ASTM A320 Grade L7 Mechanical Properties

ASTM A320 Grade L7 Mechanical Properties

Find typical requirement for ASTM A320 Grade L7 Mechanical Properties for Metric and Imperial units. All intermediary or finished products manufactured to ASTM A320 Grade L7 specification must comply with tensile strength; yield strength, elongation, reduction or area and hardness as per below requirement. This requirement is achieved by hardening AISI 4140, 4145, 4145, 4140H, 4142H or 4145H alloy steel followed by tempering at temperatures specified below.

Heat Treatment

Quenching (Hardening) & Tempering

1100º F [593º C] minimum

Mechanical Properties ^Note

Diameter, inch[mm]	Tensile Strength, min, ksi [Mpa]	Yield strength, min, ksi, [Mpa]	Elongation in 2 inch. Or 50mm, min, %	Reduction of Area, min, %	Hardness, max
2-1/2" [65]	125 [860]	105 [725]	16	50	321 HB or 35 HRC

Note : These upper diameter limits were established on the basis that these were the largest sizes commonly available that consistently met specification property limits. They are not intended as absolute limits beyond which bolting materials could no longer be certified to the specification.

V-Notch Charpy Impact Test Requirements

Test Temperature		Size of Specimen, mm	Minimum Impact Value Required for Average of Each Set of Three Specimens, ft-lbf [J]	Minimum Impact Value Permitted for One Specimen Only of a Set, ft-lbf [J]
-150º C	-101º C	10 by 10	20 [27]	15 [20]
		10 by 7.5	16 [22]	12 [16]