Import Aisi 4130 Steel Pipe — Buy in wholesale FOB from Supplier in China

AISI 4130 is a low alloy chromium-molybdenum steel pipe with nominal 0.30% carbon content, engineered for applications demanding weldability paired with hardenability superior to plain carbon grades. Big Co., Ltd. supplies this material from China in seamless mechanical tubing conforming to ASTM A519, with hot-rolled outer diameters from 51mm to 508mm, wall thickness 7-60mm, and lengths up to 16,000mm; cold-drawn dimensions range 10-50mm OD with 2-10mm wall, also to 16,000mm maximum. The composition range specified is 0.28-0.33% C, 0.80-1.10% Cr, and 0.15-0.25% Mo, with silicon 0.15-0.35% and manganese 0.40-0.60% as standard deoxidation and strengthening additions.

The lower carbon content relative to AISI 4140 provides enhanced fusion weldability, a decisive factor for structural fabrications where post-weld heat treatment may be impractical. Through-section hardenability is sacrificed to achieve this weldability, so applications requiring uniform high hardness across thick walls may need alternative grades or modified quench procedures. Big Co., Ltd. notes that controlled modifications to tube making, heat treatment, and finishing are applied per order based on end use, suggesting customization capability rather than purely commodity stock, though buyers should verify whether this implies in-house heat treatment or subcontracted processing.

Primary import markets include oil and gas flowlines, aerospace structural members, aircraft engine mounts, and hydraulic system tubing where the 100 ksi minimum UTS and 80 ksi minimum 0.2% proof stress of hardened and tempered condition meet design requirements. Surface treatments available include oil-dip, varnish, passivation, phosphating, shot blasting, and epoxy or FBE coating, allowing specification for corrosive environments. The listing does not state MOQ, price, or lead time, so buyers must confirm these directly, along with whether non-destructive testing (ultrasonic or eddy current) is standard or optional, given the critical nature of many 4130 applications.

Big Co., Ltd. is registered in Tongzhou District, Beijing 101100, China, an administrative and light industrial satellite area of the capital rather than a traditional steel manufacturing center. The supplier holds harbor trust tier status with a 0.00% response rate and zero average response hours, indicating minimal platform-mediated communication history; buyers should not infer operational scale or reliability from the company name alone. No verified factory information, quality system certification, or specific production equipment details appear in the available profile data.

The product offering centers on ASTM A519 seamless alloy mechanical tubing with order-specific process control, implying either mill-direct capability or close mill partnerships with technical coordination. The extensive size range and multiple finish options suggest inventory or production breadth, though the Beijing address raises a question about whether manufacturing occurs at this location, at affiliated mills elsewhere in China, or through third-party arrangements. Prospective importers should request facility details, applicable API or aerospace quality approvals if relevant to their market, and references for comparable supply contracts before assuming production depth matches the catalog breadth.