Metric Hex Head Bolts

Gangtong Zheli is a leading manufacturer and supplier of metric hex head bolts in China, and Gangtong Zheli also focuses on the development of product technology. Metric hex head bolts are one of the most common and widely used fasteners in the industrial sector. They utilize the international metric thread standard (ISO), with the thread diameter indicated by "M" followed by a number (e.g., M6, M8, M10...M30), and feature a standard hexagonal head for efficient installation and removal using wrenches, sockets, or power tools.

They are widely used in applications requiring high connection strength, durability, and installation efficiency, such as steel structures, mechanical equipment, automotive manufacturing, rail transportation, energy and power, and construction bridges. Whether in static load or dynamic vibration environments, metric hex head bolts provide stable and reliable connection assurance, making them a "key link" in modern industrial assembly systems.

This series of metric hex head bolts is manufactured in strict accordance with international and national standards such as ISO 4014, DIN 933, and GB/T 5782, ensuring consistent dimensional accuracy, thread compatibility, and mechanical performance to meet the high-quality assembly needs of global customers.

Core Performance and Technological Advantages

Based on our years of experience in fastener research, development, production, and field application, combined with materials engineering, mechanical analysis, and customer feedback, our metric hex head bolts possess the following core advantages in design and manufacturing:

1. Multiple Materials and Strength Grades to Suit Different Working Conditions

- Carbon Steel Series:

- Grade 8.8: General purpose, tensile strength ≥ 800MPa, suitable for general industrial assembly

- Grade 10.9: High strength, tensile strength ≥ 1040MPa, used in steel structures, bridges, and heavy equipment

- Grade 12.9: Ultra-high strength, tensile strength ≥ 1220MPa, suitable for high pre-tension connections (e.g., engines, pressure vessels)

- Stainless Steel Series:

- A2-70 (304 stainless steel): Resistant to general corrosion, suitable for indoor and outdoor environments

- A4-80 (316 stainless steel): Contains molybdenum, resistant to chloride ion corrosion, suitable for marine, chemical, food, and pharmaceutical industries

2. Precision Manufacturing Process Ensures Consistency and Reliability

- Cold Heading Forming: One-piece head forming, continuous metal fibers, improving tensile and shear performance

- Rolled Threads: High-precision rolling process, smooth and crack-free thread surface, thread accuracy up to 6g grade

- Heat Treatment Control: Quenching and tempering treatment ensures a balance of strength and toughness, preventing brittle fracture, conforming to GB/T 3098.1 standard

3. Standardized Design, Strong Compatibility, and Convenient Installation

- Standardized Head Dimensions: S=10mm (M6) to S=46mm (M30), compatible with general tools

- Wide Length Range:  Provides a variety of standard lengths from 20mm to 500mm, with support for non-standard customization

- Optional Thread Types: Coarse threads (e.g., M10×1.5) are standard, fine threads (e.g., M10×1.25) are optional, meeting different locking requirements

4. Advanced Surface Treatment for Extended Service Life

- Carbon Steel Models Available:

- Cold Galvanizing: Environmentally friendly, salt spray resistance ≥ 72 hours

- Dacromet: Chromium-free, environmentally friendly coating with corrosion resistance exceeding 500 hours, and no risk of hydrogen embrittlement.

- Hot-dip galvanizing: Suitable for long-term outdoor exposure environments.

- Stainless steel models: Naturally passivated, no electroplating required, environmentally friendly and long-lasting rust prevention.

5. Resistant to extreme environments and adaptable to complex working conditions

- Operating temperature range: -60°C to +350°C

- Excellent vibration and impact resistance, suitable for high-speed rotating equipment and buildings in earthquake-prone areas.

- Passed vibration tests, salt spray tests, and preload retention tests to ensure long-term stability.

Typical Application Scenarios

Our metric hex head bolts have been successfully applied in various industries and key projects:

Steel structure engineering: Steel beams, steel columns, and node plate connections, ensuring overall structural stability.

Bridges and tunnels: Supports, guardrails, embedded parts, and cable stay anchorages.

Heavy machinery: Excavators, cranes, and road roller chassis connections.

Power and wind power: Transmission towers, transformer installation, and wind turbine tower flange connections.

Rail transit: Rail fasteners, signal equipment, and vehicle bogie connections.

Food and pharmaceutical equipment: A4-80 stainless steel bolts used in sterile environments, meeting hygiene standards.

Why choose our metric hex head bolts? Authoritative Certification, Traceable Quality

- Certified with ISO 9001, ISO 14001, and IATF 16949 quality management systems

- Products comply with GB, DIN, ANSI, JIS, ISO, and other international standards, exported to Europe, America, Southeast Asia, and the Middle East

- Each batch provides Mill Certificates, test reports, and certificates of conformity, enabling full lifecycle traceability

Owned Production Lines, Full-Process Quality Control

- Self-built cold heading, heat treatment, thread rolling, and surface treatment workshops, mastering core processes

- Equipped with professional equipment such as spectrometers, tensile testing machines, salt spray testing chambers, metallographic microscopes, and hardness testers

- Achieves full-process quality monitoring from raw material warehousing to finished product delivery

Professional Technical Support and Customer Service

- Provides CAD drawings, torque recommendation tables, installation specifications, and anti-loosening solutions

- Supports sample delivery, non-standard customization, OEM branding, and bulk supply

- Professional technical team provides 24/7 online support to solve selection, installation, and usage problems

FAQ

Q1: What does the "M" in metric hex head bolt represent?

A: "M" represents Metric Thread, which is an internationally recognized thread standard.

Q2: What is the difference between 10.9 grade and 12.9 grade bolts?

A: 10.9 grade has a tensile strength of ≥1040MPa, and 12.9 grade has a tensile strength of ≥1220MPa. The latter has higher strength, but requires stricter control of installation torque.

Q3: Is it possible to customize full-thread or fine-pitch structures?

A: We support customization of full-thread, fine-pitch (such as M12×1.25), and special lengths. Please provide drawings or technical requirements.

Q4: How to prevent hexagon head bolts from loosening in a vibrating environment?

A: We recommend using spring washers, lock nuts, nylon locking rings, or thread locking adhesive.

Q5: What are the minimum order quantity and delivery time? 

A: The minimum order quantity for standard products is 500 pieces. Samples will be shipped in 3-5 days, and bulk orders in 7-15 days. Expedited production is available.