Common bolt material types mainly include carbon steel, alloy steel, stainless steel, copper and copper alloys, aluminum alloys, and titanium alloys.
These materials are widely used in various industrial applications due to their different mechanical properties, corrosion resistance, and cost.
1. Carbon Steel
Characteristics: Low cost, moderate strength; the most widely used bolt material.
Common grades: Q235 (corresponding to grade 4.8 bolts), 45 steel (used for grade 8.8).
Applicable scenarios: Power equipment, building structures, general mechanical connections, and other environments where corrosion resistance requirements are not high.
2. Alloy Steel
Characteristics: Added elements such as chromium, molybdenum, and manganese to carbon steel, significantly improving strength and toughness.
Common grades: 35CrMo, SCM435 (commonly used for high-strength bolts of grade 10.9 and above).
Applicable scenarios: High-stress conditions such as automotive engines, wind power equipment, and heavy machinery.
3. Stainless Steel
Features: Excellent corrosion resistance and aesthetics, suitable for humid or outdoor environments.
Main Types:
Austenitic: Such as SUS304, SUS316, strong corrosion resistance, non-magnetic or weakly magnetic.
Martensitic/Ferritic: Such as SUS430, higher strength but slightly lower corrosion resistance.
Performance Grades: A2-70, A4-80, etc., the numbers represent 1/10 of the tensile strength (e.g., 70 = 700MPa).
4. Copper and Copper Alloys (such as Brass H62)
Features: Good electrical conductivity, corrosion resistance, non-magnetic, but lower strength.
Applications: Electrical connectors, instruments, decorative fasteners.
5. Aluminum Alloys (such as 7075, 6063)
Features: Low density, lightweight, corrosion resistant, suitable for lightweight designs.
Applications: Aerospace, rail transportation, high-end sports equipment.
