Hexagonal Head Bolt Weight Chart: Comprehensive Guide

Hexagonal head bolts are categorized into two primary types: external hex bolts and internal hex socket cap screws.

The classification of bolts extends to their connection and load-bearing characteristics, with standard types and those specifically engineered for pivot applications. Pivot bolts are precision-matched to the hole dimensions and are employed in scenarios involving significant lateral forces, ensuring optimal load distribution and minimizing wear.

Head geometry plays a crucial role in bolt selection, with common variants including hexagonal, round, square, and countersunk designs. Countersunk bolts are preferred in applications demanding flush surfaces post-installation, as their tapered heads can be recessed into the mating components. Round head bolts offer similar flush-mounting capabilities. Square head bolts provide superior torque transmission but at the cost of increased spatial requirements. Hexagonal heads remain the industry standard due to their balance of torque capacity and tool accessibility.

To address vibration-induced loosening in dynamic environments, specialized bolt designs incorporate locking features. These include drilled head bolts and shaft-drilled bolts, which accommodate secondary locking mechanisms such as cotter pins or safety wire. This design approach significantly enhances the fastener’s resistance to rotational movement under vibrational loads, maintaining joint integrity in critical applications.

Hexagon Head Bolt Material

Currently, the market mainly consists of hexagon socket screws made from three types of materials: carbon steel, stainless steel, and copper.

(1) Carbon Steel.

We classify this into low carbon steel, medium carbon steel, high carbon steel, and alloy steel based on the carbon content in the material.

1. Low carbon steel with C% ≤0.25% is commonly referred to as A3 steel in China. It’s essentially known as 1008, 1015, 1018, 1022, etc., abroad. It’s primarily used for products without hardness requirements like 4.8-grade bolts, 4-grade nuts, and small screws. (Note: Drilling tail nails mainly use 1022 material).
2. Medium carbon steel contains 0.25%-0.45% carbon. It’s not currently in widespread use in the market.
3. Alloy steel: This is ordinary carbon steel with added alloy elements, enhancing some unique properties of the steel, such as 35, 40 chrome molybdenum, SCM435, 10B38. Fangsheng screws primarily use SCM435 chrome molybdenum alloy steel, which contains C, Si, Mn, P, S, Cr, Mo.

(2) Stainless Steel.

Performance grade: 45, 50, 60, 70, 80. The primary division is into austenitic (18%Cr, 8%Ni), which has good heat resistance, corrosion resistance, and weldability.

A1, A2, A4 Martensite, 13%Cr, has poorer corrosion resistance, high strength, and good wear resistance. C1, C2, C4 Ferritic stainless steel, 18%Cr, has better forgeability and stronger corrosion resistance than martensite.

The current market import materials are mainly Japanese products. The primary division by grade is SUS302, SUS304, SUS316.

(3) Copper.

The commonly used material is brass zinc-copper alloy. The market mainly uses H62, H65, H68 copper for standard parts.

Carbon steel products use the following sheet metal: serial number, type, and optional material. 1. 4.8-grade hexagon screws 1008K 1010 1015K 2. 6.8-grade hexagon screws.

Hexagonal Head Bolt Weight Chart

Hexagonal Nut Specification and Weight Table

Note:

1. If possible, do not use the dimensions inside the parentheses.
2. GB41-66 produces coarse thread (Type A); GB45-66 produces coarse and fine threads (Type A and B).