ASTM A194 Grade A B Heavy Hex Nut

The ASTM A194 Grade A and B Heavy Hex Nut is a structural fastener designed for high-pressure and high-temperature service, commonly paired with ASTM A193 and A320 stud bolts. Ningbo Steel Bolt Co., Ltd manufactures this nut from carbon steel, alloy steel, or stainless steel at its facility in Zhenhai, Ningbo, with ISO-standard production and a stated supply capacity of 100,000 pieces per month. The nut conforms to ASTM A194/A194M mechanical property requirements, with Grade A indicating a lower strength level and Grade B indicating higher strength, the latter typically quenched and tempered for enhanced performance. Available finishes include plain, zinc plating, and black oxide, giving buyers corrosion-protection options suited to different environments.

Heavy hex geometry provides greater bearing surface and wrenching area than standard hex nuts, a critical feature in petrochemical, power generation, and structural steel applications where bolt tensioning accuracy matters. The material selection, carbon, alloy, or stainless steel, determines the nut's resistance to galling, creep, and environmental corrosion; stainless variants such as 304 or 316 are standard for coastal or chemical exposure, while alloy grades handle elevated temperature cycling. Thread fit and proof load are governed by ASTM A194, with dimensional tolerances aligned to ASME B18.2.2 heavy hex pattern. Packaging in cartons or plastic bags on pallets supports containerised shipment from Ningbo or Shanghai port.

Buyers in oil and gas, construction, and marine engineering specify ASTM A194 heavy hex nuts when bolting flanges, pressure vessels, and structural connections. The Grade A/B distinction allows engineers to match nut strength to stud grade, avoiding over- or under-specification. Payment terms offered are T/T (telegraphic transfer). Prospective importers should confirm the exact steel grade, heat treatment certificate, and thread class with Ningbo Steel Bolt Co., Ltd before finalising an order, as the listing does not specify current inventory grades or minimum order quantities.

Ningbo Steel Bolt Co., Ltd operates from Panjiashan in Xiepu Town, Zhenhai District, Ningbo, Zhejiang Province, placing it within one of China's principal clusters for fastener manufacturing and port logistics. The company holds a harbor trust tier on the platform, with a response rate of 0.00 and no recorded average response hours, which indicates buyers should expect delayed or unguaranteed communication. No factory size, year of establishment, or third-party audit details are provided in the listing data, so claims about scale or seniority cannot be verified from this source alone.

The product range centres on ASTM-standard heavy hex nuts with multi-material and multi-finish options, shipped from Ningbo or Shanghai port under T/T payment terms. The absence of stated ISO 9001 or IATF 16949 certificate numbers, specific MOQ figures, or sample policy means buyers must request these directly. Importers should treat early engagement as a due-diligence phase: ask for mill test certificates, dimensional inspection reports, and previous export references before committing to volume orders.