B7 Threaded Bars
Product: B7 Threaded Bars (Alloy Steel Threaded Rods)
Standard: ASTM A193 Grade B7, ASME SA193 B7
Raw Materials: Chromium-molybdenum alloy steel (4140/4142), quenched and tempered for high strength
Surface Treatment: Plain, black oxide, hot-dip galvanizing (H.D.G), Dacromet, Geomet, oiled anti-rust
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Product Introduction
Product: B7 Threaded Bars (Alloy Steel Threaded Rods)
Standard: ASTM A193 Grade B7, ASME SA193 B7
Raw Materials: Chromium-molybdenum alloy steel (4140/4142), quenched and tempered for high strength
Surface Treatment: Plain, black oxide, hot-dip galvanizing (H.D.G), Dacromet, Geomet, oiled anti-rust
Specification Range: M6–M64, 1/4"–4"; custom cut-to-length ( special lengths available)
Property Class: ASTM A193 B7 (equivalent to 12.9 grade high strength)
Product Overview
ASTM A193 Grade B7 threaded bars are high-performance alloy steel threaded rods, engineered for high-temperature, high-pressure and heavy-load industrial applications. Processed via precision cold rolling/hot rolling and strict quenching-tempering heat treatment, they feature full-length uniform threading for continuous nut engagement, delivering exceptional tensile strength, fatigue resistance and high-temperature stability. As a core fastener in petrochemical, power and heavy industrial fields, B7 threaded bars ensure reliable and durable connections for critical equipment and structural components under extreme working conditions, fully complying with American ASTM/ASME industry standards.
Key Characteristics
- Premium alloy material: 4140/4142 Cr-Mo alloy steel with quenching-tempering treatment, achieving ultra-high strength and excellent toughness.
- Full-length precision threading: Uniform coarse/fine thread with strict tolerance control, enabling flexible nut positioning and stable load distribution.
- High-temperature adaptability: Maintains mechanical properties at temperatures up to 538°C (1000°F), suitable for high-heat industrial environments.
- Superior mechanical performance: High tensile, yield and shear strength, with excellent fatigue and impact resistance for heavy-load long-term use.
- Diverse corrosion protection: Multiple surface treatments adapt to indoor, outdoor, humid and mild corrosive industrial conditions; H.D.G for enhanced outdoor corrosion resistance.
- Customization: Support cut-to-length, thread customization and special surface treatment for project-specific requirements.
Mechanical Properties (ASTM A193 B7)
|
Characteristic |
Minimum Value |
|
Tensile Strength |
860 MPa (125,000 psi) |
|
Yield Strength (0.2% offset) |
725 MPa (105,000 psi) |
|
Hardness Range |
235–325 HB / 24–34 HRC |
|
Elongation |
16% minimum |
|
Reduction of Area |
30% minimum |
Application Fields
B7 threaded bars are the preferred fastener for high-temperature, high-pressure and heavy-load industrial scenarios, widely used in:
Petrochemical industry:
Flange connections, pressure vessels, heat exchangers, oil/gas pipelines and refinery equipment fastening.
Power generation:
Boiler systems, steam turbines, nuclear power plant auxiliary equipment, thermal power pipeline and valve connections.
Heavy machinery:
Large gearboxes, hydraulic press bases, mining equipment and steel mill rolling mill structural fastenings.
Construction & infrastructure:
High-rise building steel structure nodes, bridge bearing seats and heavy-duty support structure connections.
Industrial manufacturing:
High-pressure pumps, valves, industrial ovens and high-temperature processing equipment fixed connections.
Offshore engineering:
Offshore platform pipeline connections and marine heavy equipment fastening (with enhanced anti-corrosion treatment).
Usage Precautions
Matching Fasteners:
Exclusively pair with ASTM A194 Grade 2H/7 heavy hex nuts (2H for ambient temperature, 7 for high-temperature ≤538°C) and high-strength flat washers; avoid mixing with non-standard or low-grade fasteners.
Torque Control:
Use a calibrated torque wrench to tighten to design torque; apply high-temperature anti-seize lubricant for high-heat applications to prevent thread seizing and galling.
Temperature Limitation:
Do not use in environments exceeding 538°C (1000°F); select specialized high-temperature threaded bars for higher temperature requirements.
Environmental Adaptation:
Choose surface treatment per working conditions-black oxide/oiled for indoor dry environments, H.D.G/Dacromet for outdoor/humid industrial conditions; avoid direct use in severe marine high-chloride environments without specialized anti-corrosion treatment.
Installation & Inspection:
Clean threads and mating surfaces before installation to remove rust and debris; conduct regular inspections for loosening, corrosion or thread damage in vibration/high-pressure scenarios, and re-tighten or replace immediately if defects are found.
Critical Forbiddens:
Do not perform welding, grinding or secondary processing on threaded bars after production (will damage heat treatment performance); do not reuse fasteners in critical high-pressure/high-temperature connections; discard any bent, corroded or thread-damaged bars.
Packaging, Logistics & Quality Assurance
Packaging
- Standard: Oiled anti-rust paper wrapping + sealed plastic bags + cardboard boxes/wooden crates; wooden pallets for bulk orders (1m–6m lengths).
- Custom: Cut-to-length packaging, labeled with specification/grade/length, and vacuum anti-rust packaging for high-precision projects.
- All packaging protects threads from damage, corrosion and deformation during transportation and storage.
Logistics
- Support bulk ordering, cut-to-length small-batch orders and project-based customized orders; flexible MOQ for special specifications.
- Negotiable transportation terms (FOB, CIF, EXW, DDP) and delivery schedules, with global shipping and door-to-door delivery for large projects.
- Professional cargo handling for long-length threaded bars to avoid bending and thread damage.
Quality Assurance
- Fully compliant with ASTM A193 Grade B7 and ASME SA193 B7 standards; certified to ISO9001:2015 quality management system.
- 100% raw material inspection, batch heat treatment testing and mechanical property testing (tensile, hardness, yield); provide complete material test reports (MTR) and quality certificates for each order.
- Strict dimensional and thread precision inspection, ensuring compliance with international thread standards (UNC/UNF/Metric).
- Comprehensive after-sales service: Pre-sales technical consultation (matching, selection and torque calculation), in-sales quality tracking and after-sales installation guidance.
Main Sales Markets: North America, Europe, the Middle East, Southeast Asia, and global petrochemical, power and heavy industrial markets adhering to American ASTM/ASME standards.
Established in 2005, our company has evolved over two decades of continuous development into a leading regional enterprise in the fastener industry with fully automated end-to-end production. With an annual output value exceeding RMB 130 million, our product range covers diverse market segments from mid-range to high-end and is distributed worldwide
Our factory & quipment
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