Stainless Steel Capillary Tube

• ​Introduction

Stainless steel capillary tube refers to a thin-walled, small-diameter tube made of stainless steel. Due to its excellent corrosion resistance, high-temperature resistance, and precise dimensional control, it is widely used in industries such as fluid transfer，medical devices, and instrumentation.

• ​Main Functions

Fluid Transportation: Precise delivery of liquids/gases in medical devices and analytical instruments.

Sensing & Measurement: Serves as a core component in pressure sensors or flow meters, leveraging its high precision and stability.

Structural Support: Provides lightweight, high-strength support in miniature mechanical devices.

Thermal Management: Efficient heat exchange in aerospace and semiconductor cooling systems.

• ​Tubing Standards

ASTM A269； EN 10305-1, DIN 17458； GB/T 14976, GB/T 3090.

• ​Material & Performance

304/304L(1.4301/1.4307) is preferred for general environments; 316/316L(1.4401/1.4404) is preferred for chlorine-containing and highly corrosive environments; 321(1.4541) is the priority for high-temperature environments.

Corrosion resistance：Stainless steel materials form a dense oxide film on the surface, which can resist the corrosion of most acids, alkalis and other media. High temperature resistance：It can work stably in high temperature environments, and the specific temperature range depends on the material. Mechanical properties：Has high tensile strength and yield strength, good toughness, and is not easy to break during use. Surface finish：The inner and outer surfaces are smooth, which can reduce fluid resistance and avoid fluid pollution.

• ​Manufacturing Process

Raw Material Selection: High-purity stainless steel billets or bars are chosen to avoid impurities.

Hot Piercing: The billet is heated and pierced to form a hollow shell (seamless tube blank).

Cold Drawing: The tube blank is repeatedly drawn through dies to reduce diameter and wall thickness, improving precision and surface finish.

Annealing: Heat treatment to relieve internal stress and enhance ductility, ensuring the tube can be further processed.

Precision Cutting: The tube is cut to specified lengths using precision diamond grinding wheel for minimal deformation.

Surface Treatment: Polishing or passivation to remove burrs and enhance corrosion resistance.

Inspection: Dimensional measurement, pressure testing, and flaw detection (e.g., ultrasonic testing) to ensure quality.

• Specifications