affects quality, cost and value. During the trials, C83470 provided advantages in this regard. Current available low-lead alloys offer casting solu-
tions, but vary in their ability to be safely and effectively recycled if they should become cross-contaminated with, or cause cross-contamination of, some of the other low lead alloys or the leaded brasses. Currently, the value of the resultant cross-contaminated material may be consid- erably reduced because this material must be refined or diluted when consumed back either by the facility or an ingot maker.
Elements such as lead, bismuth, silicon or
aluminum must be either removed by refining or diluted to bring the metal back into specification for reuse. C83470 contains no lead, bismuth, silicon, aluminum or other element that causes cross-contamination and/or recycling concerns. C83470 will be easier for facilities to manage from this perspective and should potentially be more cost effective to recycle both in the facility and by an ingot maker. Should cross contamination of C83470 with another alloy occur in the facility, the sulfide pres- ent in C83470 is less likely to be a detriment to the cast- ing quality, castability and value of returns, such as gates and risers. This is because alloys other than C83470 have significantly higher tolerance for sulfur than other alloying elements. Sulfur is relatively easy to remove by refining during the recycling process, negating the need for dilution with copper.
ADVANTAGES AND DISADVANTAGES TO C83470
Advantages • Outstanding pressure tightness. • Highly recyclable, overall composition minimizes risk of cross contamination.
• Good surface finish. • Good solderability. • Test bar data indicates the alloy typically exceeds the published minimum mechanical property requirements.
• No significant sulfur dioxide detected during melting or pouring.
• Made in the U.S., available from several domestic suppliers.
Disadvantages
• Sensitive to turbulence. Non-pressurized gating sys- tems recommended.
• Attention to proper practices must be given to prevent gas issues, particularly in turbulent gating systems.
• Issues with evacuating chips in gang tooling. • Evaluating tooling design, insert geometry and coatings recommended.
C83470 directly addresses the big picture of recyclability and the costs of finite natural resources.
Applications C83470 most likely will be used in applications in the
waterworks industry and castings that must meet the require- ments of the Safe Drinking Water Act or other international standards restricting lead content. Te alloy also can be used in applications that require pressure tightness, whether for air, water, gas or oil. Other viable applications include pump components, water impellors and housings, and small gears. C83470 also has applicability for continuous cast rod, bar and shapes, as well as potential as a choice for bearings. Based upon the trials conducted over the last three years, the authors believe this alloy is a viable option to produce castings that will be in compliance with the Safe Drinking Water Act or other standards requiring castings to be low in lead. Standard melting, deoxidation and pouring practices apply with C83470 as with other leaded and non-leaded waterworks and plumbing alloys. Each facility should thoroughly investigate this alloy and implement the needed controls at each process step to ensure best results. Further research may be needed based on prod- uct applications. Results may vary.
Tis article is based on research conducted by members of the AFS Copper Alloy Division.
February 2016 MODERN CASTING | 39
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