ASTM A320 - Nuts

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Merica Sealing & Fasteners has been manufacturing anchor bolts, embeds, headed bolts and construction fasteners to customer specifications since 1981. With 120,000 square feet of manufacturing space we have the ability to supply large scale heavy construction projects as well as small same day specials.

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.

Grades

ASTM A320 L7 Alloy steel AISI 4140/4142 Quenched and tempered
ASTM A320 L43 Alloy steel AISI 4340 Quenched and tempered
ASTM A320 B8 Class 1 Stainless steel AISI 304, carbide solution treated
ASTM A320 B8M Class 1 Stainless steel AISI 316, carbide solution treated
ASTM A320 B8 Class 2 Stainless steel AISI 304, carbide solution treated, strain hardened
ASTM A320 B8M Class 2 Stainless steel AISI 316, carbide solution treated, strain hardened

 

  • A320 MECHANICAL PROPERTIES
  • A320 CHEMICAL PROPERTIES

 

Grade Size Tensile, ksi min Yield, ksi min Charpy Impact  Elong, % min RA, %, min
L7 up to 21/2 125 105 -150° F 16 50
L43 sup a 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

 

Element L7 (AISI 4140) L43 (AISI 4340) B8 (AISI 304) B8M (AISI 316)
Carbon 0.37 – 0.49% 0.38 – 0.43% 0.08% max 0.08% max
Manganese 0.65 – 1.10% 0.75 – 1.00% 2.00% max 2.00% max
Phosphorus (max) 0.04% 0.04% 0.05% 0.05%
Sulfur (max) 0.04% 0.04% 0.03% 0.03%
Silicon 0.15 – 0.35% 0.15 – 0.35% 1.00% max 1.00% max
Chromium 0.75 – 1.20% 0.70 – 0.90% 18.0 – 20.0% 16.0 – 18.0%
Nickel 1.65 – 2.00% 8.0 – 11.0% 10.0 – 14.0%
Molybdenum 0.15 – 0.25% 0.20 – 0.30% 2.00 – 3.00%