Heat with all means

Interview “Handelsblatt/Wirtschaftswoche” – Hidden Champion 2025

Text: Dr. Florian Güßgen | Photos: Dominik Asbach

The company Ipsen International has developed a furnace for hardening of steel that works with natural gas, hydrogen and electricity.

The motto of Ipsen International is “Meet the Heat”, indeed. And in the Future Lab, a hall on the factory premises in Kleve in the Lower Rhine region, you can encounter it in the flesh, this heat. The door of the high-temperature furnace opens slowly, like a gorge. A curtain of flames rises from the lower edge and the hot air can still be felt several meters away from the chamber. It is almost 1000 degrees Celsius inside the plant. “The special thing about this furnace is its adaptability,” says company boss Paul van Doesburg: “You can run it on natural gas, hydrogen or even solar power. Depending on what is available and what CO₂ footprint the customer wants to leave behind.” In other words, an all-rounder. A technologically open furnace. A model of flexible heat art. That is the promise and increasingly also the business plan of the medium-sized company. “This is where we show our customers what the future of heat treatment looks like,” says van Doesburg.

HARD STEEL FOR SPACE

They know all about this heat treatment at Ipsen: The company builds furnaces in which other companies can heat their steel products to make them more resistant, to make them harder. Typical examples include gear wheels for the automotive industry, tools such as pliers, but also components for military equipment, parts of munitions – or parts of spaceships and satellites. SpaceX, the US space company owned by Tesla boss Elon Musk, has used products hardened in furnaces from the Ipsen Group for its Starlink network satellites. Ipsen, the US subsidiary writes on Linkedln, has always helped to develop materials and components for space exploration. Now they are also on board for the return to the moon. If it’s nothing else.

Not all furnaces are the same, usually. Different furnaces are needed for different materials. Products for the aerospace industry, for example, are primarily produced in so-called vacuum furnaces manufactured by Ipsen. This type of furnace heats metal in a low pressure environment so that it does not come into contact with oxygen, which could contaminate it.

So-called atmospheric furnaces  on the other hand, work with a very slight overpressure of a few millibars. And this is where the new, variable technology comes in, with which Ipsen is not forcing its customers to have a climate-neutral production, but is just making it possible in principle.

Anything is possible, nothing is a must… Ipsen International translates this libertarian principle into the world of furnaces – and thus creates the necessary flexibility for the realities of the energy transition, in which many things are being tried out without being clear which technologies will prevail. This is a world in which it is sometimes risky to rely solely on one way. A world made for furnaces of Ipsen.

They only opened the Future Lab last year, just in time for the 75th anniversary of the company’s founding. According to the company myth, Harold Ipsen, an American engineer, made a stopover in Kleve in 1948, shortly after the war. Actually he wanted to go to the Netherlands, but then somehow ended up on the other side of the border. In the village pub, Ipsen happened to get talking to the mayor – and told him about his idea to build furnaces. And so things took their course.

STEEL MUST RELAX TOO

The mayor offered Harold Ipsen a barn – the nucleus of the company, which today has sites in Rockford, Osaka, China and India. After some ups and downs over the past decade, the Ipsen Group currently employs around 800 people, 240 of them in Kleve, and achieved a turnover of around 175 million euros in 2023.

Gas and water pipes on the housing of the high temperature furnace

Since 2007, the company has been owned by a private equity company, based in Frankfurt, Quadriga Capital.

Ipsen’s bright laboratory of the future consists of three units, arranged next to each other, that look similar, but have different functions. In the middle, about six meters high, is the new type of furnace, the all-rounder that they have named Atlas Green – whereby the green in the lettering is typographically very similar to the green of Green Peace – probably not without intention. Usually this furnace is heated to around 950 degrees Celsius; charges with a weight of up to two tons are hardened there for six or seven hours. Bora Özkan, Ipsen’s chief technologist, can explain very precisely why it is good for steel parts to relax in the heat, that it makes them less porous, more adaptable and harder. To the left of the Atlas is a furnace for preheating, to the right of it a slightly overdimensioned washing machine: this is where the material, the respective charge, is preheated and then cleaned after heat treatment, e.g. from oil.

The Atlas Green can be converted from classic fossil fuel heating with natural gas to 100 percent hydrogen within minutes or to – ideally green – electricity within seconds. The burners in the furnace roof are variable, although the gases differ in terms of energy density and combustion properties.

“With our hybrid technology, we are three and a half to four years ahead of the competition,” says Bora Özkan.

He and his development team used the time of the pandemic in particular to push ahead with the new technology. And now, says Managing Director Paul van Does- burg, the furnace fits in perfectly with the times. Yes, for many customers, green production that is as climate-neutral as possible is important. Just at what time, to what degree and in which way exactly it will turn green nobody knows yet.

Green hydrogen is not always available, and cheap electricity from renewable energies, whether from solar or wind farms, is not always  given. But the furnace remains in place.

“Our customers,” says van Doesburg,” don’t buy furnaces with a perspective of two or three years, but for 40 years. We can’t and don’t want to sell systems that are unusable within a short period of time just because the fuel cannot be supplied as promised.”

FLEXIBILITY AS THE KEY

The key term is flexibility.

“Many hardening plants have large-scale solar systems on the roofs of their factories,” says van Doesburg. At Ipsen, the procedure is as follows: Software developed by Özkan and his team can calculate exactly how much carbon dioxide the furnace emits during production, as well as the costs of each production step. If renewable energy is available and cheap, companies can harden those products for which the CO₂ footprint is particularly important. As soon as green electricity becomes more expensive, when the sun isn’t shining or the wind isn’t blowing, the focus is on those products for which natural gas or hydrogen will continue to be used. ” A very environmentally conscious customer can use the sun during the day, customer, for which emissions are less important, can heat on natural gas at night.” says Özkan. “We do not give any binding instructions but provide transparency.”

In the Future Lab, he points to a screen to show how the app can be used to switch between the furnace’s operating modes. Building the furnace is classic engineering. But Özkan says that he has more programmers on his development team than people who specialize in hardware.

The investment has already paid off for Ipsen International. “Since we added the hybrid model to our range, 80 percent of our customers have ordered this variant,” says van Doesburg. In the factory hall, he shows how the furnaces are built, how the chamber is lined with bricks and insulated and how the housing is built. According to van Doesburg, it takes around twelve weeks for a furnace to be fully assembled. Almost all of the models here in the production hall are furnaces of this new type.

Head of Technology Bora Özkan and his team have developed the hybrid furnace for hydrogen, electricity and gas

CAR CRISIS IN VIEW

Ipsen International has a broad base. In Europe, the medium-sized company mainly builds atmospheric furnaces, in the USA mainly the vacuum variant. Demand from defense companies has recently increased, a consequence of the turnaround.

Ipsen is also feeling the crisis in the German car industry. That’s clear. Van Doesburg’s customers are often suppliers. And they are currently going through a tough phase. According to the Ipsen boss, around 40 percent of the company’s turnover comes from the automotive industry. At the moment, he sometimes visits a supplier whose warehouses are full to bursting because orders from the car companies are stagnating. “I can understand if they don’t want to order a new furnace for the time being,” says van Doesburg. Nevertheless, the company feels strong and well prepared. If there is further turbulence on the market, the company will concentrate on services in the meantime, such as modernizing older furnaces. Or they will use the time to further develop the Atlas Green. There are already ideas for this, says Chief Technology Officer Bora Özkan. For the developers at Ipsen, the same principle applies as for the furnaces: The main thing is to remain flexible.