I. Normal Dry Indoor Environment
Recommended Material: Ordinary Carbon Steel Bolts
Advantages: Low cost, easy to process, strength grades cover 4.8-12.9, meeting the load-bearing requirements of most indoor equipment fixing and general mechanical assembly.
Precautions: No additional complex anti-corrosion treatment is required. Avoid long-term use in humid environments to prevent rapid oxidation and rusting.
II. Humid/Ordinary Outdoor Environment
Recommended Material: 304 (A2) Stainless Steel Bolts
Advantages: Added chromium and nickel elements form a passivation film, providing far superior rust resistance compared to carbon steel, and can withstand daily moisture and rain corrosion.
Applicable Scenarios: Outdoor railings, balcony furniture, general outdoor equipment fixing, etc.
III. High Salt Spray/Coastal/Strong Corrosive Environment
Recommended Material: 316 (A4) Stainless Steel Bolts
Advantages: Added 2%-3% molybdenum elements, increasing chloride corrosion resistance by more than 3 times compared to 304, and providing long-term resistance to seawater and salt spray corrosion.
Applicable Scenarios: Ship decks, coastal photovoltaic supports, and connections for equipment around chemical storage tanks.
IV. Heavy-Duty/High-Temperature/High-Pressure Conditions
Recommended Material: Alloy steel bolts (e.g., 40Cr, 35CrMo, 42CrMo)
Advantages: With the addition of alloying elements such as chromium and molybdenum, after quenching and tempering, the strength can reach grade 8.8 or higher, with a maximum of grade 12.9. Excellent strength stability in the temperature range of -50℃ to 300℃, and fatigue resistance is 2-3 times that of carbon steel.
Applicable Scenarios: Heavy-duty truck chassis, wind turbine main shafts, high-temperature pressure vessels, high-pressure pipeline flange connections, and other core load-bearing components.
V. Special Extreme Conditions
Marine High-Corrosion Lifting Scenarios: Uses special alloy material shackles and matching alloy steel bolts, balancing high strength and resistance to marine corrosion.
Strong Acid and Alkali Chemical Conditions: Uses special alloy material bolts with high acid and alkali resistance to prevent ordinary stainless steel from being rapidly corroded by chemical media, ensuring long-term sealing stability.
Lightweight/Aerospace applications: Titanium alloy bolts are selected, which have strength close to that of alloy steel but weigh only half as much as steel and can withstand temperatures above 300°C.
