Import 304 Stainless Steel Seamless Pipe — Buy in wholesale FOB from Supplier in China

The 304 Stainless Steel Seamless Pipe from Wuxi Hao Yao metal materials Co., Ltd. is manufactured to ASTM A312 standard, with the 18% chromium, 8% nickel austenitic composition providing baseline corrosion resistance for process piping. The supplier lists outer diameters from 9.5 mm to 406.4 mm for round tube, with wall thicknesses from 0.4 mm to 12.0 mm in standard inventory. Square and rectangular hollow sections are also offered (10x10 mm to 150x150 mm square, 10x20 mm to 100x200 mm rectangular), alongside capillary, precision, and decorative polish variants. The seamless construction, produced by hot extrusion or piercing and subsequent cold drawing, eliminates the longitudinal weld seam found in welded pipe, providing uniform circumferential strength.

The 304 grade (UNS S30400) in this pipe offers good resistance to oxidation in intermittent service to 870 degrees Celsius and continuous service to 925 degrees Celsius, though carbide precipitation sensitisation becomes a risk in the 425-860 degrees Celsius range unless low-carbon 304L or stabilised grades are specified. The seamless process yields finer grain structure and higher pressure ratings than longitudinal welded pipe of equivalent dimensions. Typical manufacturing tolerances for ASTM A312 seamless pipe include outer diameter plus or minus 0.5% (for sizes over 48.3 mm) and wall thickness minus 12.5% (standard mill tolerance). The supplier also references GB/T14976-2002 for fluid transport applications and GB/T13296-91 for boiler and heat exchanger service, indicating dual-standard capability.

Primary applications span petrochemical process lines, food and dairy hygienic piping (where internal polish to 0.8 micrometre Ra or better is typical), pharmaceutical water for injection (WFI) distribution, and high-pressure boiler tubing. The seamless construction is particularly specified where weld integrity cannot be risked, such as hydrogen service or cyclic thermal shock conditions. Buyers should confirm whether the specific pipe ordered is supplied in the annealed condition (solution treated, typically 1050 degrees Celsius rapid quench) or cold-worked, as this affects both corrosion resistance and mechanical properties. For marine or coastal installations, the buyer may need to evaluate whether 316L upgrade is justified given the modest molybdenum addition cost relative to 304.

Wuxi Hao Yao metal materials Co., Ltd. is located at Dongfang Steel City, Wuxi, Jiangsu Province, China, postal code 214000. Wuxi is a major stainless steel distribution and processing hub in the Yangtze River Delta, with proximity to Shanghai Port (approximately 120 km) and extensive cold finishing, polishing, and fabrication infrastructure. The supplier holds a 'harbor' trust tier, though response rate and average response hours both show as zero, indicating no recorded transaction history or unpopulated metrics. The listing does not state year of establishment, number of employees, annual turnover, or named client references.

The company's product scope is broad, encompassing seamless tubes, welded pipes, capillary tubes, precision tubes, mirror/decorative tubes, sanitary pipes, and square/rectangular sections across grades from 201 through 904L, including duplex and heat-resistant grades. They reference supply to chemical, petrochemical, water treatment, pulp and paper, food and sanitary equipment, boiler, and heat exchanger sectors. The listing mentions both ASTM and GB standards, suggesting export and domestic market servicing. However, no ISO 9001, PED 2014/68/EU, ASME U-stamp, or other third-party quality system certification is named. Buyers should verify current certification status and request references for comparable supply contracts in their industry sector before relying on the supplier for critical applications.