Effect of heat treatment of beryllium bronzes on the quality of critical engineering parts

Abstract

The paper considers the peculiarities of thermal hardening of beryllium bronzes (Cu + 2% Be) and the feasibility of stepwise aging on BrB2 alloy parts with different requirements for their geometry. The factors determining the occurrence of stresses in beryllium bronzes parts are described. Attention is drawn to the fact that stepwise aging does not help to straighten the details as it happens during aging in special devices. Studies have shown that for cylindrical parts, when controlling deviations in straightness, stepwise aging minimizes warpage even during heat treatment without special devices. For flat parts with stringent geometry requirements, the processing of which is carried out in devices, dispersion hardening in a free state is not acceptable. For parts made of BrB2 alloy, heat treatment of which is not economically feasible in devices, but the geometry is significant, it is recommended to introduce an operation to “relieve stress” at a temperature of 210±5°C for one hour (step aging) before the operation “dispersion hardening”, that will minimize distortion during heat treatment without the use of special devices. It is shown that in each particular case, analysis is necessary on the feasibility of using staged aging, since in some cases its use can lead to a more expensive process without a significant effect in terms of reducing warpage of parts.