Hex Head Bolt (Grade 8.8)

Basic Info

The Grade 8.8 Hex Head Bolt is one of the most versatile and commonly used high-strength bolts. Its hexagonal head allows for easy tightening with wrenches or sockets, providing excellent torque transmission. The strength grade "8.8" indicates a tensile strength of 800 MPa and a yield strength of approximately 640 MPa, making it a mainstay for machinery, structural connections, and general industrial assembly.

Key attributes

Origin

China

Head Style

Hex head

Diameter Range

M4 to M20

Thread Type

Standard metric coarse thread

Surface Finish

Zinc plated or Dacromet

Strength Grade

Grade 8.8

Material

Medium Carbon Steel

Customer reviews

James O'Connor · Equipment Maintenance Director

"Our food processing production line requires frequent disassembly and cleaning. For five years, your company's A4-80 stainless steel socket head cap screws have shown no thread galling or corrosion failure in high-temperature, high-humidity environments. The excellent chloride ion corrosion resistance has extended our equipment maintenance cycle by 30%."

Sophie Clark · Equipment Maintenance Manager

For the upgrade of our beverage filling equipment, we needed A2-70 stainless steel bolts that meet hygiene standards. Your products not only come with complete material certificates but also feature smooth, burr-free heads and threads, effectively preventing hygiene dead corners. After multiple CIP (Cleaning-in-Place) cycles, the appearance remains as bright as new.

Arjun Patel · Chief Mechanical Engineer

We needed to replace special flange connection bolts for an old imported machine, which had non-standard dimensions and required controlled head weight. Your technical team responded quickly, providing a custom solution that fully met the dimensional and performance requirements while achieving weight reduction through optimized head design, solving our urgent technical challenge.

Product Description

Product Characteristics:

Offers an excellent balance of strength and toughness, capable of withstanding high dynamic and static loads. The hex head design provides a large wrenching surface, reducing slip and allowing high clamping force. Available in fully or partially threaded versions to suit different grip lengths. Typically features surface treatment for corrosion resistance and appearance.

Product Specifications:

Conforms to international standards such as ISO 4014/4017, DIN 933/931, GB/T 5782/5783. Nominal diameters range from M4 to M48, lengths from 10mm to over 300mm. Options include full thread or shank (shank diameter ≈ pitch diameter). Grade 8.8 is most common; others include 4.8, 10.9, 12.9.

Product Applications:

Widely used in machinery frame assembly, secondary steel structure connections, automotive chassis components, construction equipment, bridge guardrails, storage racking, internal structures of wind turbine towers, and fastening for various general industrial products. It is the quintessential "all-rounder" of the bolt family.

Basic Info

Key attributes

Customer reviews

Product Description

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Product Specifications:

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