ASTM A320 L7 Heavy Hex Bolts

ASTM A320 L7 A193 B7 Dual Certified Heavy Hex Bolts

Standard: ASME/ANSI B18.2.1, ASME/ANSI B18.2.3.7M Various types of head are also available

Inch Size: 1/2”-2.3/4” with various lengths

Metric Size: 1/2-M72 with various lengths

Grade: ASTM A320 L7, ASTM A193 B7

Finish: Black Oxide, Zinc Plated, Zinc Nickel Plated, PTFE etc.

Packing: Bulk about 25 kgs each carton, 36 cartons each pallet

Advantage: High Quality and Strict Quality Control, Competitive Price,Timely Delivery; Technical Support, Supply Test Reports

Please feel free to contact us for more details.

ASTM A320

Scope Originally approved in 1948, the ASTM A320 specification covers alloy steel and stainless steel bolting materials for low temperature service. This standard covers rolled, forged, or strain 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. Below is a basic summary of a few of the common grades within the ASTM A320 specification. A number of other less common grades of ASTM A320 exist, but not covered in the description below. Grades

L7 Alloy steel	AISI 4140/4142 Quenched and tempered
L43 Alloy steel	AISI 4340 Quenched and tempered
B8 Class 1 Stainless steel	AISI 304, carbide solution treated
B8M Class 1 Stainless steel	AISI 316, carbide solution treated
B8 Class 2 Stainless steel	AISI 304, carbide solution treated, strain hardened
B8M Class 2 Stainless steel	AISI 316, carbide solution treated, strain hardened

Mechanical Properties

Grade	Size	Tensile, ksi, min	Yield, ksi, min	Charpy Impact 20-ft-lbf @ temp	Elong, %, min	RA, %, min
L7	Up to 21/2	125	105	-150° F	16	50
L43	Up to 4	125	105	-150° F	16	50
B8 Class 1	All	75	30	N/A	30	50
B8M Class 1	All	75	30	N/A	30	50
B8 Class 2	Up to 3/4	125	100	N/A	12	35
	7/8 - 1	115	80	N/A	15	35
	11/8 - 11/4	105	65	N/A	20	35
	13/8 - 11/2	100	50	N/A	28	45
B8M Class 2	Up to 3/4	110	95	N/A	15	45
	7/8 - 1	100	80	N/A	20	45
	11/8 - 11/4	95	65	N/A	25	45
	13/8 - 11/2	90	50	N/A	30	45

Recommended Nuts and Washers

Grade	Nuts	Washers
L7	A194 Grade 4 or 7	F436
L43	A194 Grade 4 or 7	F436
B8 Class 1	A194 Grade 8	SS304
B8M Class 1	A194 Grade 8M	SS316
B8 Class 2	A194 Grade 8, strain hardened	SS304
B8M Class 2	A194 Grade 8M, strain hardened	SS316

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