What is the seamless welding of rails?

welding technology of jointless track \xd\ I. thermite welding technology of rail: \xd\ (I) thermite welding technology of rail in France QPCJ: \xd\ 1. thermite welding technology of rail in France QPCJ in China: \ xd \ thermite welding technology of rail and rapid preheating (qp)+disposable crucible (CJ) welding. \xd\ Because this welding technology has many advantages such as stable welding quality, safety and reliability, simple equipment, quickness and convenience, and less interference from human factors, it has been widely used in laying inter-section seamless lines and inter-section seamless lines by the public works departments of various railway bureaus in recent years, and its remarkable safety and economic effects are widely welcomed by various railway bureaus. In addition, this welding technology is also widely used in track breaking, in-situ repair of broken joints, turnout welding and other work. \xd\ The rail thermite welding technology of RAILTECH Company in France has been widely used in TGV high-speed railway and ordinary railway in France and many other countries. In particular, its disposable crucible process is the first in the world and has been patented; Because the disposable crucible does not need to be cleaned and dried, it is very beneficial to purify steel, reduce inclusion rate and improve welding head quality. In addition, the discarded disposable crucible after use can be completely naturally biodegraded and will not cause any adverse impact on the ecological environment. \xd\ 2. The advantages of QPCJ rail thermite welding process of RAILTECH Company in France are \xd\ (1) Economical and time-saving: \ xd \ The equipment is simple, easy to carry and easy to operate when welding on site. \xd\ (2) High-quality and beautiful welding head: \xd\ The perfect metallurgical structure after thermite welding ensures that the micromechanical characteristic curve reaches the highest isotropic performance. More stable residual components and vitrification of shunt plug greatly reduce the metal inclusions in the welding head. \xd\ (3) High stability and consistency: \xd\ QPCJ The special thermal isolation structure of rail thermit welding process can provide high stability and consistency of thermal balance. Special flux and stable pouring temperature ensure the high quality of welding. \ xd \ 3. Thirteen steps of QPCJ rail thermite welding process: \xd\ (1) Preparation before going to the welding site; (2) Preparation at the welding site; \xd\ (3) Preparation of orbit; (4) Preparation of rail end; \xd\ (5) Alignment of rail ends; (6) preparation of sand mold; \xd\ (7) preheating; (8) Preparation of welding charge; \xd\ (9) pouring; (1) form removal and tumor pushing; \xd\ (11) Hot grinding; (12) cold grinding; \xd\ (13) Finishing work. \xd\ 4. Welding data sheet: \xd\ China welding data sheet \xd\ rail specification welding \xd\ width preheating gun head height pressure (KPa) preheating time demoulding \xd\ time pushing \xd\ time cusp height \ xd \ Oxygen propane \xd\ S527 2 mm 4 mm 49 74 minutes (rail head temperature 65 ~ 8℃) 5 minutes 6.5 minutes 1.6 mm\xd\ S627 2 mm 4 mm 49 74 minutes (rail head temperature 65 ~ 8℃) 5 minutes 6.5 minutes 1.6 mm\xd\ Remarks: This table is only applicable to the welding construction of special materials and equipment for QPCJ rail thermite welding process. \xd\ \xd\ (II) THERMIT's thermite welding technology for rails: \xd\ 1. Introduction: \ xd \ Germany Schmidt is an internationally renowned railway equipment supplier with a history of more than 1 years. Its main products include thermite welding agent and auxiliary equipment for rails, MT bonded insulation joints, frozen joints, etc., which are exported to more than 4 countries in the world. \xd\ Schmidt thermite welding process includes SMW-F side casting welding, SKV-F short preheating welding, SMW-F and SKV-F special-shaped rail welding, SKV-L wide seam welding, fishplate welding and rail head repair welding. \ xd \ 2. SKV-F welding process: \xd\(1) placing sealing mud pad; (2) Universal clamping assembly; \xd\(3) Preheater gun head adjustment; (4) sand mold installation; \xd\(5) Install sandpaper sheets; (6) plastering the box mud; \xd\(7) hang ash tray; (8) Rail cover; \xd\(9) Filling flux; (1) preheating; \xd\(11) Place the shunt plug; (12) ignite the flux; \xd\(13) molten steel casting; (14) removing the crucible; \xd\(15) Dismantle the sand mold; (16) pushing tumor; \xd\(17) Hot grinding; (18) cold grinding; \xd\(19) Final finishing. \xd\ 3. SKV-L wide seam welding process: \ xd \ Except for the following contents, the other processes are the same as above. \xd\(1) Rail alignment: including cusp adjustment and horizontal alignment; \xd\(2) Dismantling the sand mold: 7-9 minutes after casting is completed. \xd\ 4. welding data sheet: \xd\ welding data sheet for China (using PD3 and U71Mn flux) \xd\ rail specification welding \xd\ width preheating gun head height air pressure (KPa) preheating time demoulding \xd\ time deburring \ xd \ Time cusp height \xd\ oxygen propane \xd\ S53 1 mm 4 mm 3 1 5 minutes (rail head temperature 65 ~ 8℃) 4.5 minutes 6.5 minutes 1.5 ~ 2mm \ xd \ S63 1 mm 4 mm 3 1 5 minutes (rail head temperature 65 ~ 8℃) 4.5 minutes 6.5 minutes 1.5 ~ 2mm \ xd \ Remarks: This table is only applicable to the welding construction of special materials and equipment using Schmidt thermite welding process.