Sihe Steel
Sihe Steel
The standard ASME SA312 TP321 defines a stabilized austenitic stainless steel specifically adapted for deployment in environments where chromium carbide precipitation is a critical degradation vector. By alloying with Titanium (Ti), this material exhibits enhanced resistance to intergranular corrosion (IGC) following exposure to temperatures in the chromium carbide precipitation range of 800°F to 1500°F (427°C to 816°C).
Unlike standard 304 or 304L steels, Grade 321 prevents the depletion of chromium adjacent to grain boundaries by prioritizing the formation of titanium carbides over chromium carbides. This stabilization is defined by the requirement: Ti ≥ 5 × (C + N) min, and max 0.70%.
Our manufacturing protocols at Liaocheng Sihe Stainless Steel Material LTD ensure that cold-drawn and hot-finished seamless pipes conform strictly to chemical composition margins and mechanical testing criteria, guaranteeing reliability under intense thermal and mechanical stress profiles.
| Element | TP321 Weight (%) | TP321H Weight (%) |
|---|---|---|
| Carbon (C) | 0.08 max | 0.04 - 0.10 |
| Manganese (Mn) | 2.00 max | 2.00 max |
| Silicon (Si) | 0.75 max | 0.75 max |
| Chromium (Cr) | 17.0 - 19.0 | 17.0 - 19.0 |
| Nickel (Ni) | 9.0 - 12.0 | 9.0 - 12.0 |
| Titanium (Ti) | 5x(C+N) to 0.70 | 4x(C+N) to 0.70 |
Grade TP321 seamless pipes provide high creep rupture properties and high tensile strength (min. 515 MPa / 75 ksi) at elevated temperatures. Ideal for pressure vessel vessels and furnace headers.
Due to the addition of titanium, the carbon is locked up in safe titanium carbides, meaning that even at welding temperatures or high service conditions, the pipe is protected from IGC.
We execute inline bright annealing or subsequent stabilizing thermal cycles at 1550°F to 1650°F (843°C to 899°C) to maximize the separation of TiC over chromium compounds.
Established as a premier manufacturing destination in China, Liaocheng Sihe Stainless Steel Material LTD operates six modern production lines specializing in high-precision stainless steel coiled tubes, polishing tubes, and seamless tubing solutions. We produce goods in strict compliance with GB, ASTM, ASME, JIS, and EN standards to satisfy the critical criteria of global contractors.
Our material capabilities encompass austenitic and duplex structures including 304/304L, 316L, 321, 317L, 309S, 310S, INCOLOY 800, Duplex 2205, Super Duplex 2507, Incoloy 825, and Inconel 625.
We are distinguished by our capability to manufacture seamless coiled tubing configurations with outer diameters ranging from 0.125 inch (3.175 mm) up to 1 inch (25.4 mm), with wall thicknesses up to 0.165 inch (3 mm). To facilitate continuous control lines or umbilical structures in offshore subsea fields, we supply continuous spool lengths reaching up to 32,800 feet (10,000 meters) without orbital welds.
Liaocheng Sihe is situated in a high-density industrial metal zone in Shandong, allowing direct access to premium-grade, trace-element-controlled billets. This reduces feedstock logistics costs and ensures consistent chemical trace levels across production runs.
We operate advanced inline gas-shielded bright annealing facilities. This guarantees a scaling-free, mirror-clean internal and external surface, optimizing flow performance and preventing localized oxidation zones.
From custom export packing systems (wooden crates, metal spools) to EN 10204 3.1 certification, PMI verification, and third-party inspections (SGS, TUV), we align our export processes with the strict demands of European and American markets.
Global operators within petrochemical, subsea umbilical, and power generation sectors require uncompromising materials safety documentation. In deeper subsea exploration and extreme temperature processing, safety failures lead to severe environmental risks and capital loss.
By enforcing complete traceability back to the melt shop and checking each coil via hydrostatic, pneumatic, and eddy-current non-destructive testing (NDT), Liaocheng Sihe addresses these reliability requirements. Our systems are engineered to prevent pitting, cracking, and intergranular attack under conditions where standard grades fail.
Every manufacturing batch goes through strict quality management. Below are our plant operation approvals, quality credentials, and test documentation representations.
ASME SA312 TP321 seamless steel pipes are deployed in harsh environments requiring high heat resistance and corrosion protection.
