Gas Quenching with Controllable Heat Extraction

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High pressure gas quenching became a modern way of quenching finally machined engineering components,having many advantages compared to quenching in liquid quenchants.The main shortcoming of this technology is the problem of achieving adequate hardness in the core of bigger workpieces,because of inadequate quenching intensity.Due to the possibility to change gas pressure and its flow velocity,combined with transient spraying of liquid nitrogen during the quenching process ,the intensity of cooling can be instantly increased during selected time intervals.In this way the heat extraction dynamics can be automatically controlled,and a predetermined path of the heat transfer coefficient can be followed.Preliminary experiments show that using the controllable heat extraction(CHE) technology, the mentioned shortcoming can be eliminated.Theoretical background of the CHE technology is described,with particular attention to the depth of hardening,and to residual stresses.Possibilities and prerequisite conditions for application of the CHE technology in vacuum furnaces,and for automatic heat extraction control,are discussed.

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Periodical:

Materials Science Forum (Volumes 539-543)

Main Theme:

Edited by:

T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran

Pages:

4663-4668

DOI:

10.4028/www.scientific.net/MSF.539-543.4663

Citation:

B. Liščić "Gas Quenching with Controllable Heat Extraction", Materials Science Forum, Vols. 539-543, pp. 4663-4668, 2007

Online since:

March 2007

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$35.00

[1] N. Shimizu and I. Tamura: Effect of Discontinuous Change in Cooling Rate During Continuous Cooling on Pearlite Transformation Behavior of Steel, Transactions ISIJ, 17 (1977), pp.469-476.

[2] N. Shimizu and I. Tamura: An Examination of the Relation between Quench-hardening Behavior of Steel and Cooling Curve in Oil, Transactions ISIJ, 18 (1978) P. 445-450.

[3] N.I. Kobasko: Basics of Intensive Quenching, Advanced Materials & Processes 9/95, p. 42W-42Y. Reference to this paper should be made as follows: B. Liscic: History and Perspective of Controllable Heat Extraction During Quenching, Proceedings of the 21st ASM Heat Treating Society Conference, ASM International (2001).

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