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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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In Reply to: RE: Tubes! To Cryo Or Not To Cryo? That's The Question! posted by bfranchuk@jetnet.ab.ca on January 18, 2010 at 07:55:32:
I don't think you can question cryogenic metal treatment per se. It's clear that properly done it can make a positive difference. I think the question is whether the benefits of cryo are of any consequence when applied to vacuum tubes.
In the abstract from the Journal of Materials Processing Technology
Volume 118, Issues 1-3, 3 December 2001, Pages 350-355 - it states:
"The effect of deep cryogenic treatment (−196°C) on the properties of some tool steels was studied by means of both field tests on real tools and laboratory tests. The execution of the deep cryogenic treatment on quenched and tempered high speed steel tools increases hardness, reduces tool consumption and down time for the equipment set up, thus leading to cost reductions of about 50%. A laboratory investigation on an AISI M2 and an AISI H13 steel confirms the possibility of increasing the wear resistance and toughness by carrying out the treatment after the usual heat treatment."
From the Journal of Solid State Phenomena, volume 118:
"It is well known that the durability of tool steel could be improved by deep cryogenic treatment. It has been assumed that the increase of service life of tool steel caused by decrease of retained austenite and/or by formation of nano-scale fine η-carbide. But the principles of deep cryogenic treatment remain unclear yet. In this research, to manifest the effect of deep cryogenic treatment on wear resistance, the specimen was emerged in liquid nitrogen for 20 hours for deep cryogenic treatment after austenitizing and the following tempering temperature was varied. The microstructure of specimens was observed using TEM and the mechanical properties and wear resistance were examined. As the tempering temperature increased, the carbides became larger and fine carbides were formed above certain temperature. In the case of deep cryogenic treated specimen, the number of carbides increased while the carbides size was decreased, furthermore, the fine carbide forming temperature was lowered also. It was considered that the deep cryogenic treatment increased the driving force for the nucleation of carbides. As tempering temperature increased, hardness decreased while wear resistance and impact energy increased. The deep cryogenic treated specimens showed this tendency more clearly. It was considered that the wear resistance is affected not only to the hardness but also to the precipitation of fine carbides, and this carbide evolution can be optimized through the deep cryogenic treatment."
Whether this sort of molecular level change can be beneficially applied to tubes - who knows? Certainly not me! If these guys aren't sure I'm going to keep my options open.
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Follow Ups
- RE: Tubes! To Cryo Or Not To Cryo? That's The Question! - Jim McShane 01/18/1013:17:07 01/18/10 (3)
- Based on those journal extracts - NewbieBaby 05:14:42 01/22/10 (2)
- RE: Based on those journal extracts - Triode_Kingdom 05:55:04 01/22/10 (1)
- RE: Based on those journal extracts - Palustris 14:38:08 01/22/10 (0)
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