Corrosion-resistant, high-strength titanium has an aura. One thinks of aerospace and other high-tech industries, yet titanium’s strength and light weight, combined with its elasticity and corrosion resistance make it an excellent choice for long-term cost savings in offshore industries. Permascand, a high-tech company with a strong track record, began its experience with titanium in 1972 with the introduction of dimensionally stable anodes (DSA®) for the chlor-alkali industry.

Continuous Development
During the 1970’s Permascand also expanded into the manufacture of process equipment and piping, as well as investing in laser technology. Today the company consists of three business areas: Electrochemical Systems, Titanium Fabrication, and Titan Service Center. Permascand offers its expertise, from drawing board to finished product, to ensure the production of cost-effective, longlife products.

Titanium, which can resist seawater’s corrosive effects up to 70° C, is therefore a superior choice of material in offshore applications. Titanium’s strength, corrosion resistance and lightness mean that piping can be produced with less wall thickness, reducing total system weight by 50%.

One drawback for titanium is that wear resistance is less than optimal, but Permascand has developed a titanium nitriding process that strengthens the surface at the molecular level, providing excellent wear resistance. According to Kenneth Dahlqvist, Product Manager, “We have a case where we supplied 60 hydraulic rods to an offshore platform in 1996. They haven’t had any failure with those rods since, which shows that it works. The stainless-steel rods used before had to be shifted every year with extra maintenance costs and a huge loss of production.”

Subsea Solutions
Titanium subsea pressure vessels are another custom-made Permascand product. Mr. Dahlqvist explains, “Some companies are now drilling beyond 1,000 metres, but it is expected that in the future most of the drilling will take place in areas that are 3,000 metres deep. Another thing is that the weight of the construction in steel could become so high that it is hard to find equipment and ships that can put it on the seabed. And this is where our expertise in titanium process equipment comes in. These pieces of equipment will house the electronics or production equipment, which need to resist an outside pressure of 300 bars and an inside pressure of 20 to 50 bars. Besides that, they need to be able to stay on the seabed for up to 30 years. We can provide vessels that meet these demands.” Permascand was also involved from the beginning in the design and production of a subsea dredger that would perform seabed preparation for subsea operations.

Working together with dredging specialists GTO as well as with Nexans, a trencher/dredger manufacturer and operator, Permascand provided the trencher’s titanium framework and aluminium chassis. The three companies dramatically shortened the design and production phase by communicating quickly and efficiently via a mutually accessible 3D computer model. According to Mr. Dahlqvist, “Our input was to determine how to produce the body work cost-effectively. At the beginning of this project the client came to us with an idea of what it should look like. In their proposal a number of plates were welded together in ten different dimensions from 6 to 50 mm thickness. We were able to bring it back to three with a maximum thickness of 20 mm, which illustrates the value that we can add using our knowledge in welding, heat treatment, forming and hardening of high-strength metals. Weight distribution was an important issue, so we designed a titanium framework with hollow pipes, giving buoyancy to the top. Impact resistance was another important reason to opt for titanium. If the vehicle runs into a rock or crashes into the side of a ship, titanium is more impact-resistant than other material, reducing the risk of leakage, which would offset the balance of the vehicle.”

This is Permascand
Location: Ljungaverk, Sweden
Employees: 130
Business areas:
• Electrochemical systems
• Titanium fabrication
• Titan Service Centre
Production facilities:
• Coating plant
• Electrode workshop
• Titanium fabrication workshop
• Laser welding facilities
• Titanium stock, Titan Service Centre
• Waterjet cutting
• Titanium nitriding
• Pressure and leakage testing