Comprehensive analysis of 321 stainless steel tube

1、 Core characteristics and components

321 stainless steel tube is austenitic stainless steel, and titanium (Ti) element (content ≥ 5 × C%) is added on the basis of 304 to form better intergranular corrosion resistance and high temperature performance:

Composition range: Chromium (Cr) 17% -19%, Nickel (Ni) 9% -12%, Titanium (Ti) ≥ 0.02% 14;

Corrosion resistance: It exhibits excellent performance in oxidizing media (such as nitric acid, organic acids) and high-temperature sulfur-containing environments, with better wear and corrosion resistance than ordinary 304;

High temperature performance: Long term use temperature can reach 870 ℃, short-term temperature tolerance can reach 925 ℃, and creep resistance is significantly better than 304.

2、 Main application areas

High temperature and high pressure equipment: boiler superheater tubes, heat exchanger tubes, cracking furnace components;

Chemical and energy: acid resistant containers, petroleum drilling casings, high-temperature reaction vessels;

Special environment: sulfur-containing oil and gas transmission pipelines, support structures for nuclear energy equipment.

3、 Specifications and Execution Standards

Common specifications: outer diameter range from 6mm to 830mm, wall thickness from 1mm to 60mm, supporting seamless and welding processes;

International standards:

China: GB/T 14976-2002 (Seamless Pipes for Fluid Transport);

USA: ASTM A312/A213 (corresponding to grade S32100);

Europe: EN 10216-2 (brand 1.4541).

4、 Market and Procurement Reference

Procurement suggestion:

Prioritize selecting suppliers with titanium content testing reports;

The solid solution treatment process (1100-1150 ℃ water cooling) needs to be verified for high-temperature applications.

5、 Precautions

Welding process: It is recommended to use titanium containing welding materials (such as ER321), which require stabilization treatment (850-900 ℃ insulation) after welding to eliminate chromium carbide precipitation;

Maintenance requirements: Regularly check the integrity of the oxide layer in high-temperature environments to avoid pitting corrosion caused by chloride ion enrichment;

Anti counterfeiting identification: Confirm the Ti content (≥ 0.02%) and Cr/Ni ratio through spectral detection.

Note: The above information is comprehensive from industry standards, supplier data, and technical documents. The applicable scenarios need to be evaluated based on specific working conditions.