ASTM A320 L43 Stud Bolts
We are a professional manufacturer of A320 Grade L43 stud bolt in china
ASTM A320 Grade L43 bolts and threaded studs are manufactured from AISI 4340 material and are also quenched and tempered. L43 bolts can be as large as 4” in diameter, whereas Grade L7 does not exceed 2-1/2” diameter. L43 strength and chemical properties are virtually identical to L7 but may perform more favorably with regard to Charpy impact testing.
ASTM A320 Grade L43 is a standard material specification for alloy steel bolting materials for pressure vessels, valves, flanges, and fittings for low temperature services.
A320 Grade L43 is intended for low-temperature service down to -150° F and has a minimum Charpy impact value of 20-ft-lbf at this temperature.A320 Grades
| L7 Alloy steel | AISI 4140/4142 Quenched and tempered |
|---|---|
| L43 Alloy steel | AISI 4340 Quenched and tempered |
A320 L7 & L43 Stud bolt 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 |
A320 L7 & L43 Stud bolt Chemical Properties
| Element | L7 (AISI 4140) | L43 (AISI 4340) |
|---|---|---|
| Carbon | 0.37 – 0.49% | 0.38 – 0.43% |
| Manganese | 0.65 – 1.10% | 0.75 – 1.00% |
| Phosphorus, max | 0.035% | 0.035% |
| Sulfur, max | 0.040% | 0.040% |
| Silicon | 0.15 – 0.35% | 0.15 – 0.35% |
| Chromium | 0.75 – 1.20% | 0.70 – 0.90% |
| Nickel | 1.65 – 2.00% | |
| Molybdenum | 0.15 – 0.25% | 0.20 – 0.30% |
A320 A320 L7 & L43 Stud bolt ,Nuts and Washer recommendation
| Grade | Nuts | Washers |
|---|---|---|
| L7 | A194 Grade 4 or 7 | F436 |
| L43 | A194 Grade 4 or 7 | F436 |
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Heat Treatment of ASTM A320 L43 Stud Bolts
- Stud bolts are heat-treated by quenching and tempering to achieve the required mechanical properties and improve toughness.
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Thread Type of ASTM A320 L43 Stud Bolts
- Typically provided with Unified National Coarse (UNC) or Unified National Fine (UNF) threads, depending on the application requirements.
Specifications of ASTM A320 L43 Stud Bolts
| Specification | Details |
|---|---|
| Material Grade | ASTM A320 L43 |
| Heat Treatment | Quenched and tempered |
| Tensile Strength | Minimum 125 ksi (862 MPa) |
| Yield Strength | Minimum 105 ksi (724 MPa) |
| Elongation | Minimum 16% |
| Hardness | Maximum 321 HBW or 35 HRC |
| Operating Temperature | As low as -150°F (-101°C) or lower |
| Thread Type | UNC, UNF, or metric |
| Standards Compliance | ASTM A320/A320M, ASME SA320 |
Coating and Surface Treatments
To enhance performance and durability, ASTM A320 L43 stud bolts are often treated with coatings such as:
- Zinc Plating:
- For general corrosion protection.
- Hot-Dip Galvanization:
- Provides a thicker protective layer, ideal for outdoor or marine environments.
- PTFE Coating:
- Offers low friction and excellent resistance to chemical corrosion.
- Phosphating:
- Improves lubricity and provides basic corrosion resistance.
Application of ASTM A320 Grade L43 Stud bolt
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Cryogenic and Low-Temperature Environments:
- Specifically designed for applications in temperatures as low as -150°F (-101°C).
- Used in environments such as liquefied natural gas (LNG) plants, cryogenic storage tanks, and cold weather installations.
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Petrochemical and Chemical Industries:
- Used in pressure vessels, heat exchangers, and reactors.
- Ideal for handling processes involving low temperatures or corrosive materials.
-
Oil and Gas Industry:
- Utilized in offshore and onshore drilling operations, particularly in low-temperature regions.
- Commonly installed in pipeline flanges, valves, and equipment in refineries.
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Power Generation:
- Used in turbines and equipment where components must withstand low-temperature conditions.
- Suitable for nuclear and thermal power plants requiring secure bolting solutions.
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Pressure Vessels and Heat Exchangers:
- Applied in systems that operate at high pressures and low temperatures, ensuring safety and structural integrity.
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Marine and Offshore Applications:
ASTM Standards
A194/A194M Specification for Carbon Steel, Alloy Steel, and Stainless Steel Nuts for Bolts for High Pressure or High Temperature Service,
F436/F436M Specification for Hardened Steel Washers Inch and Metric Dimensions
F606/F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets