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Development and application of alternate timed quenching by water and air
Chen, N.L., Zhang, W.M., Gu, J.F., Zuo, X.W. , Xu, J.
Abstract: Water and air are commonly used quench media with very different quenching powers; further, they are environmentally friendly and of very low cost. Theoretically, alternate quenching by water and air can produce any desired cooling rate between those of each medium alone. While this technology has not been practicable due to the difficulties in process design and control, the recent development of numerical simulation and processing control techniques has established a solid base for its industrial application. A new technology, alternate timed quenching by water and air (AT-quenching), is proposed. The technology has been applied to a medium carbon low alloy steel, the mechanical properties of which do not meet specification after oil quenching, but which suffers cracking after water quenching. The key points are to design the process by computer simulation and to realise it with digitally controlled quenching equipment. The technology has been successfully employed in production of large forged blocks of die steel for plastics moulding, long shaft forgings and forgings for marine crankshaft, effectively solving the difficulties that traditional processes and quenchants encounter.
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