Spot welding machine welding stress changes and curves

In the early stage of the medium frequency spot welding machine, due to the effect of welding pressure, the grains with similar crystallization directions and stress directions first cause movement. As the welding current cycle continues, the solder joint displacement occurs.

Until the solder joint displacement cannot be restored, this phenomenon is called solder joint position accumulation, and then shear micro-cracks occur on a certain displacement plane. At the beginning of this displacement, the microcracks in the weld nugget stop at the grain boundaries of the grains, and when the local plastic deformation of adjacent grains exceeds a certain critical value, the cracks begin to expand.

When observing the cross section of the crack formation in the initial stage of the weld nugget of the medium frequency spot welding machine under a microscope, you can see the extrusion and extrusion of the grains. The extrusion and extrusion are not consistent with the development direction of macroscopic cracks, and the bad surface appears in a messy stripe shape.

In the second stage, the crack propagation process consists of a cycle of expansion of the tensile stripe surface, crack growth and crack closure caused by compression, and expands in a direction generally perpendicular to the direction of load action. When the crack expands, ductile slip can be seen on the crack surface. Shape, concentric circular bright lines under the microscope.

The third stage is close to destruction. As the crack expands, the stress on the surface is concentrated to expand, and the expansion rate becomes faster and faster until the crack loses stability and causes structural damage.

Suzhou Agera Automation Equipment Co., Ltd. is an enterprise engaged in the development of automated assembly, welding, testing equipment and production lines. It is mainly used in home appliance hardware, automobile manufacturing, sheet metal, 3C electronics industries, etc. According to customer needs, we can develop and customize various welding machines, automated welding equipment, assembly and welding production lines, assembly lines, etc., to provide appropriate automated overall solutions for enterprise transformation and upgrading, and help enterprises quickly realize the transformation from traditional production methods to mid-to-high-end production methods. Transformation and upgrading services. If you are interested in our automation equipment and production lines, please contact us: leo@agerawelder.com