Composition and production

The most important high-strength alloy is CuBe2 (ALBROMET W-130) containing 1.80 to 2.00 wt% Be. By annealing at 750 to 825 °C for 5 min or more, followed by water cooling, the beryllium is left in solid solution at room temperature. The alloy can then be cold worked and processed into finished product shapes. Precipitation hardening can be accomplished by aging for 0.5 to 3 hours at 315 to 400 °C. Tensile strengths up to 1500 MPa have been observed for the age-hardened condition. The electrical conductivity of the alloy CuCoNiBe (ALBROMET W-240) is 22 to 25% IACS (International Annealed Copper Standard). This high conductive alloy has a low beryllium content of about 0.5% by weight and a nickel and cobalt content of about 1%. The maximum strength for these alloys is in range of 700 to 900 MPa. Beryllium has an electrical and thermal conductivity that is about 40% that of copper.

Application

Beryllium copper is used - for example - for highly stressed springs in machines, contact springs in relays, electrical contact contacts, for non-sparking tools, for injection molds in plastics technology, and in engine construction for valve rings. 

Beryllium copper is also used for casting and ingot molds for brass casting.

Using copper alloys correctly in mold making

At EuroMold 2010, ALBROMET presented the alloys of U.S. manufacturer IBC advanced alloys to the trade public for the first time. These materials were developed for extremely competitive plastic molds. They have significant advantages over steels or aluminum. Cavities, inserts as well as cores and nozzles are successfully manufactured from these materials. The ratio of hardness (max. 40 HCR) ALBROMET W-130 and thermal conductivity (130/mm k) cannot be approached by steel or aluminum. The unit costs are significantly reduced. Component quality is significantly increased by the excellent thermal conductivity as well as the outstanding demoldability. Higher material input costs are amortized several times over by significantly lower cycle times. Two main reasons are considered in the selection process:
First, cycle time and cost reduction. Second, part quality.
Glass fiber reinforced plastics should also be considered. 

Cycle time and cost reduction

The design of plastic molds depends on the choice of materials. With decreasing cycle times due to faster cooling, the number of cavities can be reduced and in series production even one mold can be saved completely, for example two instead of three molds provides the required part quantities. This keeps a machine free for production. In this case, the savings are immense, and the profitability of the molds increases disproportionately in relation to the costs. In many cases, however, conflicting interests between the customer, the mold maker and the parts producer (supplier) have to be discussed. It is important to find an agreement in which the cost of the injection mold, part quality and cycle time are equally considered. With increased investment costs in the mold, the lowest unit costs can often ultimately be achieved.

Quality in plastic engineering

In addition to the reduced cycle time and the increased thermal conductivity of the copper alloys, the thermal homogeneity of the parts also improves during the cooling phase. This results in significantly lower warpage. If, for design reasons, insufficient cooling is generated with conventional materials, "hot spots" are formed. These are regions where the cooling rate is lower than in the rest of the component. This variable in cooling rate can lead to warpage, poorer filling, and sometimes different crystallization. There are many examples where a conventional mold made exclusively in steel has failed to maintain the tolerances of the parts produced. Inserts made of copper alloys provide remedy. Cost-conscious variant design incorporates new highly conductive materials from the outset. For modern copper materials, technologies also exist for weldability, difficult machining steps such as EDM, and coatings. The latter are necessary in the low-temperature range for processing fiberglass plastics. Here, classical processes such as electroless nickel coatings or other processes against abrasive wear up to approx. 100 °C coating temperature are used. ALBROMET recommends, for example, that the central mold inserts for oil pans be made of a copper alloy with coating. With these parts, four variants of an oil pan are produced from one mold using the so-called "family mold concept". The changeover time from one variant to the next is only 3 hours. The mold weight is approx. 20 to. The dimensions are 2130 x 1320 x 1250 mm (L/W/H). The plastic is PA6.6 GF35. 

These are only details of many possible applications.
Do not hesitate to contact us for any further information.