Pressing

This is the process used to produce seamless stainless steel tubes, which are made from low ductility alloys. It is almost impossible to press them on rolling mills. Pressing of such tubes is done either on horizontal mechanical presses or on vertical mechanical presses. For pressing some low plasticity steels and alloys, a constant pressing speed is very important. Hydraulic pressing consists of two steps: the first is the piercing of the workpiece and the second is the extrusion of the finished product. When the vertical mechanical method is used, all these operations are carried out on the same press. Drilling of blanks on drilling machines is also practiced when pipes are made of high-alloy materials. The same approach is also applicable when the billet diameter is at least 50 mm.

Vertical mechanical presses

They are used to process workpieces with an Ø of 80 to 160 mm and a length of up to 400 millimeters. Before starting the pressing, the billet is heated to t° 1000-1280°C. Then, with a slight compression on the diameter, about 2-3.5%, on the rolling machine with a heated billet remove scale. After that, the diameter of the blank should be less than the diameter of the inner bushing of the press container by 1.5-2 millimeters. Then the outer ram, the stamping device and the inner ram with a needle-shaped mandrel are brought to the workpiece. Then the metal is crimped with the stamping device. This is done to remove the "extra" metal that deforms and fills the container.

This is followed by stopping the stamping device. The die-needle, under the action of the internal ram, pierces a hole in the product, which must correspond to the inner diameter of the pipe. At the same time, the end of the mandrel enters into the inner holes of the die, which squeezes out a small part of the metal, which has the shape of a round plug. As a consequence, an annular gap is formed between the end of the mandrel and the die, which is equal to the cross-section of the hot tube. The stamping device is then lowered due to the pressure of the outer ram on it. At the same time, the metal is squeezed out through this very annular gap, which gives shape to the pipe.

When the extrusion is finished, a part of the metal is left in the container as a press residue, which is cut off by a special cutter and pushed out of the press. Under the action of gravity, the tube rolls down an inclined chute for further reduction.

Buy, price

Evek GmbH has a wide range of high quality rolled metal products in standard and non-standard sizes in stock. We deliver stainless steel pipes of various brands in retail and wholesale. All the products have quality certificate for compliance with standards and technical conditions of operation. The certificate marks the manufacturer, alloy grade, melting number, chemical composition and mechanical properties. Implementation of orders - in the shortest possible time. Preferential discounts are offered to wholesale customers.