Practical Microscopical Metallography |
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0.9 per cent 30 brass acid in alcohol allotropic alloy steels alloys aluminium ammonium persulphate amount annealed austenitic Brinell hardness brittle carbide carbon steel cast iron cementite chromium cold-worked colour combined carbon composition constitutional diagram copper critical range decarburisation dendritic deoxidiser effect elongation enclosing grains Etched with ammoniacal eutectic eutectoid ferric chloride ferrite ferrite network forging grain boundaries graphite groundmass of ferrite hardened impurities lamellar pearlite liquid magnifications malleable cast manganese manganese sulphide martensite mechanical properties microscopical examination microstructure nickel steel nitric acid normalised objective occurs ocular particles pearlite Percentage phosphide phosphorus pig iron plates polishing polyhedral grains pure quenching rate of cooling reagent rolling separation of ferrite showing silicon slag slow cooling slowly cooled solid solution solidification solution of ammonium sorbitic sorbitic pearlite specimen steel containing structure sulphur surface temperature tempering tensile strength tons per sq troostite Unetched vertical illuminator white iron zinc
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Page 91 - ... external film. Before the actual crystalline structure corresponding to the condition of the metal can be seen, this film has to be removed. The quickest and easiest way of doing this is by etching, which means eating it away with the aid of a suitable acid. Usually 2 per cent nitric acid in alcohol or a saturated solution of picric acid in alcohol is used. It must be mentioned here that with pure metals and solid solutions, a number of crystals are usually so positioned that in respect of their...
Page 115 - W. Rosenhain, SL Archbutt, and D. Hanson, "Eleventh Report to the Alloys Research Committee: on Some Alloys of Aluminium (Light Alloys),
Page 80 - ... stirring, and then after standing over night to filter through a small filter, and wash with alcohol ; one extraction will often suffice. A second extraction may, however, be necessary, the work being of course controlled by the indications of the spectroscope. After evaporating off the alcohol and ether, the salts are dissolved in the least possible quantity of water, and filtered into a weighed platinum dish. The filtrate and washings should then be concentrated to small bulk (5 or 10 cc) and...
Page 42 - ... instances of value of co-operation ; relation of laboratory operations to steel treating. TIRES AND AXLES. The Forging and Heat Treatment of Tyres and Axles, W. Sutherland. Australasian Inst. Min. & Met. — Proc, no. 63, Sept., 1926, pp. 33-46, 1 fig. Iron-iron carbide equilibrium diagram ; considers changes which occur on cooling pure carbon steels of varying carbon content from temperatures above upper limit of critical range, at which steel consists of solid solution referred to as austenite...
Page 58 - Pb., equiv. 1037, spec. grav. 11-4) is a bluish-white metal of considerable brilliancy, which soon disappears on exposure to the air, owing to the formation of a thin film of oxide. It is so soft that it may be readily cut with a knife, or may be made to take impressions, and it leaves a streak upon paper. It may be cut or beaten into thin sheets, but in ductility and tenacity it is low in the scale of metals. It is readily fusible at a temperature of about 625°, and at a higher...
Page 116 - Metnls, 1923, 29, 491. process of bringing about the formation of fully saturated solid solutions even without relying upon their subsequent decomposition, which is characteristic of age-hardening. Thus, under equilibrium conditions, aluminium can hold 5 per cent, of copper in solid solution at 500° C., and even at ordinary temperatures about 3 per cent. Yet, if an alloy of aluminium with 4 per cent, copper is prepared in the ordinary way, it is found to contain a considerable amount of free CuAlz,...
Page 15 - ... inches from the objective. The objective produces an enlarged real image of a portion of the object under examination. For visual examination, the ocular is arranged to give a further enlarged virtual image of that produced by the objective ; for photomicrography the ocular is arranged AB F1G.
Page 56 - ... lamellar as in pearlite. It consists of minute particles of carbide in a ground mass (or matrix) of ferrite and on further tempering the carbide particles coalesce. Sorbitic Pearlite. — A minutely lamellar microstructure of some quenched but untempered steels, which are not completely martensitic. It is often irresolvable under the microscope, and frequently etches dark very rapidly, in which case it is known as troosto-sorbite.
Page 42 - ... Introduction; Preparation of Specimens for Micro-examination; The Microscope and Method of Microscopical Examination; Low-power Photomicrography and Macrography; The Structure of Pure Metals and of Alloys; The Structure and Properties of Ingot Iron and Wrought Iron; The Structure and Properties of Normalized and Annealed Carbon Steels, and the Effect of Hot - and Cold - work; The Structure and Properties of Hardened and Tempered Carbon Steels; The Structure and Properties of Alloy Steels and...