Product Summary

Longze DIN 976-1 Metric Stud Bolts are high-precision fully threaded fasteners engineered for continuous tensioning in structural steel, chemical piping, and heavy-duty concrete

anchoring. Manufactured in Yongnian, China, our stud bolts are cold-rolled to ensure grain flow continuity and superior thread fatigue life. Whether you require the extreme

corrosion resistance of SS316 for offshore platforms or the high-tensile clamping force of Class 10.9 alloy steel for bridge construction, Longze delivers the exact mechanical performance your engineering specs demand.

• ✔ Cold-Rolled Strength: Every stud is produced via cold-rolling, which work-hardens the threads, making them significantly stronger and smoother than cut threads.

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• ✔ Guaranteed Straightness: We implement a dedicated straightening stage for all rods up to 3 meters, ensuring a ±0.1mm/m straightness tolerance for jam-free nut engagement.

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• ✔ True Material Integrity: We provide full heat treatment for Class 8.8 and 10.9 studs and utilize genuine Ni-Cr balanced stainless steel to prevent premature pitting.

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• Standards: DIN 976-1 (Form A), 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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• Standard Lengths: 1,000mm, 2,000mm, 3,000mm (Custom cut-to-length available).

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• Material Grade: Stainless Steel 304/316 | Carbon Steel Class 8.8, 10.9, 12.9.

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• Surface Finish: Hot Dip Galvanized (HDG), Zinc Plated, PTFE/Teflon (Blue/Green), Plain.

Mechanical Properties & Material Standards

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

• Material Grade	Tensile Strength (min)	Yield Strength (min)	Hardness Range	Best Application
  Class 8.8	800 MPa	640 MPa	22 - 32 HRC	Structural Steel / Framing
  Class 10.9	1040 MPa	940 MPa	32 - 39 HRC	High-Pressure Piping
  SS304 (A2)	700 MPa	450 MPa	200 - 280 HV	General Industrial / Food
  SS316 (A4)	800 MPa	600 MPa	240 - 320 HV	Marine / Chemical / Oil

Standard Cross Arm Dimensions

• Common angle steel configurations for standard utility pole mounting.

• Thread Size (D)	Pitch (Metric)	Sectional Area (mm²)	Proof Load (8.8)	Max Torque (10.9)
  M16	2.0 mm	157 mm²	91.0 kN	280 Nm
  М20	2.5 mm	245 mm²	142 kN	540 Nm
  M24	3.0 mm	353 mm²	205 kN	930 Nm
  M30	3.5 mm	561 mm²	325 kN	1900 Nm

Galvanizing & Corrosion Resistance

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

• Surface Treatment	Process	Salt Spray Test	Service Life	Best Environment
  Zinc Plated	Electrolytic	72 - 144 Hours	High	Indoor / Dry
  Hot Dip Galv.	Thermal Bath	500 - 800 Hours	Maximum	Outdoor Infrastructure
  PTFE (Teflon)	Fluoropolymer	1000 - 2000 Hours	Extreme	Subsea / Petrochemical
  SS316 Polished	N/A	1000+ Hours	Lifetime	Marine / Coastal

Avoid Pitfalls:

• Nut Jamming on HDG: For hot-dip galvanized studs, we ensure the threads are rolled to 6g/6h tolerances after accounting for the zinc layer thickness, preventing "lock-up" during field installation.

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• Brittle Fracture in 10.9: We perform precise tempering cycles to prevent hydrogen embrittlement, ensuring that high-strength studs have the necessary ductility to withstand seismic or vibration loads.

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• Burrs & End Chamfering: Longze DIN 976-1 studs feature a 45° end chamfer (Form A), removing sharp burrs that can damage nuts and slow down your assembly line.

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Perfect Fit Assembly:

• Matched Nut/Washer Kits: We recommend pairing our 10.9 studs with Longze Class 10 Nuts и 200HV Washers for a fully certified high-tensile connection.

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• Custom Identification: Need to distinguish grades on-site? We can provide Color-Coded End Painting (e.g., Yellow for 8.8, Red for 10.9) for instant visual verification.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including ultrasonic testing for internal flaws in M36+ sizes, thread pitch gauge verification, and material spectrometer analysis.

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

• Q: Can you provide PTFE-coated stud bolts in specific colors? A: Yes, we offer Blue, Green, and Red Teflon coatings which provide low friction and extreme chemical resistance for oil & gas piping.

• Q: Do you offer MTR (Mill Test Reports)? A: Absolutely. Every shipment comes with a full chemical and mechanical test report linked to your specific batch number.