Grade 4 hexagonal nuts are general-purpose fasteners widely used in industrial assembly, construction projects and the hardware supply sector. Thanks to their key advantages—compliance with standards, consistent performance, excellent value for money and broad compatibility—they have become the preferred standard component for major purchasers, engineering firms and equipment manufacturers.

From raw material selection, stamping and forming, precision thread turning, end-face grinding to surface treatment, each stage of the process is subject to quality control by dedicated personnel, ensuring product quality right from the source

Grade 4 hexagon nuts are general-purpose, cost-effective fasteners suitable for the vast majority of standard fastening applications. Not limited to any single sector, they have a wide range of applications and are essential fasteners across all industries.

To ensure proper installation, equipment safety and product service life, and to avoid issues such as loosening, rusting or breakage caused by installation errors or mismatched operating conditions, please note the following points.

• Strictly match the operating conditions; overloading is strictly prohibited: Grade 4 nuts are made of Q235 carbon steel and are not heat-treated for strengthening; they are suitable only for general static, medium-to-low load fastening applications. They must not be used as substitutes for Grade 8 or Grade 10 high-strength nuts in high-stress applications such as heavy machinery, high-pressure equipment, environments subject to high-frequency vibration, load-bearing bridges, or precision pressure-bearing equipment. Use in overloaded or high-vibration environments carries a high risk of thread stripping, nut cracking, connection loosening or even detachment, which may compromise equipment and project safety.
• Follow standard installation procedures and avoid forceful assembly: Before installation, remove metal shavings, oil residue and impurities from the threads of the nuts and bolts to ensure clean and smooth thread engagement, and to prevent residual debris from causing improper assembly. During assembly, do not strike the components violently or force them in, to prevent stripped threads or cracking of the nut body; It is recommended to tighten the nuts manually or using a standard torque tool at a constant speed, applying even and moderate force without over-tightening, to avoid stress concentration causing hidden damage and subsequent failure during long-term use.
• Select the appropriate surface finish according to the application: Uncoated Grade 4 nuts have no anti-corrosion treatment and are only suitable for standard indoor conditions that are dry, free from moisture and corrosion, and for short-term assembly use; they must not be used in outdoor or exposed environments. In damp environments, outdoor settings exposed to rain, construction sites with high levels of moisture, or installations near water sources, it is essential to use rust-resistant nuts with zinc plating, hot-dip galvanising or Dacromet coating to effectively prevent rust and corrosion, thereby avoiding fastening failure or structural loosening caused by rusted nuts.
• Standardised assembly; avoid mixing with non-standard components: When in use, these nuts must be paired with standard coarse-threaded bolts and threaded rods of the same specification and in accordance with the same national standards. Mixing with non-standard threads, fine-threaded components or damaged threaded fittings is strictly prohibited, as this may result in poor engagement, excessive clearance and a risk of loosening. For assemblies requiring anti-loosening protection, these nuts may be used in combination with matching flat washers and spring washers to enhance structural stability, making them suitable for long-term equipment operation and environments subject to minor vibrations.
• Standardised storage and moisture protection: Unused Grade 4 nuts must be stored in a dry, well-ventilated, indoor warehouse protected from rain. Avoid long-term outdoor storage, exposure to direct sunlight or damp conditions to prevent surface oxidation, rusting and thread seizing. Bulk stock must be sorted and stacked neatly, with different specifications stored separately to avoid deformation or thread damage caused by knocks or crushing, which could affect subsequent assembly and use.
• It is recommended to use nuts from the same production batch for large-scale engineering projects: When using Grade 4 nuts in bulk for large-scale engineering projects or complete machine assembly, it is advisable to select nuts from the same production batch. Products from the same batch exhibit a high degree of uniformity in dimensional accuracy, mechanical properties and process parameters, which can effectively prevent assembly deviations and uneven stress distribution caused by batch variations, thereby ensuring the consistency and stability of the overall engineering and equipment assembly.