The Vallourec plants in Düsseldorf Reisholz (Germany) and in Aulnoye-Aymeries (France) can produce some special products for highly specific applications such as tubes with integrated bottom, reduced ends or expanded end.
Some special applications require tubes with a closed or sealed end. One example are hydraulic cylinders, which normally have a lid welded to one end. But there is a much easier solution: the process used in Reisholz can produce tubes with an integral bottom.
The advantages of an integrated bottom
- no welding
- reduced risk of crack starter or corrosion cracks
- homogeneous material properties
- reduced fabrication complexity
Another specialty made in Reisholz are tubes with reduced ends. This is possible for tubes with an outside diameter of over 600 mm and lengths of over 6 m. Such bottlenecks are used, for example, in fittings and headers. Products with a bottleneck at one end and an integral bottom at the other are of course also available.
Just like a tube end can be reduced, it can also be expanded or its wall thickness increased. Again, many different combinations are possible, including an integral bottom or wall thicknesses varying over the product length. The result is a huge number of variants and special solutions.
The PFP (Premium Forged Pipes) Process in Aulnoye-Aymeries (France) has also its specialties. It can produce tubes and pipes with :
- varying external contour,
- integral end,
- varying internal contour and
- with limitless varieties.
Seamless tubes are manufactured using a forging process patented by Vallourec. The key unit is a forging machine with four radially arranged hammers. The size range covers outside diameters of 209 to 406 mm and wall thicknesses of 25 to 100 mm. In addition, the plant can produce pipes with varying internal and external contours as well as wall thicknesses. The varieties are almost limitless.
The benefits of this process
- Monolithic components instead of welded or threaded assemblies for maximum safety and strength
- Reduced machining requirements and costs thanks to near-net shape and dimensions of premium-forged pipes
- Straightforward manufacture of complex components