Product Details

Thread Specifications and Performance Grades

The thread specification range for hex bolts is M1.6~M64, which can be fully threaded.
 Performance grades include 5.6, 8.8, 9.8, 10.9, A2-70, A4-70, A2-50, A4-50, CU2, CU3, AL4, etc.
Among them, Grade A is suitable for bolts with a diameter of d = 1.6mm~24mm and a length of l ≤ 10d or l ≤ 150mm,
 while Grade B is suitable for bolts with a diameter greater than 24mm or a length exceeding the above range.

Nominal Diameter and Thread Dimensions

Taking an M8 stainless steel hex bolt as an example, its actual shank outer diameter is 7.76~7.972mm.
The thread major diameter, pitch diameter, and minor diameter can be calculated according to the standard.
Bolts of different diameters correspond to different head sizes and wrench specifications, which can be selected with reference to the standard size table.

Bolt Length and Marking Method

The length of a hex bolt is usually expressed as the nominal length. For example, for a fully threaded M12×80mm bolt with grade 8.8, Grade A,
the marking is GB/T5783 M12X802. The length can be chosen according to design requirements and the standard preferred length table.

High‑Strength Carbon Steel Hex Bolts 

Hex bolts are one of the most widely‑used general‑purpose fasteners for mechanical and structural connections. Our hex bolts cover multiple international mainstream standards including DIN931, DIN933, ISO4014, ISO4017, GB/T5782, GB/T5783. We supply both partial‑thread and full‑thread types to meet different assembly requirements.

Material options include carbon steel and alloy steel. Strength grades contain 4.8, 8.8, 10.9, 12.9. High‑grade 8.8,10.9 and 12.9 bolts are quenched and tempered to achieve high tensile strength and good mechanical performance, suitable for heavy‑load and high‑stress working conditions. Grade 4.8 is for general light‑duty assembly.

Metric size range covers M6, M8, M10, M12, M14, M16, M18, M20, M22, M24, M27, M30 and above. Custom lengths are available according to customer drawings or requirements. Thread tolerance can be Class A or Class B. Matched nuts, flat washers and spring washers can be provided as complete bolt sets.

Multiple surface treatments are optional for different anti‑corrosion demands. Black oxide (oxidized black) is for indoor dry environment for temporary rust prevention. Zinc‑plating offers moderate corrosion resistance for indoor and mild outdoor conditions. HDG hot‑dip galvanized provides excellent anti‑rust performance for outdoor, coastal and steel‑structure projects. Dacromet and Geomet are zero‑hydrogen‑brittlement coatings for high salt‑fog environment. Xylan / PTFE(Teflon) coating is available as custom option for low‑friction, chemical‑resistant working scenarios.

These hex bolts are extensively applied in machinery manufacturing, equipment assembly, steel structure engineering, construction industry, automobile, truck and trailer, railway facilities, agricultural machinery, pipeline installation, container, solar‑power support and other general industrial fields. They feature stable mechanical property, easy installation and reliable clamping performance.

We can provide mill test reports and support third‑party inspection. Packing can be 25kg per carton box or bulk packing as your request. Custom specifications are acceptable.