy. Therefore, in the process of heating the heating area and the welding area to the first temperature, in order to enable the overall temperature of the two areas to quickly reach the specified temperature, the overall heating speed is 90-110 ℃/min, and preferably, the heating is controlled at 100 ℃/min; in the process of heat preservation of the heating area and temperature rise of the welding area, in order to avoid that the temperature of the welding area is too fast to be raised than that of the heating area so as to form a large temperature difference between the two areas, the temperature rise speed of the second temperature is 15-25 ℃/min, and preferably, the temperature rise is controlled to be 20 ℃/min.

Further, the lateral surface of the sleeve comprises an abutting surface for abutting to the surface of the steel rail. The lateral wall of the sleeve comprises a section of attaching surface which is used for attaching to the surface of the steel rail so as to avoid the overflow of molten metal from the contact surface of the cable and the steel rail in the heat release welding process and be more beneficial to forming an effective joint. Simultaneously, when using the exothermic welding mould of integrated into one piece, because of exothermic welding mould hole is arc, will wrap up 70% of the surface area of sleeve pipe, difficult drawing of patterns in the welding mould of following after the welding, set up one section binding face with the lateral wall of copper sheathing after, because the binding face need with rail surface laminating, consequently mostly be the plane or be close to the plane, reduced exothermic welding mould dissolving hole to sheathed tube parcel, more be favorable to the postwelding drawing of patterns.

As a preferable structure of the sleeve, an inclined plane is arranged on the end face of the sleeve, and the angle of the inclined plane is 30-60 degrees. When the exothermic welding mould is used for welding, because the metal solution in the melting material cavity generally flows into the welding cavity and the wiring groove from top to bottom, the upper side of the sleeve sleeved on the cable generally melts first, so that the consistency of the fusion depth of the top and the bottom of the welding joint is poor, the fusion depth of the top area on the steel rail is generally about 5 times that of the bottom area on the steel rail, and the connection strength is low. For solving this problem, process out a 30 ~ 60 inclined planes at sheathed tube terminal surface, at exothermic welding in-process, the sheathed tube minor face is last, aims at the discharge gate in melting material chamber, and sheathed tube long limit is down to when making high temperature solution from the top down flow, more high temperature melts and flows along the inclined plane downwards, make the fusion district degree of depth of whole solder joint more balanced, thereby improve joint strength. Preferably, the angle of the inclined plane is 40-50 degrees, and further preferably, the angle of the inclined plane is 40 degrees.

As another preferred structure of the bushing in the present invention, the bushing includes a first tube, and a second tube drivingly connected to the first tube, the second tube includes an outer tube and an inner tube located inside the outer tube, and the inner tube is used for accommodating a plurality of wires of a cable; the connecting column is connected on the outer pipe and the inner pipe, the first lug is arranged on the outer pipe, the second lug is arranged on the inner pipe, and the first lug rotates and passes through the second lug to push the second lug to move towards the center of the inner pipe.

In this technical scheme, the sleeve pipe includes first pipe and second pipe, has seted up the accommodation hole on the first pipe in order to be used for putting into the second pipe. The first pipe is in transmission connection with the second pipe, and the second pipe can be driven to rotate synchronously by rotating the first pipe. In one or more embodiments, the first and second tubes are drivingly connected by meshing of the drive teeth.

The second tube includes an outer tube and an inner tube for receiving the ends of a plurality of wires that make up the cable to prevent the wires of the cable from loosening during the exothermic welding process. The outside cover of inner tube is equipped with the outer tube, and is connected with the spliced pole between interior, the outer tube to make the inner tube can be along with outer tube synchronous revolution.

The outer pipe is also provided with a first lug, and the inner pipe is provided with a second lug. When the connecting column is not broken, the inner tube and the outer tube move synchronously, so that the first lug and the second lug are relatively static. When the spliced pole is broken, the outer tube can rotate for the inner tube, and at the rotation in-process, first lug rotates through the second lug, and promotes the second lug moves towards the inner tube center. Preferably, the first bump and the second bump are hemispheroids, and the sum of the radii of the first bump and the second bump is larger than the width of the gap between the inner tube and the outer tube.

