Technical Resources
Grade & Finish Comparison Guides
Quantified comparisons of class 8.8 / 10.9 / 12.9, 304 versus 316 stainless, zinc plated versus hot-dip versus Dacromet, and nylon insert versus all-metal lock nuts versus threadlocker — written to help structural, petrochemical, automotive and marine projects specify correctly the first time.
01Grade 8.8 vs 10.9 vs 12.9 Bolts: Strength, Hardness, Toughness and PriceComparison of the three carbon steel property classes 8.8, 10.9 and 12.9 per GB/T 3098.1 / ISO 898-1: nominal tensile 800/1000/1200 MPa, minimum yield 640/940/1100 MPa, hardness 22-32/32-39/39-44 HRC, plus quench-and-temper duty, toughness and relative price (1 / 1.2-1.4 / 1.5-1.8).02304 vs 316 Stainless Bolts: The Corrosion Gap Measured by PRENThe pitting equivalence number PREN (%Cr + 3.3x%Mo + 16x%N) quantifies the gap between 304/A2 and 316/A4: 18-20 vs 24-26, about 35% higher. Conclusions for indoor, inland-outdoor, coastal and chemical environments, with strength classes (A2-70/A4-80) and cost compared.03Zinc Plated vs Hot-Dip vs Dacromet: Salt Spray, Hydrogen Embrittlement and Thread FitThe three most-used fastener finishes in export orders compared: electro-zinc (blue-white 48-72 h / yellow 96-240 h), hot-dip galvanizing (1000 h+, 50-100 um) and Dacromet (500-1000 h+, 4-10 um, hydrogen-free) across salt-spray life, temperature limits, hydrogen-embrittlement risk, relative cost and thread fitability.04Anti-Loosening Options: Nylon Insert vs All-Metal Lock Nut vs ThreadlockerBolts loosen through transverse slip, not vibration as such. This comparison covers the three mainstream locking routes - nylon-insert lock nut (DIN985), all-metal lock nut (DIN980) and threadlocker - on transverse-vibration behaviour, remakes, temperature ceiling and relative cost, with a three-step decision path.
Ready to Sort Out Your Fastener Specification?
Contact our engineering team for torque data, non-standard production or a competitive quote. We reply within 24 hours.