Welding of different sheet metals
Due to increasingly complex constructions, there are more and more welded joints under sheets of unequal thickness. For example, joining an outer skin with support profiles or crash reinforcements inside the car body. These joints of unequal thickness have always existed, but the use of increasingly special materials (high-strength steel grades) makes this problem more explosive than ever.
Basically, the dimensioning of the welding equipment and the choice of parameters should be based on the standard values for the thinner sheet. This applies up to a sheet thickness ratio of 1.5. This means that one sheet can be up to 1.5 times thicker than the other. If there are major differences between the two materials, the so-called comparative sheet thickness from DVS leaflet 2902 Part 4 should be used. These comparative sheet thicknesses are available up to sheet thickness differences of 1 to 3. Such connections should be avoided. In addition to the comparative sheet thickness, variations with different electrodes on the two different sheets are still possible. However, this has to be determined in each individual case and your HWH partner can certainly help you.
For multi-cut joints, i.e. 3 or 4 plate welds, the thinner plates should be placed between the thicker ones if possible. Which, of course, is rarely constructively possible.