The Carbon Steel Double End Stud Bolt (also known as a double-end threaded stud, tap-end stud, or DIN 938 / DIN 939 stud) is a heavy-duty industrial connection fastener featured with threaded profiles at both ends separated by an unthreaded center shank. Commonly threaded into cast iron or steel housing bodies at one end (tap end) and tightened with a hex nut at the other (nut end), this fastener is engineered for heavy machinery, valve flanges, engine cylinder heads, and pressure vessels in compliance with global ISO standards.
Technical Specifications of Carbon Steel Double End Stud Bolt
We manufacture double end stud bolts in Class 4.8 low-carbon steel for standard structural connections and Grade 8.8 medium-carbon alloy steel for high-stress dynamic loads. Depending on the base housing metal, engagement lengths vary according to international standards: DIN 938 (~1d for steel housing), DIN 939 (~1.25d for cast iron housing), and DIN 835 (~2d for aluminum alloy housing).
| Parameter | Class 4.8 Double End Stud | Grade 8.8 High Tensile Double End Stud |
|---|---|---|
| Core Material Grade | Low Carbon Steel (Q195 / Q235B) | Medium Carbon Steel (45#) / 40Cr Steel |
| Tensile Strength (Min) | 400 N/mm² (400 MPa) | 800 N/mm² (800 MPa) |
| Yield Strength (Min) | 320 N/mm² (320 MPa) | 640 N/mm² (640 MPa) |
| Tap End Length Options | DIN 938 (1d), DIN 939 (1.25d), DIN 835 (2d) | DIN 938 (1d), DIN 939 (1.25d), DIN 835 (2d) |
| Surface Finish | Black Oxide (Oiled) / Zinc Plated | Black Oxide (Oiled) / Zinc Plated / HDG |
Forging and Heat Treatment Process for Carbon Steel Double End Stud Bolt
At our manufacturing facility in Handan, China, double end stud bolts undergo high-precision cold heading or hot forging, dual-end thread rolling, and thermal treatment:
- Precision Cutting & Shank Forming: Carbon steel wire rods are cut to exact length and formed with smooth center shank transitions to ensure uniform axial load distribution.
- Dual-End Precision Thread Rolling: Rolled metric 6g threads on both ends ensure precise thread pitch alignment and fatigue resistance under cyclic vibration.
- Quenching & Tempering (For Grade 8.8): Controlled mesh-belt furnace heat treatment delivers a homogeneous martensitic structure with 800 MPa tensile strength.
- Black Oxide Chemical Treatment: Chemical blackening applies a protective micro-layer of rust-inhibiting oil that seals metal pores against indoor oxidation.
Heavy Duty Applications of Carbon Steel Double End Stud Bolt
Double-end stud bolts are essential in applications requiring frequent disassembly where female threads in expensive cast equipment need protection from wear:
- Valves, Pumps & Pipe Flanges: Connecting high-pressure pipeline flanges and valve covers where one end remains permanently anchored into the valve body.
- Engine Blocks & Automotive Assemblies: Securing cylinder heads, exhaust manifolds, and transmission housings to engine blocks.
- Heavy Machinery & Gearboxes: Fastening heavy reducer gearboxes, hydraulic equipment bases, and industrial press frames.
Quality Control and Export Packaging for Carbon Steel Double End Stud Bolt
Handan YiHao Fastener enforces comprehensive Quality Control (QC) standards for all overseas export shipments. Inspection procedures include dual-end thread ring gauge pass/fail tests, end marking verification (e.g. 8.8 stamp), tensile load testing, and dimensional tolerance checks.
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 ocean freight.
Request Factory Direct Pricing for Carbon Steel Double End Stud Bolts
Looking for a trusted manufacturer in Handan, China for Class 4.8 or Grade 8.8 carbon steel double end stud bolts (DIN 938 / DIN 939 / GB 898)? Contact Handan YiHao Fastener today for technical datasheets, custom tap-end lengths, matching hex nuts, and direct bulk export quotes.
