Quality control method for numerical-control gas pressure welding of rail

Abstract

The invention discloses a steel rail digital control air pressure welding quality control method which comprises: getting relationship of temperature- resistance of deformation-deformation by implementing welding heat / pressure simulating test on steel rail for welding, and getting the optimum parameters in the three welding stages, and pre-setting them in the digital controller; controlling the heater swing device with automatic control function, air quality flow control unit, oil pressure adjusting device of the digital control pump station by the digital controller according to the pre-set parameters, to realize closed-loop control on the entire welding process.

Description

Technical field [0001] The invention relates to a welding quality control method for rail pressure welding of rail transit seamless lines. Background technique [0002] Rail gas pressure welding is the main method used for on-site rail welding in the construction of seamless lines such as railways, light rails, and subways in my country. Welding temperature field and extrusion upsetting deformation are the key links to determine the quality of gas pressure welding joints. While controlling the airflow size and ratio, swing frequency and amplitude, and heating time of the heater, the cooperation of welding upsetting pressure is also required. Only in this way can the required temperature field and good deformation intercrystallization and recrystallization be obtained in the heating zone, so as to achieve the effect of high-quality welding. In order to prevent damage to the welding head due to the resistance of the ballast bed and the gravity of the ramp during on-site weldi...

AI Technical Summary

Problems solved by technology

[0004] (1) The coordination and cooperation of the welding process is under the unified command of the welder squad leader. The constant value control and switching of the "three-stage welding pressure" is watched by the welder squad leader, and the oil pump operator is ordered to operate the manual control. The coordination between the worker squad leader and the oil pump operator It is difficult to cooperate, the switching time is not easy to control synchronously and accurately, the pressure control error is large, the precision is low, and misjudgment occurs from time to time, which affects the quality of welded joints

[0005] (2) The control of the amount of upsetting depends entirely on the observation of the welder's squad leader with the naked eye, so the amount of upsetting of the welded joints varies from time to time, and the consistency is poor, which affects the quality of the welded joints

[0006] (3) Parameters of the welding process: the oxygen and acetylene flow, the pressure of the upsetting cylinder during the welding process are manually recorded, and there are few recorded parameters (only one set of parameters for each welded joint), and the quality of the welded joint cannot be traced due to human factors.

[0007] (4) After the welding head is welded, the pressure-holding and pushing operation cannot be reliably performed, so there is a serious potential safety hazard of tearing

[0008] In short, when the rail gas pressure welding method is used for on-site construction work, manual operation controls the welding process, and it is impossible to detect the displacement in the pre-pressing stage, the displacement in the low-pressure stage, and the upsetting amount in the upsetting stage in real time. The relationship between resistance and deformation indirectly determines the welding temperature, and implements the optimal control of extrusion upsetting deformation and upsetting speed, pressure holding time, pressure holding push convex and pressure holding normalizing. Therefore, the quality of welded joints cannot be reliably guaranteed

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