The traditional methods of shaping

The traditional methods of shaping metals by casting or by hot or cold working are difficult and sometimes impossible to apply to many metals. Such refractory metals include tungsten (m. p. 3380 C), molybdenum (2622) and tantalum ( 2996 C) whose melting points are too high to enable them to be melted by conventional means. In these cases an alternative procedure has emerged based on the fact that metals in powdered from may be caused to adhere together without being melted by employment of high pressure. The technique known as powder metallurgy consists in subjecting the powdered metal contained in a mould or die of the shape desired to a high pressure followed by sintering at a suitable temperature. The method provides either finished metal components or compact blocks of metal for subsequent mechanical working. Having been applied first to the refractory metals the method has been extended to many of the more tractable metals.
The technique originated nore than a century ago. The preparation of compact platinum from the then infusible metal by W. H. Wollaston 1830 represents one of the earliear applications of powder metallurgy.
Production of powder of the requisite properties is an important stage in the procedure of powder metallurgy. Powders of metals and alloys may be produced by mechanical methods such as grinding, machining and milling; other metal powders can be obtained by reduction of the metal oxide by hydrogen or carbon. Copper, iron, cobalt, molybdenum and tungsten can all be so prepared in powder from from their oxides. Electrolysis is also, and aluminum, tin, and lead are transformed into powder form by atomization, molten metal being poured through an orifice into a chamber and sprayed with a high pressure jet of inert gas, the instantaneous chiling converting the metal into a finely divided dust.
At the present day powder metallurgy is mainly used in making large numbers of identical components usually of relatively small size, such as permanent magnets, coins, medals, small gear wheels and brushes for motors and dynamos. A movel extension of its application is in the oilless bearing which can be impregnated with oil and made self-lubricating. Such bearings are designed to retain with in their structure a sufficient amount of oil to last for several years.

Результаты (английский) 1:

The traditional methods of shaping metals by casting or by hot or cold working are difficult and sometimes impossible to apply to many metals. Such refractory metals include tungsten (m. p. 3380 C) amp (2622) and tantalum (2996 C) 3 melting points are too high to enable them to be melted by conventional means. In these cases an alternative procedure has emerged based on the fact that metals in powdered from may be caused to adhere together without being melted by employment of high pressure. The technique known as powder metallurgy consists in subjecting the powdered metal contained in a mould or die of the desired shape to a high pressure followed by sintering at a suitable temperature. The method provides either finished metal components or compact blocks of metal for suggested mechanical working. Having been applied first to the refractory metals, the method has been extended to many of the more tractable metals.The technique originated nore than a century ago. The preparation of compact platinum from the then infusible metal by w. h. Wollaston 1830 represents one of the earliear applications of powder metallurgy.Production of powder of the requisite properties is an important stage in the procedure of powder metallurgy. Powders of metals and alloys products may be mass-produced by mechanical methods such as grinding, machining and milling; other metal powders can be obtained by reduction of the metal oxide by hydrogen or carbon. Copper, iron, cobalt, and tungsten amp can all be so prepared in powder from from their oxides. Electrolysis is also, and aluminum, tin, and lead are transformed into powder form by atomization, molten metal being poured through an orifice into a chamber and sprayed with a high pressure jet of inert gas, the instantaneous chiling machine the metal into a finely divided dust.At the present day powder metallurgy is mainly used in making large numbers of identical components usually of relatively small size, such as permanent magnets, coins, medals, small gear wheels and brushes for motors and dynamos. (A) extension of its movel application is in the oilless bearing which can be impregnated with oil and made self-lubricating. Such bearings are designed to retain in their structure with a sufficient amount of oil to last for several years.

Результаты (английский) 3:

the traditional methods of shaping metals by casting or by hot or cold working are difficult and sometimes impossible to apply to many metals. such refractory metals include tungsten (m. p. 3380 c) go (2622) and tantalum (2996 c) whose melting points are too high to enable them to be melted by conventional means. in these cases an alternative procedure has emerged based on the fact that metals in not working a few times and may be caused to adhere together without being melted by employment of high pressure. the technique known as powder metallurgy consists in subjecting the not working a few times metal contained in a cold or die of the shape desired to a high pressure followed by sintering at a suitable temperature. the method provides either finished metal components or compact blocks of metal for subsequent mechanical working. having been applied to the refractory for which the method has been extended to many of the more tractable metals.the technique on nore than a century ago. the preparation of compact platinum from the then infusible metal by w. h. Wollaston 1830 represents one of the earliear applications of powder metallurgy.production of powder of the requisite properties is an important stage in the procedure of powder metallurgy. Powders of metals and alloys may be produced by mechanical methods such as grinding, machining and milling; other metal powders can be obtained by reduction of the metal oxide by hydrogen or carbon. copper, iron, cobalt, and go tungsten can all be so prepared in powder from from their oxides. Electrolysis is also, and aluminum, tin, and lead are transformed into powder form by atomization, molten metal being poured through an orifice into a chamber and sprayed with a high pressure jet of inert gas, the instantaneous frequencies chiling the metal into a finely divided dust.at the present day powder metallurgy is mainly used in making large numbers of identical components is of relatively small size, such as permanent magnets, governments, medals, small gear wheels and brushes for motors and dynamos. a movel extension of its application is in the oilless bearing which can be impregnated with oil and made self - lubricating. such bearings are designed to retain, in their structure, a sufficient amount of oil to last for several years.