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 New York City: see New York, city. New York City City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. , examined the potential of graphite-containing copper alloy composites for plumbing applications as a substitute for lead-containing copper alloys Copper alloys are alloys with Copper as their principial component. They have high resistance to corrosion. Due to its high electric conductivity, pure electrolytic copper is used mostly for making of electrical cables. . 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 De`zinc`i`fi`ca´tion n. 1. The act or process of freeing from zinc; also, the condition resulting from the removal of zinc. resistance. The graphite helps in machining because it is a solid lubricant Lubricant A gas, liquid, or solid used to prevent contact of parts in relative motion, and thereby reduce friction and wear. In many machines, cooling by the lubricant is equally important. 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 Impressed by Swami Vivekananda's views on science, and leadership abilities, Jamsetji Nusserwanji Tata wanted him to guide his campaign. Vivekananda endorsed the project with enthusiasm, and Tata, with the aim of advancing the scientific capabilities of the country, constituted a , both of Bangalore, India, teamed with H.Md. Roshan, Indian Institute The Indian Institute in central Oxford, England is located at the north end of Catte Street on the corner with Holywell Street and faching down Broad Street from the east.[1] of Technology, Madras Madras. 1 State and former province, India: see Tamil Nadu. 2 City, India: see Chennai. , India, to study the effects trace elements Trace elements A group of elements that are present in the human body in very small amounts but are nonetheless important to good health. They include chromium, copper, cobalt, iodine, iron, selenium, and zinc. Trace elements are also called micronutrients. 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. |
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