DIN 931 / ISO 4014 Hex Head Bolts | Stainless Steel A2 & A4 | Full Thread / Partial Thread | Various Sizes & Strength Grades | Corrosion-Resistant Fasteners

Product Description

The DIN 931 / ISO 4014 Hex Head Bolts are internationally standardized fasteners designed for high-strength and precision fastening requirements. Manufactured with a hexagonal head and partially threaded shank, these bolts provide excellent clamping force, reliable mechanical performance, and convenient installation using standard tools.

Produced according to DIN 931 and ISO 4014 specifications, these stainless steel hex head bolts ensure dimensional accuracy, thread consistency, and dependable fastening quality across various industrial fastening requirements.

Made from premium Stainless Steel A2 and A4, these bolts offer outstanding corrosion resistance, oxidation resistance, and long-term durability. Their robust construction and standardized design make them suitable for environments requiring stable fastening performance and resistance to moisture, chemicals, and temperature variations.

What Are DIN 931 / ISO 4014 Hex Head Bolts?

DIN 931 and ISO 4014 are international standards that define the dimensions, tolerances, threading, and mechanical properties of hex head bolts with partial thread configurations.

These bolts feature:

• A six-sided hexagonal head
• Metric threading
• Partially threaded shank
• Standardized dimensions for interchangeability
• High tightening torque capability

The partially threaded structure improves shear strength and load distribution compared with fully threaded bolts in many fastening assemblies.

DIN 931 vs ISO 4014

DIN 931 and ISO 4014 are highly similar standards for metric hex head bolts. ISO 4014 is considered the international equivalent that gradually replaced DIN 931 in many global markets.

Both standards are widely recognized in international fastening systems and maintain strong dimensional compatibility.

Stainless Steel Material Options

A2 Stainless Steel

A2 stainless steel is equivalent to 304 stainless steel and provides excellent general corrosion resistance and mechanical stability.

Features:

• Good corrosion resistance
• Excellent formability
• Strong oxidation resistance
• Suitable for humid environments

A4 Stainless Steel

A4 stainless steel is similar to 316 stainless steel and contains molybdenum for enhanced corrosion resistance.

Features:

• Superior chemical resistance
• Better saltwater corrosion protection
• Excellent durability in harsh environments
• Improved resistance to acids and chlorides

Product Specifications

Key Features of DIN 931 / ISO 4014 Hex Head Bolts

1. High Corrosion Resistance

Manufactured from stainless steel A2 and A4, these bolts provide excellent resistance against rust, oxidation, moisture, and chemical exposure.

2. Precision Manufacturing

Produced according to DIN 931 and ISO 4014 standards, ensuring consistent thread accuracy and dimensional precision.

3. Strong Mechanical Performance

The partially threaded design enhances shear strength and improves load-bearing capacity during fastening.

4. Easy Installation

The hex head structure allows convenient installation and removal using common wrenches and socket tools.

5. Wide Size Availability

Available in multiple diameters, lengths, and strength grades to meet diverse fastening requirements.

Mechanical Properties

Surface Characteristics

Unlike carbon steel bolts requiring external coatings, stainless steel hex head bolts achieve corrosion resistance directly through the chromium-rich alloy composition.

Benefits of Stainless Steel Surface:

• No peeling or flaking coatings
• Long-lasting appearance
• Reduced maintenance requirements
• Enhanced oxidation resistance
• Improved durability in humid environments

Manufacturing Process

DIN 931 / ISO 4014 Hex Head Bolts are typically produced through advanced cold forging or hot forging methods, followed by precision thread rolling and quality inspection.

Production Steps:

1. Raw material selection
2. Wire drawing or bar preparation
3. Head forging
4. Thread rolling
5. Heat treatment (if required)
6. Surface cleaning and passivation
7. Dimensional and mechanical inspection
8. Packaging and shipment

Strict quality control ensures compliance with international fastening standards.

Available Customization Options

Advantages of Partial Thread Design

The partial thread configuration of DIN 931 / ISO 4014 bolts provides several engineering advantages:

• Improved shear resistance
• Better alignment during assembly
• Reduced stress concentration
• Enhanced clamping performance
• Increased structural stability

This design is especially preferred when precise load distribution is required.

FAQ

What is the difference between DIN 931 and ISO 4014?

DIN 931 is the original German standard, while ISO 4014 is the international equivalent standard. Their dimensions and specifications are largely interchangeable.

Are DIN 931 bolts fully threaded?

No. DIN 931 / ISO 4014 bolts are typically partially threaded hex head bolts. Fully threaded versions are generally covered under DIN 933 / ISO 4017.

What is the difference between A2 and A4 stainless steel?

A2 stainless steel offers excellent general corrosion resistance, while A4 stainless steel provides enhanced resistance to chemicals, saltwater, and chloride environments.

What strength grades are available?

Common stainless steel strength grades include A2-50, A2-70, A4-70, and A4-80.

Are custom sizes available?

Yes. Custom diameters, lengths, thread pitches, and packaging options can usually be provided according to customer requirements.

Do stainless steel bolts require additional coating?

No. Stainless steel bolts naturally resist corrosion due to their chromium content and typically do not require zinc plating or other protective coatings.

What is the advantage of a hex head bolt?

Hex head bolts provide higher torque transmission, easier installation, and compatibility with standard tightening tools.

Are these bolts compliant with international standards?

Yes. DIN 931 / ISO 4014 Hex Head Bolts are manufactured according to internationally recognized dimensional and mechanical standards.