Heat treatment of brass
Brass is a copper-zinc alloy, with a bright golden yellow luster on the surface, high corrosion resistance in the atmosphere, fresh water and sea water, good strength, wear resistance, heat resistance, electrical conductivity, thermal conductivity It has high plasticity, good cold and hot pressure processing performance, can be welded, brazed and cold cut, and can be strengthened by heat treatment.
There are 11 varieties of ordinary brass, the main purpose: H59, H62, H63 aluminum alloy quenching furnace agent, H65 brass is used to manufacture hardware daily necessities, screws, nuts, pins, anchors, cushion rolls, springs, screens, Radiator, various deep extension force parts, welding parts, hot punching and hot rolling parts, etc.; H68, H68A, H70 brass are used to manufacture complex cold drawn parts and deep drawn parts, such as radiator shell, duct, bellows , Bullet casings, detonators, etc.; H80, H85 brass are used to make paper nets, thin-walled tubes, and house building supplies; H90, H96 brass are used to manufacture conduits, condensation tubes, radiator tubes, automobile water tanks, drain pipes, conductive Parts, medals, artworks, etc. Brass plays an increasingly important role in the rapidly developing machinery manufacturing industry. Selected representative H59, H62, H68, H96 four kinds of brass for analysis, test and research, and the H box-type resistance furnace price of 62 brass for cryogenic treatment strengthening test, and achieved practical results.
The chemical composition, organization and performance of brass
Brass is Cu-zN alloy, and its structure is (a+8) two-phase structure. Zn can dissolve into Cu to form a solid solution. Above 456 ℃, its solubility increases with the temperature drop; at 456 ℃, the solubility of Zn in a solid solution is greater, 39%; and below 456 ℃, Zn is in a The solubility in solid solution decreases with decreasing temperature. Brass with Zn content <39%, through recrystallization annealing and slow cooling, can obtain a single a solid solution structure, that is, single-phase brass (face-centered cubic lattice), excellent plasticity, both in hot and cold states Very good formability; when the zinc content is 39%-46%, at 456-458 ℃ above is a + 8 two-phase structure, that is, two-phase brass, 8 phase is an electronic compound Cu-Zn-based solid solution, body center Cubic lattice; when the temperature drops to 456 ~ 458 ℃, an ordered transformation occurs, forming an ordered solid solution 13' phase. 8-phase plastic has good plasticity, high strength and hardness, and 13' phase is hard and brittle, and phase should be avoided during heat treatment. Therefore, dual-phase brass is suitable for hot working, that is, processing in a + B dual-phase state, but not suitable for cold working in a + I 3 state. Two-phase brass has high strength and good corrosion resistance, and is widely used in the manufacturing industry. However, when the zinc content is greater than 46%, the brass structure is all brittle I 3 phase, the plasticity is very poor, no practical value.
What is the heat treatment of brass?
2020 06/16