Brass - H59 CNC Machining

H59 brass is the cheapest brass, with high strength and hardness and good plasticity, it can still withstand pressure processing well in the hot state, with general corrosion resistance, and other properties similar to H62.

Mechanical properties

Tensile strength σb (MPa): ≥294

Elongation δ10 (%): ≥25

Note: The tensile mechanical properties of the plate

Specimen size: thickness 0.5 ~ 15

(1) Room temperature organization of ordinary brass is a copper-zinc binary alloy, its zinc content varies widely, so its room temperature organization is also very different. According to the Cu-Zn binary state diagram, there are three kinds of room temperature organization of brass: brass with zinc content below 35%, the microstructure at room temperature consists of single-phase α solid solution, called α brass; brass with zinc content in the range of 36% to 46%, the microstructure at room temperature consists of (α + β) two phases, called (α + β) brass (two-phase brass); brass with zinc content More than 46% to 50% of the brass, the microstructure at room temperature consists only of β phase, called β brass.

(2) Pressure processing performanceAlpha single-phase brass (from H96 to H65) has good plasticity and can withstand hot and cold processing, but alpha single-phase brass is prone to medium-temperature brittleness during hot processing such as forging, and its specific temperature range varies with the amount of Zn, generally between 200 and 700°C. Therefore, the temperature should be higher than 700℃ during hot processing. Single-phase α brass medium-temperature brittle zone is mainly due to the presence of Cu3Zn and Cu9Zn two ordered compounds within the α-phase of the Cu-Zn alloy system, the orderly transformation occurs at low and medium temperatures when heated, making the alloy brittle; in addition, there are traces of lead and bismuth in the alloy and copper form a low melting point eutectic film distributed on the grain boundaries, the intergranular rupture occurs during hot processing. Practice shows that the addition of trace amounts of cerium can effectively eliminate medium-temperature brittleness.

Two-phase brass (from H63 to H59), in addition to the α-phase with good plasticity in the alloy organization, there is also a β-solid solution based on the electronic compound CuZn. β-phase has high plasticity at high temperatures, while the β′-phase (ordered solid solution) at low temperatures is hard and brittle in nature. Therefore, (α + β) brass should be forged in the hot state. The β brass containing more than 46% to 50% zinc is hard and brittle and cannot be pressure processed.

(3) Mechanical properties The mechanical properties of brass are different due to the different zinc content. For α brass, with the increase of zinc content, σb and δ are increasing. For (α+β) brass, the room temperature strength increases until the zinc content is increased to about 45%. If the zinc content is increased further, the strength decreases sharply due to the appearance of the more brittle r-phase (Cu5Zn8 compound-based solid solution) in the alloy organization. （The room temperature plasticity of (α+β) brass always decreases with the increase of zinc content. Therefore, copper-zinc alloys containing more than 45% zinc have no practical value.

Common brass has a wide range of applications, such as water tank belts, water supply, and drainage pipes, medallions, bellows, serpentine pipes, condensation tubes, shells, various complex shapes of punching products, small hardware, etc. With the increase of zinc content from H63 to H59, they can well withstand hot processing and are mostly used for various parts of machinery and electrical appliances, stamping parts, and musical instruments.

Heat treatment

Hot working temperature 730～820℃

Annealing temperature 600～670℃.