In the realm of high-temperature industrial applications, Stainless Steel 304H (UNS S30409) stands as a critical material choice. Unlike its counterparts 304 or 304L, the "H" designation signifies a higher carbon content (0.04 - 0.10%). This specific metallurgical calibration is engineered to enhance the material’s creep strength and structural stability at temperatures exceeding 525°C (975°F).
The controlled carbon level ensures that the pipe maintains its dimensional integrity under prolonged stress and thermal cycles, making it indispensable for heat exchangers and boiler tubes.
304H requires a grain size of ASTM No. 7 or coarser. This coarse-grained structure is the secret behind its superior high-temperature performance compared to fine-grained 304L.
While optimized for heat, it retains excellent corrosion resistance to atmospheric exposure and a wide range of organic and inorganic chemicals.
Years of Expertise
Authorized Patents
International Standard Compliance
Customized Manufacturing
Established in 2003, Shaanxi Kerlimar Engineers Co., Ltd. has long been engaged in international trade business, mainly a variety of pipes, carbon steel, alloy steel, stainless steel material, seamless pipe, straight seam welded pipe, spiral welded pipe and matching pipe fittings. Manufacturing standards for ASTM, ASME, EN, JIS and so on, in line with international standards.
Our chairman, Mr. Ming SUN, is a strong environmentalist. Under his leadership, we've expanded from steel piping to clean energy technology. Since 2019, focus has shifted to vertical axis wind power technology, solving wind power bottlenecks with over 40 patents authorized.
Recognition: National High-tech Enterprise (2020), COP28 Dubai Participant (2023), and Excellence Award in the 11th China Innovation Competition.
The demand for high-grade 304H pipes is surging globally, driven by the modernization of energy grids and the expansion of the petrochemical industry in the Middle East, Southeast Asia, and North America. Procurement officers are now looking beyond "cost-per-ton" and focusing on "lifecycle durability."
In thermal cracking and refinery piping, 304H pipes prevent premature failure in environments where temperatures fluctuate between 500°C and 800°C.
Supercritical and ultra-supercritical power plants utilize 304H for steam headers and reheater tubes to maximize thermodynamic efficiency.
Used in exhaust manifolds and high-pressure steam lines where weight-to-strength ratios and heat resilience are paramount.
The future of 304H piping lies in Smart Integration and Carbon Neutrality. As Shaanxi Kerlimar moves forward, our roadmap includes:
The primary difference is the carbon content. 304H has a higher carbon range (0.04-0.10%), which provides better strength at elevated temperatures, whereas standard 304 has a maximum carbon of 0.08%.
Our pipes are manufactured strictly according to ASTM A312, ASME SA312, and international equivalents like EN 10216-5. We provide full MTC (Mill Test Certificates) with every shipment.
With 21 years of experience and a National High-tech Enterprise certification, we conduct rigorous NDT (Non-Destructive Testing), including ultrasonic and hydrostatic tests, to ensure zero defects.
Yes, 304H is increasingly being evaluated for high-temperature hydrogen service due to its resistance to hydrogen embrittlement compared to lower-grade steels.
Committed to rural revitalization and global double carbon goals.
Kerlimar
