Our company offers custom cold-forged bolts based on customer drawings or sample requirements.
material selection
We use alloy steels such as 35CrMo and 42CrMo, as well as 304/316 stainless steel. We use spectrometers to test the composition to ensure that the S and P impurity content is ≤0.025%, ensuring the quality of cold-forged bolts from the source.
Core Machining Capabilities
Cold Forging
Our company is equipped with 3-6 station fully automatic cold heading machines, capable of forming bolts in a single operation, with dimensional tolerances within ±0.05 mm.
Thread Rolling
We use fully automatic thread rolling machines to roll the threads on the bolt shanks, maintaining a thread profile integrity of ≥95%, with diameter and pitch accuracy controlled to ±0.02 mm.
Heat Treatment
We use fully automatic mesh belt furnaces for quenching and tempering of bolts, achieving a yield strength of 800-950 MPa and a hardness of HRC 32-36.
Surface Treatment
We offer a variety of surface treatments, including phosphating, zinc plating, and Dacromet coating, to enhance corrosion resistance.
Quality Control
Dimensional Testing
Diameter, length, head size, and thread pitch are inspected using CMMs, vision machines, and thread gauges to ensure compliance with standards.
Mechanical Testing
Bolt strength and toughness are verified through tensile, hardness, and impact testing to ensure they can withstand actual loads in applications.
Corrosion Testing
Surface-treated bolts undergo salt spray testing to verify their long-term rust and corrosion resistance.
Why We Deserve Your Trust
Strict Quality Inspection
Our company is equipped with spectrometers, hardness testers, and CMM testing equipment to meticulously inspect raw materials, performance, and dimensions to ensure high product quality.
Quick Response
Our customer service team responds to inquiries within 24 hours, provides quotes or samples within 2–3 days, and handles after-sales issues within 48 hours, minimizing customer wait times throughout the entire process.
High Cost-Effectiveness
Located in Ningbo's core manufacturing area, our company boasts a centralized network of raw material suppliers, effectively reducing procurement costs and offering customers more competitive pricing.
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Q: What is the common specification range for cold-forged bolts?
A: We offer cold-forged bolts in sizes M6–M30 and lengths from 20–300 mm.
Q: What are cold-forged bolts suitable for?
A: Cold-forged bolts are commonly used for securing automotive engine cylinder heads, connecting construction machinery booms, and beam-column joints in steel structures.
Q: Can a test report be provided before delivery?
A: Yes, we can provide dimensional, performance, and salt spray test reports.
Q: What is the minimum order quantity for custom bolts?
A: The minimum order quantity for standard specifications is 5,000 pieces, and small trial orders for special specifications are available.
Q: Can complex head shapes be processed?
A: Yes, hexagonal, hexagonal, flange, and plum heads can all be cold forged.
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