Method for measuring laser welding temperature field in real time

Abstract

The invention provides a method for measuring a laser welding temperature field in real time. The method comprises the following specific steps of: measuring and preparing, namely placing a sample piece which is made of the same material as that of a solid piece to be welded at the front of the solid piece, wherein the welding seam of the sample piece and the welding seam of the solid piece are positioned on the same track, a double-wire thermocouple is embedded into the welding seam of the back of the sample piece, and a welding machine is provided with a thermal radiation image acquisition device; calibrating the sample piece, namely welding the sample piece, acquiring temperature data by using the double-wire thermocouple, acquiring image information by using the thermal radiation image acquisition device and establishing the corresponding relation between the temperature data and the image information; and measuring the solid piece, namely welding the solid piece, acquiring image data information by using the thermal radiation image acquisition device, and inquiring the established corresponding relation to obtain the temperature field data of a solid piece welding processing area. During welding of the sample piece, the temperature is measured by using the thermocouple, and the calibration accuracy of the image data of the temperature field is guaranteed; and during welding of the solid piece, only a thermal radiation image temperature measurement device is adopted, the defect of low response speed of the thermocouple is overcome, and the requirement of real-time temperature measurement in a welding process is met.

Description

technical field [0001] The invention relates to the technical field of laser welding process monitoring, in particular to a method for real-time measurement of the temperature field in a processing area during the laser welding process. Background technique [0002] The dynamic distribution of the temperature field in the processing area during laser welding directly affects the shape, metallographic structure, mechanical properties and stress deformation of the joint, and ultimately affects the quality of the joint. Therefore, the real-time measurement of the temperature field in the welding processing area is of great significance to the control of welding quality. However, in the process of laser welding, not only the welding heat cycle is fast, but also the temperature of the molten pool is high, which brings difficulties to the real-time and accurate measurement of the welding temperature field. The traditional thermocouple temperature measurement method has the charac...

AI Technical Summary

Problems solved by technology

However, in the process of laser welding, not only the welding heat cycle is fast, but also the temperature of the molten pool is high, which brings difficulties to the real-time and accurate measurement of the welding temperature field.

The traditional thermocouple temperature measurement method has the characteristics of high precision, but the response speed is slow, it needs to be in contact with the base metal during the measurement process, and it is a point measurement, which is difficult to meet the requirements of real-time temperature field measurement for welding

The thermal radiation temperature measurement method has the characteristics of non-contact and fast response. However, the radiation emissivity of an object will vary with its material, temperature, and radiation wavelength, which will affect the thermal radiation temperature measurement results, and environmental factors will also affect the measurement results. have a certain impact

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