Characteristics of NGK BERYLCO alloys

High Strength, Moderate Conductivity System

BERYLCO® 25 alloy, UNS C17200, can attain mechanical properties up to 200 ksi UTS and hardness of Rockwell C45. BERYLCO® 33-25, UNS C17300 is the free machining version with the same characteristics as BERYLCO® 25.

At a moderate conductivity of 22%, these alloys offer the best wear resistance, fatigue strength, and hardness available in the copper alloy system.

High Conductivity, Moderate Strength

BERYLCO® 10 and 14, UNS C17500 and C17510, can attain conductivity over 45% IACS and strengths up to 140 ksi UTS. This combination of properties make these alloys ideally suited for heat dissipating modules, resistance welding components, and other electrical applications.

Machinability

Beryllium copper can be machined into intricate shapes. Its machinability in the age hardened condition is comparable to many other copper base alloys, and better than stainless steels. Its dimensional stability is far superior to any other copper base alloy.

Abrasive Wear Resistance

Beryllium copper offers attractive wear resistant properties compared to other copper base alloys and many ferrous alloys because of its complex oxide transfer wear films.

The high strength of age hardened parts makes them capable of sustaining bearing loads far in excess of other copper base alloys and gives the added advantage of compatibility with high hardness ferrous alloy shafts.

Corrosion Resistance

Beryllium copper has corrosion resistance nearly equal to nickel silver and is not susceptible to hydrogen embrittlement.

High Fatigue Strength

Beryllium copper is known to have high fatigue strength because of its toughness and resistance to local deformation.

Non-Magnetic

The non-magnetic characteristic of beryllium copper alloys makes them extremely useful for housing sensitive detectors affected by magnetic fields.

Heat treatment

Heat treatment is the most important process for this alloy system. While all copper alloys are hardenable by cold working, beryllium copper is unique in being hardenable by a simple low temperature thermal treatment. It involves two basic steps. The first is called solution annealing and the second, precipitation or age hardening.

Solution Annealing

The material is heated to within about 200ºF of the alloy melting temperature. At this point the contained beryllium is essentially “dissolved” in the copper matrix (Alpha phase). By rapidly quenching to room temperature this solid solution structure is retained. The material at this stage is very soft and ductile and can be readily cold worked by drawing, forming rolling, or cold heading. The solution annealing operation is part of the process at the mill and is not typically used by the customer. Temperature, time at temperature, quench rate, grain size, and hardness are all very critical parameters and are tightly controlled by NGK Berylco.

Age Hardening

Age hardening significantly enhances the material’s strength. This reaction is generally carried out at temperatures between 500ºF and 1000ºF depending on Alloy and desired characteristics. This cycle causes the dissolved beryllium to precipitate as a beryllium rich (gamma) phase in the matrix and at the grain boundaries. It is the formation of this precipitate which causes the large increase in material strength. The level of mechanical properties attained is determined by the temperature and time at temperature. It should be recognized that beryllium copper has no room temperature aging characteristics. Material is available from NGK Berylco in the annealed cold worked or age hardened condition.