Fig. 26 Series of fractographs of Charpy V-notch specimens of 4340 steel tested at different temperatures, showing the change in appearance and estimated percentages of fibrous fracture. Source: Army Materials and Mechanics Research Center, Watertown Arsenal More

Fig. 15 Incubation time prior to hydrogen stress cracking for AISI type 4340 and type D-6AC steel contoured double-cantilever beam test specimens as a function of decrease in stress intensity More

Fig. 6 This close-tolerance sand casting, although designed to be cast from 4340 steel, was produced in type 431 stainless because of the foundry's greater experience with stainless steel. Increase in material cost was more than offset by higher percentage of acceptable castings. More

Fig. 8 Continuous-cooling transformation diagrams for AISI (a) 4140 and (b) 4340 steels More

Fig. 6 Transformation of retained austenite in 4130 and 4340 steel More

Fig. 10 Tempering behavior of a 4340 steel (0.355 C, 0.66 Mn, 0.042 P, 0.017 S, 0.28 Si) at various temperatures as a function of time. Adapted from Ref 18 More

Fig. 15 Tempering curves for (a) 4140 and (b) 4340 steels. Source: Ref 17 More

Fig. 10 Delayed-failure characteristics of unnotched specimens of SAE 4340 steel during cathodic charging with hydrogen under standardized conditions. Electrolyte: 4% H 2 SO 4 in water. Poison: 5 drops/liter of cathodic poison composed of 2 g phosphorus dissolved in 40 mL CS 2 . Current density More

Fig. 44 Typical Jominy curve for a high-hardenability (4340) steel More

Fig. 17 Surface characteristics of 4340 steel (quenched and tempered, 30 HRC) produced by ECM. (a) Gentle conditions produce slight surface pitting but no other visible changes. (b) Abusive conditions produce surface roughening but no other visible effect on microstructure. (c) Gentle and abusive More

Fig. 18 Surface characteristics of 4340 steel (annealed, 31 to 36 HRC) produced by CM. (a) Gentle conditions produce no visible surface effects and a surface finish of 0.9 μm (35 μin.). (b) Abusive conditions produce a slight roughening and a surface finish of 3 μm (120 μin.). (c) Gentle More

Fig. 20 Residual stress from surface milling 4340 steel (quenched and tempered to 52 HRC). Tool 100 mm (4 in.) diam single-tooth face mill with Carboloy 370 (C-6) carbide End cutting edge angle 5° Peripheral clearance 8° Cutting speed, m/min (ft/min) 55 (180) Feed, mm/tooth More

Fig. 22 Change in deflection versus tool wearland for the face milling of 4340 steel (quenched and tempered to 52 HRC) Tool 100 mm (4 in.) diam single-tooth face mill with Carboloy 370 (C-6) carbide End cutting edge angle 5° Peripheral clearance 8° Cutting speed, m/min (ft/min More

Fig. 24 Loss of fatigue strength from the abusive grinding of 4340 steel (quenched and tempered to 50 HRC). Fatigue tests involved cantilever bending at room temperature and zero mean stress. Source: Ref 9 More

Fig. 27 Effect of shot peening on the stress-corrosion resistance of AISI 4340 steel (50 HRC). Source: Ref 14 More

Fig. 20 Flow lines in a closed-die forging of AISI 4340 alloy steel. Hot 50% HCl. Original magnification approximately 0.75× More

Fig. 10 Forging pressure for AISI 4340 steel upset at various temperatures and two strain rates. Source: Ref 29 More

Fig. 4 Effect of cutting speed on chip formation of AISI 4340 steel. (a) Cutting speed of 120 m/min (400 sfm). (b) Cutting speed of 975 m/min (3200 sfm). Source: Ref 1 More

Fig. 8 Variation of cutting force with speed for AISI 4340 steel. Source: Ref 1 More

Fig. 9 Variation of chip/tool interface temperature with speed for AISI 4340 steel. Adapted from Ref 36 More