Carbon Steel Threaded Rod — Factory Direct Supplier | Huaxia-Steel
Huaxia-Steel manufactures carbon steel threaded rod, fully threaded studs, and double-end studs for construction, machinery, oil and gas, and general industrial applications. Our threaded rods are produced to ASTM A193 B7, ASTM A307 Grade A, DIN 976-1, and ISO 898-1 Class 8.8 standards, with diameters from 1/4 inch (M6) to 4 inches (M100) and standard lengths of 1 meter, 2 meters, and 3 meters. Custom lengths and specialty threads (ACME, UNC, UNF, metric coarse/fine) are available on request. As a factory-direct supplier, we offer full material traceability, competitive pricing, and export documentation for global delivery.
Product Overview
Threaded rod — also known as all-thread rod, fully threaded bar, or studding — is a length of steel bar threaded along its entire length. It serves as a versatile fastening element for anchoring, hanging, coupling, and structural clamping applications. Carbon steel threaded rod provides the strength required for structural connections at a fraction of the cost of alloy steel alternatives, with surface treatments available to extend service life in corrosive environments.
Double-end studs feature threads on both ends with an unthreaded center section, designed for flange bolting and through-bolt applications where nuts are required on both ends. Fully threaded studs are used where the fastener passes through one component and threads into another, or where two nuts clamp a component between them.
Specifications and Dimensions
| Parameter | Specification |
|---|---|
| Diameter | 1/4″–4″ (M6–M100) |
| Standard Length | 1m, 2m, 3m (39″, 78″, 118″) |
| Custom Length | Cut to any length on request (±1mm tolerance) |
| Thread Standard | UNC, UNF (ASME B1.1); Metric coarse/fine (ISO 261/262); ACME (ASME B1.5) |
| Thread Class | 2A/2B (inch); 6g/6H (metric) |
| Straightness | ≤ 1mm per meter (typical) |
Standard Sizes and Weights (ASTM A193 B7, UNC Threads)
| Diameter | Threads Per Inch | Weight (kg/m) | Tensile Strength (MPa) |
|---|---|---|---|
| 1/4″ | 20 | 0.22 | 860 |
| 3/8″ | 16 | 0.50 | 860 |
| 1/2″ | 13 | 0.89 | 860 |
| 5/8″ | 11 | 1.39 | 860 |
| 3/4″ | 10 | 2.00 | 860 |
| 1″ | 8 | 3.56 | 860 |
| 1-1/4″ | 7 | 5.57 | 860 |
| 1-1/2″ | 6 | 8.02 | 860 |
| 2″ | 4.5 | 14.26 | 860 |
Metric Sizes (ISO 898-1 Class 8.8)
| Diameter | Pitch (coarse) | Weight (kg/m) | Tensile (MPa) | Yield (MPa) |
|---|---|---|---|---|
| M8 | 1.25 | 0.32 | 800 | 640 |
| M10 | 1.50 | 0.50 | 800 | 640 |
| M12 | 1.75 | 0.73 | 800 | 640 |
| M16 | 2.00 | 1.29 | 800 | 640 |
| M20 | 2.50 | 2.01 | 800 | 640 |
| M24 | 3.00 | 2.90 | 800 | 640 |
| M30 | 3.50 | 4.54 | 800 | 640 |
| M36 | 4.00 | 6.53 | 800 | 640 |
| M42 | 4.50 | 8.89 | 800 | 640 |
Material Grades and Standards
| Standard | Grade/Class | Material | Tensile (MPa) | Yield (MPa) | Application |
|---|---|---|---|---|---|
| ASTM A193 | B7 | 4140 alloy steel (Q&T) | 860 | 720 | High-pressure; high-temp |
| ASTM A193 | B7M | 4140 alloy steel (Q&T) | 690 | 550 | Sour service (NACE MR0175) |
| ASTM A307 | Grade A | Low-carbon steel | 414 | — | General purpose |
| ASTM A307 | Grade B | Low-carbon steel | 414–724 | — | Flange bolting (cast iron) |
| ISO 898-1 | Class 4.8 | Low-carbon steel | 420 | 340 | Light-duty applications |
| ISO 898-1 | Class 8.8 | Medium-carbon steel (Q&T) | 800 | 640 | Structural; machinery |
| ISO 898-1 | Class 10.9 | Medium-carbon alloy (Q&T) | 1,000 | 900 | Heavy structural; automotive |
| DIN 976-1 | Property class 8.8 | Medium-carbon steel | 800 | 640 | General engineering |
Manufacturing Process
Material Preparation
Threaded rod is manufactured from hot-rolled round bar or wire rod. For high-strength grades (ASTM A193 B7, Class 10.9), medium-carbon or alloy steel round bars (AISI 4140, 5140, or equivalent) are selected. For general-purpose grades (A307, Class 4.8), low-carbon steel (SAE 1008–1022) is used.
