Harden and temper

T. H. Spenser and co-workers. Induction Hardening and Tempering, American Society for Metals, Metals Park, Ohio, 1964. 

Fig. 5. Micrographs of the microstructure of fully hardened and tempered tool steels produced by the powder metallurgy technique, showing uniform distribution and fine carbide particles in the matrix, (a) M-42 (see Table 6) and (b) cobalt-free AlSl T-15 having a higher concentration of fine carbide...

Fig. 12.23 shows the variation of hardness with distance from surface for a chromised high-carbon steel (1% C). The full line represents the material as treated , the broken line corresponds to conditions after full-hardening and tempering. The apparent greater depth of the hard zone in the heat-treated material is due to the effect of small concentrations of chromium... 

Some data on corrosion rates24 in acetic acid (5%) and phosphoric acids (5%) at 49°C and measured pitting potentials of martensitic steels and Type 409 and 430 ferritic steels are given in Tables 4.17 and 4.18, respectively. The martensitic steel samples were hardened and tempered at 204° C. 

Post quench hardening and tempering of D2/TiN does not influence the coating residual stresses significantly (Figure 16a). This is due to the almost equal specific substrate volumes... 

These processes of hardening and tempering can be -understood by consideration of the phases which can be formed by iron and carbon. Carbon is soluble in y-iron, the form stable above 912 C. If the steel is quenched from above this temperature there is obtained a solid solution of carbon in a-iron. This material, called martensite, is very hard and brittle (Fig. 26-8). It confers hardness and brittleness upon hardened high-carbon steel. Martensite is not stable at room temperature, but its rate of conversion to more stable phases is so small at room temperature as to be negligible, and hardened steel containing martensite remains hard as long as it is not reheated. 

L( aving those plates for a moment, get some silver-steel or cast-steel and turn the punches, leaving the pilot K equal in diameter to that of the punch L. Notice also that the punch m is slightly longer than L, which enables it to enter the metal and form a steady for the weaker punch. The punches are hardened and tempered, leaving the end N soft, allowing it, after being driven into plate F, to be riveted over into a chamfer provided. 

Induction Heating, Fig. 6 Hardening and tempering of a tube (Source ITG Induktionsanlagen GmbH)... 

High-alloyed steels with a martensitic microstructure show machining results, which heavily depend on the workmaterial hardness and thus on the applied heat treatment. However, hardened and tempered martensitic stainless steels can be machined relatively well with suitable cutting parameters, tool materials, and coating systems, respectively. The dominant failure modes when using coated carbide tools for cutting hardened... 

Cold chisels are used for cutting metal. They are made from high-carbon steel, hardened and tempered at the cutting end. The opposite end, which is struck by the hammer, is not hardened but is left to withstand the hammer blows without chipping. 

The engineer s hammer consists of a hardened and tempered steel head, varying in mass from 0.1kg to about 1kg, firmly fixed on a tough wooden handle, usually hickory or ash. 

Dies are used to cut external threads and are available in sizes up to approximately 36mm thread diameter. The common type, for use by hand, is the circular split die, made from high-speed steel hardened and tempered and split at one side to enable small adjustments of size to be made. Fig. 2.19. 

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