Sandvik hollow bar brings 100 years of maintenance-free service to Norway’s high-speed railway

Sanmac 2205 long lifetime, low weight and ‘maintenance free’ duplex (austenitic-ferritic) stainless steel was chosen for critical ‘hanger’ components based on an entirely new hollow bar design.

The hangers will support a section of the 12km long high-speed rail tunnel which includes the station. Inside the tunnel are two parallel tracks that will, in the future, enable two high-speed trains to pass each other at maximum speeds of 250km/h – something which has never been performed before.

The choice of duplex was specified by Ramboll, the engineering company for the project, after it was determined that the construction must remain maintenance free for 100 years. It is estimated that more than four million movements will occur in the tunnel during that time. The railway is also the first of its kind to be situated inside a mountain, which places extra demands on the steel.

“Sandvik Sanmac 2205 duplex stainless steel is a perfect grade where a material with high corrosion and fatigue resistance, and high mechanical strength, is required that could also provide excellent machinability. Duplex stainless steel is unbeatable if you need these properties,” says Viktor Stefansson, global product manager for hollow bar at Sandvik.

Construction on the Holmestrand station could only commence after the hangers – from which the rest of the structure is hung – were mounted. Sandvik helped control the logistic planning for the tunnel to a very tight schedule.

“When Sandvik came into the picture, they showed craftsmanship and were trustworthy, being the right partner,” said Jan Beckers, managing director of Hollandia, the company responsible for fabrication and erection of the steel. Construction company Hent has managed the overall station building project.

Support from Sandvik that was integral to the project included recommending improved dimensions for the Sanmac 2205 hanger components which guaranteed optimal use of the material and saved Hollandia more than 100 tonnes of material. Sandvik was able to supply the components cut to length and on time according to a tight schedule.

The project could not have been completed on time without Sandvik’s support, said Dyon Hermsen, Dutch area sales area manager, Sandvik, who alongside the production unit worked closely with the customer: “Hollandia chose Sandvik because they felt we could help achieve the tight delivery times specified for their performance, as a trusted partner.

“We had seven weeks from order to delivery. As the construction was one of the first activities before continuing with the station, Sandvik’s hollow bar had the highest prioritisation. There was no room for mistakes so we had the whole chain – R&D, planning and production – with us.”

Sandvik anticipates similar projects for its duplex stainless steel hollow bar after successful completion of the Holmestrand station, which formally opened at the end of 2016. Construction work began on the station in 2010.

Sandvik Materials Technology www.smt.sandvik.com