. Journal . It is now found the cutting -peed permissible is reduced if thetemperature in hardening lias somewhat exceeded that ofcherry-redoes-, it is urn• iter treatment at much higher temperatures. The accompanying ourvc (Fig. 1) Fiar. l. cu Wl in «n X 1C BRi- - \ e o t>PH > POIN1 CHABACTCIttZT c or i7o» i-y> ilon mo ■»» TEMPERATURES. illustrates this, Beyond 1,900° or 8,000 F. the steeles, and the limit of safety is therefore passed. Steelised for the Taylor-White process should contain at i per ■•• rit. of Cr, and at least 1 per cent of Mo or ; the results are bette
. Journal . It is now found the cutting -peed permissible is reduced if thetemperature in hardening lias somewhat exceeded that ofcherry-redoes-, it is urn• iter treatment at much higher temperatures. The accompanying ourvc (Fig. 1) Fiar. l. cu Wl in «n X 1C BRi- - \ e o t>PH > POIN1 CHABACTCIttZT c or i7o» i-y> ilon mo ■»» TEMPERATURES. illustrates this, Beyond 1,900° or 8,000 F. the steeles, and the limit of safety is therefore passed. Steelised for the Taylor-White process should contain at i per ■•• rit. of Cr, and at least 1 per cent of Mo or ; the results are better when higher proportions of these metajs are used. The percentage of carbon present, appears to have little or no effect on the results. During ■ BS] the proportion of chromium carbide present isreduced, and the relvely grain of the fractured steel whencooled under ordinary circum-tanec- is replaced by a Fig. grain, often with sparkling grains interspersed. After heat-lug, the tool is cooled rapi llv to a point below thebreaking-down temperature (1,550 1,700 K.) insbad bath and then slowly in air or lime. It is essential tbatthe temperature should not rise. After cooling off. however,the efficiency may be increased by subjecting the materialto a temperature of Too — 1,21)0 F. for about tool is originally heated in a coke furnace until thesteel crumbles when tapped with ii rod, lie lead bath mis shown in Fig. 2; it consist* of a east-iron lead-pot set ina coke tire, the temperature of which is controlled l>\ anaii-blast. If the lead become too hot, it i- cooled b]immersing within it a cooling-pipe with water circulatingthrough it I In temperaturi of the buh i- observed bycomparing the colour. us viewed through the pipe T, andthe blackened wooden tube surrounding it, with an ineau-descenl electric lump, run at constant voltage with the aidof a rheostat, the light of which l
Size: 1583px × 1579px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
