A research team from the NUST MISIS pressure metal processing department has developed a new technology that simplifies the process of hot-rolled seamless pipes made of alloy and high-alloy steel. One notable feature of this technique is the use of two simple punches to turn an irregular billet into a hollow "sleeve".
Some components require high-strength alloys, and seamless pipes made of alloys and high-alloy steels are mainly used in the natural gas, petroleum, chemical, and energy industries. The rolling process of these types of steel tubes is extremely complicated and expensive to produce, so the workpieces themselves are much more expensive than traditional carbon steel.
The standard technology of alloy steel hot-rolled seamless steel tubes can be divided into several stages: cutting long solid semi-finished metal "rods" into short billets, further processing the workpiece to form tough parts, and then heating the workpiece with a furnace. This is followed by "reworking", which translates the workpiece into hollow sleeve rolls and simple punches. Finally, the sleeve is rolled into a tube on a continuous rolling mill.
The main reason for the low productivity of this process is the rapid wear of simple punches, because almost every tough part needs to be replaced after manufacturing, and it often also causes production defects.
NUST MISIS scientists have developed a technology that can extend the life of simple punches several times. They propose a two-stage strengthening method using lubricants and coolants on a cross-screw mill.
The newly developed technology, hot-rolled pipe made of alloy steel and alloy, is significantly more efficient, and the process has been implemented in several companies in the Russian pipeline industry. Due to the improvement of simple punches and the use of liquid glass lubricants and water cooling in the process, the wear resistance of simple punches has increased by 5-6 times.
In the experimental part of the research, NUST MISIS scientists obtained a seamless tube with a diameter of 90 to 270 mm made of alloy steel (X10CrNiTi18-10). This work was done under the conditions of NUST MISIS Pressure Metal Processing Division and equipment using EZTM, and the project was supported by Vyksa Steel Works and Volzhsky Pipe Plant.