A hex bolt is a fastener consisting of a head and a screw (a cylinder with external threads). It is also called a hexagonal head bolt and is a very common industrial fastener.
The head of a hexagonal bolt is hexagonal and can be tightened or loosened using tools such as a wrench or screwdriver. Its main function is to connect and fix two or more parts to make them a whole, thereby ensuring the stability and safety of the equipment.
Carbon Steel Metric Hex Bolts are essential industrial fasteners consisting of a hexagonal head and a threaded screw (cylinder with external metric threads). Widely used across sectors like automotive manufacturing, aerospace, and heavy machinery, these bolts excel at connecting and securing two or more parts, turning discrete components into a stable, safe assembly. Unlike standard bolts, their design prioritizes reliability under high torque, making them a go-to choice for applications requiring long-term structural integrity.
All our carbon steel metric hex bolts comply with international standards including DIN931, DIN933, ISO4014, and ISO4017 – ensuring compatibility with global equipment and assembly requirements. Their application range spans high-strength scenarios: from securing heavy-load machinery parts to reinforcing automotive chassis, and even supporting industrial piping systems.
The most distinctive feature is the hexagonal head – a six-sided shape that provides maximum contact with tools like wrenches or socket sets. Our bolts come with multiple professional surface treatments: blue zinc, yellow zinc, white zinc, and black zinc finishes. These coatings not only enhance the bolts’ aesthetic (a smooth, uniform metallic sheen) but also form a protective layer against rust and wear.
The bolts feature precise metric threads with diameters ranging from M6 to M100 (supplemental imperial options: 1/4"-4" for cross-market compatibility). The threads are evenly cut to ensure tight, non-loosening engagement with nuts, while the overall length of the bolt is customizable based on user needs (e.g., short lengths for thin panels, longer variants for thick structural parts).
Crafted from high-grade carbon steel, the bolts have a solid, robust texture with no visible defects (e.g., cracks, burrs). Different material grades (e.g., Class 8.8 from 10B21 or 40CR steel, Class 12.9 from 42CRMO steel) exhibit subtle differences in surface hardness – higher grades have a slightly darker, denser appearance due to their alloy composition.
| Standard | DIN931, DIN933, ISO4014, ISO4017 |
| Thread Diameter | Metric: M6-M100 Imperial: 1/4"-4" |
| Material | Class 8.8: 10B21, C45, 40CR, 35CRMO, 42CRMO Class 10.9: 40CR, 35CRMO, 42CRMO Class 12.9: 40CR, 35CRMO, 42CRMO A2-70/A2-80: SS304 A4-70/A4-80: SS316 |
| Surface | Blue zinc, yellow zinc, white zinc, black zinc bolts |
| Grade | 4.8, 8.8, 10.9, 2, 5, 8 |
The six-sided head design distributes torque evenly across the bolt’s surface, reducing the risk of slippage during tightening or loosening. This not only protects the bolt and tool from wear but also ensures consistent preload – critical for preventing part loosening under vibration (e.g., in automotive engines).
Unlike specialized fasteners, carbon steel metric hex bolts can be quickly disassembled with common tools (wrenches, socket sets), minimizing maintenance time. Their compatibility with standard metric nuts and various base materials (steel, aluminum, plastic) makes them flexible for mixed-material assemblies.
Our bolts cover grades from 4.8 (general-purpose) to 12.9 (high-tensile). For example, Class 10.9 bolts (made from 35CRMO steel) can withstand extreme loads, making them suitable for aerospace or construction machinery that bears thousands of pounds of pressure.
The zinc-based surface treatments create a barrier against moisture, chemicals, and environmental factors. Even in humid or outdoor environments (e.g., outdoor signage frames), yellow zinc-plated carbon steel hex bolts maintain corrosion resistance for years.
Every batch of bolts is tested against DIN and ISO standards to verify thread accuracy, head dimensions, and tensile strength. This ensures our products meet the requirements of global markets, from Europe to North America.
We implement inspection at every production step: raw material testing (to confirm carbon steel purity), in-process checks (for thread cutting and head forming), and final testing (tensile and torque load verification). No bolt leaves the factory without passing a 100% quality check.
All carbon steel used is sourced from certified suppliers, with complete traceability documents (including material certificates and batch numbers). This allows customers to track the origin of their bolts, critical for industries like healthcare or food processing with strict compliance demands.
The hexagon shape balances manufacturing efficiency and functional performance. It provides a larger contact area for tools than square or round heads, enabling better torque transfer while being easier to machine than more complex shapes.
Standard tools include wrenches (adjustable or fixed-size) and socket sets – the tool size matches the hex head dimensions (ranging from 4mm to 55mm in our product line). For high-precision applications, a torque wrench is recommended to control tightening force.
First, measure the thread diameter (e.g., M8 means 8mm diameter) and thread length (to ensure full engagement with the nut). Then, measure the head diameter and thickness to match the tool and installation space. For example, an M6 hex bolt typically has a 10mm head diameter.
Yes. We offer bespoke manufacturing for carbon steel metric hex bolts – including custom thread lengths, non-standard head sizes, and specialized surface treatments (e.g., anti-corrosion coatings for marine use). Minimum order quantities (MOQ) depend on the customization scope.
