NTT Group extends product service life by upgrading to Hardox® HiAce steel

Fewer than 300 people reside in the village of Lingbo, located in Hälsingland, Sweden. But among its residents is one of Europe's leading manufacturers and assemblers of conveyor chains and sprockets – the NTT Group.

The family-owned company was founded in 1969, and today, has an organization that spans Sweden, Norway, Finland, Denmark, Poland and Germany. Its operations in Lingbo – formerly known as Kedjeexperten i Lingbo AB – have been part of the NTT Group since 2005.

“Our typical customers for our conveyor chains, sprockets and sliding wear plates are sawmills, heating plants and pulp and paper manufacturers. They all want more durable products that simply require less maintenance, which obviously we do our best to help them with,” says Johnny Andersson, supervisor at the NTT Group in Lingbo.

Build for highly corrosive and acidic environments

One of the company's latest challenges was at SCA Östrand’s pulp and paper mill in Timrå, Sweden. Here, logs are continuously fed from timber trucks into the company’s plant via a chain conveyor system that slides over steel sliding plates.

“It is an incredibly tough environment. It's highly corrosive and acidic, which is created by bark and water. The logs are continuously sprayed with recirculated water that flushes away residue. The operating conditions inside the log conveyor accelerate the corrosive wear on the steel plates and the chain guides. At the same time, operations are constantly ongoing with no opportunities for maintenance, so we can only use the highest quality for everything, such as Hardox HiAce steel,” says Viktor Åkerlund, assembly leader at the NTT Group.

Service life up to twice as long

The solution to the problem at SCA Östrand was to upgrade the sliding plates from Hardox^® 450 to Hardox^® HiAce wear steel. Hardox^® HiAce is truly wear resistant, especially in acidic and corrosive environments that threaten to eat away at equipment. The upgrade to the corrosion-resistant wearl plates has increased the lifespan of SCA Östrand’s products by up to two times.

“Earlier, we saw a lot of wear inside the conveyors, but today we think that it works much better with the material we received. Where we have been using Hardox HiAce the longest, we have used it for two years, and on some parts we see no wear at all and a lot less wear on the parts that used to wear down the most,” says Håkan Persson, Head of Department Maintenance at SCA Östrand.

Early adopter of Hardox^® HiAce

The NTT Group has been a SSAB customer since 2020 when Hardox^® HiAce was first launched. According to Per-Olof Kull, Technical Project Manager at SSAB , the development of Hardox^® HiAce started several years earlier in an effort to find an optimal hardness for making the best possible product for corrosive wear.

“The garbage truck segment was where we started the whole process for the development of Hardox HiAce. The operating environment there is both highly corrosive and abrasive, which means they have the same challenges as the pulp and paper industry. The NTT Group was one of the first to use Hardox HiAce in the paper industry. Today, thanks partly to the early tests carried out by the NTT Group, Hardox HiAce is now used all over the world,” says Per-Olof Kull.

A successful partnership with SSAB

Johnny Andersson, supervisor at the NTT Group in Lingbo, says that the reaction to Hardox^® HiAce from their customers has been overwhelmingly positive since they can see that the steel better withstands aggressive environments. He also believes that the collaboration with SSAB is an important factor behind the NTT Group’s increased use of Hardox^® HiAce products.

“We have an excellent relationship with SSAB. They have extensive technical know-how that we can always use whenever we or our customers have questions. It is also a bit special to be early in using this new material and processing it, but we have received a lot of help from SSAB,” says Johnny Andersson.