Manual Arc Welding of Heavy Crane Rails
There are usually four types of crane rails, namely square steel crane rail, railway rails, heavy rails and special rails. At present, heavy duty rails are mostly used in domestic heavy duty units. Non-integral orbits has great drawbacks in actual application. Glory Steel could offer square steel crane rail for crane manufacturers. When the walking wheel crosses the rail joint, the wheel will impact the end of the rail, which will generate large impact force, causing the end of the rail to collapse within 40mm to 60mm, gradually forming concaves with different sizes, increasing the impact force of crane group wheels. The impact force will accelerate the crushing damage at the end of the rail, make the orbital force worse, accelerate the wear of the wheel, and generate impact load when the crane wheel passes through it, which will cause adverse effects in the bearing of the main beam and make the cracking of between the beam and the reinforcing plate. Therefore, it is of great practical significance to realize the overall rail of heavy cranes by welding method. The weldability mainly depends on the content of carbon and manganese. As the carbon content increases, the weldability gradually deteriorates. The influence of manganese and silicon in carbon steel can be converted into the equivalent of how much carbon content.
Preventing cracks is the key to rail welding. The rail joint is designed to make sure the surface of the weld has sufficient hardness, the wear resistance is not lower than the body, and the interior has good toughness. Preheating should be carried out before rail welding. The preheating range is between 100mm and 200mm at both ends of the welding section, and the preheating temperature is 350°C. The minimum temperature during the welding process shall not be lower than 350°C. If it is lower than 350°C, it needs to be heated again. In order to prevent the temperature from being uneven during the preheating, which is easy to cause temperature unevenness and affect the welding quality, the aluminum silicate insulation felt, the steel plate and the far-infrared heating piece are used to form a box heater for heating to ensure uniform temperature on both sides of the joint. After the rail joint pad is placed and the welding temperature is reached, the welding sequence is from bottom to top, in accordance with the rail bottom, the rail belly, and the upper section of the rail, and the surrounding is repaired. During the welding process, the following points should be noted. We should clean up in time after each welding. Whether the deslagging is thorough will directly affect the quality of the weld joint of the rail joints. Each layer of the weld must be visually inspected and flaws should be repaired in time. The temperature of the rail joint should be measured at any time. When the temperature is lower than 350 °C, the welding should be stopped, and the joint weld bead must be reheated to 350 °C before welding. Tooling fixtures are used to control rail deformation. When the rail belly is welded, we should pay attention to the angle contraction. If necessary, tooling tool for anti-deformation can be gradually removed. The weld is to be inspected for coloring, the weld is required to be uniform, and there should be no defects such as cracks, slag inclusions, and fusion. Surface hardness HB≥240.
The method of welding the rail butt by manual arc welding has achieved very good results through practical application, which can ensure the quality of the rail joint and the surface hardness meets the requirements for use. Moreover, the process equipment is simple, the cost is low, the certain economic benefits are obtained, and the welding of the seamless track of the heavy crane is realized, which has the value of being promoted and used in the crane manufacturing industry.
There are usually four types of crane rails, namely square steel crane rail, railway rails, heavy rails and special rails. At present, heavy duty rails are mostly used in domestic heavy duty units. Non-integral orbits has great drawbacks in actual application. Glory Steel could offer square steel crane rail for crane manufacturers. When the walking wheel crosses the rail joint, the wheel will impact the end of the rail, which will generate large impact force, causing the end of the rail to collapse within 40mm to 60mm, gradually forming concaves with different sizes, increasing the impact force of crane group wheels. The impact force will accelerate the crushing damage at the end of the rail, make the orbital force worse, accelerate the wear of the wheel, and generate impact load when the crane wheel passes through it, which will cause adverse effects in the bearing of the main beam and make the cracking of between the beam and the reinforcing plate. Therefore, it is of great practical significance to realize the overall rail of heavy cranes by welding method. The weldability mainly depends on the content of carbon and manganese. As the carbon content increases, the weldability gradually deteriorates. The influence of manganese and silicon in carbon steel can be converted into the equivalent of how much carbon content.
Preventing cracks is the key to rail welding. The rail joint is designed to make sure the surface of the weld has sufficient hardness, the wear resistance is not lower than the body, and the interior has good toughness. Preheating should be carried out before rail welding. The preheating range is between 100mm and 200mm at both ends of the welding section, and the preheating temperature is 350°C. The minimum temperature during the welding process shall not be lower than 350°C. If it is lower than 350°C, it needs to be heated again. In order to prevent the temperature from being uneven during the preheating, which is easy to cause temperature unevenness and affect the welding quality, the aluminum silicate insulation felt, the steel plate and the far-infrared heating piece are used to form a box heater for heating to ensure uniform temperature on both sides of the joint. After the rail joint pad is placed and the welding temperature is reached, the welding sequence is from bottom to top, in accordance with the rail bottom, the rail belly, and the upper section of the rail, and the surrounding is repaired. During the welding process, the following points should be noted. We should clean up in time after each welding. Whether the deslagging is thorough will directly affect the quality of the weld joint of the rail joints. Each layer of the weld must be visually inspected and flaws should be repaired in time. The temperature of the rail joint should be measured at any time. When the temperature is lower than 350 °C, the welding should be stopped, and the joint weld bead must be reheated to 350 °C before welding. Tooling fixtures are used to control rail deformation. When the rail belly is welded, we should pay attention to the angle contraction. If necessary, tooling tool for anti-deformation can be gradually removed. The weld is to be inspected for coloring, the weld is required to be uniform, and there should be no defects such as cracks, slag inclusions, and fusion. Surface hardness HB≥240.
The method of welding the rail butt by manual arc welding has achieved very good results through practical application, which can ensure the quality of the rail joint and the surface hardness meets the requirements for use. Moreover, the process equipment is simple, the cost is low, the certain economic benefits are obtained, and the welding of the seamless track of the heavy crane is realized, which has the value of being promoted and used in the crane manufacturing industry.
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