Thread Rolling
Threads are formed by cold rolling between precision ground dies rather than cutting. Rolling produces work-hardened threads with superior fatigue resistance, smoother surface finish, and higher strength than cut threads. The grain flow follows the thread contour, eliminating stress concentrations at thread roots.
Heat Treatment
High-strength threaded rods undergo controlled heat treatment:
Surface Treatment
After threading and heat treatment, rods receive surface treatment based on application requirements:
- Black oxide: Minimal protection; primarily aesthetic
- Zinc electroplating: 5–12 microns; indoor corrosion protection
- Hot-dip galvanizing: 50–85 microns; outdoor and marine environments
- Dacromet/Geomet: 6–12 microns; 500+ hours salt spray; automotive and industrial
- PTFE coating: Chemical resistance; low friction
Applications
- Construction: Concrete form ties, anchor bolts, suspended ceiling hangers, curtain wall anchors
- Machinery: Equipment leveling and anchoring, press clamping, jig and fixture construction
- Oil and Gas: Flange stud bolts (B7/B7M), vessel manway studs, valve bonnet studs
- Power Generation: Turbine casing bolts, heat exchanger studding, ductwork hangers
- Automotive: Engine assembly fixtures, body shop clamping, prototype fastening
- Marine: Dock fender attachment, bollard anchoring, equipment mounting (galvanized or stainless)
- General Industrial: Sign and lighting pole bases, railing posts, shelving systems
Surface Treatment and Corrosion Protection
| Coating | Thickness | Salt Spray Life | Best For |
|---|---|---|---|
| Black oxide | < 1 micron | < 24 hours | Short-term indoor; painted after installation |
| Zinc electroplate (clear) | 5–8 microns | 48–96 hours | Indoor dry environments |
| Zinc electroplate (yellow) | 8–12 microns | 96–200 hours | Indoor humid environments |
| Hot-dip galvanized | 50–85 microns | 1,000+ hours | Outdoor; marine; industrial atmospheres |
| Dacromet / Geomet | 6–12 microns | 500–1,000 hours | Automotive; high-performance industrial |
| PTFE (Xylan) | 15–25 microns | Varies | Chemical exposure; low friction; galling prevention |
Quality Assurance
Every batch of threaded rod undergoes rigorous quality control:
- Chemical Analysis: Spectrometric verification of carbon, manganese, chromium, and other alloying elements per heat
- Dimensional Inspection: Major diameter, pitch diameter, thread angle, and length verification using thread ring gauges and calipers
- Mechanical Testing:
- Tensile test on full-size or machined specimens
- Hardness test (HRC for B7; HV or HRB for lower grades)
- Wedge tensile test to evaluate thread ductility
- Coating Quality: Thickness measurement (magnetic or Eddy current), adhesion test, and salt spray testing for coated products
- Visual Inspection: Surface defects, thread burrs, straightness, and marking verification
Documentation includes EN 10204 3.1 Mill Test Certificate, mechanical test reports, and coating inspection certificates.
Packaging and Shipping
- Standard bundles: 50–100 pieces per bundle for diameters ≤ M24; 25–50 pieces for larger diameters
- Bundle securing: Steel strapping at 3 points; plastic end caps to protect threads
- Coated rods: Interleaved with VCI paper or polyethylene wrapping to prevent coating damage
- Wooden crates: For precision-cut lengths or export orders requiring additional protection
- Marking: Grade, diameter, length, standard, heat number, and country of origin tagged on each bundle
- Container loading: Bundles stowed horizontally with dunnage; weight distribution optimized for safe transport
Ordering Information
For a detailed quotation, please provide:
- Diameter (inch or metric)
- Thread standard and pitch (UNC, UNF, metric coarse/fine)
- Length required (standard 1m/2m/3m or custom cut length)
- Material grade: ASTM A193 B7, A307 Grade A, ISO 8.8, or equivalent
- Quantity (pieces or meters)
- Surface treatment
- Destination port and Incoterms
Contact Huaxia-Steel today for competitive pricing on carbon steel threaded rod. We stock common diameters in ASTM A193 B7 and ISO 8.8 grades for immediate shipment, and manufacture custom sizes with fast turnaround. Request your threaded rod quotation and receive a detailed proposal within 24 hours.
