What Is A 8.8 Hex Bolt?
Grade 8.8 hexagon bolts are among the most widely used high-strength bolts in the industrial sector. The designation ‘Grade 8.8’ indicates their mechanical performance grade: the first ‘8’ denotes a nominal tensile strength of ≥800 MPa, whilst the ‘8’ following the decimal point indicates a yield-to-tensile strength ratio of ≥0.8, meaning a yield strength of ≥640 MPa. Achieving these core performance characteristics is dependent on the selection of high-quality materials and rigorous quality control.
The selection of materials for Grade 8.8 hexagon bolts must strictly comply with the GB/T 3098.1 national standard. High-quality alloy steel is the primary choice, as ordinary carbon steel lacks the necessary strength to meet the high-strength requirements. There are two main types of materials commonly used:
45 medium-carbon steel and 40Cr low-alloy steel. 45 steel offers outstanding value for money; after quenching and tempering, it can meet the demands of conventional high-strength applications such as mechanical and equipment assembly;
40Cr alloy steel, due to the addition of chromium, exhibits superior hardenability; after tempering, it achieves uniform hardness and offers superior toughness and wear resistance, making it suitable for applications involving heavy loads and frequent stress cycles.
As a manufacturer of Grade 8.8 hexagon bolts, our control over materials extends throughout the entire production process:
Raw material intake: We test chemical composition and mechanical properties using methods such as spectroscopic analysis and tensile testing to ensure the materials meet standard requirements.
Production process: We strictly adhere to quenching and tempering processes to ensure the bolt core achieves the required martensitic microstructure, thereby delivering the high-strength properties demanded by the design.
Prior to dispatch: We conduct random sampling to test key parameters such as hardness and tensile strength, thereby preventing any non-conforming products from entering the market.
The outstanding performance of our M8.8 hexagon bolts stems from the use of suitable alloy steel, strict national standards, and the manufacturer’s meticulous control throughout the entire production process. We remain steadfast in our adherence to material standards, crafting every bolt with care to provide safe and reliable fastening solutions for a wide range of industries.
