New Copper Alloys - Summer 1998

Copper Applications in Innovative Technology

By Robert Solbach

Notes from CDA's Standards Advisory Committee Meeting

(8/25/98)

UNS numbers are registered in response to requests to the CDA Standards Advisory Committee. The requests must be for actively produced, and commercially available alloys. Required in the registration request are the major controlling element ranges, along with maximums for significant "residual" elements. Associated mechanical and physical properties are also requested as supporting data.

At times, there is confusion about how a UNS number may be used. It is appropriate to use the number for the composition as listed, or even for an element range tighter than registered. However, it is not correct or appropriate to apply the UNS number to a composition outside the registered limits.

New Registered Alloys, Summer 1998

The following alloys have been added to the CDA registered listing. Appropriate additions are being made where data are available, to the mechanical, physical, forms and applications database listings. Where available, appropriate applications from the data sheet request forms, have been included for information.

In the High Copper alloy group, two new Olin Brass strip alloys were registered, C18600 and C18610. They both fit into the electrical and electronic connector and lead frame application areas, for automotive, appliance and chemical process sensor family of materials. Their strengthening mechanism comes from a Cr-Ti-Zr intermetalic formation. They are available as strip in the TM02, TM04, and TM08, mill hardened tempers, with nominal UTS of from 76 to 94 ksi. They are all directed at higher temperature applications.

Copper-zinc alloy C25600 was registered. Olin Brass is developing mechanical properties for this new alloy. With approximately 28% zinc, it fills a void in the alloy family. The alloy is found in DIN 17660 and 17670 specifications.

Waterbury Rolling Mills requested registration of four flat product alloys. Two were added in the copper-zinc-tin group, C41120 and C42510, and are available as annealed (OSO15) and 5 cold rolled tempers (to H01 to H08), from 54 to 95 ksi nominal UTS. The nickel addition reportedly improves strength without any change in electrical conductivity (of 40% IACS for C41120, and 35% IACS for C42510).

The two copper-tin-phosphorus group alloys, C50580, and C52480, are nickel modified C52400 versions, to boost strength and stress relaxation. They are available as annealed (OSO15) and 6 cold rolled tempers (from H01 to H10). Their nominal UTS range is from 53 to 89 ksi for C50580, and from75 to 146 ksi for C52480. All four alloys are directed at the auto terminal, electrical connector, lead frame and contact spring application area.

Alloy C66950, requested by Wieland-Werke, Germany, is intended to fit into the nickel free, manganese bronze family. Its attributes include being silver colored, and an anti allergic type material for clothing accessories. It is available in the soft (annealed), nominal 65 ksi. UTS, and 1/2H, TD02, nominal 75 ksi. UTS tempers. It is a deep-drawable type material.

The Japanese Copper Development Association (for Mitsubishi Electric) requested registration of a copper-nickel flat product alloy that fits into the electrical conducting connector, lead frame and spring for relay family. It was given Alloy No. C70230. The higher strength and higher temperature characteristics are developed from the precipitation strengthening process. It is available as a flat product in1/2H (TD02) temper with a nominal 92 ksi. UTS, and H (TD04) temper with a nominal 114 ksi. UTS. Electrical conductivity is 47% IACS.

Outokumpu American Brass's request for a copper-nickel-zinc alloy registration resulted in the assignment of Alloy No. C74400. It is intended for uses in the new ICA design of cross-flow Cupro-Braze radiators and heater headers. Is available as strip, in the soft\light-annealed temper, with a typical UTS of 51 ksi.

Revisions to Previously Registered Alloys

Composition adjustments were made to several alloys. The printed composition for alloy C19025 listed an entry for silicon in error. The correct constituent is tin .7 - 1.1%.

The registered bismuth lever of casting alloy C89520 was adjusted to 1.6 - 2.2% to reflect further refinements in its development process by I. Schumann & Co. It is in balloting action in ASTM B30, ingot, and B584, sand casting documents.

C89844 "copper + sum of named elements" was changed from 99.5%, min. to 99.3%, min. at the request of NIBCO Inc.

Reactivated Alloys

Copper-zinc Alloy C66900 was reactivated (inactive since 1992) at the request of Olin Brass.

ASME Boiler and Pressure Vessel Code Activity

A liaison report on ASME BPVC activity presented at the summer Standards Advisory Committee meeting included the following information pertaining to the consolidation of responsibilities.

"In the future, the Subcommittee on Materials of the Boiler and Pressure Vessel Committee will be responsible for developing code requirements for properties of metallic materials, eliminating the need for duplicate materials groups in other Committees."

Bismuth Related Matters

Another item from the summer Standards Advisory Committee meeting was the following informational note. A lengthy discussion concerning bismuth contamination in brass alloys C83600 and C84400 occurred during the ASTM B05 Spring Casting Subcommittee Meeting. Details are reported in the ASTM B0505 Minutes, item 6C. The major point presented was:

"...that some melters are reporting bismuth contamination in brass alloys UNS C83600 and C84400, presumably from Bi-contaminated machining chip that are finding their way into the scrap stream."

It was reported that the introduction of bismuth, even in PPM levels, dramatically affects the hot working and electrical conductivity characteristics of the resultant product form. ASTM B0505 Task Group 558c was formed "...to initiate a dialog regarding the recycling of Bi containing scrap and its impact on other products with ISRI (Institute of Scrap Recycling Industries) and BBIM (Brass and Bronze Ingot Manufacturers) and any other interested parties."

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