The object of the present invention is to provide a kind of employing CrMnNiMo series austenite---the ferrite dual phase steel is as dielectric material, with the glisten method of welding of high manganese steel frog and carbon steel rail.This method is saved the energy, and is with short production cycle, automaticity height, production efficiency height.
This high manganese steel frog and carbon steel rail add medium flash welding method, it is characterized in that: employing CrMnNiMo series austenite---the ferrite dual phase steel is as dielectric material, and its technical process is: (1) carbon steel rail is preheating to 200-600 ℃; (2) medium is butt welded to the carbon steel rail flash; (3) welding point is incubated 10-30 minute stress relief annealing between 800-900 ℃; (4) medium is cut stayed 20-40mm length; (5) cut and stay medium and high manganese steel frog flash of light welding; Carbon steel rail weld preheating optimum temperature is 400 ℃, and dielectric material composition (weight %) is: C :≤0.1, Cr:18-20, Mn:4-6, Ni:6-8, Mo:2-3, S+P≤0.04, and all the other are iron; Ferritic content (weight %) is about 10% in the dual phase steel: during the flash of light welding, and flashing speed 〉=3mm/s, upset speed 〉=100mm/s, upset pressure 〉=70Mpa; Each material extension elongation equates during welding.
High manganese steel frog and high carbon steel rail are welded together, have certain degree of difficulty selecting for use on dielectric material and the production technology.Because rail steel requires slow cooling in welding process, to prevent occurring martensite and the bigger thermal stress of generation in the heat affected area, and potassium steel in welding process in the heat affected area very easily along the austenite grain boundary carbide precipitate with the grain growth phenomenon takes place, this all can cause the strong attenuation of its performance, therefore, require after the potassium steel welding cold as quickly as possible.In addition, the coefficient of thermal expansion of two kinds of materials differs bigger, directly will produce very big internal stress at the welding point place after the welding, and it not only reduces the intensity and the toughness of welding point, and reduces its fatigue life.
The invention reside in and utilize dielectric material that two kinds of diverse high manganese steel frogs of welding performance and carbon steel rail welding are arrived together.Its basic principle is that dielectric material is a kind of austenite-ferrite dual phase steel, and it is subjected to be difficult in the thermal process that grain growth takes place and carbide is separated out phenomenon follow-up, and physical properties such as its linear expansion coefficient, fusing point, thermal conductivity factor are suitable with potassium steel simultaneously.Fusing point and the heat-transfer rate of considering medium are all low than carbon steel, for guaranteeing the abundant of welding point fusion, earlier the carbon steel rail are preheated to 200-600 ℃, then welding.Because the physical property of dielectric material and carbon steel differs bigger, the welding point interior welds stress of this moment is bigger, and this will seriously reduce the mechanical property of joint, therefore, carry out the high temperature, short time stress relief annealing to it.Yet can effectively postpone the Alloy Elements Mo that carbide forms owing to contain in the medium, therefore be subjected to (comprising flash of light welding and stress relief annealing) in the thermal process at follow-up high temperature, short time, it is organized and still is the austenite of small grains-ferrite duplex structure.Because the physical property of dielectric material and potassium steel is very approaching, so after medium and high manganese steel frog welding, the welding stress of welding point inside is less relatively.In addition, because the flash of light speed of welding is very high, hot input quantity in welding process in the welding point heat affected area is less, the cooling velocity of postwelding joint is very fast, therefore, the postwelding joint cools off in air, can guarantee that carbides-free is separated out in the potassium steel heat affected area, thereby makes whole welding joints have excellent mechanics and serviceability.
The present invention has taken into full account the essential distinction of two kinds of material physical properties, before welding, carbon steel is carried out preheating, improved the welding effect of two kinds of materials greatly, and postwelding only needs to carry out stress relief annealing in 10-30 minute 800-900 ℃ of insulation to welding point, just can guarantee the mechanical property and the serviceability of welding point, shorten process cycle, improved production efficiency.In addition, what the present invention adopted is austenite-ferrite dual phase steel, wherein contain the elements Mo of strengthening matrix, the more single-phase austenite of this material has higher intensity and work hardening capacity, therefore the dual phase steel welding medium is when reality is used, and can not go out phenomenon when the austenite welding medium is long slightly and the phenomenon of wearing and tearing too early in the welding medium position that produces.
The flash butt welding that the present invention utilized belongs to the high temperature solid-state welding.By extruding force metallic atom is engaged one another in the solid-state temperature scope and form joint.In order to realize welding requirements, must remove the oxide-film and the Pingdu that improves contact-making surface on surface to weldment, achieve the goal by bigger plastic deformation.Because the dielectric material that adopts is to contain the higher austenite of Cr, Mn, Ni and Mo-ferrite dual phase steel here, this steel have elevated temperature strength height, conduction and poor thermal conductivity, fusing point low, again a large amount of alloying elements that easily form refractory oxides are arranged, therefore, when flash butt welding, requirement has big upset pressure, high flash of light and upset speed.Flashing speed 〉=3mm/s, upset speed 〉=100mm/s, upset pressure 〉=70Mpa.
Because selected dielectric material is the austenite-ferrite dual phase steel that contains Mo among the present invention, Mo can postpone separating out the time of carbide in the austenite-ferrite steel, make medium in welding and follow-up short time high temperature stress relief annealing process, be unlikely to have carbide to be separated out, it can make medium have higher intensity and work hardening ability simultaneously.
The high manganese steel frog and the carbon steel rail welding part that utilize the present invention to prepare, the chemical composition of potassium steel is generally C:1.1-1.4, Mn:11-14, all the other are Fe and small amount of impurities, the chemical analysis of carbon steel rail is generally C:0.6-0.8, Mn:0.6-1.5, all the other are Fe and small amount of impurities, the tensile strength of welding point reaches more than the 650Mpa, each regional impact flexibility numerical value is all higher, the whole quiet curved value of rail is for being that amount of deflection reached more than the 22mm when quiet curved load was 100T under 1 meter the condition in span, and counter-bending fatigue strength reaches more than the 250MPa.These performance indications can both satisfy the performance requirement of actual railway transportation to high manganese steel frog and carbon steel rail welding structure.