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Micrographic examination of metals
298
CURRENT ToPIcs.
Micrographic Examination of Metals.
J. S. G. PRI~:RoSt.'.
(Eng., Dec. I, 1911, 7 4 8 . ) - - T h e advantages of the use of the microscope in addition to chemical analysis and mechanical tests in the examination of metals are set forth. In the case of fractures, not only can the examination be made right up to the fracture itself. but also incorrect heat treatment or the presence of fatigue may be detected. Microphotographs are given illustrating the causes of a number of failures in iron and steel, which were revealed only by this method of analysis. These include the fracture of a wroughtiron angle bar which caused a boiler explosion; a mild steel plate which fractured on bending, although the test piece had passed the specification tests; a locomotive axl~ which broke while the engine was travelling at express speed: and a motor-car steering rod, the fracture of which was shown to be due to imperfect case-hardening. Attention is called to the fact that a piece of work may often be examined by the microscope before putting the material into service to determine whether it is in the proper structural condition for use.
Compound Britannia Metal Sheet.
ANon,-. (Brass World,
viii, I, IO.)--Owing to the increase in the price of tin, M'r. Lewis B. Tebbetts, of the Hovt Metal Company, has invented a compound Britannia metal shee}. The outside sheet is composed of Britannia metal (tin, antimony, and copper), and the base sheet is a lead alloy (lead and antimony). First the base metal is melted in a suitable open-face mold, and on this base metal, while it remains in a molten state, an umnolten body of facing metal is placed in the form of ~ rolled sheet. The facing body floats on the surface of the molteT~ base metal until it becomes fused thereto. The two plates fused together are then rolled till the composite metal plate is of the desired thickness. " Canadium," a N e w Element. A . G . FRENCtI. (Chem. News, civ, 2 8 3 . ) - - A supposed new metallic element, probably of the platinum group, has been discovered in the trap-dyke of the Nelson District of British Columbia. It has been found along with platinum and metals of that group in the form of grains and scales, in quantities varying from a few grains weight to three ounces per ton. This metal is white, of brilliant lustre, softer than platinum, ruthenium. palladium, or osmium, and has a melting point approaching that of silver. It is unaffected by moist air, or by heating in air for a long time. Iodine, hydrogen sulphide, or soluble sulphides do not affect it, but it is soluble in nitric and hydrochloric acids, and acts electronegatively to silver in dilute acids. It is not precipitated from its solutions by alkali chlorides or iodides.
Pitting of Nickel Deposits. ANON. 3 5 o . ) - - T h e pitting of nickel deposits may 5 to 6 ounces of boric acid in each gallon well as preventing pitting, it gives a whiter
(Brass World. vii, Io, be prevented by using of nickel solution. As deposit.
CURRENT ToPIcs.
Micrographic Examination of Metals.
J. S. G. PRI~:RoSt.'.
(Eng., Dec. I, 1911, 7 4 8 . ) - - T h e advantages of the use of the microscope in addition to chemical analysis and mechanical tests in the examination of metals are set forth. In the case of fractures, not only can the examination be made right up to the fracture itself. but also incorrect heat treatment or the presence of fatigue may be detected. Microphotographs are given illustrating the causes of a number of failures in iron and steel, which were revealed only by this method of analysis. These include the fracture of a wroughtiron angle bar which caused a boiler explosion; a mild steel plate which fractured on bending, although the test piece had passed the specification tests; a locomotive axl~ which broke while the engine was travelling at express speed: and a motor-car steering rod, the fracture of which was shown to be due to imperfect case-hardening. Attention is called to the fact that a piece of work may often be examined by the microscope before putting the material into service to determine whether it is in the proper structural condition for use.
Compound Britannia Metal Sheet.
ANon,-. (Brass World,
viii, I, IO.)--Owing to the increase in the price of tin, M'r. Lewis B. Tebbetts, of the Hovt Metal Company, has invented a compound Britannia metal shee}. The outside sheet is composed of Britannia metal (tin, antimony, and copper), and the base sheet is a lead alloy (lead and antimony). First the base metal is melted in a suitable open-face mold, and on this base metal, while it remains in a molten state, an umnolten body of facing metal is placed in the form of ~ rolled sheet. The facing body floats on the surface of the molteT~ base metal until it becomes fused thereto. The two plates fused together are then rolled till the composite metal plate is of the desired thickness. " Canadium," a N e w Element. A . G . FRENCtI. (Chem. News, civ, 2 8 3 . ) - - A supposed new metallic element, probably of the platinum group, has been discovered in the trap-dyke of the Nelson District of British Columbia. It has been found along with platinum and metals of that group in the form of grains and scales, in quantities varying from a few grains weight to three ounces per ton. This metal is white, of brilliant lustre, softer than platinum, ruthenium. palladium, or osmium, and has a melting point approaching that of silver. It is unaffected by moist air, or by heating in air for a long time. Iodine, hydrogen sulphide, or soluble sulphides do not affect it, but it is soluble in nitric and hydrochloric acids, and acts electronegatively to silver in dilute acids. It is not precipitated from its solutions by alkali chlorides or iodides.
Pitting of Nickel Deposits. ANON. 3 5 o . ) - - T h e pitting of nickel deposits may 5 to 6 ounces of boric acid in each gallon well as preventing pitting, it gives a whiter
(Brass World. vii, Io, be prevented by using of nickel solution. As deposit.