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Steel MakingThe Care Of Carburizing CompoundsOf all the opportunities for practicing economy in the heat-t... Rate Of Cooling At the option of the manufacturer, the above treatment of gea... The Effect The heating at 1,600 deg.F. gives the first heat treatment w... Heat Treatment Of Gear Blanks This section is based on a paper read before the American Gea... The Penetration Of Carbon Carburized mild steel is used to a great extent in the manufa... Placing The Thermo-couples The following illustrations from the Taylor Instrument Compan... Sulphur Sulphur is another impurity and high sulphur is even a greate... Steel Before The 1850's In spite of a rapid increase in the use of machines and the ... Heavy Forging Practice In heavy forging practice where the metal is being worked at... Nickel-chromium A combination of the characteristics of nickel and the charac... Process Of Carburizing Carburizing imparts a shell of high-carbon content to a low-... Blending The Compound Essentially, this consists of the sturdy, power-driven separa... Open Hearth Process The open hearth furnace consists of a big brick room with a l... William Kelly's Air-boiling Process An account of Bessemer's address to the British Association w... The Theory Of Tempering Steel that has been hardened is generally harder and more br... For Milling Cutters And Formed Tools FORGING.--Forge as before.--ANNEALING.--Place the steel in a ... Heat-treating Department The heat-treating department occupies an L-shaped building. ... Properties Of Steel Steels are known by certain tests. Early tests were more or l... Gas Consumption For Carburizing Although the advantages offered by the gas-fired furnace for ... Steel Worked In Austenitic State As a general rule steel should be worked when it is in the a... |
Application To The Automotive IndustryCategory: APPLICATION OF LIBERTY ENGINE MATERIALS TO THE AUTOMOTIVE INDUSTRY The information given on the various parts of the Liberty engine applies with equal force to the corresponding parts in the construction of an automobile, truck or tractor. We recommend as first choice for carbon-steel screw-machine parts material produced by the basic open hearth process and having the following chemical composition; Carbon, 0.150 to 0.250 per cent; manganese, 0.500 to 0.800 per cent; phosphorus, 0.045 maximum per cent; sulphur, 0.075 to 0.150 per cent. This material is very uniform and is nearly as free cutting as bessemer screw stock. It is sufficiently uniform to be used for unimportant carburized parts, as well as for non-heat-treated screw-machine parts. A number of the large automobile manufacturers are now specifying this material in preference to the regular bessemer grades. As second choice for carbon-steel screw-machine parts we recommend ordinary bessemer screw stock, purchased in accordance with S. A. E. specification No. 1114. The advantage of using No. 1114 steel lies in the fact that the majority of warehouses carry standard sizes of this material in stock at all times. The disadvantage of using this material is due to its lack of uniformity. The important criterion for transmission gears is resistance to wear. To secure proper resistance to wear a Brinell hardness of from 512 to 560 must be obtained. The material selected to obtain this hardness should be one which can be made most nearly uniform, will undergo forging operations the easiest, will be the hardest to overheat or burn, will machine best and will respond to a good commercial range of heat treatment. It is a well-known fact that the element chromium, when in the form of chromium carbide in alloy steel, offers the greatest resistance to wear of any combination yet developed. It is also a well-known fact that the element nickel in steel gives excellent shock-resisting properties as well as resistance to wear but not nearly as great a resistance to wear as chromium. It has been standard practice for a number of years for many manufacturers to use a high nickel-chromium steel for transmission gears. A typical nickel-chromium gear specification is as follows: Carbon, 0.470 to 0.520 per cent; manganese, 0.500 to 0.800 per cent; phosphorus, 0.040 maximum per cent; sulphur, 0.045 maximum per cent; chromium, 0.700 to 0.950 per cent. There is no question but that a gear made from material of such an analysis will give excellent service. However, it is possible to obtain the same quality of service and at the same time appreciably reduce the cost of the finished part. The gear steel specified is of the air-hardening type. It is extremely sensitive to secondary pipe, as well as seams, and is extremely difficult to forge and very easy to overheat. The heat-treatment range is very wide, but the danger from quenching cracks is very great. In regard to the machineability, this material is the hardest to machine of any alloy steel known. Next: Composition Of Transmission-gear Steel Previous: Piston Pin
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