ASTM A320 Grade L7

ASTM A320 Grades

Mechanical properties of fasteners made of carbon steel and alloy steel L7

The Grade L7 Stainless Steel Bolting for Low-Temperature Service-1

The ASTM A320 Grade L7 specification covers stainless steel bolting materials for low temperature service. This standard cover rolled, forged, or strains hardened bars, bolts, screws, studs, and stud bolts used for pressure vessels, valves, flanges, and fittings. Like the ASTM A193 specification, unless otherwise specified, the 8UN thread series is specified on fastener larger than 1” in diameter.

ASTM A320 Grade L7
L7 Hex bolts, screws, stud bolts, double ended studs, Stud for foundation, wind energy bolts, Fasteners for wind turbines
ASTM A320 Grade L7 Chemical properties

Property class

Chemical composition

C.

Mn.

Si.

P.

S.

Cr.

Ni.

Mo.

V.

Ti.

L7

0.38---0.48

0.75---1.00

0.15---0.35

0.035 max.

0.040 max.

0.80---1.10

-

0.15-0.25

-

-

ASTM A320Grade L7 Mechanical properties

Class, Diameter In

Heat TreatmentB

Tensile Strength, min, ksi [MPa]

Yield Strength, min, ksi [MPa] (0.2 % offset)

Elongation in 2 in. or 50 mm min, %

Reduction of Area, min, %

Hardness max

21⁄2 [65] and under

quenched and tempered

125 (860)

105 (725)

16

50

321 HBC or 35 HRC