The 321H pipe differs from 321 primarily because of its precisely regulated higher carbon content (0.04% to 0.10%). The carbon content is specifically engineered to provide superior high-temperature strength and enhanced creep-rupture properties above 538°C (1000°F).
ASTM A312 ASTM A312 Stainless Steel 321H Seamless Pipe Manufacturer
We at Zhejiang Xintongda Special Steel (XTD) are one of China’s leading manufacturers and suppliers of stainless steel 321H seamless pipes. SS 321H pipe is a titanium-stabilised, high-carbon austenitic stainless steel grade. This pipe primarily contains chromium (17-19%), nickel (9-12%), and carbon (0.04-0.10%), with titanium added at a minimum of 4×(C+N) to stabilise the alloy against chromium carbide precipitation. We manufacture our pipes using advanced cold-drawing and hot-finishing methods in accordance with ASTM A312, EN, JIS, and GB standards specifications. Our pipes are intended for high-temperature, high-pressure industrial applications. This grade exhibits outstanding resistance to intergranular corrosion and high creep strength above 538 °C (1000°F), as well as stable performance in demanding environments. Our ASTM A312 TP321H seamless pipes are commonly used in petrochemical facilities, refineries, heat exchangers, power plants and oil and gas processing systems. As a multiple international certified manufacturer with over 4 decades of experience, we maintain an annual supply capacity of 25,000 tons. We deliver stock products in a lead time of one week, and for production orders, we deliver in 15-60 days.
Product specifications:
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Standard ASTM A312 -
OD Range 6-1016 mm -
Thickness 1-65 mm -
Length ≤ 18 m
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Technical Data
Technical Data
SS 321H Seamless Pipe Manufacturing Process
We use high-quality raw materials for manufacturing our 321H seamless stainless steel pipe. The material meets the chemical composition standards. Hot extrusion and piercing are used to shape the raw material into a hollow shell. We then cold-draw/cold-roll the pipe to ensure its dimensional accuracy. It is then followed by heat treatment, which improves mechanical and corrosion resistance. To know more about our manufacturing process, check out our page.
What are the Key Features of 321H Stainless Steel Pipe?
The key benefits of SS 321H seamless pipe include excellent corrosion resistance, superior high-temperature strength, enhanced creep resistance from titanium stabilisation, improved mechanical properties from controlled carbon content, and outstanding oxidation resistance.
- Corrosion Resistance: With chromium (17-19%) and nickel (9-12%), it offers superior resistance to an extensive range of corrosive conditions. This corrosion resistance provides significant benefits in oxidising and moderately corrosive environments, particularly at elevated temperatures. This extends the service life of the pipe.
- High-Temperature Strength: Grade 321H offers high-temperature strength primarily due to controlled higher carbon content, while titanium stabilisation prevents intergranular corrosion. It has a higher carbon content than Grade 321 and is ideal for pressurised applications that operate at high temperatures.
- Titanium Stabilised: Adding titanium to the SA312 TP321H material composition binds carbon. This prevents chromium carbides from forming at the grain boundaries. This important property ensures that the material remains resistant to intergranular corrosion even after being exposed to temperatures in the sensitisation range.
- High Carbon Content: The "H" in the designation signifies a controlled higher carbon content, placing the carbon range between 0.04% and 0.10%. This increased carbon composition provides the material with improved high-temperature mechanical properties compared to the standard 321 grade.
- Oxidation Resistance: SS 321H pipe provides oxidation resistance when used at high temperatures. The chromium content enables the formation of a stable chromium oxide layer, providing oxidation resistance and dimensional stability at elevated temperatures.
ASTM A312 TP321H Seamless Pipe Equivalent Material
ASTM A312 TP321H seamless pipe is also known by its equivalent material designations: UNS S32109, EN 1.4878 (X8CrNiTi18-10), and GOST 12X18H10T.
| GRADE | UNS | GB | JIS | ISO | DIN/EN | GOST | |
| ISC | NEW | ||||||
| 321H | S32109 | S32169 | 07Cr19Ni11Ti | SUS321HTP | X8CrNiTi18-10 | 1.4878 | 12X18H10T |
100% Certified Testing & Documentation
- EN 10204 3.1 and EN 10204 3.2 Material Test Certificates (MTC)
- Raw Materials Certificate
- 100% PMI
- Heat Treatment Charts
- Third-Party Inspection Report
- Surface roughness and size measurement
- Manufacturer Test Certificate (Impact Testing, Flattening, Flare, Bend, Hardness, Intergranular, Pitting Corrosion, Grain size, ET, UT, HT)
- Laboratory Test Certificate from the Government-Approved Lab
ASTM A312 SS 321H Seamless Pipe Industrial Applications
The applications of ASTM A312 321H seamless pipe include high-temperature pressure vessels and piping systems, where corrosion and creep are major concerns. The 5 key application qualities of this material are listed below.
Aerospace
The UNS S32109 pipe is used in aircraft for high-temperature, non-structural systems such as engine exhaust lines, hot air ducts, and ground test equipment. It offers excellent heat strength, oxidation resistance, and weld stability at elevated temperatures.
Chemical Processing
Stainless steel 321H seamless pipes are widely used for handling hot, corrosive chemicals, like distillation and separation columns. In the chemical industry, titanium stabilisation is essential for preventing intergranular corrosion in heat-affected weld zones.
Oil and Gas
The material is specified for heat exchangers, furnace parts and piping in refineries and petrochemical facilities. The pipes maintain their strength and corrosion resistance under both high heat and aggressive chemical exposure.
Power Generation
We supply these pipes for boiler and heater tube applications in power plants. The excellent creep-rupture properties of the "H" grade ensure sustained strength in prolonged, high-pressure steam service.
Petrochemical
We supply 321H stainless steel seamless pipes for petrochemical systems operating at elevated temperatures and under continuous thermal cycling. The titanium-stabilised alloy resists intergranular corrosion and maintains mechanical strength in high-temperature processes and heat-transfer applications.
Frequently Asked Questions
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How does 321H pipe differ from 321?
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How does the carbon content in seamless 321H stainless steel pipe affect its performance?The higher carbon content enhances elevated-temperature creep and stress-rupture performance. At room temperature, ASTM A312 specifies a minimum tensile strength of 515 MPa and minimum yield strength of 205 MPa.
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What temperature range can seamless 321H stainless steel pipe handle effectively?The seamless 321H stainless steel pipe operates well at high temperatures ranging from 800 to 1500°F (427°C to 816°C). Its higher carbon content provides improved creep and stress rupture resistance.