Induction heater and method for realizing non-preheating cladding of alloy on steel rail by using same

Abstract

The invention discloses an induction heater which comprises a heating zone 1 and a heating zone 2, wherein the heating zone 1 is divided into two heating surfaces; a first heating surface is shaped like a trapezoid without the bottom; a second heating surface is a U-shaped one; the two lateral sides of the trapezoid-shaped heating surface are connected with the U-shaped heating surface; and an included angle is formed between the first heating surface and the second heating surface. When the induction heater is used to perform alloy cladding on a steel rail, preheating does not need to be performed in advance, so that on the premise of the same steel rail cladding speed, heat energy required by the method is only one third or less of the prior art; and meanwhile, the method lays a foundation for miniaturization of a generator or even construction without the aid of a rail car. By performing detailed analysis on structure phase change and heat transmission of a steel rail in the cladding process, the invention breaks through the theory that the steel rail must be preheated prior to welding for the first time, and presents that the steel rail can be directly subjected to alloy cladding without being preheated while generation of martensite can be avoided. The technology disclosed by the invention is put forward for the first time at home and abroad.

Description

technical field [0001] The invention belongs to the field of metal material high-carbon steel surface cladding and railway track circuit signal control. Background technique [0002] In the bad section of the railway track circuit (or called "undead" or "white belt" section), a layer of anti-rust and wear-resistant alloy is clad on the surface of the rail by plasma cladding, which can effectively eliminate the bad track circuit shunt Phenomenon. However, during the cladding process, the temperature of the cladding area on the surface of the rail is very high, and it is in a molten state, and the matrix structure whose temperature in the heat-affected zone under the cladding area exceeds the phase transition temperature will undergo phase transformation. Theoretically, when the rail cools down, when the cooling rate exceeds the CCT curve range of the rail material, the rail will produce a martensite structure. Martensite is a hard and brittle structure, which greatly re...

AI Technical Summary

Problems solved by technology

Although only the part to be clad on the surface of the rail is heated, during the heating process, the heat inside the rail is continuously and rapidly transferred, and the heated area increases, which wastes a lot of heat energy

[0009] 3) Due to the increase of the temperature of the rail itself, during cladding, the range where the temperature of the heat-affected zone of the rail exceeds the phase transition temperature increases, the area for controlling the cooling rate increases, and heat energy is consumed

[0012] 2. Due to the need to ensure the preheating temperature of the rail, the moving speed of the sensor and the plasma torch should not be too fast, resulting in low cladding speed, long time and low efficiency

The bad cladding construction of the railway track branch is a three-level construction. During the construction, the section is closed, so it is impossible to give too much construction time. For the long bad branch section, the existing method cannot be constructed

[0013] 3. The rail absorbs a lot of heat energy, the thermal stress of the rail is large, and the deformation of the rail increases

[0014] 4. Most of the bad sections of the railway branch are on both sides of the station, about 700-800m away from the station, and there are generally no roads near the section

Because there are many strict regulations and many procedures to be followed in the use of railcars, it brings many difficulties to the construction

[0015] 5. The cladding zone is located in the center of the rail head surface, and the ultrasonic flaw detection probe is just on the cladding zone, which affects the normal flaw detection of the works

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