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17 Cards in this Set
- Front
- Back
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Compare historical needs/uses of copper to its primary use(s) today.
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Early uses included tools and hardware and cooking utensils. Nowadays coper is important as a conductor (wires), potable water supply, and bearing surfaces. Still is important because of its resistance to corrosion
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Why was copper one of the first engineering materials?
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Mass copper could be excavated without any treatment or difficult separation.
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Compare the cost of copper to low-carbon steel and discuss the cause.
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Copper is 6x more expensive and the supply has been reduced so much that we get most of it from ore with only 1.5% Cu in it.
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Discuss the purification of copper ore.
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1. Smelting- 30% Copper Matte
2. Oxidation- 98-99% Blister Copper 3. Electrolytic refining- 99.9% Electrolytic Touch Pitch |
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Common designation systems used for copper (ASTM and UNS and CDA)
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UNS #s are the CDA # with a C prefix and a suffix of two zeros.
>180 ASTM #s covering compositions/forms of copper alloy Proper Drawing Spec example: ASTM B36, UNS C23200 |
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Difference between wrought and cast and importance of difference
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Wrough is formed by shaping a pliable mass, cast is hardened into a shape from its liquid form.
Different compositions. Wrought coppers are ordered with tempers and finishes; cast are not. |
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When can trace amounts of oxygen have a negative impact on copper and how can oxygen be reduced in copper?
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Oxygen causes embrittlement at temperatures above 700F when it combines with hydrogen and forms water vapor which causes internal pressures and blistering.
Phosphorous can be added to remove the oxygen but reduces electrical conductivity greatly. |
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UNSC17200- discus effect of its major alloying element, how it is accomplished thru precipitation-hardening
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Be Copper:
Be strengthens the copper alloy to strengths rivaling carbon alloys. Precip. hardening occurs after the Be reaches its solubility limit with copper and precipitates out in the form of a separate Cu-Be compound. If kept at an elevated temperature for long periods, it will age harden further. |
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What differentiates alpha and beta brasses?
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Alpha: FCC: <38% Zn
Beta: BCC: after 38% Zn Beta forms, at 50% structure is entirely Beta |
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What structures are expected in Red Brass UNSC23000
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100% FCC alpha
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What structures are expected in Inhibited Admiralty Brass?
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100% FCC alpha
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What structures are expected in Naval Brass?
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Mostly FCC alpha
Small amt of BCC beta |
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What structures are expected in Cast Silicon Brass?
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100% FCC alpha
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What are copper-tin alloys and how does the tin strengthen copper?
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Copper-tin alloys are bronzes
Tin forms a hard brittle delta phase that strengthens through lattice distortion. |
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How are UNS C65500 and C87300 strengthened, hardened and have improved corrosion resistance?
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Silicon is soluble in copper up to about 4% at room temp and accomplishes all three.
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what are the major alloying elements in UNS C61400 and what are their advantages?
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Aluminum Bronze has Cu, Al, and Fe.
Cu is the host Al and Fe are solute. Fe increases strength and hardness The alloy can be quench-hardened and annealed. |
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Nickel and Copper demonstrate what type of solubility, are called what, and are great for what?
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Cupronickels, unlimited solid solubility, best corrosion resistance
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