M20 High Tensile Bolts

The m20 high tensile bolts is produced by the Gangtong Zheli factory, a leading manufacturer and supplier in China. We have ISO 9001 certification and can make customized products. M20 high-strength bolts are industrial-grade fasteners with a nominal diameter of 20mm, possessing excellent tensile and shear strength. They are widely used in critical structural components such as bridges, high-rise buildings, wind turbine towers, heavy machinery, pressure vessels, rail transit, and petrochemical industries, where high demands are placed on connection safety, durability, and fatigue resistance.

Unlike ordinary bolts, M20 high-strength bolts utilize high-quality alloy steel materials and precision heat treatment processes, resulting in higher yield strength, tensile strength, and pre-tension control capabilities.  They maintain connection stability and reliability under harsh working conditions such as high loads, high vibrations, and extreme temperature differences, effectively preventing loosening, slippage, or fracture.

This series of m20 high tensile bolt is manufactured in strict accordance with international and national standards such as ISO 898-1, GB/T 3098.1, ASTM A325, and ASTM A490.

Core Performance and Technological Advantages

Based on our over 15 years of experience in the R&D, mass production, and engineering services of high-strength fasteners, our M20 high-strength bolts possess the following core advantages in material selection, process control, and performance verification:

1. High-Strength Materials and Precision Heat Treatment for Stable Mechanical Performance

- Material Selection:

- 35#, 45# carbon steel: Suitable for 8.8 grade bolts

- 40Cr, 35CrMoA, 42CrMoA alloy steel: Used for 10.9 grade and above high-strength bolts, possessing excellent hardenability and toughness

- Heat Treatment Process:

- Adopts quenching and tempering treatment (quenching + high-temperature tempering) to ensure a balance between core toughness and surface hardness

- Tensile strength: 8.8 grade ≥ 800MPa, 10.9 grade ≥ 1040MPa, 12.9 grade ≥ 1220MPa

- Complies with GB/T 3098.1 standard, with tensile, impact, and hardness tests performed on each batch

2. Precision Manufacturing Process for Consistent Dimensions and Reliable Connections

- Cold Heading Forming: The head is formed in a single cold heading process, resulting in continuous metal flow lines and improved tensile performance

- Rolled Threads: High-precision rolling process, thread accuracy reaches 6g grade, ensuring perfect fit with nuts

- Full Thread or Half Thread Design: Flexible selection based on connection length to improve assembly adaptability

3. Multiple Surface Treatments to Meet Different Environmental Requirements

- Dacromet: Chromium-free environmentally friendly coating, salt spray test resistance ≥ 1000 hours, no hydrogen embrittlement risk, suitable for coastal and chemical environments

- Hot-Dip Galvanizing: Thick coating, strong corrosion resistance, suitable for long-term outdoor exposed structures

- Phosphating + Oiling: Improves rust resistance and friction coefficient stability, facilitating torque control

- Stainless Steel (A4-80): Resistant to chloride ion corrosion, suitable for marine engineering and food and pharmaceutical equipment

4. Flange and Anti-Loosening Design for Enhanced Connection Safety

- Flanged Type: Flange diameter approximately 30mm, expanding the bearing surface and preventing loosening

- Serrated flange or nylon insert: Provides self-locking function, suitable for high-vibration environments

- Torque-tension control design: Used with a torque wrench to ensure the preload force meets the requirements

5. Full-process quality control to ensure product consistency

- Raw material incoming inspection (spectroscopic analysis, mechanical performance testing)

- Online monitoring of the production process (dimensions, hardness, thread gauge inspection)

- 100% magnetic particle testing or ultrasonic testing of finished products (optional)

- Material certificate, test report, and certificate of conformity provided for each batch

Typical Application Scenarios

Our M20 high-strength bolts have been successfully applied in numerous major engineering and industrial projects, helping customers achieve structural safety, efficient construction, and long-term durability:

Bridge engineering: Used in main beam connection nodes, bearing dynamic loads and wind vibrations

Wind turbine towers: Connection between tower sections, requiring extremely high fatigue resistance and corrosion resistance

Rail transit: Rail fasteners, bogie connections, ensuring safe operation

Heavy machinery: Connection of key structural components of excavators and cranes

Pressure vessels and petrochemical equipment: Long-term stable operation in high-temperature and high-pressure environments

Why choose our m20 high tensile bolts? Authoritative Certification, Quality Assurance

- Passed international certifications such as ISO 9001, IATF 16949, ISO 17025, CE, and RoHS

- Products comply with multiple national standards including GB, ISO, ASTM, and DIN, and are exported to Europe, America, Southeast Asia, and the Middle East.

- Third-party testing reports (such as SGS, BV) are available.

Owned Production Base, Controllable Process

- Self-built full-process production line including cold heading, heat treatment, thread rolling, surface treatment, and testing laboratory.

- Equipped with high-end equipment such as spectrometers, universal material testing machines, salt spray testing chambers, metallographic microscopes, and torque testers.

- Achieves full traceability management from raw materials to finished products.

Professional Technical Support and Engineering Services

- Provides selection suggestions, torque parameter tables, installation guidance videos, and CAD drawings.

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

- Technical team provides 24-hour response to solve problems such as thread stripping, breakage, and insufficient pre-tightening force.

Genuine Customer Reviews and Industry Reputation

“Stable strength, good Dacromet corrosion resistance, suitable for wind power projects.” — A new energy engineering company

“On-time bulk delivery, complete test reports, meeting national standards.” — Jiangsu Steel Structure Factory

“12.9 grade bolts are used in heavy equipment with excellent vibration resistance.” — Shandong Machinery Manufacturer

FAQ

Q1: What are the common lengths of m20 high tensile bolts?

A: Standard lengths range from 40mm to 300mm, and can also be customized according to drawings.

Q2: What is the difference between 8.8 and 10.9 grade M20 bolts?

A: 10.9 grade has higher strength and is suitable for high pre-tightening force connections, requiring the use of a torque wrench to control the tightening force.

Q3: Do high-strength bolts require special nuts?

A: It is recommended to use high-strength nuts (such as grade 10 or 12) and high-strength flat washers to ensure connection reliability.

Q4: How to prevent hydrogen embrittlement in high-strength bolts? A: Avoid electroplating; prioritize processes without the risk of hydrogen embrittlement, such as Dacromet, hot-dip galvanizing, or mechanical galvanizing.

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

A: The minimum order quantity for standard products is 100 pieces. Samples are shipped within 5-7 days, and bulk orders within 15-30 days. Expedited shipping is available.