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 and strain-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
|Identification||L7, L7M, L70||L7A, L71||L7B, L72||L7C, L73||L43||L1|
|Grade||Chromium- 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|
|Phosphorus, max||0.035||0.005 over||0.035||0.005 over||0.035||0.005 over||0.035||0.005 over||0.035||0.005 over||0.035||0.005 over|
|Sulfur, max||0.040||0.005 over||0.040||0.005 over||0.040||0.005 over||0.040||0.005 over||0.040||0.005 over||0.050||0.005 over|
ASTM A320 TENSILE STRENGTH AND HARDNESS CHART
|Grade and Class||Diameter||Heat Treatment||Tensile Strength Min KSI||Yield Strength 0.2% Offset KSI||Elongation in 2in. Min, %||Reduction of Area Min, %||Hardness max|
|L7, L7A, L7B, L7C, L70, L71, L72, L73||2-1/2" and under||quench and tempered||125||105||16||50|
|L43||4" and under||quench and tempered||125||105||16||50|
|L7M||2-1/2" and under||quench and tempered @ 1150F, min||100||80||18||50||235 HB / 99HRB|
|L1||1" and under||quench and tempered||125||105||16||50|
|CLASS 1: B8, B8C, B8M, B8P, B8F, B8T, B8LN, B8MLN||ALL||carbide solution treated||75||30||30||50||223 HB or 96 HRB|
|CLASS 1A: B8A, B8CA, B8MA, B8PA, B8FA, B8TA, B8LNA, B8MLNA||ALL||carbide solution treated||75||30||30||50||192 HB or 90 HRB|
|CLASS 2: B8, B8C, B8P, B8F, B8T||3/4" and under||carbide solution treated and strain hardened||125||100||12||35||321 HB or 35 HRC|
|over 3/4 to 1" incl||115||80||15||30||321 HB or 35 HRC|
|over 1" to 1-1/4" incl||105||65||20||35||321 HB or 35 HRC|
|over 1-1/4" to 1-1/2" incl||100||50||28||45||321 HB or 35 HRC|
|CLASS 2: B8M||3/4" and under||carbide solution treated and strain hardened||110||95||15||45||321 HB or 35 HRC|
|over 3/4 to 1" incl||100||80||20||45||321 HB or 35 HRC|
|over 1" to 1-1/4" incl||95||65||25||45||321 HB or 35 HRC|
|over 1-1/4" to 1-1/2" incl||90||50||30||45||321 HB or 35 HRC|