Based on the current aviation industry standard

national standard

national military standard and international standard of resistance spot welding

the relationship between minimum nugget diameter

minimum shear strength and plate thickness in resistance spot welding of aluminum alloy

titanium alloy

steel and super alloy is summarized. The conclusion shows that for resistance spot welding of various alloys under various heat treatment conditions

there is a boundary point in the thickness range of 1.2 ～ 1.5 mm. At the left and right of the boundary point

the minimum nugget diameter and minimum shear strength are approximately linear with the plate thickness（for ultimate strength in 1 035 ～ 1 275 MPa and more than 1 275 MPa of high temperature alloy material

the thickness of 2.5 mm to the right

need to be subdivided）

at the same time

strength of materials is put forward as the principle of classification system. This conclusion can be used to predict the minimum nugget diameter and the minimum shear strength of resistance spot welding of various plate thickness of new materials and those not covered in the standard.