Brass is a common metal alloy in our lives. In our impression, the hardness of brass is generally not high, which is relatively soft compared to other metal alloys. The method of making brass harder in brass machining is：

Add trace cobalt to aluminum brass to study the influence of trace cobalt, smelting and casting process and processing parameters on the mechanical properties of strip produced by rolling method. Explore the use of aluminum brass to replace the widely used elastic copper alloy materials. Feasibility of tin phosphor bronze.

The research results show that cobalt can effectively reduce the grain size of the as-cast alloy, change the shape of the grain, improve the tensile strength and hardness of the alloy, and ensure that the alloy has good ductility. The brass band produced by adding 0.4% cobalt in aluminum brass and using a reasonable processing technology has better performance than tin phosphor bronze. The 0.25mm thick strip has a tensile strength of 840.4MPa and an elongation rate 2.8%, the Vickers hardness value is 228, and the maximum tensile strength (805MPa) of the QSn6.5-0.1 strip in the bit hard state is increased by 4.4%, which meets the requirements for the use of elastic components; at the same time, because the brass contains 22.7% zinc can effectively reduce costs and has practical application value.