Durit Hartmetall GmbH

Linderhauser Str. 139, 42279 Wuppertal
Telephone 49-202-55109-0
Fax 49-202-55109-25

Hall map

VALVE WORLD EXPO 2018 hall map (Hall 4): stand A21

Fairground map

VALVE WORLD EXPO 2018 fairground map: Hall 4


Dipl.-Ing. (FH) Heinz-Achim Kordt


+49 202 55 109 36


Dipl.-Ing. Björn Feltes


+49 202 55 109 12


Alexandra Hase

Marketing / Pressearbeit

+49 202 55 109 63


Our range of products

Product categories

  • 02  Valve Components and Parts
  • 02.02  Castings
  • 02.02.01  Investment Castings

Investment Castings

  • 02  Valve Components and Parts
  • 02.02  Castings
  • 02.02.03  Wear-resistant Castings

Wear-resistant Castings

  • 02  Valve Components and Parts
  • 02.03  Components
  • 02.03.05  Valve Balls

Valve Balls

  • 02  Valve Components and Parts
  • 02.03  Components
  • 02.03.10  Valve Seats

Valve Seats

  • 02  Valve Components and Parts
  • 02.03  Components
  • 02.03.13  Valve Discs

Valve Discs

  • 02  Valve Components and Parts
  • 02.11  Gaskets and Sealing Systems
  • 02.11.03  Seals


  • 06  Engineering and Software
  • 06.07  Coating


Company news




Sep 10, 2018

About the benefit of variety

Tungsten carbide begets ingenuity.
Wear – no, thanks. All producing industrial sectors agree on this demand and that is why they prefer tungsten carbide as a highly resilient material. Since virtually all users are constantly concerned with increased efficiency and profitability by extended service lives, this raises one question: Is it possible to universally achieve this aim by means of standard solutions?

“No, certainly not according to our experience“, says Stefan Grötschel from the construction department at DURIT Hartmetall GmbH in Wuppertal. “More than 90 per cent of all applications require customized products for optimized wear protection. Only those tungsten carbide components individually adjusted to the respective production conditions feature exactly the desired properties required in each case. This cannot be achieved with catalogue standards. On that account, our company offers more than 60 different sorts of tungsten carbide, which were developed in-house. We are sure: Variety creates advantages.”

So it won’t work without a broad basis. According to the experts from Wuppertal, this is absolutely necessary for designing and producing the best suited component in the right material composition, precision, and shape for each requirement. Ultra-fine to coarse grain sizes, different degrees of hardness, complex geometries and sizes, bore diameters of 0.5 mm to outer diameters of up to 500 mm.

It’s the composition that counts
There are numerous possibilities of differentiation within this range. The versatile sintered material made of tungsten carbide and a suitable binder can be specifically adjusted to certain operating conditions by the use of corresponding additives or mixtures. For example, if a good corrosion resistance in addition to wear resistance is required, the commonly used cobalt binder should be replaced by nickel. Another advantage: The residual magnetism is reduced to the minimum. If there is an extreme risk of corrosion, a nickel-chrome binder should be preferred. The share of chrome ensures improved chemical resistance and electrolytic stability. Generally one thing needs to be considered: The higher the binder share, the higher the toughness, while the wear resistance decreases adequately.

Performance down to the last grain
There’s a lot more to the modification of tungsten carbide. In addition to the grain size, there are some more aspects for improving the performance in some respects. Stefan Grötschel explains: “Fine or ultra-fine grain is characterized by even structure and hardness, by exceptional edge stability, and ideal suitability for purely abrasive wear applications. On the contrary, medium-sized grain proves to be the best choice where increased impact resistance is required. If the tungsten carbide needs to absorb particularly heavy shocks and strokes, coarse grain provides the required fracture toughness. So we are able to individually respond to practical challenges and to develop solutions ideally complying with the users’ requirements.”

The positive effects of the carbide’s variety may be illustrated by some distinctive examples in valve technology.

A cage of resistance
The task of reducing cages in valves is to decrease the discharge pressure in the system. In this context, there was a practical problem associated to wear, which resulted from previously used components made of tempered steel. Since the required service lives could not be attained due to quickly occurring wear effects, the involved company was looking for a substitute material featuring an essentially higher wear resistance and a consistently good chemical resistance. GD08NC, a special sort of tungsten carbide by DURIT with a specific nickel/chrome binder perfectly complied with this demand. The service life of the reducing cage could thus be extended by several weeks. This change incidentally paid off within a short period of time – by a remarkably improved service life as well as by reduced effort and expenditure of time and maintenance costs.

The material that progress is made of.
This flexible sintered material also features a broad potential for innovative developments. Due to proven competence in tungsten carbide and long-term cross-sector experience, DURIT is able to produce complex inner contours made of tungsten carbide. A process which was only possible by means of casting techniques. For many users, this new production process implies real progress. For instance, this trend-setting method resulted in an immediate benefit for a company previously struggling with excessively heavy wear in its production processes. The initial situation: The company used to work with chilled cast iron valves extremely strained by abrasion, which lasted only for three weeks on average. This was reflected in correspondingly high maintenance costs. It got even more complicated since those valves were not only supposed to control the flow rate, but also to execute a 45 degree turn of the flow and to pass into a subsequently installed expansion stage. Accordingly, there were increasingly high wear effects in the deflection area.

