How to choose welding process parameters

Update:27 Sep 2020

Spot welding machine e-book welding process parameters […]

Spot welding machine e-book welding process parameters mainly include electron beam current, accelerating voltage, welding speed, focusing current and working distance. Generally speaking, penetration is directly proportional to acceleration voltage and beam current, and inversely proportional to beam spot diameter, working distance, and welding speed.
The increase in acceleration voltage can increase the penetration depth. Under the condition of keeping other parameters unchanged, the cross-sectional aspect ratio of the weld is proportional to the acceleration voltage. Increasing the electron beam current will increase the penetration depth and penetration width. Increasing the welding speed will narrow the weld and reduce the penetration depth. The focus state of the electron beam has a great influence on the penetration depth and weld formation. A smaller focus can narrow the weld and increase the penetration depth.
For different equipment, welding the same part, due to the difference in electron gun structure, acceleration voltage and vacuum, the beam quality of the electron beam is also different, and the electron beam welding process parameters used are also different. Even for the same e-book welding equipment, welding the same part, several sets of parameters may be applicable. As shown in the figure, the electron beam welding process parameters of steel have a large selection range. According to the specific requirements of different parts, more suitable process parameters can be selected for metallographic welding.
For certain e-book welding equipment, the acceleration voltage is generally fixed, and only minor adjustments are made when necessary. When welding thick plates, the focus should be located at the depth of 0.5~0.75mm below the surface of the workpiece; when welding thin plates, the focus should be located on the surface of the workpiece. The working distance should be within the optimum range of the equipment. The welding speed is the main adjustment process parameter.
The welding input of the spot welder is the result of the comprehensive effect of welding process parameters. For a material, the welding thickness and welding heat input have a corresponding functional relationship. When electron beam welding, the calculation formula of heat input is:
The heat input is directly proportional to the electron beam welding power and inversely proportional to the welding speed.
First, the corresponding relationship between welding heat input and welding thickness is used to preliminarily select welding process parameters, which can be used as actual welding process parameters after correction by static experiments. For this, the cross section of the weld, the satellite of the weld and the prevention of weld defects should also be considered, and the welding process parameters should be determined by comprehensive selection and testing.