347  is niobium-stabilized austenitic stainless steel bright bar. Niobium is added based on 304 with Nb ≥10×C and C ≤0.08%. Niobium combines carbon to form stable NbC, inhibiting chromium carbide precipitation at grain boundaries at 425~850℃ and eliminating intergranular corrosion after welding or long-term medium-high temperature service, as a molybdenum-free stabilized stainless steel.
Single-phase austenite and nearly non-magnetic after solution annealing. Balanced room-temperature mechanical properties with excellent plasticity, deep drawability and cold heading performance for uniform plastic deformation without brittle fracture. It cannot be hardened by heat treatment; cold working causes work hardening, while high toughness can be restored via solution annealing at 980~1080℃.

Chemical element content (%)

Specification：1.00~300.00mm

Application: It is mainly used to manufacture boiler steam pipe fasteners, medium-temperature heat exchanger mandrels, heat treatment furnace tool bars, medium-temperature reactor valve stems for petrochemical industry, power plant medium-temperature auxiliary shafts, high-temperature hot air circulation valve bodies, connectors for chloride-free high-temperature sterilization equipment, kiln support bolts, stainless steel standard parts under repeated thermal cycles, steam pipe flanges, etc.
Widely applied in thermal power boiler auxiliary parts, petrochemical medium-temperature units, industrial heat treatment furnaces, food high-temperature sterilization equipment, thermal steam pipe networks, waste incineration medium-temperature pipelines, HVAC heat exchange equipment and other industries.

Core Advantages Over Competitors

1. High quality stability: Full closed-loop production and online spectral inspection strictly control C, Cr, Ni, Nb with stable Nb/C ratio. Uniform segregation-free austenitic microstructure ensures negligible batch fluctuation of medium-temperature anti-sensitization, creep strength and mechanical properties for consistent mass production of high-temperature welded parts.

2. Excellent surface quality: Dedicated high-precision cold drawing & centerless grinding lines produce bars free of scale, scratches and pits with smooth uniform finish. Smooth surface reduces alternating thermal stress concentration to extend fatigue life under hot-cold cycles; secondary polishing is unnecessary for most conventional machining.

3. Ultra-high dimensional accuracy: Precision cold rolling mills and automatic online dimension detectors narrow tolerance range with tiny single-bar error and strong batch uniformity. Unified part specifications during automatic mass production raise finished yield and machining precision.

4. Rich product variety: According to market demand and customer's special requirements, customized products are provided to meet the use requirements under various complex working conditions, providing customers with more choices.

5. Perfect after-sales service: The perfect after-sales service system can respond to customer needs and feedback in a timely manner. For problems encountered by customers during use, technical support and solutions are provided to customers quickly.

We mainly engage in cold heading wire, bar, peeled bar, and profiled bar; our products cover 11 series and more than 300 grades, and we continue to develop a variety of professional steels. We can provide all-round solutions such as cold heading finishing line manufacturing and high-precision bright bar customization, and provide one-stop procurement services and package procurement solutions for global customers. The website displays some grades. If you don’t have the grade you need, please contact us by phone or email.