The offshore and subsea environment represents one of the greatest challenges in modern engineering. The manufacture of components for these applications demands a combination of extreme precision, advanced materials, and certified processes capable of ensuring reliable performance under extremely harsh environmental conditions.
From control and isolation valves to pump bodies and structural housings, every component must guarantee total integrity against corrosion, hydrostatic pressure, and long-term operation in environments where human intervention is both complex and costly.
The Demands of the Offshore and Subsea Environment
Operation on marine platforms, floating installations, or subsea systems requires components that can maintain their structural integrity in environments where maintenance is complex and expensive. Saltwater, constant humidity, and high hydrostatic pressures create extreme working conditions that can only be addressed through precision engineering and meticulous control at every stage of the manufacturing process.
Surface treatments, the use of high-alloy stainless steels, and corrosion-resistant alloys help mitigate the effects of the marine environment. At the same time, high-rigidity multi-axis machining ensures tight tolerances even in large-scale components. Long-term reliability is achieved not only through dimensional precision but also through the mechanical stability of materials and the quality of surface finishes, ensuring perfect sealing and continuous maintenance-free operation for years.
Materials for Offshore and Subsea Machining
Material selection is crucial to the service life of any subsea component. For this reason, these applications use super duplex and high-alloy austenitic stainless steels, which offer an excellent balance between mechanical strength and resistance to chloride-induced corrosion.
Nickel- and cobalt-based alloys, such as Inconel or Stellite, are also employed for components exposed to extreme temperatures or stress, while titanium alloys are used in applications that demand high specific strength and complete immunity to saltwater corrosion. All materials are subject to full traceability and undergo mechanical and metallurgical validation testing before machining.
Machining of Deepwater Control Valves
Valves and control bodies are critical elements in subsea fluid production and distribution systems. At Arri, we operate Trevisan machining centres capable of handling valve bodies up to Ø2400 mm and 25 tonnes, enabling the production of large-format parts with total precision and geometric stability.
The machining of bodies, obturators, and seats requires continuous metrological control to ensure leak-tight sealing under extreme pressure conditions. The combination of integrated turning-milling technology and advanced CAM programming enables the production of complex geometries with micrometric tolerances. Surface finishes are verified to guarantee roughness values below Ra 0.4 µm in sealing areas, ensuring reliable tightness throughout the entire service life of the component.
Quality Control and Certifications
The high demands of the offshore and subsea sectors require operations under certified quality systems and strictly controlled procedures. Arri operates a management system compliant with ISO 9001:2015 and incorporates qualified welding procedures in accordance with ASME Section IX.
All components are inspected using non-destructive testing methods, including ultrasonic, liquid penetrant, and magnetic particle inspection, carried out by qualified personnel. Every material and machining operation is digitally documented and traceable, from the casting certificate to the final inspection report.
Our Technical Capability
With a high-capacity production infrastructure, a well-established quality culture, and a specialised technical team, Arri positions itself as a strategic partner for manufacturers and operators in the offshore and subsea industries.
Our combination of technical resources, metrological precision, and experience in high-criticality projects allows us to deliver reliable and competitive solutions, engineered to withstand the challenges of the most demanding marine environments.
