The Stainless Steel Hex Bolt is an indispensable high-grade fastener engineered for environments demanding exceptional chemical resistance, sanitary cleanliness, and long-term anti-rust endurance. Manufactured from premium austenitic stainless steel grades (SS304 / A2-70 and SS316 / A4-80), this fastener forms a self-healing chromium oxide passive film that prevents pitting, atmospheric oxidation, and chemical degradation in accordance with international ISO standards.
Technical Specifications of Stainless Steel Hex Bolt
Austenitic stainless steel property ratings specify both mechanical strength and alloy composition. Grade A2-70 (SS304) provides robust corrosion resistance for general outdoor and food-grade machinery, while Grade A4-80 (SS316) contains molybdenum (2-3% Mo) to withstand harsh chloride environments, marine salt spray, and acidic chemical processing.
| Grade Marking | Stainless Material Grade | Tensile Strength (Min) | Yield Strength (Min) | Corrosion Environment |
|---|---|---|---|---|
| A2-50 / A2-70 | AISI 304 / SS304 (1.4301 / 06Cr19Ni10) | 500 – 700 N/mm² (700 MPa) | 450 N/mm² (450 MPa) | Freshwater, Atmospheric & Food Industry |
| A4-70 / A4-80 | AISI 316 / SS316 (1.4401 / 06Cr17Ni12Mo2) | 700 – 800 N/mm² (800 MPa) | 600 N/mm² (600 MPa) | Marine Coastal, Salt Spray & Chemical Processing |
Cold Heading and Passivation Process for Stainless Steel Hex Bolt
At our manufacturing facility in Handan, China, stainless steel hex bolts are forged and surface-treated to guarantee clean aesthetics and precise thread engagement:
- Precision Cold Heading: High-speed multi-station former presses shape the hexagonal head with crisp bevels and clear property head stamps (e.g., A2-70, A4-80, or manufacturer codes) without work-hardening micro-cracks.
- High-Precision Thread Rolling: Rolled metric 6g threads establish precise pitch concentricity, preventing anti-galling or thread seizing during high-speed installation.
- Chemical Pickling & Acid Passivation: Chemical washing removes free iron particles introduced during tooling, forming a dense passive chromium oxide film on all exposed surfaces.
- Optional Anti-Galling Coatings: Specialized wax lubricants or PTFE coatings can be applied upon request to eliminate friction seizing during automated power driving.
Corrosion Resistant Applications of Stainless Steel Hex Bolt
Thanks to their non-magnetic properties, chemical stability, and bright clean finish, stainless steel hex head bolts are widely specified in critical hygienic and harsh outdoor sectors:
- Marine Engineering & Offshore Infrastructure: Securing boat hardware, dock fittings, desalination plants, and coastal railing systems using SS316 (A4-80).
- Food, Beverage & Pharmaceutical Processing: Assembling sanitary piping, stainless steel tanks, bottling equipment, and cleanroom machinery.
- Chemical Plants & Water Treatment: Fastening pump housings, valve flanges, and wastewater pipeline brackets exposed to aggressive media.
Quality Control and Export Packaging for Stainless Steel Hex Bolt
Handan YiHao Fastener enforces comprehensive Quality Assurance (QA) protocols for all export shipments. Testing procedures include Positive Material Identification (PMI) chemical spectro-analysis to verify Nickel and Chromium content, thread ring gauge pass/fail tests, and tensile strength testing.
All export items are packed in heavy-duty 25kg inner cartons, neatly stacked on ISPM 15 compliant fumigated wooden pallets, and wrapped in protective stretch film to prevent moisture contamination during ocean transit.
Request Factory Direct Pricing for Stainless Steel Hex Bolts
Looking for a trusted manufacturer in Handan, China for SS304 (A2-70) or SS316 (A4-80) stainless steel hex bolts? Contact Handan YiHao Fastener today for technical datasheets, full thread/partial thread options, sample shipments, and direct bulk export quotes.
