Beryllium copper

Beryllium bronze is a bronze with beryllium as the main added element. The beryllium content of beryllium bronze is 0.2% to 2%, and a small amount (0.2% to 2.0%) of cobalt or nickel is added to the third component. The alloy can be strengthened by heat treatment. It is an ideal elastic material with high conductivity and high strength. Beryllium bronze is non-magnetic, anti-spark, anti-wear, anti-corrosion, anti-fatigue and anti-stress relaxation, and is easy to cast and pressure formed.

Density: 8.3 g/cm3
Electrical conductivity: ≥18% IACS
Thermal conductivity (20°C) : ≥105w/m.k
Elastic modulus: 128 GPa
Hardness before quenching: 200-250HV
Hardness after quenching: 36-42 HRC

By composition, it is divided into high conductivity beryllium bronze ( Be 0.2% ~ 0.6%) and High strength beryllium bronze (Be of 1.6% to 2.0%).
According to the manufacturing process, it can be divided into cast beryllium bronze and wrought beryllium bronze.
For wrought beryllium bronze, C17000 and C17200 are high strength ones, C17500 is high conductivity one.

Beryllium bronze has good comprehensive properties. Its mechanical properties, namely strength, hardness, wear resistance and fatigue resistance, rank first among copper alloys. Its conductivity, heat conduction, nonmagnetic and anti-spark properties can not be compared by other copper alloys. The strength and conductivity of beryllium bronze in the soft state of solid solution are at the lowest value. After processing hardening, the strength is improved, but the conductivity is still at the lowest value. After aging heat treatment, the strength and conductivity of beryllium bronze are significantly increased.
The machining, welding and polishing properties of beryllium bronze are similar to those of high copper alloys. In order to improve the machining performance of the alloy and adapt to the precision requirements of precision parts, a high strength beryllium bronze (C17300) containing 0.2%~0.6% lead was developed in various countries. Its properties are equivalent to C17200, but the cutting factor of the alloy has been increased from 20% to 60%(free cutting brass is 100%).

Beryllium bronze is a typical aging alloy.
Typical heat treatment process of high strength beryllium bronze as follows
The solute atomic beryllium is fully solute in the copper matrix at the appropriate temperature of 760~830°C (at least 60min for each 25mm thick plate), forming α supersaturated solid solution with a face-centered cubic lattice. Then, after 2~3h of thermal insulation at a temperature of 320-340°C, the dissolution and precipitation process was completed to form the γ′ phase (CuBe2 metastable phase), which co-grated with the matrix and caused stress field and strengthened the matrix.

Typical heat treatment process of high conductivity beryllium bronze as follows
Keeping at a high temperature of 900~950°C for a period of time to complete the solid solution process, and then keep at a temperature of 450~480 for 2~4h, the precipitation process was realized. Due to the addition of cobalt or nickel in the alloy, the dispersion strengthening particles are mostly intermetallic compounds formed by cobalt or nickel and beryllium. In order to further improve the strength of the alloy, the alloy is often subjected to a certain degree of cold processing after the solution heat treatment and before the aging heat treatment, in order to achieve the comprehensive strengthening effect of cold work hardening and aging hardening. Its cold working degree does not exceed 37% commonly. The heat treatment of solution should be carried out by the alloy manufacturer.
The high strength spring element can be obtained by aging heat treatment after blanking the strip into parts through solution heat treatment and cold rolling. In recent years, the United States has developed by beryllium copper manufacturers to complete the aging heat treatment of the strip, the customer can be directly made into parts for use.
Annealed (A): Solution annealed, the alloy is in the softest state, and it is easy to be pressed and formed, and waiting for the next step of cold processing or direct aging strengthening treatment.
Hard (H): Take cold rolled sheet metal as an example, 37% of cold working degree is full hard (H). 21% cold working degree is semi-hard (1/2h). 11% cold working degree is 1/4 hard (1/4H). Users can choose the appropriate soft and hard state according to the shape of the parts to be punched.
Heat treatment (HT): In the case of deformation and aging process, the state is expressed as HT.

Capillary tube

• _◎ OD 0.30 ~ 3.0 mm
• _◎ WT 0.05 ~ 0.5 mm

Precision seamless tube

• _◎ OD 3.0 ~ 100 mm
• _◎ WT 0.10 ~ 10.0 mm