Assembly of sheet materials, tube assembly, drawing method and tools for drawing

摘要

The present invention provides an assembly of sheet materials in which a first sheet of material and a second sheet of material are disposed in an overlapping relationship, with a plurality of joint portions being formed therebetween by drawing an overlapping part of the first and second sheets of materials at a plurality of positions. The plurality of joint portions includes at least one first joint portion in which the first sheet of material is laterally extruded into the second sheet of material and at least one second joint portion in which the first sheet of material and the second sheet of material are in contact with each other in a cup-like surface configuration.