Stainless Steel Double End Stud Bolt SS304 SS316 A2-70 A4-80 (DIN 938 / DIN 939)

The Stainless Steel Double End Stud Bolt (also known as a stainless double-end threaded stud, tap-end stud, or DIN 938 / DIN 939 stainless stud) is a high-precision, corrosion-resistant connection fastener featuring external threads at both ends separated by an unthreaded center shank. Engineered to protect delicate internal female threads in expensive cast equipment, one end (tap end) remains permanently anchored into the housing, while the other end (nut end) is secured with a stainless hex nut. Manufactured from premium austenitic stainless steel (SS304 / A2-70 and SS316 / A4-80), this fastener creates a self-healing passive chromium oxide layer that prevents chemical corrosion and atmospheric rust in accordance with global ISO standards.

Technical Specifications of Stainless Steel Double End Stud Bolt

Austenitic stainless steel double end studs provide non-magnetic physical properties and exceptional chemical resistance. Grade A2-70 (SS304) provides 700 MPa tensile strength for general outdoor building connections and food machinery. Grade A4-80 (SS316) contains 2–3% Molybdenum addition to achieve 800 MPa tensile strength while resisting aggressive chloride ion pitting in marine environments and chemical processing plants. Tap end engagement lengths follow international standard conventions: DIN 938 (~1d), DIN 939 (~1.25d), and DIN 835 (~2d).

Forging and Passivation Process for Stainless Steel Double End Stud Bolt

At our manufacturing plant in Handan, China, stainless steel double end studs are precision-machined and chemically treated to guarantee smooth assembly and long-term anti-rust performance:

• Precision Shank Cutting & Forming: Stainless wire rods are cut to exact lengths with clean center shank transitions, ensuring perfectly aligned axial clamping force.
• Dual-End Precision Thread Rolling: Rolled metric 6g threads on both ends establish smooth pitch concentricity, preventing galling or thread seizing during installation into tapped holes.
• Acid Pickling & Chemical Passivation: Chemical washing strips free iron micro-particles left by tooling, regenerating a dense chromium oxide passive film over all surfaces.
• Optional Anti-Galling Coatings: Specialized dry-wax lubricants or electropolishing can be provided upon request to prevent friction galling in high-speed automated power assembly.

Corrosion Resistant Applications of Stainless Steel Double End Stud Bolt

Stainless steel double end stud bolts are specified in critical sanitary, marine, and chemical applications where frequent disassembly is required without damaging housing threads:

• Chemical Plants, Valves & Pipe Flanges: Connecting stainless pipeline flanges, pump housings, and chemical reactor covers.
• Food, Beverage & Sanitary Equipment: Assembling stainless bottling lines, dairy processing tanks, and pharmaceutical cleanroom equipment.
• Marine Engineering & Offshore Hardware: Securing boat hardware, seawater desalinization plant manifolds, and coastal pump bases using SS316 (A4-80).

Quality Assurance and Export Packaging for Stainless Steel Double End Stud Bolt

Handan YiHao Fastener enforces strict Quality Assurance (QA) standards for all overseas export orders. Testing procedures include Positive Material Identification (PMI) chemical spectro-analysis for Nickel and Chromium content, dual-end thread ring gauge checks, and tensile strength validation.

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 ensure safe maritime transport.