On the Shear-Strength of Brazed Joints

Abstract

Authors studied about the shear-strength on brazed joints at the room and elevated temperatures, especially on the factors that affected on shear strength of brazed joints.
Those factors were the strength of base metal, the kinds of brazing filler metals, the annealing after brazing, the thickness of filler metals in brazed joints and the roughness of filling surfaces.
Base metals Selected the electric tough pitch copper and 0.45%C carbon steel, and ten filler metals selected from Ag-P-Cu, Ag-Cu-Cd-Zn and Cu systems. Specimens were used in a ring and plug type.
The results of investigation were concluded as follows ;
1. As to the filler metals which were stronger than base metals, the shear-strength of brazed joints of copper was nearly equal to that of base metals without relation to various filler metals.
2. As to the base metals which were stronger than the filler metals, the shear-strength of brazed joints of steel was different with the filler metals.
3. After annealing process had been adopted to brazed carbon steel joints, those shear-strength was dropped about 8-25%. When base metal was copper, its effect was negligible.
4. The thickness of filler metals in brazed joints had no effect on shear-strength of brazed joints without relation to copper and stell.
5. The smoothness of brazed surfaces had a slight effect on shear-strength, smooth surfaces in joints were better at shear strength than rough surfaces. The former's strength was 10% stronger than the latter's.