Import A320 L7 Black Finish Thread Rod — Buy in wholesale FOB from Supplier in China

The A320 L7 black finish thread rod from Ningbo S&D Metalwork Co., Ltd is an fully threaded fastener manufactured to ASTM A320 / A320M standards for low-temperature service applications. The supplier stocks diameters from 1/2 inch up to 2-1/2 inch in imperial sizes, and M12 through M64 in metric sizes, with lengths available up to 235 inches or 6000 mm, with 12-foot lengths being a popular standard option. The material grade is A320 L7 or L7M, an alloy steel quenched and tempered for high strength and toughness at sub-zero temperatures, and the finish is supplied as black oxide, though the listing notes various finishes are available on request.

ASTM A320 L7 thread rod is typically produced from AISI 4140 or 4142 chromium-molybdenum alloy steel, heat-treated to achieve a minimum tensile strength of 125 ksi and yield strength of 105 ksi at room temperature, with Charpy V-notch impact requirements verified at -150°F (-101°C). The L7M variant uses the same base material but receives a lower tempering temperature to meet slightly different mechanical requirements. Black finish refers to a black oxide conversion coating that provides mild corrosion resistance and glare reduction without the dimensional changes of plating; for more aggressive environments, hot-dip galvanising or zinc plating are common alternatives that buyers may specify. Thread form is Unified National Coarse (UNC) for imperial sizes and standard metric coarse for metric sizes, with Class 2A / 6g tolerances being standard unless Class 3A / 4g6g is ordered for tighter fit.

This threaded rod serves primarily in petrochemical, LNG, and cryogenic infrastructure where bolting must retain integrity at temperatures down to -150°F, including flange connections on valves, pumps, and pressure vessels. Power generation, offshore platforms, and Arctic construction are significant demand sectors. Buyers should confirm with Ningbo S&D Metalwork Co., Ltd the exact grade (L7 versus L7M), required finish specification, and whether full material test reports including Charpy impact data are available, as these are standard requirements for project documentation but are not explicitly stated in the listing.

Ningbo S&D Metalwork Co., Ltd is based in Yinzhou District, Ningbo, Zhejiang Province, China, with the postal address 315114. The company holds a harbor trust tier on the platform, though its response rate is recorded at 0.00 percent with zero average response hours, indicating no engagement data is available from recent buyer interactions. The listing provides no information about factory size, year of establishment, annual output, quality certifications, or export experience, so buyers should treat these as unverified and request direct documentation.

The product range visible from this listing centres on ASTM-specification threaded rod and stud bolts, with particular emphasis on low-temperature service grades. The supplier explicitly notes availability of multiple finishes beyond the standard black oxide, suggesting some flexibility in customisation, though no minimum order quantities, lead times, or packaging details are provided. Buyers are advised to conduct standard supplier verification, including requesting a mill test certificate, ISO quality system certification if claimed, and references for prior A320-grade shipments before committing to volume orders.