The straight pipe flange butt welding machine is used for the end butt joint of hot coil flange, which can greatly improve the welding quality and efficiency of hot coil flange, and ensure that the welding joint is free of slag inclusion, air hole and other defects. After turning, the welding joint is almost invisible, and it can ensure that the quality of the whole flange can be approached or reached through ultrasonic flaw detection. The main features are as follows: < br style = "list style type: none;" / > & nbsp; & nbsp; The straight pipe flange assembly welding machine adopts full hydraulic drive, the key components are foreign famous brands, the working pressure is stable and the response is fast; the welding parameters and pressure specifications are all set by the human-machine interface and can be saved; the pressure, temperature, liquid level, welding current and welding distance of the hydraulic station are real-time monitored, abnormal alarm is given, automatic shutdown protection and prompt are given; quick change and wear-resistant design of welding mold are adopted, and With flange positioning function, improve work efficiency; three-phase frequency conversion technology, no need to compensate the power grid, saving energy; manual loading and unloading, welding process automatically completed. The important process parameters of butt welding machine for straight pipe flange are: extension length, flash allowance, flash speed, flash current density, etc. < br style = "list style type: none;" / > & nbsp; 1. The extension length of weldment: < br style = "list style type: none;" / > & nbsp; & nbsp; the extension length of weldment is the length of weldment extending from static fixture and movable fixture, which can be selected according to the properties of weldment and material. Generally, it should be greater than half of the diameter of the weldment, and P = 0.7-1.0d (D is the bar diameter). Flash allowance: < br style = "list style type: none;" / > & nbsp; 2. Flash allowance: < br style = "list style type: none;" / > & nbsp; & nbsp; the reserved length of weldment shortened due to flash, also known as the amount of burning, can be selected according to the material properties, the cross-section size of the weldment and whether it is preheated or not. Flash speed is the instantaneous approaching speed of weldment under stable flash condition. Also known as the instantaneous feeding speed of moving fixture, also known as burning speed. < br style = "list style type: none;" / > & nbsp; & nbsp; increase the secondary cut-off voltage, reduce the cross-section size of the weldment, appropriately increase the preheating temperature, use preheating (compared with continuous flash welding) to weld small section chain (compared with large section chain), and welding materials with easy oxidation and good thermal conductivity can choose higher flash speed. When the flash speed is low in the later stage of flash, dangerous oxide film interlayer defects are easy to appear in the joint; if the flash speed is not properly increased, the heating zone will be narrowed and the temperature gradient will be increased, then the required welding power will be increased and the flame mouth depth will be increased after the lintel blasting. The flash speed should be the average flash speed. Flash current density (secondary no-load voltage): < br style = "list style type: none;" / > & nbsp; & nbsp; 4. Flash current density (secondary no-load voltage): < br style = "list style type: none;" / > & nbsp; & nbsp; flash current density (secondary cut-off voltage) has a significant impact on the heating of weldments. It is related to welding method, material property and welding section size. It usually varies over a wide range. The selection principle of secondary no-load voltage is to select lower no-load voltage as far as possible under the condition of stable flash, and to reduce the short-circuit impedance of welding machine, especially the resistance. Therefore, it is very important to keep the welding circuit clean.