China Pure Copper Vibra of Lok Fittings 2

Mechanical property
The mechanical properties of the brass in this Fittings are different due to the content of zinc. The mechanical properties of the brass vary with the content of zinc. For alpha brass, both σb and δ increase with the increase of zinc content. For (α+β) brass, the strength at room temperature increases until the zinc content increases to about 45%. If the zinc content is further increased, the strength of the alloy decreases sharply due to the appearance of more brittle r phase (solid solution based on Cu5Zn8 compound) in the microstructure. The room temperature ductility of (α+β) brass decreases with the increase of zinc content. So the copper zinc alloy containing more than 45% zinc has no practical value.
The Fittings of Pure Copper Lok common brass are widely used, such as water tank belt, water supply and drainage pipe, medal, bellows, serpentine pipe, condensing pipe, shell casing and all kinds of complex shape products, hardware etc. With the increase of zinc content from H63 to H59, they are well able to withstand hot processing, mostly used in mechanical and electrical parts, stamping parts and Musical Instruments.
In order to improve the corrosion resistance, strength, hardness and cutting properties of brass, adding a small amount of copper - zinc alloy (generally 1% ~ 2%, a few up to 3% ~ 4%, extremely individual up to 5% ~ 6%) tin, aluminum, manganese, iron, silicon, nickel, lead and other elements, forming three, four, or even five yuan alloy, that is complex brass, also known as special brass.
Zinc equivalent coefficient
The structure of complex brasses can be calculated according to the "zinc equivalent coefficient" of the elements added to the brass. Because the addition of a small amount of other alloying elements to a Cu-Zn alloy usually merely shifts the α/(α+β) phase region in the Cu-Zn diagram to the left or right. So the microstructure of special brasses is usually equivalent to that of ordinary brasses with increased or decreased zinc content. For example, the microstructure of a Cu-Zn alloy with 1% silicon is equivalent to that of a Cu-Zn alloy with 10% zinc. So the "zinc equivalent" of silicon is 10. The "zinc equivalent coefficient" of silicon is the highest, and the α/(α+β) phase boundary in Cu-Zn system moves to the copper side significantly, that is, the α phase region is strongly reduced. The "zinc equivalent coefficient" of nickel is negative, that is, it expands the α phase region.
The α and β phases in special brasses are complex solid solutions with high strengthening effect, while the α and β phases in common brasses are simple Cu-Zn solid solutions with low strengthening effect. Although zinc equivalents are equivalent, the properties of multicomponent solid solutions are not the same as those of simple binary solid solutions. Therefore, a small amount of multiple hardening is a way to improve the properties of the alloy.