When the sleeve is sleeved, firstly, the end parts of the wires of the cable are all plugged into the inner tube, then the first tube is rotated, the outer tube is driven by the first tube to synchronously rotate and the inner tube is driven by the connecting column to synchronously rotate, the inner tube further drives the wires inside to rotate, gaps among the wires are gradually reduced in the rotating process, the end parts of the cable are more compact, meanwhile, the wires apply reaction force to the inner tube, so that the rotation of the inner tube is blocked, and the first lug and the second lug are not contacted in the rotating process; when continuing to exert the turning force to first pipe, but the inner tube is difficult to when further rotatory, spliced pole atress fracture between inner tube and the outer tube, after the spliced pole fracture, exert the force on the outer tube again and make the outer tube rotate for the inner tube rapidly, first lug strikes the second lug, because the outer tube is supported by first pipe, be difficult to produce deformation, consequently under the impact of first lug again, the second lug moves to the inner tube center, drive the local area on the inner tube of being connected with the second lug and press to the wire, make the inner wall of inner tube play the effect of the wire after stabilizing the compactness, it is loose once more to avoid the wire after external force removes.

In the technical scheme, the structure of the sleeve is optimized, the end part of the wire of the cable can be quickly screwed while the sleeve is installed, the phenomenon that a single wire is broken due to heat loss in the heat release welding process is avoided, meanwhile, gaps among the screwed wires are greatly reduced, metal solution passing through the gaps of the wires is reduced, and the connection strength is further improved; in addition, the arrangement of the connecting column can prevent the lead from being worn and damaged due to over-tightening when the lead rotates by experience, and the lug can push the inner tube to rapidly extrude the lead after the connecting column is broken, so that the fixing capacity of the screwed lead is effectively improved.

Furthermore, an accommodating hole for accommodating the second pipe is formed in the first pipe, first teeth are arranged on the inner wall of the accommodating hole, and second teeth meshed with the first teeth are arranged on the outer pipe. Preferably, the first and second teeth are unidirectional meshing drive teeth, such that the first tube can be driven by the second tube when rotated in only one direction, e.g. clockwise, and the second tube is unaffected by the first tube when rotated in the opposite direction, e.g. counter-clockwise.

Furthermore, a plurality of anti-skidding teeth are arranged on the inner wall of the inner pipe and are uniformly distributed along the circumferential direction of the inner wall of the inner pipe. The anti-slip teeth uniformly distributed along the inner wall of the inner pipe can be inserted into gaps among the wires at the edge in the process of screwing the wires, so that the inner wall can better drive the cable to integrally rotate. More importantly, when the second lug is pressed towards the center of the inner pipe by the pressure of the first lug, the evenly distributed anti-skid teeth can be further embedded into the gaps of the wires on the outer wall of the cable, and the inner pipe is easier to be locally sunken, for example, the anti-skid teeth are more inclined to be sunken towards the places with thinner thickness between the adjacent anti-skid teeth.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. according to the invention, through temperature control of the heating area and the welding area of the steel rail, the steel rail brittle fracture caused by overheating and large temperature gradient of the steel rail can be avoided, the steel rail can be heated to a specified temperature more quickly and with a reasonable temperature gradient, the temperature difference between the heating area and the welding area is small, the temperature field is continuous, the metallographic structure at the joint of the cable and the steel rail is kept as pearlite, and unfavorable metallographic structures such as Ma's are avoided, so that the connection strength of the cable and the steel rail is remarkably improved;

2. in the cooling process, the steel rail and the heat release die are wrapped and covered, so that the formation of martensite and bainite caused by too fast temperature drop can be avoided, and the joint connection strength is further improved;

3. in the process of heat preservation of the heating area and temperature rise of the welding area, the problems of local overhigh temperature, overlarge temperature gradient and energy loss easily caused by overhigh temperature rise and overlow temperature rise can be solved by adjusting the temperature rise speeds of the heating area to the first temperature and the second temperature;

4. the copper sleeve can prevent the wires of the cable from scattering in the heat release welding process, and is beneficial to forming an effective joint, the side wall of the sleeve is provided with a section of binding surface, so that the overflow of molten metal from the contact surface of the cable and the steel rail in the heat release welding process can be effectively reduced, and the inclined surface is arranged on the end surface of the sleeve, so that when a high-temperature solution flows from top to bottom, more high-temperature melt flows downwards along the inclined surface, the depth of a fusion area of the whole welding spot is more balanced, and the connection strength is improved;

