Industry knowledge
Track screws bolts need to withstand high-frequency vibration, heavy loads and harsh environments. The choice of materials directly affects their life and safety. Mainstream materials include:
1. Carbon steel (such as Q235, 45# steel)
- Features: low cost, moderate strength (tensile strength ≥ 400MPa), widely used for ordinary track fixation.
- Limitations: easy to rust, galvanized or blackened (the thickness of the galvanized layer is usually 5-15μm, refer to GB/T 13912-2020).
2. Stainless steel (such as 304, 316)
- Features: strong corrosion resistance (316 stainless steel salt spray resistance > 500 hours, refer to ASTM B117), suitable for humid or chemical corrosion environments.
- Limitations: lower strength than alloy steel (304 stainless steel tensile strength ≥ 515MPa), higher cost.
3. Alloy steel (such as 40Cr, 35CrMo)
- Features: high strength (tensile strength of 40Cr after quenching and tempering ≥980MPa, refer to GB/T 3077-2015), used for high-speed rail and heavy-load tracks.
- Limitations: heat treatment (quenching + tempering) is required to improve performance, and the processing cost is high.
