Stainless Steel Seamless Pipe

• ​Introduction

Stainless steel seamless tubes are cylindrical hollow products fabricated from solid stainless steel billets through processes like piercing and extrusion. Their defining characteristic is exceptional corrosion resistance, attributed to alloying elements such as chromium that form a self – repairing passive oxide film on the surface. This property, along with their seamless structure offering superior pressure resistance and structural integrity, makes them indispensable in core applications across multiple industries, including Petroleum and Chemical Industry, Construction and Decoration, Food and Beverage Processing, Medical Equipment Manufacturing, Energy and Power Industry, Marine Engineering, and Seawater Desalination.

• ​Main Functions

High-Pressure Fluid Transmission：Capable of withstanding high internal pressures, it is ideal for transporting high-pressure fluids like oil, gas, and high-temperature steam in the petrochemical and power generation industries.

Corrosion-Resistant Applications：Exhibits excellent resistance to various corrosive media, making it suitable for use in chemical plants, marine engineering, and pharmaceutical equipment, where exposure to corrosive substances is common.

Structural Support in Harsh Environments：Used as structural components in harsh environments such as offshore platforms and nuclear power plants, providing stable support while enduring extreme conditions.

• ​Tubing Standards

ASTM A312, ASTM A213, ASTM A240，ASTM A269，ASTM A268，ASTM A789 ; EN 10216 – 5, EN 10296 – 1 , EN 10312 ; GB/T 14976，GB/T 21833;

• Material & Performance

304/304L，316/316L，410，430，2205，2507 etc.； 1.4301/1.4306,1.4401/1.4404,1.4006,1.4016,1.4462,1.4410 etc.

Exceptional Corrosion Resistance：Stainless steel seamless tubes can resist a wide range of corrosive substances, making them suitable for transporting corrosive media in the Petroleum and Chemical Industry, seawater in Seawater Desalination, etc. The self – repairing passive oxide film ensures continuous protection.​

Superior Pressure Resistance：The seamless structure enables the tubes to withstand high internal and external pressures, which is essential for applications in high – pressure pipelines of the Energy and Power Industry and Marine Engineering.​

High – Temperature and Low – Temperature Performance：Maintaining good mechanical properties across a broad temperature range, these tubes are applicable in high – temperature scenarios of the Energy and Power Industry and low – temperature environments in some specialized food processing.​

Hygienic and Non – Toxic：This property makes them ideal for the Food and Beverage Processing and Medical Equipment Manufacturing industries, ensuring product safety and hygiene.​

High Ductility and Toughness：Allows for complex shaping and processing, meeting the diverse requirements of different core application industries, from the precise manufacturing of medical equipment to the structural design in Construction and Decoration.

• ​Manufacturing Process

Raw Material Preparation — Selection: High-purity stainless steel round billets.

Heating Process — Protective Atmosphere Heating: Heated in a protective furnace filled with nitrogen (N₂) or argon (Ar) to 1100~1250℃ ,with heating rate ≤5℃/min to avoid thermal cracking.

Piercing & Forming — Piercing: Hollow billets are formed by two-roll skew rolling.

Rolling & Sizing — Multi-pass Rolling: Extended rolling by continuous tube mill.

Heat Treatment — Solution Treatment: Heated to 1050~1150℃ and water-quenched to dissolve carbides into austenite, enhancing corrosion resistance; martensitic steels (e.g., 410) require annealing for stress relief.

Surface Treatment — Pickling & Passivation； Electro-polishing (Optional): For food/medical grade tubes, Ra≤0.8μm achieved via electro-polishing.

Sizing & Straightening — Diameter tolerance controlled by sizing mill and straightene.

Testing — Corrosion resistance: Intergranular corrosion test , salt spray test . Mechanical properties: Tensile test , hardness test .

• Specifications