The influence of the pressed hollow billet of brass 59Cu–3,5Mn–2,5Al–0,5Fe–0,4Ni stracture on the fracture mode of destruction with following hot stamping

The influence of the hot stamping temperature on the structural state of brass 59Cu–3,5Mn–2,5Al–0,5Fe–0,4Ni and the character of blocking rings destruction of the synchronizer of the car transfer change box have been investigated. It is shown that the lack of ductile $\alpha $-phase in the investigated alloy in combination with high temperature of heating $(780\ {}^\circ \mathrm C)$ before stamping leads to intergranular brittle fracture under the action of residual stresses. Decrease in temperature stamping to $700\ {}^\circ \mathrm C$ with the same structural condition of the brass excludes cracking of the brass rings under the effect of residual stresses and changes the character of destruction under bending load with rock-like to pits-like one.