Hexagonal head bolts are divided into two types: external hexagonal bolts and internal hexagonal screws, usually used for fastening mechanical equipment.
Hexagonal head bolt material
At present, there are three main materials of hexagonal screws on the market: carbon steel, stainless steel, and copper.
（1） Carbon steel. We distinguish low carbon steel, medium carbon steel, high carbon steel, and alloy steel based on the carbon content in carbon steel materials.
1. Low carbon steel with C% ≤ 0.25% is commonly referred to as A3 steel in China. It is commonly referred to as 10081015181022 in foreign countries. Mainly used for grade 4.8 bolts, grade 4 nuts, small screws and other products without hardness requirements (note: drill tail nails are mainly made of 1022 material).
2. Medium carbon steel 0.25% 0.45%. Currently, it is basically not used in the market.
3. Alloy steel: Adding alloying elements to ordinary carbon steel increases some special properties of the steel, such as 35, 40 chromium molybdenum, SCM435, 10B38. Aromatic screws mainly use SCM435 chromium molybdenum alloy steel, which is mainly composed of C Si、Mn、P、S、Cr、Mo。
（2） Stainless steel. Performance level: 45, 50, 60, 70, 80 mainly divided into austenite (18% Cr, 8% Ni) with good heat resistance, corrosion resistance, and weldability. A1, A2, A4 martensite, 13% Cr have poor corrosion resistance, high strength, and good wear resistance. C1, C2, C4 ferritic stainless steel. 18% Cr has good forging properties and stronger corrosion resistance than martensite. At present, the main imported materials in the market are Japanese products. Mainly divided by level into SUS302, SUS304, and SUS316.
（3） Copper. The commonly used material is brass zinc copper alloy. H62, H65, and H68 copper are mainly used as standard parts in the market. The disc elements used in carbon steel products can be selected from the following materials: 1. 4.8 grade hex screws 1008K 1010 1015K 2. 6.8 grade hex screws.
Bolt standards
National standard for hexagon bolts GB/T5782-86
The standard specifies hexagonal head bolts with thread specifications of M3~M64, grade A and B, grade A is used for bolts with D<=24 and L<=10D or L<=150mm (whichever is smaller); B-grade is used for bolts with D>24 or L>10D or L>150 (whichever is smaller).
Dimensions of external hexagonal bolts
External hexagonal bolt standard: DIN ANSI BS GB
Material: stainless steel or carbon steel
Diameter: 5mm~20mm, 1/4 “~3/4″
Length: 8mm~200mm, 5/16 “~8″
Thread: metric, coarse, fine, imperial
Mechanical properties: 4.8, 5.8, 6.8, 8.8, 9.8, 10.9, 12.9
Surface treatment: natural color, galvanized, blackened, nickel plated
Post time: Jun-25-2024