The experts at DURIT solved this problem by their newly developed process, which enabled a production of valve inserts made of tungsten carbide GD10. By this means, the service life of this component was 15 times higher.

Ready for opposing various kinds of wear
The well-known advantages of tungsten carbide include resistance to abrasion and corrosion. But it also proves successful against damaging effects induced by cavitation, which often occurs in connection with rotodynamic pumps and valve components and which causes increased wear. Depending on specific requirements, special sorts of fine grain as well as corrosion-resistant qualities are applied in this context. The textural composition of these sorts of tungsten carbide prevents any damage of the component by the release of single particles during the implosion of vapour bubbles. The attack by aggressive media is effectively arrested as well.

These few application examples plainly show the importance of a careful on-site analysis of the production conditions. Even if it is eventually all about attaining an ideal ratio of material input, costs, and service life: The right choice of material and fully meeting the user’s desires should always be based on a detailed knowledge of the current difficulties in production.   And: Variety makes it possible.

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Sep 10, 2018

Investing for saving.

Wear protection pays off.
The costs are huge. Economies all over the world have to bear the consequences of wear, corrosion, and mechanical load in the amount of two to five per cent of the gross domestic product. The loss just in Germany runs into high two-digit billions.

By now, there is no way around active wear protection in many sectors, since the use of recent research findings and innovative technology may help saving a lot of money. Starting with consumption of material and energy via production costs to expenditures on maintenance and technical services.

But due to global competition, the Olympic maxim is still valid: faster, higher, further. However: Intensified process conditions and the demand for increasing quantities cause a disproportional progression of wear related to machines and components. This development is individually amplified by the use of particularly abrasive substances.

High-tech quality tungsten carbide
In order to achieve maximum efficiency, faster lead times, and preferably long service lives, production systems have to be optimized and updated. At the same time it is necessary to significantly increase the load capacity in continuous operation. Tungsten carbide proves successful in this connection. The sintered materials made of tungsten carbide combined with an appropriate binder adjusted to each kind of application offer advantages especially relevant in high-performance production. These include enormous wear and pressure resistance, exemplary resilience towards abrasion, electric conductivity, low fracture susceptibility as well as chemical and thermal stability. That means: Tungsten carbide lasts considerably longer – even under extreme conditions in a rough environment.

DURIT Hartmetall GmbH provides a practical example from petrochemistry: When separating solids from quench oil, the load on the components in the lower part of a hydrocyclone separator is extremely high due to high flow velocities. Hence, the use of GD10, a highly abrasion-resistant sort of tungsten carbide, made this area resistant to wear. Moreover, the experts decided to assemble the separation valve with this exceptionally hard tungsten carbide quality, which is also dimensionally stable especially in the sealing area. The additional costs arising from the use of tungsten carbide amortized within a few month due to a considerably higher service life of the hydrocyclone.

A range with profitable possibilities
Due to the positive experience with the use of tungsten carbide in production processes, more and more users proceed to replace tools and elements exposed to wear by resilient parts made of tungsten carbide.

But this complete replacement is not the only investment opportunity for sustainable wear protection. The company DURIT from Wuppertal shows that there are also other opportunities to effectively avert detrimental influences in industrial production. And indeed, in a cost-efficient way.

Thus, DURIT does not only offer components and precision tools made of customized tungsten carbide varieties, they also develop component coatings made of other, often inferior materials. The result is surprising. These high-quality wear protection layers significantly improve the properties of the basic material. This optimization process makes the respective component overall much more stable and durable.

In order to constantly find the best solution for the use of tungsten carbide, this company from the Bergisch Land consistently focuses on a large variety. The experts provide a range of about 60 different sorts of tungsten carbide of their own development as a broad basis for a customer-specific material composition.

Another interesting option for a highly efficient wear protection is the combination of tungsten carbide components with coated parts made of steel, aluminium, or cast iron as well as suitable synthetics. This easily works out. Tungsten carbide firmly and safely adheres to the substrate – if attached by gluing, soldering, shrinking, casting, or by a mechanical friction-locked attachment. Certainly, the best choice of attachment is principally dependent on the field of application the piece is used in. One thing is for sure: Since only heavily loaded surface areas of the components are made of sheer tungsten carbide, maintenance costs are decreased in the long run.

After all, repairing used and worn components is also worth considering. Correspondingly, wear-resistant coatings may quickly prepare the components for long-term use. This reprocessing pays off if the restoration charges range considerably below the price for the replacement of the parts.

Considering total costs
That much is clear: Before investing in effective wear protection, users should carefully look at the total costs. This implies some important questions. At which process step is the use of a particularly resilient material absolutely necessary? Where might be another material more suitable for increasing the resilience of components or elements? When might be a coating of the parts the best choice?

Without a detailed analysis of individual production conditions on site, these key questions may not be answered adequately. One criterion for taking one or another investment decision will always be a cost-efficient relationship between required material, material costs, and service life. With this in mind, the choice of material plays a prominent role.

