Olier, Y. Bossu, E. Rouesne, R. Mocellin, M. Nerino, M. Deaver, C. Nagele, J. Tube Pipe J. Montmitonnet, R. Hamery, Y. Chastel, J. Doudoux, J. Lodej, K. Niang, P. Montmitonnet, J. Siebel, F. Stahl Eisen 74 , — Yoshida, T. Matsui, T. Otani, K. Ann CIRP 24, — Mulot, A. Hacquin, P. Aubin, P. Montmitonnet, and S. Girard, R. Weisbecker, M. Lebensohn, C. Acta Metall. Solids Struct. Chaboche, A review of some plasticity and viscoplasticity constitutive theories.
Bari, T. Velay, G. Bernhart, L. Download references. The authors gratefully acknowledge K. Sornin, E. The mandrel is located inside the tube in a fixed position and rotated by the mandrel thrust block.
The mandrel itself is tapered in the rolling direction. The dies have matching grooves on their circumferences. Figure 3 shows the mill saddle's rolling action. During the forward and backward strokes, the dies reduce the tube in the same way that a rolling pin rolls out pastry.
The grooves' cross sections decrease along the circumference and are nearly circular. In the dead-center positions of the mill saddle, the dies briefly disengage the tube. During these end-of-stroke periods, the hollow advances and rotates.
Both the forward and return strokes form the tube. Depending on the groove design, the forming process requires more than 10 steps, feeding and rotating the tube to different positions in relation to the forming die pass. The large number of small forming steps helps to ensure a constant wall thickness and nearly homogeneous material characteristics in the rolled tube.
Optimizing the process is a matter of matching the feed increment n and the rotation angle a in the two dead-center positions with the tube material and quality requirements. In some cases, the process can achieve variations smaller than 0. The roughness value of the finished tube usually is less than that of a drawn tube. With stainless steel tubes, for example, cold pilgering can achieve Ra values smaller than 0.
The feed increment on the input side is an indication of the overall efficiency of the cold pilger mill operation. The length of finished tube per stroke of the mill saddle is calculated as the product. The annual output can be estimated as the product of finished tube per stroke and the number of strokes per year, whereby the output depends on the tube material, the required dimensional tolerances, the tool design, tooling quality, and lubricant.
In most applications, the cold pilgered tubes are immediately ready for finishing or shipment. In other cases, additional cold pilgering or drawing operations are required. When additional cold-working steps are necessary, the tubes often require intermediate annealing. The cold pilgering process is suitable for all metals. Typical materials are mild steel, stainless steel, ferritic steel, low-alloy steel, copper and copper alloys, titanium alloys, zirconium alloys, and nickel alloys see Figure 4.
Using cold pilgering to reduce precious metals is conceivable, because practically no material loss occurs. Some applications, such as baseball bats and golf clubs, rely on cold pilgering to create the intermediate, tapered shape. Other applications are lightning poles, finned tubes, and nonround tubes with internal or external longitudinal ribs.
This special forming process is indispensable for numerous applications, and cost-effective for many others, for a variety of reasons. The cross-section reductions attained are higher than those achieved by other processes. Apart from machines and plants for tube production and tool dressing, we also supply a range of facilities downstream of cold pilgering, such as.
Tools perfectly tailored to the rolling process are essential for producing top-quality tubes. That's why our product portfolio also features grinding machines for dressing dies and mandrels. These are specially designed for machining tools used in cold pilger mills.
So you get precisely ground dies and mandrels that ensure consistently high productivity and tube quality. There is a huge demand for the automation of complete pipe and tube finishing lines and integrated individual machines.
However, not only a service partner for your plants and machines, SMS group is also there for your staff. That ensures you strengthen your competence as a plant owner. Whether you require one-off equipment checks, continuous condition monitoring, remote service, or regular plant inspections: our service experts will take care of it all. You can even outsource your complete maintenance operations to us. This ensures excellent plant availability plus best production results.
That's why SMS group constantly monitors the availability of all parts and, where necessary, offers modern alternatives - even for parts from third-party suppliers. This ensures competitiveness and full productivity over the entire life cycle of your plant.
Even plants "built to last" need to be critically examined from time to time, because markets and production processes are continuously evolving.
Together with you, our service experts will find the best revamp options for your requirements. Once again bang up to date, your plants will then be ready to bolster your strong position on the market. For easy identification of defects and malfunctions and quick initiation of measures for fault elimination. Regular inspections and maintenance form the basis for safeguarding the efficiency of your equipment.
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