5. the structure of the sleeve is optimized, the end parts of the wires of the cable can be quickly screwed while the sleeve is installed, the phenomenon that a single wire is broken due to heat loss in the heat release welding process is avoided, meanwhile, gaps among the screwed wires are greatly reduced, metal solution passing through the gaps of the wires is reduced, and the connection strength is further improved; in addition, the arrangement of the connecting column can prevent the lead from being worn and damaged due to over-tightening when the lead rotates by experience, and the lug can push the inner tube to rapidly extrude the lead after the connecting column is broken, so that the fixing capacity of the screwed lead is effectively improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a block flow diagram of an exothermic welding process in an embodiment of the present invention;

FIG. 2 is a schematic illustration of a rail and weld, weld zone, and hot zone in an embodiment of the present invention;

FIG. 3 is a schematic diagram of a jacketed cable according to an embodiment of the present invention;

FIG. 4 is a schematic view of the abutment surface of the sleeve engaging the rail according to the embodiment of the present invention;

FIG. 5 is a schematic view of the structure of the sleeve in the embodiment of the present invention;

FIG. 6 is a schematic view of the inner tube of the second tube of the bushing in an embodiment of the present invention;

FIG. 7 shows the metallographic structure of the rail at the weld according to the embodiment of the present invention.

Reference numbers and corresponding part names in the drawings:

1-cable, 11-lead, 2-sleeve, 21-first tube, 211-first tooth, 22-outer tube, 222-second tooth, 23-inner tube, 231-anti-slip tooth, 24-connecting column, 25-first lug, 26-second lug, 27-binding face, 28-inclined face;

30-rail, 31-weld, 32-weld zone, 33-heat zone.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

In the description of the present invention, it is to be understood that the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore, should not be taken as limiting the scope of the invention.

Example 1:

an exothermic welding process for cables and rails as shown in fig. 1 to 3, comprising the steps of:

heating the steel rail 30 to a heating area 33 on the steel rail 30 and a welding area 32 when the temperature is higher than a first temperature, preserving the heat of the heating area 33, and continuously heating the welding area 32 to a second temperature, wherein the temperature of any point on the steel rail 30 is not higher than 800 ℃;

fixing a heat-releasing welding mould on the heated steel rail 30, sleeving the sleeve 2 on the end part to be connected of the cable 1, putting the cable into the heat-releasing welding mould for heat-releasing welding, and cooling after heat-releasing welding;

in the cooling process, the steel rail 33 and the heat release welding mould are covered and wrapped by adopting a heat insulation material;

in the extending direction of the steel rail 30, the horizontal distance between any point in the welding area 32 and the welding point is not greater than a first distance, and the horizontal distance between any point in the heating area 33 and the welding point is greater than the first distance and is less than or equal to a second distance.

As shown in fig. 2, the welding area 32 is a region on both sides of the welding point 31 of the cable and the rail 30, the shortest distance between the boundary of the region and the welding point 31 is a first distance, similarly, the heating area 33 is a region on both sides of the welding area 32, the shortest distance between the boundary of the heating area 33 close to the welding point 31 and the welding point 31 is a first distance, and the shortest distance between the boundary of the heating area 33 far from the welding point 31 and the welding point 31 is a second distance.

In one or more embodiments, before heating the steel rail, the surface of the steel rail is polished to clean a rust and carburized layer, and the thickness of the carburized layer of the steel rail is about 0.1-0.5 mm. Through the carburization layer of polishing off the rail surface, rather than only rust, be favorable to further improving the joint strength of the tie point of cable and rail.

In one or more embodiments, the exothermic welding mold is heated to 150-200 ℃ prior to securing the exothermic welding mold to the rail. In some preferred embodiments, when the flux is ignited, the welding cavity position of the heat-release welding mould and the waist area opposite to the steel rail plane where the welding point is located are immediately heated, the flame outer flame temperature is controlled within 800 ℃, so that the metal of the welding joint is crystallized and compacted, and the steel rail is slowly cooled after crystallization, so that martensite and bainite are avoided.

In one or more embodiments, before the exothermic welding, the end sleeve of the welded cable is heated, wherein the heating temperature is 200-300 ℃.

In this embodiment, through the heating region to the rail, weld zone's temperature control, not only can avoid the rail overheated, the rail brittle failure that temperature gradient caused greatly, can be faster and keep heating the rail to appointed temperature with reasonable temperature gradient, and the heating region is little with weld zone's difference in temperature, the temperature field is continuous, be favorable to keeping the metallographic structure to be pearlite in the junction of cable and rail, avoid forming unfavorable metallography such as madrid, thereby the joint strength of cable and rail has been showing to be improved, compare in traditional adoption bolt nail expansion or brazed mechanical connection mode, the easy not hard up of joint under the long-term vibration condition has been solved from the root, corrode, contact resistance grow scheduling problem.

