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Steel MakingSteel Before The 1850'sIn spite of a rapid increase in the use of machines and the ... Testing And Inspection Of Heat Treatment The hard parts of the gear must be so hard that a new mill f... Mushet And Bessemer That Mushet was "used" by Ebbw Vale against Bessemer is, perh... Annealing Method Forgings which are too hard to machine are put in pots with ... Short Method Of Treatment In the new method, the packed pots are run into the case-har... Fatigue Tests It has been known for fifty years that a beam or rod would fa... The Care Of Carburizing Compounds Of all the opportunities for practicing economy in the heat-t... Tensile Properties Strength of a metal is usually expressed in the number of pou... Hardening High-speed Steels We will now take up the matter of hardening high-speed steels... Quenching It is considered good practice to quench alloy steels from th... Carburizing By Gas The process of carburizing by gas, briefly mentioned on page ... Chrome-nickel Steel Forging heat of chrome-nickel steel depends very largely on ... Effects Of Proper Annealing Proper annealing of low-carbon steels causes a complete solu... Protectors For Thermo-couples Thermo-couples must be protected from the danger of mechanica... An Automatic Temperature Control Pyrometer Automatic temperature control instruments are similar to the ... Annealing In Bone Steel and cast iron may both be annealed in granulated bone. ... Heat Treatment Of Punches And Dies Shears Taps Etc HEATING.--The degree to which tools of the above classes shou... High-chromium Or Rust-proof Steel High-chromium, or what is called stainless steel containing f... High Speed Steel For centuries the secret art of making tool steel was handed ... For Milling Cutters And Formed Tools FORGING.--Forge as before.--ANNEALING.--Place the steel in a ... |
Nickel-chromiumCategory: ALLOYS AND THEIR EFFECT UPON STEEL A combination of the characteristics of nickel and the characteristics of chromium, as described, should obviously give a very excellent steel as the nickel particularly affects the ferrite of the steel and the chromium the carbon. From this combination, we are able to get a very strong ferrite matrix and a very hard tough cementite. The strength of a strictly pearlitic steel over a pure iron is due to the pearlitic being a layer arrangement of cementite running parallel to that of a pure iron layer in each individual grain. The ferrite i.e., the iron is increased in strength by the resistance offered by the cementite which is the simple iron-carbon combination known to metallurgists as Fe3C. The cementite, although adding to the tensile strength, is very brittle and the strength of the pearlite is the combination of the ferrite and cementite. In the event of the cementite being strengthened, as in the case of strictly chromium steels, an increased tensile strength is readily obtained without loss of ductility and if the ferrite is strengthened then the tensile strength and ductility of the metal is still further improved. Nickel-chromium alloy represents one of the best combinations available at the present time. The nickel intensifies the physical characteristics of the chromium and the chromium has a similar effect on the nickel. For case-hardening, nickel-chromium steels seem to give very excellent results. The carbon is very rapidly taken up in this combination, and for that reason is rather preferable to the straight nickel steel. With the mutually intensifying action of chromium and nickel there is a most suitable ratio for these two alloys, and it has been found that roughly 2-1/2 parts of nickel to about 1 part of chromium gives the best results. Therefore, we have the standard types of 3.5 per cent nickel with 1.5 per cent chromium to 1.5 per cent nickel with 0.6 per cent chromium and the various intermediate types. This ratio, however, does not give the whole story of nickel-chromium combinations, and many surprising results have been obtained with these alloys when other percentage combinations have been employed. Next: Vanadium Previous: Chromium
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