Tin replaces lead in automobile steel.Car engines already run on unleaded gasoline. Now, researchers have found a way to get the lead out of the engine itself. Scientists at the University of Pittsburgh have created a leadfree steel that can be used in automobile engines and transmissions. Not only is the new alloy environmentally friendly Environmentally friendly, also referred to as nature friendly, is a term used to refer to goods and services considered to inflict minimal harm on the environment.[1] , it also may cost less and be easier to recycle than the traditional metal. The type of steel commonly used for machined car parts contains a low concentration of lead, about 0.15 to 0.33 percent by weight. Lead makes the material, known as 12L14, easy to drill and cut, but its presence also requires that steelmakers follow strict safety measures safety measures, n.pl actions (e.g., use of glasses, face masks) taken to protect patients and office personnel from such known hazards as particles and aerosols from high-speed rotary instruments, mercury vapor, radiation exposure, anesthetic and to ensure that lead fumes fumes odorous gases and other volatile materials; inhalation of irritating fumes causes coughing and, if sufficiently severe, irreversible pulmonary edema. and dust don't endanger en·dan·ger tr.v. en·dan·gered, en·dan·ger·ing, en·dan·gers 1. To expose to harm or danger; imperil. 2. To threaten with extinction. workers or pollute pol·lute v. 1. To make unfit for or harmful to living things, especially by the addition of waste matter; contaminate. 2. To make less suitable for an activity, especially by the introduction of unwanted factors. the environment. Anthony J. DeArdo and C. Isaac Garcia found that tin can replace the lead in 12L14 without changing the steel's mechanical properties. They expect a patent for the material in the next few weeks. DeArdo and Garcia began looking for Looking for In the context of general equities, this describing a buy interest in which a dealer is asked to offer stock, often involving a capital commitment. Antithesis of in touch with. alternatives to leaded steel 5 years ago, when steelmakers became concerned that the government might ban lead as an ingredient. "Since 12L14 is the workhorse work·horse n. 1. Something, such as a machine, that performs dependably under heavy or prolonged use: "the 50-year-old DC-3 ... for machining applications, there was not a suitable candidate to replace this material," says Garcia. Although lead has been in steel for many years, there was no scientific agreement on how it makes the metal easier to machine, Garcia says. Using a field-ion microscope field-ion microscope: see microscope. that could identify the positions of individual lead atoms in the alloy, he and DeArdo determined the mechanism. They learned that lead atoms collect at the edges of metal grains, making it easier for the grains to slide past each other and separate. Machining a part essentially fractures the material, says Garcia. Carving steel parts, for example, "produces small chips, like sharpening a pencil." The researchers then looked for other, nontoxic elements that could also collect at these grain boundaries Grain boundaries The internal interfaces that separate neighboring misoriented single crystals in a polycrystalline solid. Most solids such as metals, ceramics, and semiconductors have a crystalline structure, which means that they are made of atoms which are and produce a machinable steel. Tin at a concentration of 0.035 to 0.08 percent by weight--significantly less than the amount of lead it replaces--worked best out of all the alternatives they tried. The Curtis Screw Co. in Buffalo, N.Y., has cut about 15,000 pounds of the leadfree steel into precision parts, says president Bob Squier. "It machines at least as well as 12L14. That's encouraging," he reports. Tests at the University of Pittsburgh had indicated that tools can machine the new steel much more easily than they can 12L14, Squier says, but so far, tests in his factory haven't borne that out. The steel should cost less to produce, Garcia says, since steelmakers won't have to collect lead fumes emanating from molten metal. Chips and scraps cut from traditional steel parts also contain lead and must be handled in a special way, but the new material can be melted down without such precautions. "Leaded scrap is very difficult to get rid of," says Squier. "It's not environmentally friendly." Lead is not a big concern in recycling old cars because the small amount of lead in them becomes diluted in the overall mix of scrap metal, says Greg Crawford of the Steel Recycling Institute in Pittsburgh. Curtis Screw already has a production order from the Ford Motor Co. for parts made out of the new alloy, says Squier. Whether the steel catches on will depend on automaker demand, but "we're pretty excited about it," he says. |
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