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At room temperature, ES-1's yield (tensile strength before deformation) is 193,900 psi (1,337 MPa), ultimate strength (breaking point) is 246,700 psi (1,701 MPa). At 900°F (482°C), yield is 191,400 psi (1,320 MPa), and ultimate strength is 215,700 psi (1,487 MPa). Rockwell C hardness is 45.6 (448 HV10). For toughness, the Charpy notch impact is 56.2 foot-pounds (76 J) at room temperature, and 42.7 ft-lbs (58 J) at -40F (-40°C).[1]
ES-1 is a balance of cost, tensile strength, high temperature tensile strength and toughness. By varying the heat treatment to include water or liquid nitrogen quenching, or omitting the normalization heat-treat to permit work hardening, properties can be improved.[2] ES-5, with an economical air and water quench,[3] provides 244,800 psi (1,688 MPa) of high-rate yield strength, and 291,900 psi (2,013 MPa) high-rate ultimate strength.[4] Low-rate yield strength is 216,000 psi (1,489 MPa), and low-rate ultimate strength is 270,200 psi (1,863 MPa).
By comparison, ordinary structural steel has a yield strength of 36,000 psi, 4150 "ordnance" steel (used in high-quality military gun barrels) has a yield strength of 75,000 psi. |
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