High-pressure and hydraulic tubing is designed for applications where pressure containment and mechanical integrity are primary engineering requirements. Typical applications include hydraulic power and control systems, valve actuation, wellhead and downhole control, chemical injection, pressure testing, specialised sampling and high-pressure process equipment.

Unlike general instrumentation tubing, high-pressure tubing is normally selected as part of a defined tube-and-fitting system. Pressure capability depends on the tube outside diameter, wall thickness, material, material condition, temperature, manufacturing route, connection design and applicable engineering requirements. The pressure rating of one configuration must therefore never be assumed to apply to another size or material.

Stainless steels in cold-worked or otherwise strengthened conditions are commonly used where high strength and controlled dimensional performance are required. Super duplex stainless steels and nickel alloys may be selected where high pressure is combined with demanding chloride, seawater, chemical or sour-service conditions. Material condition is particularly important because mechanical properties and pressure capability can change with heat treatment or cold working.

High-pressure tubing systems may be divided into medium-, high- and ultra-high-pressure configurations according to the manufacturer’s design and connection system. Each configuration has its own tube, fitting, connection and installation requirements. The manufacturer’s published pressure rating should always be considered together with the applicable temperature limits, material condition and connection hardware.

Relevant standards and design references may include ASTM material and tubing specifications, ASME B31.3 and applicable manufacturer-specific design requirements. For hydraulic and high-pressure systems, correct tube preparation, fitting assembly, make-up procedure and installation torque are critical to maintaining system integrity.

Inspection requirements depend on the application and specification and may include dimensional inspection, material certification and heat traceability, surface inspection, hardness verification, pressure testing and non-destructive examination. For critical high-pressure systems, the complete tube-and-fitting assembly should be verified against the manufacturer’s installation and testing requirements.

Fatigue is an important consideration where tubing is exposed to repeated pressure cycles, vibration or mechanical movement. Applications involving frequent cycling require evaluation of the tube material, wall thickness, connection design, installation configuration and expected number of pressure cycles. Special tubing conditions or manufacturing processes may be specified for high-cycle applications.

Service life depends on pressure cycling, temperature, corrosion, vibration, installation quality and operating conditions. TSI therefore treats high-pressure and hydraulic tubing as a system-specific engineering item rather than a generic tube commodity.

TSI supplies high-pressure and hydraulic tubing for hydraulic control, wellhead and downhole systems, chemical injection, pressure testing, subsea control and specialised industrial applications, subject to the specified service and manufacturer’s design requirements.