Scientists at the S. A. Khristianovich Institute of Theoretical and Applied Mechanics (ITAM) of the Siberian Branch of the Russian Academy of Sciences, together with the mining and processing equipment manufacturer Gormasheksport, have developed a wear-resistant gradient coating for the teeth of screw-toothed crushers. The coating, based on a metal matrix of iron, tungsten, and molybdenum with ceramic components, reduces the wear rate of crushing teeth by four times compared with standard parts. Parts with the new coating have already been installed on industrial machines and are undergoing operational trials at three plants — within the structures of NLMK, Evrazruda, and RUSAL. A key role in the research was played by the synchrotron radiation of the VEPP-3 and VEPP-4 sources at the Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences in Novosibirsk.
Crusher tooth coating: material composition and wear mechanics
Screw-toothed crushers process ore, coal, flux limestone, and petroleum coke. At one of the mining and processing plants, a limestone crusher processes about 700 tons of ore per hour, while during operation the teeth experience about 35 million load cycles. The service life of standard teeth on this ore is 8 thousand hours.
The main problem is temperature. When rock is crushed, mechanical energy is converted into heat, and the tooth surface heats up to 400–500 degrees Celsius. According to synchrotron radiation experiments, the new material begins to lose its strength characteristics only after 1300 degrees Celsius.
Synchrotron radiation in materials science: in situ experiments at VEPP-3 and VEPP-4
Synchrotron radiation made it possible to conduct in situ experiments — to observe the behavior of the material directly under load, rather than merely recording the fact of destruction after the event. The scientists were able to determine at which points cracks originate and to adjust the coating composition to prevent failures.
The use of synchrotron radiation sources in creating new materials significantly expands our capabilities. Experiments under both static and dynamic loading using SR make it possible to find out where destruction begins, identify the centers of failure, and subsequently prevent their occurrence
An additional effect is self-sharpening of the tooth during operation. The gradient structure of the coating wears unevenly, preserving the cutting geometry and increasing crushing efficiency.
Performance specifications of the new coating for screw-toothed crusher teeth
- Matrix base: iron, tungsten, molybdenum with ceramic components
- Compressive strength limit: 25–30% higher compared with the best grades of high-strength alloys
- Reduction in wear rate: 4 times compared with standard parts
- Temperature degradation threshold: reduction in strength characteristics — after 1300 °C
- Operating tooth surface temperature in service: 400–500 °C
- Additional effect: tooth self-sharpening
- Status: industrial trials at NLMK, Evrazruda, and RUSAL plants
- Funding: grant from the Federal Scientific and Technical Program for the Development of Synchrotron and Neutron Research through 2030
Before the launch of the Shared Research Facility SKIF — the Siberian Circular Photon Source — Russian materials scientists worked with the VEPP-3 and VEPP-4 sources, designed for small samples. According to Stepanenko, the launch of SKIF will make it possible to study large full-scale samples under real industrial loads — a qualitatively different level of experimentation.
A fourfold reduction in wear rate in the mining industry is not an abstract figure. For a plant processing 700 tons of ore per hour, replacing teeth means stopping the line. If the service life of a part grows from 8 to a notional 32 thousand hours, the interval between repairs and operating costs will change radically. Trials at the enterprises of three major metallurgical groups in the country mean that the technology has already moved beyond the laboratory test bench.