ASTM A320 Specification

ASTM A320 Specification

The ASTM A320 specification is another popular specification used in the fastener industry.  This specification covers alloy steel bolting materials for pressure vessels, valves, flanges, and fittings for low-temperature service. Each alloy shall conform to the prescribed chemical composition requirements. The material, as represented by the tension specimens, shall conform to the requirements as to tensile properties such as tensile strength, yield strength, elongation, and hardness. The material shall meet the prescribed impact energy absorption requirements and the recommended test temperature. Mechanical tests shall be conducted on the material, namely: impact testing, tension testing, and hardness testing.  Several grades are covered, including both ferritic and austenitic steels designated L7, B8, etc. Selection will depend on design, service conditions, mechanical properties, and low-temperature characteristics. ASTM A320 chemical requirements are listed underneath the ASTM A320 mechanical requirements.  Many of Lightning Bolt’s items are also duel certified.  Email us today to find out how we can help!  sales@lightningboltandsupply.com

 

ASTM A320 TENSILE STRENGTH AND HARDNESS

ASTM A320 TENSILE STRENGTH AND HARDNESS CHART

Grade and ClassDiameterHeat TreatmentTensile Strength Min KSIYield Strength 0.2% Offset KSIElongation in 2in. Min, %Reduction of Area Min, %Hardness max
FERRITIC STEELS
L7, L7A, L7B, L7C, L70, L71, L72, L732-1/2" and underquench and tempered1251051650
L434" and underquench and tempered1251051650
L7M2-1/2" and underquench and tempered @ 1150F, min100801850235 HB / 99HRB
L11" and underquench and tempered1251051650
AUSTENTIC STEELS
CLASS 1: B8, B8C, B8M, B8P, B8F, B8T, B8LN, B8MLNALLcarbide solution treated75303050223 HB or 96 HRB
CLASS 1A: B8A, B8CA, B8MA, B8PA, B8FA, B8TA, B8LNA, B8MLNAALLcarbide solution treated75303050192 HB or 90 HRB
CLASS 2: B8, B8C, B8P, B8F, B8T3/4" and undercarbide solution treated and strain hardened1251001235321 HB or 35 HRC
over 3/4 to 1" incl115801530321 HB or 35 HRC
over 1" to 1-1/4" incl105652035321 HB or 35 HRC
over 1-1/4" to 1-1/2" incl100502845321 HB or 35 HRC
CLASS 2: B8M3/4" and undercarbide solution treated and strain hardened110951545321 HB or 35 HRC
over 3/4 to 1" incl100802045321 HB or 35 HRC
over 1" to 1-1/4" incl95652545321 HB or 35 HRC
over 1-1/4" to 1-1/2" incl90503045321 HB or 35 HRC

ASTM A320 CHEMICAL REQUIREMENTS

ASTM A320 GRADES L7, L7M, L70, L7A, L7B, L72, L7C, L73, L43, L1

IdentificationL7, L7M, L70 L7A, L71 L7B, L72 L7C, L73 L43 L1 
GradeChromium- Molybdenum (AISI 4140, 4142, or 4145)Carbon- Molybdenum (AISI 4037)Chromium- Molybdenum (AISI 4137)Nickel-Chromium-Molybdenum (AISI 8740)Nickel-Chromium- (AISI 4340)Low-Carbon Boron

Element

Range

Tolerance +/-

Range

Tolerance +/-

Range

Tolerance +/-

Range

Tolerance +/-

Range

Tolerance +/-

Range

Tolerance +/-

Carbon0.38-0.48.0020.35-0.40.0020.35-0.40.0020.38-0.43.0020.38-0.43.0020.17-0.24.002
Manganese0.75-1.000.040.70-0.900.030.70-0.900.030.75-1.000.0040.60-0.850.030.70-1.400.004
Phosphorus, max0.0350.005 over0.0350.005 over0.0350.005 over0.0350.005 over0.0350.005 over0.0350.005 over
Sulfur, max0.0400.005 over0.0400.005 over0.0400.005 over0.0400.005 over0.0400.005 over0.0500.005 over
Silicon0.15-0.350.020.15-0.350.020.15-0.350.020.15-0.350.020.15-0.350.020.15-0.300.02
Nickel------0.40-0.700.031.65-2.000.05-
Chromium0.80-1.10---0.80-1.100.050.40-0.600.030.70-0.900.03-
Molybdenum0.15-0.250.20-0.300.020.15-0.250.020.20-0.300.020.20-0.300.02-
Boron------------

