Full annealing

Full annealing is done on steels to achieve maximum softness. They are placed in a furnace and taken to a suitable temperature. The furnace is switched off, thus preventing the steel from re-hardening as it cools. 

For carbon and low-alloy steels, full annealing requires heating to a temperature of 1350°F to 1750°F (730°C to 955°C). The steel is held at this temperature long enough to ensure through-... 

Nevertheless, Carlson s essentially semi-empirical method has gained acceptance, and has been used as the basis for further developments such as the multi-kinetic model of Ketcham et al. (1999). This paper is one of three (Carlson et al. 1999, Donelick et al. 1999, Ketcham et al. 1999) that have addressed many of the earlier criticisms of the Carlson (1990) model. This research group has also produced a substantial annealing data-set of mixed-compositional apatites and established a model to deal with crystallographic effects, both of which have been incorporated into their full annealing model. 

Full Anneal Austenitizing and then cooling at a rate such that the hardness of the part is minimum. 

FIGURE 14.8 DSC thermograms of water-quenched, air-annealed (cooled from 220°C to ambient temperature in 5 min), and full-annealed (cooled from 220° C to ambient temperature in 105 min) PLLA samples. DSC scans were performed at a heating rate of 10 °C/min. Adapted from Ref. 61 by permission of John Wiley Sons, Inc. 

Heat Treatment. The alloy is usually given a full anneal with a reheat (see table). A beta anneal enheinces creep resistance and toughness. 

Heat TVeatment. Stress relief anneal can be accomplished using a full annealing treatment or, in the case of aged material, a stress relief may be obtained by partial reaging at the same aging temperature used initially (see table). 

State the purposes of and describe procedures for the following heat treatments process annealing, stress relief annealing, normalizing, full annealing, and spheroidizing. 

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