Fig. 3 Example of the preheating effect during heat treatment. Without preheating, showing large differences in temperature from surface to core; reduction in temperature delta when preheating is used More

Fig. 13 Effect of preheating on hardness gradient in a ring gear. See Table 8 for preheating procedure. More

Fig. 18 Tungsten-halogen-based infrared die preheater used in preheating forging dies More

Fig. 8 Illustration of hybrid friction stir processing with laser preheating. (a) Schematic. FSW, friction stir welding. (b) Actual. Source: Ref 17 More

Fig. 27 Preheating of castings. Specific part should be heated in such a manner that the weld is under compressive stress on cooling. See text for discussion. More

Fig. 4 Proper method of preheating cast iron castings to prepare samples for welding. (a) Casting at room temperature. (b) Heat applied to perimeter of casting. (c) Vertical members of casting in tension. (d) Vertical members in compression ready to be welded. Source: Ref 5 More

Fig. 4 Proper method of preheating cast iron castings to prepare samples for welding. (a) Casting at room temperature. (b) Heat applied to perimeter of casting. (c) Vertical members of casting in tension. (d) Vertical members in compression ready to be welded More

Fig. 27 Effect of preheating on the hardness of 15 mm (0.6 in.) thick D-6ac low-alloy ultrahigh-strength steel More

Fig. 12 Effect of preheat on HIC susceptibility. Preheat increases critical stress needed to cause HIC. LCS, lower critical stress More

Fig. 13 Effect of carbon equivalent on preheat requirements. Amount of preheat needed to prevent HIC is proportional to the carbon equivalent of the steel being welded More

Fig. 10 The major components of a dryer used to preheat induction furnace charge material. Integrated scrap preheat process combines (1) weigh hoppers, (2) preheat hood, (3) material transfer mechanism, and (4 and 5) furnace-charging apparatus into a single automated process. More

Fig. 4 Preheat hearth More

Fig. 21 Weld attaching the head to the shell of a steam preheater that cracked because of poor root penetration in original and first replacement joint designs. (a) and (b) Sections taken through the head-to-shell joint. Etched in hot 50% hydrochloric acid. Actual size. The section More

Fig. 12 Example of an 8000 ton isothermal forge press. Billet preheat chamber, transfer mechanisms, forge dies, and induction heating coils are all enclosed with a vacuum chamber. Courtesy of Pratt & Whitney More

Fig. 32 Predicted temperature profiles for beryllium strip