Small diameter stainless steel pipe

Small diameter stainless steel pipes refer to stainless steel pipe products with an outer diameter typically ranging from 3mm to 60mm. The main materials used in the production of such pipes are high-quality stainless steels, including 304 or 316 stainless steel. These materials are lightweight, have high strength, and possess excellent corrosion resistance and durability.

Small diameter stainless steel pipes are mainly applied in industries that require high precision and strict tolerances, such as precision instruments, medical equipment, food processing, chemical engineering and other fields.

Definitions and size specifications

According to industry standards, the outer diameter (OD) of small-diameter stainless steel pipes is usually between 3 mm and 60 mm, and the wall thickness (WT) varies from 0.08 mm to 10 mm.

For example, the standard dimensions include:

1/8 inch (3.175mm)
1/4 inch (6.35mm)
1/2 inch (12.7mm)
3/4 inch (19.05mm)
1 inch (25.4mm)

The wall thickness can be selected according to different schedules (such as SCH 5S, 10S, 40S, 80S) to meet different pressure and structural requirements.

Conforming standards

Small diameter stainless steel pipes usually comply with the following international standards:

ASTM A213: Seamless austenitic and ferritic alloy steel tubes for boilers, superheaters and heat exchangers.
ASTM A269: Seamless and welded austenitic stainless steel tubes for general services.
ASTM A270: Sanitary stainless steel pipes suitable for the food and pharmaceutical industries.
ASTM A554: Welded stainless steel pipes suitable for mechanical structures and decorative purposes.
ASME B36.19M: Specifies the dimensions and wall thickness of stainless steel pipes (Schedule 5S to 160S).

Common grades

The commonly used stainless steel grades for small-diameter stainless steel pipes include:

304/304L: A general-purpose austenitic stainless steel with excellent corrosion resistance and machinability.
316/316L: Molybdenum-containing austenitic stainless steel, with stronger corrosion resistance, suitable for Marine and chemical environments. The low carbon content of 316L makes it more suitable for welding applications.
321: Titanium-stabilized austenitic stainless steel, suitable for high-temperature environments.
2205: Duplex stainless steel, featuring excellent strength and corrosion resistance, is suitable for chemical and Marine engineering.

Types of pipes

According to the manufacturing process and application, small-diameter stainless steel pipes can be classified as:

Seamless Pipe: Manufactured through hot rolling or cold drawing processes, it is suitable for high-pressure and high-temperature environments.
Welded Pipe: Made by welding stainless steel strips, it has a relatively low cost and is suitable for general structural and decorative purposes.
Polished Tube (Polished tube) : The surface is mirror-finished or brushed and is often used in decorative and food processing equipment.
Capillary Tube: The outer diameter is usually less than 6 mm, and the wall thickness is thin. It is suitable for precision instruments and medical equipment.

Typical applications

Small-diameter stainless steel pipes are widely used in multiple industries:

Food and beverage processing: conveying pipelines, cleaning systems, equipment structures, etc.
Pharmaceutical and medical equipment: aseptic delivery, laboratory equipment, surgical instruments, etc.
Architecture and Decoration: railings, handrails, curtain wall structures, furniture, etc.
Chemical and petroleum industry: small-diameter fluid conveying pipelines, instrument pipelines, etc.
Automobiles and aerospace: fuel pipes, hydraulic systems, structural components, etc.

Read more: Schedule 80 stainless steel pipe  or  Schedule 40 stainless steel pipe