In some embodiments, the first distance is 15-25 cm, and the second distance is 80-120 cm.

In some embodiments, the first temperature is 380-420 ℃.

In some embodiments, the second temperature is 600-800 ℃.

In some preferred embodiments, the heating rate of the heating area 33 and the welding area 32 to the first temperature is 90 to 110 ℃/min, and the heating rate of the welding area 32 to the second temperature is 15 to 25 ℃/min.

According to a detection report (report number: JCBG (01)220504018) issued by the State Metal product quality supervision and inspection center according to GB/T13298-2015 Metal microstructure verification method, the metallographic structure of the detected steel rail at the welding position is shown in figure 7, and the detection result is pearlite and no martensite, thereby meeting the technical requirements.

Example 2:

on the basis of example 1, as shown in fig. 3 and 4, the lateral surface of the sleeve 2 includes an abutting surface 27, and the abutting surface 27 is used for abutting against the surface of the steel rail 30. The design of the abutting surface 27 can prevent molten metal from overflowing from the contact surface of the cable and the steel rail during the heat release welding process, and is more beneficial to forming an effective joint. In addition, because the binding face needs to be bound with the surface of the steel rail, the binding face is mostly a plane or a plane close to the plane, the package of a dissolving hole of the heat-release welding mould on the sleeve is reduced, and the demoulding after the welding is more facilitated. In one or more embodiments, the cross section of the sleeve is semicircular or D-shaped, and a plane where a straight side of the semicircular or D-shaped is located serves as an abutting surface.

In a partially preferred embodiment, a bevel 28 is provided on the end face of the sleeve 2, and the angle of the bevel 28 is 30-60 °.

In the exothermic welding process, the sheathed tube minor face is last, aims at the discharge gate in melting material chamber, and sheathed tube long limit is under to when making high temperature solution from the top flow down, more high temperature melts and flows along the inclined plane downwards, makes the fusion district degree of depth of whole solder joint more balanced, thereby improves joint strength. Preferably, the angle of the inclined plane is 40-50 degrees, and further preferably, the angle of the inclined plane is 40 degrees.

Example 3:

on the basis of the above embodiment, as shown in fig. 5 and 6, the sleeve 2 includes a first tube 21, and a second tube drivingly connected to the first tube 21, the second tube includes an outer tube 22 and an inner tube 23 located inside the outer tube 22, and the inner tube 23 is used for accommodating the plurality of wires 11 of the cable 1; a connecting column 24 connected to the outer tube 22 and the inner tube 23, a first lug 25 arranged on the outer tube 22, and a second lug 26 arranged on the inner tube 23 are arranged between the outer tube 22 and the inner tube 23, and the first lug 25 rotates and passes through the second lug 26 to push the second lug 26 to move towards the center of the inner tube 23.

When the sleeve is sleeved, firstly, the end parts of the wires of the cable are all plugged into the inner tube, then the first tube is rotated, the outer tube is driven by the first tube to synchronously rotate and the inner tube is driven by the connecting column to synchronously rotate, the inner tube further drives the wires inside to rotate, gaps among the wires are gradually reduced in the rotating process, the end parts of the cable are more compact, meanwhile, the wires apply reaction force to the inner tube, so that the rotation of the inner tube is blocked, and the first lug and the second lug are not contacted in the rotating process; when the rotating force is continuously applied to the first pipe, but the inner pipe is difficult to further rotate, the connecting column between the inner pipe and the outer pipe is broken under stress, after the connecting column is broken, the force applied to the outer pipe enables the outer pipe to rapidly rotate relative to the inner pipe, the first lug impacts the second lug, and the outer pipe is supported by the first pipe and is difficult to deform, so that under the impact of the first lug, the second lug moves towards the center of the inner pipe to drive a local area on the inner pipe connected with the second lug to press towards the wire, so that the inner wall of the inner pipe plays a role in stabilizing and compacting the wire, and the wire is prevented from being loosened again after the external force is removed.

In one or more embodiments, the tightness of the wires can be controlled by adjusting the strength, number, and mounting location of the connecting posts.

In some embodiments, the first tube 21 has a receiving hole for receiving the second tube, the inner wall of the receiving hole has a first tooth 211, and the outer tube 22 has a second tooth 222 engaged with the first tooth 211.

