ASTM A320 L7M STUD BOLTS

We stock a large amount of ASTM A320 L7M Stud Bolts up to 2-1/2 inches in diameter. Call or email us Lightning Bolt and Supply today, where our fastener experts can meet all of your fastener needs… Any fasteners / any material.

ASTM A320 L7 Stud Bolts are specially engineered for LOW temperature performance. These fasteners are commonly used for valves, flanges, fittings, and pressure vessels . ASTM specifications recommend a minimum Charpy impact value for ASTM A320 L7M Stud Bolts to be 20-ft-lbf @ -100F. The Charpy impact test determines the total amount of energy that is absorbed by a material during fracture, thereby indicating the material’s notch toughness. This test, also known as a pendulum fracture test, dates back to the turn of the 20th century when it was first developed by S. B. Russell and Georges Charpy, and is still used to test high grade fasteners and other products to this day.

Material of grades L8, L8A, L8B, L*C, L8M, L43, L70,L71, L72 & L73 shall show a minimum impact energy absorption of 20ft-lbs, and a Grade L1 a minimum impact absorption of 40 ft-lbs at the test temperature specified by ASTM A320.

ALL materials under A320/A320M shall be charpy tested.  However, the only exceptions where impact tests are not required are:

  • carbide solution treated or strain hardened grades B8, B8F, B8P B8M, B8T, B8LNabove -325F;
  • for carbide solution treated grades B8, B8P, B9C, and B9LN above -425F
  • Fora all ferritic and austentic steel grades of bolting 1/2″ diameter and smaller.

Heat treated conditions for the austentic stainless steels include:

  • Carbide solution treated (Class 1)
  • Carbide solution treated after finishing (Class 1A)
  • Annealed andstrain-hardened (Class2)

Why Lightning Bolt ASTM A320 L7M STUD BOLTS?

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.

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 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

CALL: 225-272-6200 24/7

Lightning Bolt & Supply, INc

CALL: 225-272-6200 24/7