Metals and Materials.
Page 44
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The special metals used on various parts of cars have in many cases been mentioned in the various detailed descriptions of vehicles. One or two exhibitors show, separately, special material suitable for automobile construction. W. F. Flather, Limited, of the Standard Steel Works, Love Street, Sheffield, has an exhibit (Stand No. 201) of its " Ubas " brand of steel for ease-hardening, etc., and this is well 1nown in motorcar work as being of high quality. Some specimens of this d netal which, after case-hardening, have been subjected to torsion until broken, show remarkable results, the soft centre preventing fracture for a long time, although the harder outer skin is cracked. A gear wheel of this material was shown in igo5; since that time it has run 33,000 miles, and still is in useable condition. Examples are shown of 25 per cent, nickel steel valves, case-hardened nickel steel, forging-s, high-speed files, etc. A class of metal increasingly used in motor work is bright-drawn bar, and, often, the outer finish of this covers somewhat inferior metal. This company makes a speciality of high-class bar of this type, as the following results from a tensile test show—
Tensile strength, 35.25 tons per sq. in. Elastic limit, 31.29 tons per sq, in. Elongation, 31.5 per cent.
Reduction of area, 52 per cent.
The high elastic limit, equal to 88 per cent. of the final strength, will be noted, and the figures clearly show the high quality of this material.
The Kirlsstall Forge Company, of Kirkstall, near Leeds (Stand No. 89), has devoted considerable attention to a pure-carbon steel of high grade, which it makes in five grades varying from a soft material, for articles requiring to be case-hardened, to one suitable for cranks and shafts for special purposes. Tensile tests of the two extreme grades
of this metal, which is called "Puritza," are given below for the " No. m " and " No. 5 " grades, respectively :—Ultimate tensile strength, 23 and do tons per sq. in. ; elastic limit, 14 and 45 tons per sq. in. ; elongation in 2 inches, 53 and 23 per cent.; reduction of area, 70 and 45 per cent. Examples are shown of the softer material which, after casehardening, shows a reduction of area of 30 per cent. after a tensile test. Good bend tests of case-hardened square sections are also exhibited.
Winans and Robinson, Limited, of Rugby, shows examples of bearings and bushes cast by its well-known " Eatonia " method and, for comparison, articles cast in the ordinary way. There are, too, several cranks, etc., of Vanadium steel, and some most remarkable turnings of this metal which, although subjected, as all turnings are, to the very considerable strains set up in being torn off she bar, are similar to minute springs in their behaviour.