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Steel MakingUses Of The Various Tempers Of Carbon Tool SteelDIE TEMPER.--No. 3: All kinds of dies for deep stamping, pres... Non-shrinking Oil-hardening Steels Certain steels have a very low rate of expansion and contract... Carbon In Tool Steel Carbon tool steel, or tool steel as it is commonly called, us... Preventing Decarbonization Of Tool Steel It is especially important to prevent decarbonization in such... Heat Treatment Of Lathe Planer And Similar Tools FIRE.--For these tools a good fire is one made of hard foundr... Annealing In Bone Steel and cast iron may both be annealed in granulated bone. ... Protective Screens For Furnaces Workmen needlessly exposed to the flames, heat and glare from... The Influence Of Size The size of the piece influences the physical properties obta... Tempering Colors On Carbon Steels Opinions differ as to the temperature which is indicated by t... Carbon Tool Steel Heat to a bright red, about 1,500 to 1,550 deg.F. Do not ham... Oil-hardening Steel Heat slowly and uniformly to 1,450 deg.F. and forge thorough... Heat Treatment Of Gear Blanks This section is based on a paper read before the American Gea... Hardening High-speed Steels We will now take up the matter of hardening high-speed steels... The Pyrometer And Its Use In the heat treatment of steel, it has become absolutely nece... Piston Pin The piston pin on an aviation engine must possess maximum res... Quenching The Work In some operations case-hardened work is quenched from the bo... Nickel-chromium A combination of the characteristics of nickel and the charac... S A E Heat Treatments The Society of Automotive Engineers have adopted certain heat... Hardening The forgings can be hardened by cooling in still air or quen... Temperatures To Use As soon as the temperature of the steel reaches 100 deg.C. (... |
Detrimental ElementsCategory: HIGH-SPEED STEEL Sulphur and phosphorus are two elements known to be detrimental to all steels. Sulphur causes red-shortness and phosphorus causes cold-shortness. The detrimental effects of these two elements counteract each other to some extent but the content should be not over 0.02 sulphur and 0.025 phosphorus. The serious detrimental effect of small quantities of sulphur and phosphorus is due to their not being uniformly distributed, owing to their tendency to segregate. The manganese and silicon contents are relatively unimportant in the percentages usually found in high-speed steel. The detrimental effects of tin, copper and arsenic are not generally realized by the trade. Small quantities of these impurities are exceedingly harmful. These elements are very seldom determined in customers' chemical laboratories and it is somewhat difficult for public chemists to analyze for them. In justice to the manufacturer, attention should be called to the variations in chemical analyses among the best of laboratories. Generally speaking, a steel works' laboratory will obtain results more nearly true and accurate than is possible with a customer's laboratory, or by a public chemist. This can reasonably be expected, for the steel works' chemist is a specialist, analyzing the same material for the same elements day in and day out. The importance of the chemical laboratory to a tool-steel plant cannot be over-estimated. Every heat of steel is analyzed for each element, and check analyses obtained; also, every substance used in the mix is analyzed for all impurities. The importance of using pure base materials is known to all manufacturers despite chemical evidence that certain detrimental elements are removed in the process of manufacture. The manufacture of high-speed steel represents the highest art in the making of steel by tool-steel practice. Some may say, on account of our increased knowledge of chemistry and metallurgy, that the making of such steel has ceased to be an art, but has become a science. It is, in fact an art; aided by science. The human element in its manufacture is a decided factor, as will be brought in the following remarks: The heat treatment of steel in its broad aspect may be said to commence with the melting furnace and end with the hardening and tempering of the finished product. High-speed steel is melted by two general types of furnace, known as crucible and electric. Steel treaters, however, are more vitally interested in the changes that take place in the steel during the various processes of manufacture rather than a detailed description of those processes, which are more or less familiar to all. In order that good high-speed steel may be furnished in finished bars, it must be of correct chemical analysis, properly melted and cast into solid ingots, free from blow-holes and surface defects. Sudden changes of temperature are to be guarded against at every stage of its manufacture and subsequent treatment. The ingots are relatively weak, and the tendency to crack due to cooling strains is great. For this reason the hot ingots are not allowed to cool quickly, but are placed in furnaces which are of about the same temperature and are allowed to cool gradually before being placed in stock. Good steel can be made only from good ingots. Steel treaters should be more vitally interested in the important changes which take place in high-speed steel during the hammering operations than that of any other working the steel receives in the course of its manufacture. Next: Quality And Structure Previous: Standard Analysis
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