acier nitrurant
- Domaine
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- métallurgie acier
Terme :
- acier nitrurant n. m.
Traductions
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anglais
Auteur : Schuurmans Stekhoven, G.,Définition
The name used in reference to those types of alloy steel that are susceptible to hardening by the nitriding process; the essential alloying elements are one or more of those that form stable nitrides: aluminium, chromium, vanadium; molybdenum is also added because the nitriding process takes places in that range of temperature which favours the occurrence of temper brittleness in certain types of steel, viz. those that contain high properties of manganese, chromium and phosphorus; the presence of molybdenum markedly reduces the tendency; nitralloy, a special range of steel suitable for nitriding, has the following range of composition: c 0.38-0.43 %, si 0.2-0.3 %, mn 0.4-0.6 %, cr 1.6-1.8 %, al 0.8-1.25 %, ni 0.3-6 %, mo 0.15-0.25 %; chromium-molybdenum-nickel and other medium carbon steels that do not contain aluminium are being nitrided, but the surface hardness obtained in such steels is much less than that obtained with steels containing aluminium - the values lying between 600 and 900 d.p.h.; nitrided parts can be softened by heating in a bath of fused salts containing equal parts of sodium and potassium chlorides at about 815 °C; nitrided steels show a great improvement in endurance and wear-resistance properties over other steels, and since the nitride case retains its hardness at elevated temperatures, they have marked advantages for use as liners in high-power aircraft engines, motor cars, etc.; leaded bronzes containing 80 % cu, 10 % sn and 10 % pb, and graphite bronzes are generally used as bushings against nitrided nitralloy.
Terme :
- nitralloy