Roll pin

Carbon Steel (e.g., 65Mn, C67S) is the most common choice due to its high hardness and excellent elasticity, making it ideal for heavy-duty mechanical applications. However, it requires surface treatments like black oxide or zinc plating to prevent rust. Stainless Steel (e.g., SUS304, SUS316) offers superior corrosion resistance for marine or food-grade environments but generally has lower shear strength compared to high-carbon spring steel.

Slotted Roll Pins are single-turn pins with a longitudinal gap, best for general-purpose fastening where cost-efficiency is a priority. Coiled Roll Pins (Spiral Pins) are made by wrapping steel 2.25 times; they are superior for high-vibration environments because they provide 360-degree contact with the hole wall, distributing stress more evenly and preventing hole damage.

B2B buyers should ensure products meet ISO 8752 (heavy duty slotted) or ISO 8750 (coiled) standards. For the US market, ASME B18.8.2 is the benchmark. Always request a Material Test Report (MTR) and a RoHS/REACH certification to ensure the absence of hazardous substances, especially for electronics or consumer goods applications.

The most critical dimensions are the expanded diameter (d1) and the chamfer length. The pin must be slightly larger than the nominal hole size to ensure a friction fit. Use a caliper or micrometer to verify that the diameter meets the upper and lower limits specified in the technical drawing, as a pin that is too small will vibrate loose, while one too large will crack the housing.

Brittleness is often caused by hydrogen embrittlement during the electroplating process. To mitigate this, require the supplier to perform a baking process (de-embrittlement) immediately after plating. You should also request a Hardness Test Report (HRC/HV) and a Double Shear Strength Test from a third-party lab before the final balance payment.

Since roll pins are low-value, high-volume items, shipping costs often outweigh unit costs. Negotiate based on weight-based tiers rather than just unit count. On Made-in-China.com, look for suppliers with 'Audited Supplier' status and ask for FOB (Free On Board) pricing to maintain control over your logistics costs, or CIF if you prefer the supplier to handle insurance and freight to your port.

Roll pins are heavy and dense. Ensure the supplier uses double-walled corrugated cartons with a weight limit of no more than 15-20kg per box to prevent bursting. For sea freight, all cartons must be palletized and shrink-wrapped with moisture-proof desiccant bags inside the polybags to prevent surface oxidation during long-transit maritime humidity.

Utilize the Secured Trading Service on Made-in-China.com to ensure your payment is only released after you confirm receipt of goods. For large industrial orders, consider hiring a third-party inspection agency (like SGS or Intertek) to perform a Pre-Shipment Inspection (PSI) to verify the quantity and technical specifications match your Proforma Invoice.