A new high strength copper-tin-zinc alloy for connectors and otherconductive springs

摘要

Waterbury Rolling Mills, over the past decade, has developed manyHigh Performance Alloys (patented). Six of these alloys have beenimproved tin brass alloys which exhibit an excellent combination ofmechanical strength, including tensile and yield strength, andformability, as measured by the radius to thickness ratios in bending.The alloys also have very good electrical and thermal conductivity andhigh resistance to thermal stress relaxation. These alloys were targetedfor applications which included conductive springs, contacts andterminals for electronic, electric and automotive connectors and otherelectromechanical components. Earlier technical papers have previouslyintroduced these alloys. These alloys have already been selected andspecified in many applications over higher cost alternative alloys. Thecurrent paper describes the latest and strongest alloy in the highperformance tin brass alloy family developed by Waterbury Rolling Mills.The alloy is an improved tin brass with additions of small amounts ofiron, nickel and phosphorus, with special processing that results in theformation of iron nickel phosphides, with controlled particle sizes.Presence of these particles facilitates high strength with goodformability. Contrary to the normal experience, the high strength isalso accompanied by higher conductivity. The new alloy, containing 3%tin and approx. 8% zinc, is an inexpensive substitute for many existingalloys. One of them is alloy C52100, a phosphor bronze which contains 8%tin. The alloy presented has similar strength and formability as C52100but has approximately double the electrical conductivity and superiorresistance to stress relaxation at elevated temperatures. BesidesC52100, the alloy presented is also capable of replacing very expensivealloys like beryllium coppers and copper-nickel-silicon alloys, in manyapplications. This paper presents comparative data of the new alloy withother alloys commonly considered by design engineers for highperformance applications. The alloy described in this paper addressesthe growing demand of the connector industry for cost-effective highperformance alloys