Thread flat rolling die

The performance of a rolling die is primarily determined by its base material. You should prioritize High-Speed Steel (HSS) like M2 (6-5-2) or M35 (containing Cobalt) for high-tensile fasteners, or Cr12MoV (D2) for standard applications. Ensure the material undergoes vacuum heat treatment to achieve a hardness of HRC 59-62 for standard screws or HRC 62-65 for stainless steel applications to prevent premature chipping or wear.

Compatibility depends on three critical dimensions: Length, Width, and Thickness. You must verify the die face dimensions (e.g., 90x25x105mm) against your machine's slide plate specifications. Additionally, specify the thread profile (Metric, UNC, UNF, or BSW) and the accuracy class (e.g., 6g or 2A). For high-speed production, request lead-in and lead-out chamfering to reduce impact stress and improve thread entry.

To maximize tool life, especially when rolling hard materials like stainless steel or grade 12.9 bolts, consider surface coatings. TiN (Titanium Nitride) or TiAlN (Titanium Aluminum Nitride) coatings can significantly reduce friction and heat buildup. Nitriding is another cost-effective option to increase surface hardness and prevent galling (material transfer) during the rolling process.

A high-quality die should exhibit zero visible grinding cracks under magnification. The pitch error should be controlled within ±0.005mm, and the surface roughness (Ra) of the thread grooves should be less than 0.4μm. Requesting a metallographic analysis report and a hardness test certificate from the supplier is standard practice for B2B procurement to ensure consistency across batches.

Always request a pre-shipment inspection (PSI). For precision tools like rolling dies, ask the supplier to provide a video of a trial run or a sample of the rolled screw produced by the specific die set you are purchasing. Utilize Made-in-China.com's Secured Trading services to ensure payment is only released once the shipping documents are verified and the goods meet the agreed-upon technical specifications.

Since rolling dies are often customized, volume-based pricing is key. Negotiate a 15-20% discount for annual blanket orders where the supplier stocks semi-finished blanks. For lead times, standard sizes usually take 7-10 days, while custom profiles may take 20-30 days. Ensure the contract includes a penalty clause for late delivery to protect your production schedule.

Thread rolling dies are heavy and prone to rust. Insist on anti-rust oil coating and VCI (Volatile Corrosion Inhibitor) paper wrapping. The dies should be packed in individual wooden cases or heavy-duty plastic boxes with internal padding to prevent the thread teeth from clashing during transit. For international shipping, Sea Freight (LCL) is most economical for bulk, but Air Express (DHL/FedEx) is recommended for urgent replacements due to the high value-to-weight ratio.