1976 Volume 45 Issue 4 Pages 295-301
In diffusion welding, ideal atomically flat and clean surfaces are capable of bonding spontaneously when brought into intimate contact which produces the metallic bond. However the properties of real surfaces affect the quality of welds.
This paper describes the influence of process parameters on the joining process, using copper, surface contamination of which does not seem to have so strong effect on weldability. Especially the diffusion welding process is investigatedd from the characteristic value at high temperature that is measured in terms of investigation of the welding process between conical specimen and flat one. The following results were obtained.
1. The result obtained from investigation about the welding process between conical specimen and flat one:
A) The ratio (As) of the projected area of the indentation to the load does not depend on angle of cone (30°-160°) and load (8.24 kg).
B) The ratio (As) is the mechanical characteristic value at high temperature, and is formulated by temperature and time.
C) Tensile strength of the contacting part is coincident with one of the base metal.
2. The result obtained from investigation about the butt diffusion welding process of bar:
A) The results obtained from welding process between conical specimen and flat one can be applied even in the case of bar.
B) Real contact area is calculated by As⋅WL/A (WL: welding load, A: apparent area).
C) Joint strength is calculated by K⋅As⋅WL/A⋅SB (K: material constant, SB: tensile strength of base metal). But the finer surface roughness is at higher temperature, the higher the joint strength is than calculated value.
D) Welding deformation is closely related to As⋅WL/A.