Preferably, the first and second teeth are unidirectional meshing drive teeth, such that the first tube can be driven by the second tube when rotated in only one direction, e.g. clockwise, and the second tube is unaffected by the first tube when rotated in the opposite direction, e.g. counter-clockwise.

In some embodiments, a plurality of anti-slip teeth 231 are disposed on the inner wall of the inner tube 23, and the anti-slip teeth 231 are uniformly distributed along the circumferential direction of the inner wall of the inner tube 23.

When the second lug is pressed towards the center of the inner pipe by the pressure of the first lug, the evenly distributed anti-skid teeth not only can be further embedded into the gaps of the wires on the outer wall of the cable, but also the inner pipe is easier to be locally sunken, for example, the anti-skid teeth are more inclined to be sunken towards the places between the adjacent anti-skid teeth, wherein the thickness of the anti-skid teeth is thinner.

As used herein, "first," "second," etc. (e.g., first tube, second tube, first tooth, second tooth, etc.) merely distinguish the respective components for clarity of description and are not intended to limit any order or to emphasize importance, etc. Further, the term "connected" used herein may be either directly connected or indirectly connected via other components without being particularly described.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. An exothermic welding process for cables and rails, comprising the steps of:

heating the steel rail (30) to a heating area (33) on the steel rail (30), keeping the temperature of a welding area (32) higher than a first temperature, keeping the heating area (33) warm, and continuing to heat the welding area (32) to a second temperature, wherein the temperature of any point on the steel rail (30) is not higher than 800 ℃;

fixing a heat-release welding mould on the heated steel rail (30), sleeving a sleeve (2) on the end part to be connected of the cable (1), placing the sleeve into the heat-release welding mould for heat-release welding, and cooling after the heat-release welding;

in the cooling process, the steel rail (33) and the exothermic welding mould are covered and wrapped by adopting a heat-insulating material;

wherein, along the extending direction of the steel rail (30), the horizontal distance between any point in the welding area (32) and the welding point is not more than a first distance, and the horizontal distance between any point in the heating area (33) and the welding point is more than the first distance and is not more than a second distance.

2. An exothermic welding process for cables and steel rails according to claim 1, wherein the first distance is 15 to 25cm and the second distance is 80 to 120 cm.

3. An exothermic welding process for cables and steel rails according to claim 1, wherein the first temperature is 380 to 420 ℃.

4. An exothermic welding process for cables and rails according to claim 1, wherein the second temperature is 600 to 800 ℃.

5. The exothermic welding process for cables and steel rails according to any one of claims 2 to 4, wherein the heating speed of the heating zone (33) and the welding zone (32) to the first temperature is 90 to 110 ℃/min, and the heating speed of the welding zone (32) to the second temperature is 15 to 25 ℃/min.

6. An exothermic welding process for cables and rails according to claim 1, characterized in that the lateral surface of the sleeve (2) comprises an abutment surface (27), the abutment surface (27) being intended to be applied to the surface of the rail (30).

7. An exothermic welding process for cables and steel rails according to claim 6, characterized in that the end face of the sleeve (2) is provided with a bevel (28), and the angle of the bevel (28) is 30-60 °.

8. An exothermic welding process for cables and steel rails according to claim 6, characterized in that the sleeve (2) comprises a first tube (21) and a second tube drivingly connected in the first tube (21), the second tube comprising an outer tube (22) and an inner tube (23) located inside the outer tube (22), the inner tube (23) being internally adapted to house the conductors (11) of the cable (1);

be provided with between outer tube (22) and inner tube (23) and connect spliced pole (24), first lug (25) of setting on outer tube (22) and setting on inner tube (23) and second lug (26) of setting on inner tube (23) on outer tube (22), first lug (25) rotate and pass can promote during second lug (26) move towards the center of inner tube (23).

9. The exothermic welding process for cables and steel rails according to claim 8, wherein the first tube (21) is provided with a receiving hole for receiving the second tube, the inner wall of the receiving hole is provided with first teeth (211), and the outer tube (22) is provided with second teeth (222) engaged with the first teeth (211).

10. An exothermic welding process for cables and steel rails according to claim 8, wherein the inner wall of the inner tube (23) is provided with a plurality of anti-slip teeth (231), and the anti-slip teeth (231) are uniformly distributed along the circumferential direction of the inner wall of the inner tube (23).

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