ASTM A320 L7M Stud bolt HDG Hot Dip Glavanized Hext nuts manufacturer in China
ASTM A320Material and Grade (L7M):Enhanced toughness and ductility are required for temperatures as low as -150°F (-101°C).
L7M refers to alloy steel used in stud bolts per ASTM A320, designed for cryogenic and low-temperature applications.
Typical material includes chromium-molybdenum steel (4140 )
ASTM A320 L7M stud bolt A194 7M Heavy Hex nuts Supply Scope:
FULL-THREAD, 8-UN, ASME B18.2.1/B1.1 CL.2A/ A194/A194M-7M, WITH TWO HEAVY HEX. NUTS, ASME B18.2.2/B1.1 CL.2B,
BOLT, StdBlt, A320L7M/7M, Stud Bolt – Threaded Full Length Alloy Steel Per ASTM A320-L7M with Three Carbon Steel Nuts Per A194-7M Threads to ISO Metric DIN 13 with Nuts to DIN 934
| Standard: | ANSI/ASME B 18.31.2,DIN975/DIN976, |
| Diameter: | 1/4″-5″,M6-M125 |
| Length: | ≤9m or 30feet |
| Material: | ASTM A320 L7M stud bolt |
Hot-Dip Galvanizing (HDG):
- HDG involves coating the stud bolt with a layer of zinc to protect against corrosion.
- The zinc layer is applied by immersing the stud bolt in molten zinc.
- HDG is ideal for outdoor or marine environments where corrosion resistance is critical.
The stud bolt must comply with ASTM A320 L7M for material and mechanical properties.
The galvanizing process must meet ASTM A153 or ASTM F2329 standards for hot-dip galvanizing.
ASTM A320 L7M stud bolt with hot-dip galvanizing (HDG) is a specialized fastener designed for low-temperature environments with added corrosion protection
chemical composition range for Grade L7M bolts:
| Element | Percentage (%) |
|---|---|
| Carbon (C) | 0.37 max |
| Manganese (Mn) | 0.65–1.10 |
| Phosphorus (P) | 0.035 max |
| Sulfur (S) | 0.040 max |
| Silicon (Si) | 0.15–0.35 |
| Chromium (Cr) | 0.75–1.20 |
| Molybdenum (Mo) | 0.15–0.25 |
| Vanadium (V) | 0.03 max |
Mechanical Properties:
- Tensile Strength: Minimum 105 ksi (724 MPa).
- Yield Strength: Minimum 75 ksi (517 MPa).
- Elongation: Minimum 20% (measured on a standard 2-inch gauge length).
- Reduction of Area: Minimum 50%.
- Charpy Impact Test:
- Ensures performance at low temperatures, typically down to -150°F (-101°C).
Heat Treatment:
- Bolts must be quenched and tempered to achieve the required mechanical properties and toughness.
Surface Treatment
- Hot-Dip Galvanizing (HDG) is often applied for enhanced corrosion resistance in harsh environments.