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Sep 10, 2018

The art of transformation.

From an inferior material to optimized quality.
The production between costs and efficiency. In order to achieve a satisfying result, numerous industrial companies often have to manage a balancing act. The example of components and parts makes it particularly obvious. Since elements with an inferior material quality are frequently used due to cost reasons, several losses in terms of resilience, efficiency, and durability have to be accepted. But there’s something to be done about that.
The task is evident. The components’ features have to be improved accordingly. Especially with regard to wear resistance and corrosion protection. The art of transforming a low-price part into a high-class product can be found in a customized surface treatment.

A resistant surface finish
To that end, those parts of the components exposed to wear are partially coated with carbides, ceramics, or metals using professional treatments. The choice of material is precisely adjusted to individual practical requirements. A high-tech finish extremely resistant to different damaging influences is thus developed. This also includes thermal, abrasive, and chemical resistance. Furthermore, some coating systems are biocompatible or electrically insulating.

Convincing cost reasons
Up-to-date coatings have not only proved successful in many sectors due to their application-related advantages. Cost aspects play an important role as well. While the susceptibility to wear of the treated components considerably decreases, performance and durability increase. For the companies, this results in extended service lives, reduced material consumption, higher productivity, improved process dependability, and lower maintenance efforts. Altogether, this leads to significant savings rapidly turning to account.

Perfectly coated in any case
The range of coatings is so huge by now, so that there is always an ideal solution for each application. As for instance reliable sealing systems in the fittings industry. Highly wear-resistant alloys, for example with tungsten carbide, became widely favoured since they attain prime values in terms of strain related to temperature, pressure, abrasion, and flow velocity.

Thermal spraying as preferred procedure
When it comes to optimizing large and heavy components by means of an extremely resilient coating, thermal spraying is an approved and ideal procedure. This process can be explained in a simple way: Small particles of the coating material are heated and accelerated in a sprayer. When temperature and velocity reach a sufficiently high level, the actual spraying process starts. On the surface of the component, the ejected particles create a smooth layer, which firmly unites with the surface and then it exactly features the properties requested by the user.

In contrast to common thermal spraying, the process of high velocity oxygen fuel is conducted in a high-speed mode, in which the accelerated process gas reaches supersonic velocities of more than 2,000 m/s. The velocity of the jet particles increases adequately to up to 800 m/s. By using low thermal but high kinetic energy, high velocity oxygen fuel offers excellent adherence of the coating without any considerable strain of the surface material. So this universal application technique is suited for all market-based materials.ochgeschwindigkeits-Flammspritzen eineH

Due to the virtually unlimited range of additives that may be combined with different basic materials, it is generally possible to find the perfect wear protection without any difficulties. The thickness of the layer ranges from 0.3 to 0.8 mm. Post-processing steps like lathing, honing, or lapping are easily possible. The new surface is convincing in all aspects for all practical purposes. Wear-resistant, thermally stable, diffusing, and thus highly adherent as well as corrosion-resistant against alkaline, acidic, and aqueous solutions.
More possibilities
 “For us, thermal spraying techniques belong to the best suited methods for multiply increasing wear protection and for permanently optimizing production processes”, tells Heinz-Achim Kordt, Head of Design at the tungsten carbide manufacturer DURIT from Wuppertal. “We expanded our process technology and we invested in a new laser cladding system. So we are able to use metal or ceramic powders for creating wear-resistant protective coats in a specialized fusing process.”

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About us

Company details

Business segment:
For more than 35 years, DURIT Hartmetall develops and produces tungsten carbide tools and components. More than 500 employees - application developers, engineers and specialists - do the utmost to achieve optimized productivity for clients worldwide. Working together at sites in Germany, Portugal and Brazil, DURIT strives for outstanding results, reliability and efficiency in all industries. The DURIT range of services covers precisely customer needs. Regardless of whether you require standard or custom manufactured items, mass produced or individually fabricated parts.

Research and development:   
DURIT offers more than 60 different tungsten carbide grades of significant quality. The development takes place in our own company lab, partly in cooperation with scientific institutions in Germany and Portugal.

DURIT Hartmetall GmbH was founded October 1 1982 in Wuppertal / Germany. Until today we are a modern, family-owned and managed enterprise.

Product range:     
Engineering components and Precision tools made of tungsten carbide:

i.e., valve seats and valve cones, valve balls, seal faces, pistons, forming and drawing dies, knives and cutting strips, cutting dies, pressing moulds and liners, dies, arbors, bearing shells, nozzles as well as special components according to customer drawing.

Coatings for all sectors and application purposes:

Branches / Applications:
DURIT offers effective product solutions and services for different industries and challenging niche manufacturers worldwide, i.e.:

» automotive
» forming
» chemical, petrochemical, petroleum industries
» pharmaceutical industries and medicine
» powder processing
» plant engineering
» and many more

Germany:        Linderhauser Str. 139, 42279 Wuppertal
Portugal:         Arruamento C, Zona Industrial - Apartado 24, 3854-909 Albergaria a`Velha

500 employees worldwide

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Company data



Company information as a PDF file