Double End Bolts
Product: Double End Bolts (Stud Bolts)
Standards: DIN 939, DIN 940, ASTM A193, ASME B18.31.2, GB/T 901
Raw Materials: Carbon steel (Q235, 35K, 45K), alloy steel (40Cr, 35CrMo, 42CrMo, 25Cr2MoVA), stainless steel (304/316/316L)
Surface Treatment: Plain, zinc plated (blue/white/yellow), black oxide, hot-dip galvanizing (H.D.G), Dacromet, Geomet, passivation (stainless steel)
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Product Introduction
Product: Double End Bolts (Stud Bolts)
Standards: DIN 939, DIN 940, ASTM A193, ASME B18.31.2, GB/T 901
Raw Materials: Carbon steel (Q235, 35K, 45K), alloy steel (40Cr, 35CrMo, 42CrMo, 25Cr2MoVA), stainless steel (304/316/316L)
Surface Treatment: Plain, zinc plated (blue/white/yellow), black oxide, hot-dip galvanizing (H.D.G), Dacromet, Geomet, passivation (stainless steel)
Specification Range: M6–M64, 1/4"–2"; customizable length for special requirements
Property Classes: 4.8, 8.8, 10.9, 12.9 (carbon/alloy steel); A2/A4 (stainless steel); B7/B16 (high-temperature alloy steel)
B1=1.25d
Product Overview
Double end bolts, also known as stud bolts, are specialized fasteners with fully threaded ends and a smooth unthreaded shank in the middle (or fully threaded for full-length types). Designed for permanent and high-strength fixed connections, they are widely used to fasten two or more components-especially in scenarios where one side is inaccessible for nut installation, or vibration, high temperature, and heavy load require superior connection stability. Compliant with international and national standards, these bolts offer customizable specifications to match diverse industrial application needs, delivering reliable clamping force and anti-loosening performance.
Key Characteristics
- Dual-thread design: Uniformly threaded both ends for secure nut engagement, ensuring balanced load distribution and stable connection.
- Material versatility: Carbon steel for general load, alloy steel for heavy-duty/high-strength scenarios, stainless steel for corrosive environments, and high-temperature alloy steel for thermal industrial conditions.
- Precision threading: Fine/coarse thread options with strict tolerance control, ensuring smooth assembly and no cross-threading risks.
- Corrosion resistance: Diverse surface treatments adapt to indoor, outdoor, humid, industrial, and mild marine environments; stainless steel variants for strong corrosion conditions.
- Customization: Support non-standard length, thread pitch, and material customization for special equipment and project requirements.
Main Types & Application Fields
Common Types
- DIN 939: Half-thread double end bolts (smooth shank middle), standard for general industrial use.
- DIN 940: Full-thread double end bolts, ideal for narrow installation spaces and full-length clamping needs.
- ASTM A193 B7: High-temperature alloy steel double end bolts, for petrochemical, power plant high-temperature pipelines and equipment.
- Stainless steel double end bolts (304/316): For food, pharmaceutical, marine, and chemical industries with corrosion resistance requirements.
Core Application Fields
Mechanical manufacturing:
Engines, gearboxes, heavy machinery bases, and equipment housing connections.
Petrochemical & power:
Pipelines, pressure vessels, heat exchangers, and boiler high-temperature/high-pressure component fastening.
Construction & bridge:
Steel structure beam-column connections, prefabricated building components, and bridge bearing seat fixed connections.
Automotive & aerospace:
Auto chassis, engine parts, and aerospace light-weight high-strength component fastening.
Marine & offshore:
Ship hulls, offshore platforms, and marine equipment (stainless steel/H.D.G variants).
General industry:
Pump valves, fans, and electrical equipment fixed connections in vibration-prone scenarios.
Usage Precautions
Matching:
Pair with grade-compatible nuts (e.g., 8.8 bolts with 8H nuts, B7 bolts with 2H nuts) and flat washers; ensure thread pitch consistency (fine/coarse thread).
Installation:
Clean threads and mating surfaces before installation; apply anti-seize lubricant for high-temperature/high-vibration scenarios to prevent thread seizing.
Torque control:
Use a calibrated torque wrench to tighten nuts to the designed torque; avoid over-tightening to prevent thread deformation or bolt breakage.
Environmental adaptation:
Select surface treatment/material per the working environment-H.D.G for outdoor/humid conditions, 316 stainless steel for marine/high-chloride environments, high-temperature alloy steel for ≥300℃ conditions.
Inspection & maintenance:
Regularly check for loosening, corrosion, or thread damage; replace bolts immediately if fatigue or deformation is detected; re-tighten nuts per torque requirements in vibration-prone equipment.
Forbidden:
Do not mix bolts of different grades, materials, or specifications; do not use damaged or deformed bolts; avoid welding or secondary processing on bolts after installation.
Packaging, Logistics & Quality Assurance
Packaging
- Standard packaging: Sealed anti-rust plastic bags, cardboard boxes, wooden pallets, iron drums; customized packaging (fixed quantity, project labeling, vacuum anti-rust) available for customer needs. All packaging protects threads from damage and corrosion during transportation and storage.
Logistics
- Support bulk, small-batch, and project-based ordering; flexible MOQ for customized specifications.
- Negotiable transportation terms (FOB, CIF, EXW, DDP) and delivery schedules to align with production and project timelines.
- Global shipping available, with professional logistics solutions for large and heavy cargo.
Quality Assurance
- Compliant with DIN, ASTM, ASME, GB/T and other international/national standards; certified to ISO9001:2015 quality management system.
- 100% raw material inspection and batch testing for mechanical properties (tensile, yield strength) and dimensional accuracy; provide complete quality inspection reports and material certificates.
- Long-term after-sales service: Pre-sales technical consultation (matching and selection), in-sales quality tracking, and after-sales installation guidance.
Main Sales Markets: North America, Europe, Southeast Asia, the Middle East, and global industrial and construction markets.
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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