Printer Friendly

Material changes emerging.

As proved by presentations at the Casting Congress, copper research continues to follow the path of searching for alternative materials and ways to improve copper alloy casting.

P.K. Rohatgi, S. Ray, D. Nath, University of Wisconsin-Milwaukee, and N. Church, International Copper Assn., New York City, examined the potential of graphite-containing copper alloy composites for plumbing applications as a substitute for lead-containing copper alloys.

There is a growing concern about the potential health hazards of lead leaching from lead-containing, copper-based alloys currently used in plumbing applications. Attempts are being made to develop lead-free alloys or composites for plumbing applications that will have adequate machinability.

Conducting material synthesis, corrosion testing and machinability tests on a commercial copper alloy, the authors found lead-free alloys containing graphite are machining-free due to the graphite composition. This alloy has a higher corrosion resistance than the base alloy, possesses satisfactory solderability and platability, and its graphite particles don't significantly affect dezincification resistance.

The graphite helps in machining because it is a solid lubricant and reduces friction at the chip-tool interface. The copper-graphite composite alloys appear to be promising substitutes for currently used lead copper alloys and represent future foundry products.

P. Sriram, Rapsri Engineering Industries, Ltd., and S. Seshan, Indian Institute of Science, both of Bangalore, India, teamed with H.Md. Roshan, Indian Institute of Technology, Madras, India, to study the effects trace elements have on the casting characteristics and mechanical properties of two zinc-aluminum (ZA) cast alloys.

Developed in the 1970s, the ZA alloys have become attractive alternatives to conventional cast bearing materials such as bronzes and cast irons. Although they can be manufactured by any process and offer excellent mechanical properties, the ZA alloys experience unique underside shrinkage problems.

Trace elements are added to assist shrinkage problems and generally enhance mechanical properties, with the exception of dross forming elements.

The authors found that Sr, Ca, Li, Na, Be and K eliminate underside shrinkage in ZA alloys. However, fluidity and mold filling ability is reduced by adding Na, Sr, Be, Ca, Li and K. Ti and Zr promote hot tearing.

The authors estimate that ZA cast alloys will substitute 150,000 tons of conventional alloys in the next five years.
COPYRIGHT 1992 American Foundry Society, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1992, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:96th AFS Casting Congress Milwaukee; copper alloy casting
Publication:Modern Casting
Date:Jun 1, 1992
Previous Article:Studies 'clear air' on EPC.
Next Article:Reclamation & feeding explored.

Related Articles
Research focuses on improving alloys.
Melt treatments of copper alloys.
Permanent mold cast copper alloys provide opportunities for conversion success.
Copper permanent molders discuss casting conversions.
Metalcasters Gather Deep in the Heart of Texas.
Converting to Low-Lead Copper Casting: Three Foundries' Experiences.
Calendar of events.
Q Can we use existing gating and casting methods to cast lead-free copper alloys?
Copper Alloy.
Consortium works to develop no-lead copper alloys in wake of new law.

Terms of use | Copyright © 2017 Farlex, Inc. | Feedback | For webmasters