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 Wysłany: Pią 10:57, 07 Sty 2011 Temat postu: ugg milano Vacuum gas quenching of high-speed stee |
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High-speed steel vacuum gas quenching the microstructure and hardness
In the high temperature (~ 760X3) from the secondary carbides precipitate in austenite, leaving the lower the degree of austenite Taijin, thus weakening the secondary hardening effect and affect the booming high-speed steel hard. Lekie-Ewing, such as working 【that high-speed steel vacuum gas quenching tempering effect of the reason why no significant precipitation hardening is due to gas quenching of the cooling rate is not high,[link widoczny dla zalogowanych], so high-speed steel in the quench cooling process along the austenite grain boundaries and due to the precipitation of carbides. The experiment has been observed under light microscope to the true air speed steel samples quenched thicker grain boundary in the electron microscope further confirmed that carbide precipitation along the grain boundary and grain interior (Fig.  , and the larger sample size , are the more carbide precipitation. Kuai 1989 l (a) alkali crystal precipitation Mei {SEM aims as tb) alkali extraction of material grain interior replica 6C00 × objective 8W6M05Cr4V2 vacuum gas quenching of steel after the organization (the sample size I in the 3O × 30ram, quenching I1230 \advanced industrial countries have now entered the application phase,[link widoczny dla zalogowanych], China has also started to introduce and conduct research. Neider-man 【study the high pressure gas quenching of a large section of M2 high speed steel and hardness, and heat and salt Popular quenching were compared. The results showed that vacuum high pressure gas quenching (0.5MPa) and the salt bath cooling Hardening two fastest carbide precipitation in the high temperature (900 ~ 1000 \Even if the section size is large enough to 1l4.3mm of M2 high speed steel,[link widoczny dla zalogowanych], in the gas (N 0.5MPa pressure gas quenching vacuum furnace can be achieved after the same salt bath quenching effect that secondary hardening effect is obvious carbide precipitation is suppressed. Merlini, who's work I have similar results. However, if the gas pressure down to 0.15 ~ O.2MPa, the section size is greater than l2.2mm high-speed steel tools, vacuum gas quenching were still not inhibit the precipitation of secondary carbides can be seen, cooling the gas pressure on the workpiece significantly affect the cooling rate. In addition, oil quenching to air cooling,[link widoczny dla zalogowanych], when the workpiece cooled to 1090 \speed to avoid carbide precipitation temperature range of four, conclusions 4.1 1l3O ~ l240 ℃ temperature range of quenching, when the insulation factor of 20 ~ 60s/ram when the pre-rolled steel with different deformation, W6MoSCr4V2 actinides in high-speed grain size is generally 11 (10.5) Grade 10 (9.5) level range. And, when quenching temperature is low, the heat coefficient have little effect on the grain size. 4.2 bath Hardening compared to the same quenching temperature (1220 \HRc0.5 ~ 1.5J600 \consultations between the hardness and red, should adopt the vacuum pressure (05MPa) or vacuum-cooled gas quenching oil quenching. 4.3 high-speed steel vacuum quenching is sometimes mixed grain tissues. In order to avoid mixed crystal, can be imposed before quenching 840 ~ 85O ℃, 4h full annealing. References [1] Zhao Ziwei, etc. - University of Technology on i sin, '19 \. 727 [3] to actually Yap so hungry actinium. 93 (1977) 1.90 [●] into actually eup, heat treatment. 23'1893) 4.202 [5] J. G. Conybear, V ~ tcuUmMetallurgy, (1977) 111 [6] P. Leckie-Ewingeta】, Met. Trar0.1A '1970) 51427 £ 3J. M. Netderman,[link widoczny dla zalogowanych], tools of copper vacuum high pressure gas with offend only. Third National Thermal pull Portugal} Pei Selected sack PolyU station. Machinery Industry Press pulled, (19951,3 ¨ [] N. Merliniet】, HeatTrea ~ ng.14 (1982) 1.42
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