Standard component products not only require precision, but also meet structural strength and performance requirements, which are related to factors such as materials, processes, and heat treatment of standard components. Different materials and processes are suitable for different needs.
Procurement should identify the strength grade, material anti-corrosion, and dimensional tolerances to prevent substandard tensile strength, insufficient hardness, and defective materials from entering the construction site.
One Mechanical properties and materials
1. Determination of mechanical performance level
Force situation
Pre tightening degree
Assembly process
Anti loosening measures
The higher the strength of a bolt, the better. The higher the strength, the lower the toughness. The selection of high-strength bolts (grade 10.9 or above) must consider the impact of the environment on performance.
2. Strength level
The level directly determines: tensile bearing capacity, shear resistance, fatigue resistance, and anti loosening and anti vibration capacity.
4.8 level: ordinary static light load, indoor conventional fixed and decorative auxiliary materials can be used;
Grade 8.8: Medium to high strength, standard equipment rack, steel structure, and main load-bearing points of suspended ceilings;
Grade 10.9/12.9: Heavy duty, vibration equipment, heavy-duty steel structures, mechanical main load-bearing bolts.
The procurement must require that the strength grade and mechanical properties of the bolts meet the standards, and the tensile strength and yield strength comply with the corresponding national standards. It is strictly prohibited to purchase non-standard products that use ordinary carbon steel to impersonate high strength. The performance can be verified through third-party mechanical tests.
3. Material
Carbon steel: indoor dry, ordinary structure, with the highest cost-effectiveness
304 stainless steel: outdoor, humid, kitchen and bathroom, outdoor equipment, rust resistant and durable
316 stainless steel: specifically designed for coastal salt spray and chemical corrosion environments
High strength bolts must be made of high-quality alloy steel of 35 # or above, which has undergone complete quenching and tempering heat treatment to eliminate defective products processed with inferior carbon steel that has not undergone heat treatment. The process compliance can be confirmed through material spectrum testing and hardness sampling.
II Surface treatment
Bolts have a wide range of applications and require various surface treatments, mainly including galvanizing, anti-corrosion phosphating, and Dacromet. According to the thickness, color, corrosion resistance, and process of the coating, it can be divided into various types. Surface treatment is not only related to the corrosion resistance of products, but also affects the functionality of machinery, so it is important to understand commonly used surface treatments.
III Dimensions
Precision dimensional tolerances determine assembly accuracy and fastening stability.
The bolt head has clear strength grade markings, and the thread accuracy and head to edge dimensions meet the national standard tolerance requirements. There are no cutting corners or cutting corners to ensure installation compatibility and connection reliability.
Post time: 9月-14-2026