ASTM A320 B8, B8A

IdentificationB8, B8A B8C, B8CA 
GradeUnstablized 18 Chromium-8 Nickel (AISI Type 304 Stainless)Stabilized 18 Chromium-8 Nickel (AISI Type 347)

Element

Range

Tolerance +/-

Range

Tolerance +/-

Carbon, max0.080.01 over0.080.01 over
Manganese, max2.000.04 over2.000.04 over
Phosphorus, max0.0450.010 over0.0450.010 over
Sulfur, max0.0300.005 over0.0300.005 over
Silicon1.000.05 over1.000.05 over
Nickel8.0-10.50.159.0-13.00.15
Chromium18.0-20.00.2017.0-19.00.20
Columbium + Tantalum--10X Carbon, min0.05 under

ASTM A320 B8T, B8TA, B8P, B8PA

IdentificationB8T, B8TA B8P, B8PA 
GradeStabilized 18 Chromium-8 Nickel (AISI 321)Unstabilized 18-Chromium-8Nickel (AISI Type 305 with restricted Carbon)

Element

Range

Tolerance +/-

Range

Tolerance +/-

Carbon, max0.080.01 over0.080.01 over
Manganese, max2.000.04 over2.000.04 over
Phosphorus, max0.0450.010 over0.0450.010 over
Sulfur0.030, max0.005 over0.030, max0.005 over
Silicon, max1.000.05 over1.000.05 over
Nickel9.0-12.00.1510.5-13.00.15
Chromium17.0-19.00.2017.0-19.00.20
Molybdenum---
Selenium---
Titanium5x Carbon, min0.05 under-

ASTM A320 B8F, B8FA, B8M, B8MA

IdentificationB8F, B8FA   B8M, B8MA 
GradeWith Added Sulfur (Type 303)With Added Selenium (Type 303 Se)With Added Sulfur (Type 303)

Element

Range

Tolerance +/-

Range

Tolerance +/-

Range

Tolerance +/-

Carbon, max0.150.01 over0.150.01 over0.080.01 over
Manganese, max2.000.04 over2.000.04 over2.000.04 over
Phosphorus, max0.200.010 over0.200.010 over0.0450.010 over
Sulfur0.15, min.0200.06, max0.010 over0.030, max0.005 over
Silicon, max1.000.05 over1.000.05 over1.000.05 over
Nickel8.0-10.00.108.0-10.00.1010.0-14.00.15
Chromium17.0-19.00.2017.0-19.00.2016.0-18.00.20
Molybdenum--2.00-3.000.10
Selenium-0.15-0.35--
Titanium----

ASTM A320 B8LN, B8LNA

TypeAustenitic Steels, Classes 1, 1A, and 2   
IdentificationB8LN, B8LNA
GradeUnstablilized 18 Chromium-8 Nickel with Nitrogen (AISI Type 304N with restricted Carbon)Unstabilized 18 Chromium-10 Nickel-2 Molybdenum with Nitrogen (AISI Type 316N with restriced carbon)

Element

Range

Tolerance +/-

Range

Tolerance +/-

Carbon, max0.0300.005 over0.0300.005 over
Manganese, max2.000.04 over2.000.04 over
Phosphorus, max0.0450.010 over0.0450.010 over
Sulfur, max0.0300.005 over0.0300.005 over
Silicon, max1.000.05 over1.000.05 over
Nickel8.0-10.50.1510.0-14.00.15
Chromium18.0-20.00.2016.0-18.00.20
Molybdenum--2.00-3.000.10
Nitrogen0.10-0.160.010.10-0.160.01

Why Lightning Bolt for ASTM A320 Fasteners?

Lightning Bolt & Supply has been servicing North America’s industrial fastener needs for over 25 years.  Since then, our focus on the production of high quality parts at competitive pricing has allowed us to become an industry leader.  Our niche in exotic high nickel alloy fasteners include materials such as: hastelloy, Inconel, monel, A-286, 904L, Alloy-20, duplex stainless as well as many additional alloys.

Being centrally headquartered in Baton Rouge, Louisiana, we are capable of shipping to jobsites all over the world.  Many of our industrial projects that we supply material to include anchor bolts, and also stud bolts of many different ASTM grades.  These include B7, L7, B16, B8, B8M, stain hardened and many more.  In addition to being an ISO certified fastener manufacturer, we were awarded “Corporate Supplier of the Year” by WBENC.

CALL: 225-272-6200 24/7

Lightning Bolt & Supply, INc

CALL: 225-272-6200 24/7