Search results
Results from the WOW.Com Content Network
In materials science, quenching is the rapid cooling of a workpiece in water, gas, oil, polymer, air, or other fluids to obtain certain material properties. A type of heat treating , quenching prevents undesired low-temperature processes, such as phase transformations, from occurring.
Comparing air and water, air has vastly lower heat capacity per gram and per volume (4000) and less than a tenth the conductivity, but also much lower viscosity (about 200 times lower: 17.4 × 10 −6 Pa·s for air vs 8.94 × 10 −4 Pa·s for water). Continuing the calculation from two paragraphs above, air cooling needs ten times of the ...
Depending on the alloy and other considerations (such as concern for maximum hardness vs. cracking and distortion), cooling may be done with forced air or other gases, (such as nitrogen). Liquids may be used, due to their better thermal conductivity, such as oil, water, a polymer dissolved in water, or a brine.
The two important aspects of quenching are the cooling rate and the holding time. The most common practice is to quench into a bath of liquid nitrite-nitrate salt and hold in the bath. Because of the restricted temperature range for processing it is not usually possible to quench in water or brine, but high temperature oils are used for a ...
Frequently used in mixtures with e.g. nitrogen or air. Nitrogen: N 2: 1.15: 28: 1.251 – – not Often used at high pressure. Does not facilitate combustion. Can be used with 10–20% of SF 6 as a lower-cost alternative to SF 6. Can be used standalone or in combination with CO 2. Non-electron attaching, efficient in slowing electrons. Air: 29 ...
Quenching, in the context of pollution scrubbers, refers to the cooling of hot exhaust gas by water sprays before it enters the scrubber proper. Hot gases (those above ambient temperature) are often cooled to near the saturation level. If not cooled, the hot gas stream can evaporate a large portion of the scrubbing liquor, adversely affecting ...
Biermann, A.E. (1941). "The design of fins for air-cooled cylinders" (PDF). Report Nº 726.NACA.; P V Lamarque, "The design of cooling fins for Motorcycle Engines", Report of the Automobile Research Committee, Institution of Automobile Engineers Magazine, March 1943 issue, and also in "The Institution of Automobile Engineers Proceedings, Session 1942-1943, pp 99-134 and 309-312.
Of the cooling mechanisms responsible for forming volcanic glass, the most effective is quenching by water, followed by cooling by entrained air in an eruption column. The least effective mechanism is cooling at the bottom of a flow in contact with the ground.