Hardide Coatings and Master Flo Valve (MFV) have developed a new solution to protect high temperature, high pressure (HT/HP) subsea choke valves.The valves are the first of their kind to feature the Hardide-T coating, which can be applied to choke valve stems so they can withstand temperatures up to 400°F and pressures of 20,000 psi.Canada-headquartered MFV found that alternative hard coatings previously applied to the stem assembly were not rated to sufficiently high temperatures. The challenge was to have a durable coating with a completely smooth finish to form a tight metal to metal seal.The two companies worked together to engineer a solution and develop a manufacturing process plan.Philip Kirkham, CEO of Hardide Coatings, said: “The subsea market is constantly evolving and we must react to the changes. Developments in coating technology for HT/HP applications were essential and we have worked with MFV to create the right solution for them. Its success has been demonstrated by qualification to all API requirements and deployment deepwater for a major oil and gas operator.“Hardide-T is one of our toughest coatings and has overcome a key challenge for MFV. It is used on two of their product lines and has the potential to expand into other subsea choke valve sizes and models with HT/HP requirements.”Hardide Coatings and MFV oversaw the manufacturing process and fine-tuned it to ensure specific surface finish and geometrical tolerance requirements were met.The coating has been applied to MFV’s P4-15K choke valve, which is rated from -20°F to 400°F and 15,000psi, and the P4-20K choke valve, which is rated to the same temperatures but a greater pressure of 20,000psi.They are typically installed on subsea production trees and are used for single/multi-phase production or water/chemical/gas injection. There is also an application for use on a capping stack, designed to be deployed in the event of a blow-out situation.