Fig. 17 Microstructure of (a) upper bainite and (b) lower bainite in a Cr-Mo-V rotor steel. 2% nital + 4% picral etch. Original magnification: 500×. (c) S5 tool steel austenitized, isothermally transformed (partially) at 540 °C (1000 °F) for 8 h, and water quenched to form upper bainite (dark More

Fig. 21 Microstructure of (a) upper bainite and (b) lower bainite in a Cr-Mo-V rotor steel. 2% nital + 4% picral etch. 500× More

Fig. 22 TEM micrographs of (a) upper bainite and (b) lower bainite in a Cr-Mo-V rotor steel More

Fig. 22 Microstructure of (a) upper bainite and (b) lower bainite in a Cr-Mo-V rotor steel. 2% nital + 4% picral etch. 500× More

Fig. 23 TEM micrographs of (a) upper bainite and (b) lower bainite in a Cr-Mo-V rotor steel More

Fig. 15 Lower bainite. (a) Light micrograph illustrating sheaves of lower bainite in a partially transformed (668 K) Fe-0.3C-4Cr wt% alloy. The light matrix phase is martensite. (b) Corresponding transmission electron micrograph illustrating subunits of lower bainite. Source: Ref 2 More

Fig. 36 Appearance of upper bainite (a and b) and lower bainite (c) in eutectoid steel (0.8% C) at original magnification 250× (left) and 2000× (right). (a) The structure is pearlite with some upper bainite after isothermal exposure at 500 °C (930 °F) for 0.5 s. (b) Upper bainite is dominant More

Fig. 5 Light micrograph showing patches of upper bainite (dark) formed in 4150 steel partially transformed at 460 °C (860 °F). Courtesy of F.A. Jacobs More

Fig. 6 Light micrograph showing lower bainite (dark plates or needles) formed in 4150 steel. Courtesy of F.A. Jacobs. More

Fig. 15 Grain-boundary transition products (primarily bainite) observed 1 mm (0.04 in.) below the surface of a 10V45 bar. Hardness: HRC 59. Portions of bar with a more effective quench showed HRC 61 at a similar depth. More

Fig. 10 Lower bainite generated by isothermal transformation of 52100 at 230 °C (445 °F) for 10 h. Reprinted with permission from Carl Hanser Verlag, Muenchen. Source: Ref 16 More

Fig. 15 Comparison of single-stage and two-stage bainite transformation process. Source: Ref 15 More

Fig. 8 Transformation-expansion comparison of martensite and bainite at various carbon contents. This applies to the commercial austempering range of 260 to 399 °C (500 to 750 °F). Source: Ref 4 More

Fig. 18 Light micrograph showing patches of (a) upper bainite formed in 4150 steel partially transformed at 460 °C (860 °F) and (b) lower bainite (dark plates) in 4150 steel (nital etch). Courtesy of F.A. Jacobs ( Ref 25 ) More

Fig. 5 Upper bainite in UNS 43600 steel. Etched with picral. 500× More

Fig. 6 Lower bainite in UNS 43600 steel. Matrix is untempered martensite. 500× More

Fig. 3 Basic microstructures and processing of special cast iron (B: Bainite, M: Martensite, ADI: austempered ductile iron). Source: Ref 3 More

Fig. 1 Nucleation of ferritic bainite during austempering at 360 °C (680 °F) of (a) spheroidal and (b) flake graphite cast irons. Background is martensite. Source: Ref 1 More

Fig. 15 Upper bainite formed isothermally at 480 °C (900 °F) in AISI 4142 alloy steel. (Left) 845 °C; 480 °C for 30 s; water quenched. (Right) 845 °C; 480 °C for 2 h; water quenched. Both etched with 4% picral. 1000× More