Product Summary

Longze High-Strength Stud Bolts (DIN 976-1) and Fully Threaded Rods are engineered for high-pressure piping, structural steel bracing, and heavy-duty concrete anchoring.

Manufactured in Yongnian, China, our threaded rods are produced via high-precision cold rolling, ensuring superior thread strength and surface finish compared to cut threads.

Whether for coastal infrastructure or industrial boiler assembly, Longze stud bolts provide the uniform tension and mechanical stability required for critical fastening applications.

• ✔ Cold-Rolled Precision: Our rolling process creates a continuous grain flow, increasing the fatigue resistance of the threads by up to 30% over traditional cutting methods.

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• ✔ Superior Straightness: We implement a 3-step straightening process to ensure that even 3-meter rods meet strict industrial tolerances, preventing installation jamming.

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• ✔ High-Tensile Performance: Fully heat-treated to meet ISO 898-1 Class 8.8, 10.9, and 12.9, providing consistent yield strength across the entire length of the rod.

• Standards: DIN 976-1 (Form A/B), DIN 975, ISO 898-1, ASME B18.31.3.

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• Diameter Range: M6 to M64 | 1/4" to 2-1/2".

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• Length Range: 10mm to 3000mm (Standard 1m, 2m, 3m or custom cut-to-length).

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• Material Grade: Carbon Steel (Class 4.8, 8.8, 10.9, 12.9) | Stainless Steel 304 (A2) & 316 (A4).

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• Surface Finish: Hot Dip Galvanized (HDG), Zinc Plated, Black Oxide, PTFE/Teflon Coating, Dacromet.

Mechanical Properties & Material Standards

• Matching the steel grade to the structural requirements of the transmission line.

• Property Class	Bahan	Tensile Strength (min)	Yield Strength (min)	Hardness Range
  Class 8.8	Medium Carbon Steel	800 MPa	640 MPa	22 - 32 HRC
  Class 10.9	Alloy Steel	1040 MPa	940 MPa	32 - 39 HRC
  Class 12.9	Alloy Steel	1220 MPa	1100 MPa	39 - 44 HRC
  Stainless 316	A4-80	800 MPa	600 MPa	240 - 320 HV

Standard Cross Arm Dimensions

• Common angle steel configurations for standard utility pole mounting.

• Thread Size (D)	Pitch (Metric)	Sectional Area (mm²)	Proof Load (Class 8.8)	Recommended Torque
  M12	1.75 mm	84.3 mm²	48.9 kN	80 - 90 Nm
  M16	2.0 mm	157 mm²	91.0 kN	190 - 210 Nm
  M20	2.5 mm	245 mm²	142 kN	370 - 400 Nm
  M24	3.0 mm	353 mm²	205 kN	640 - 700 Nm

Galvanizing & Corrosion Resistance

• Ensuring 30+ years of service life in corrosive environments.

• Thread Size (D)	Pitch (Metric)	Sectional Area (mm²)	Proof Load (Class 8.8)	Recommended Torque
  M12	1.75 mm	84.3 mm²	48.9 kN	80 - 90 Nm
  M16	2.0 mm	157 mm²	91.0 kN	190 - 210 Nm
  M20	2.5 mm	245 mm²	142 kN	370 - 400 Nm
  M24	3.0 mm	353 mm²	205 kN	640 - 700 N

Avoid Pitfalls:

• Oversized HDG Threads: We prevent "nut jamming" on hot-dip galvanized rods by utilizing undersized thread rolling before the galvanizing bath, ensuring a perfect 6h/6g fit after the zinc layer is applied.

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• Brittle Fracture in 12.9: We perform precise tempering cycles for Class 12.9 rods to achieve the perfect balance between high hardness and sufficient ductility, preventing catastrophic failure under high-tension loads.

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• End-Face Burrs: Every Longze DIN 976-1 stud is chamfered (Form A or B) to remove sharp burrs, protecting workers' hands and allowing for immediate nut engagement on the job site.

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Perfect Fit Assembly:

• Matched Heavy Hex Nuts: We provide DIN 934 or ASTM A194 2H Nuts that are batch-matched to our stud bolts to ensure consistent thread pitch and load distribution.

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• Custom Color Coding: For large-scale projects, we can paint the end-faces of the rods (e.g., Yellow for 8.8, Red for 10.9) for instant grade identification on-site.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including laser-straightness measurement, ultrasonic testing for internal flaws in large diameters (M36+), and thread pitch verification.

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• Sea-Worthy Packaging: Threaded rods are bundled with steel strapping, wrapped in moisture-proof plastic sleeves, and secured in reinforced wooden crates for maritime export.

• Q: Do you offer PTFE-coated stud bolts for oil and gas applications? A: Yes, we provide Xylan/Teflon coatings in various colors (Blue, Green, Red) which offer extreme corrosion resistance and low friction for subsea and chemical piping.

• Q: Can you cut 3-meter rods to specific lengths for us? A: Absolutely. We have high-speed automatic sawing machines in our Yongnian factory that can cut and chamfer rods to any specific length with a ±1mm tolerance.