Application of CBN/PCD tool in the field of rail brake discs

In recent years, as urbanization accelerates and rail speeds increase, disc brakes have become increasingly common. As an essential part of these systems, brake discs are vital for maintaining effective rail braking. This is especially true for subways where stations are close together and braking distances are limited. The requirements for brake discs in such environments are particularly stringent.

The materials used for rail brake discs primarily fall into two categories: iron-based metals and composites. Iron-based materials include cast iron and steel. Cast iron options consist of gray cast iron, vermicular cast iron, and ductile cast iron, while steel choices encompass carbon steel, alloy cast steel, and alloy forged steel.

Composite materials, such as aluminum-based and carbon-carbon composites, represent another category. These advanced composites combine matrix materials like metals or ceramics with reinforcing elements like fibers, whiskers, or particles. They offer benefits like reduced noise, minimized vibrations, and improved productivity. However, their production processes are complex and costly.

To meet the demands of machining rail brake discs, Hualing employs cubic boron nitride (CBN) tools in grades BNK30 and BN-S300, alongside diamond tools. These tools not only ensure superior surface finishes for the discs but also enhance overall production efficiency.

Hualing is a leading domestic manufacturer of super-hard tools, specializing in the research and development of CBN tools and high-grade diamond tools designed for brittle and hard materials. Their innovative tools, including the BN-S300 and BNK30 grades, are extensively utilized across industries such as automotive manufacturing, heavy-duty machining, high-speed processing, and challenging material cutting. Specifically, the BN-S300 and BNK30 tools are tailored for efficient gray cast iron brake disc machining, delivering excellent results.

The BN-S300 grade consists of high-purity, high-density polycrystalline CBN sintered under extreme conditions. With a CBN content exceeding 97%, this tool features exceptional wear resistance and edge strength due to Hualing’s unique isostatic pressure mixing technology. This ensures consistent blade density and uniformity, providing long tool life in both continuous and interrupted cutting applications.

The BNK30 grade combines imported nano-bonding agents with high-purity sub-micron and nano-CBN particles. Sintered under high pressure without a carbide substrate, these polycrystals exhibit remarkable hardness and fine particle sizes, making them ideal for high-speed finishing tasks. Additionally, these CBN blocks can be brazed onto carbide substrates via a high-vacuum process, enabling the creation of CNC tools in various configurations.

For composite brake discs, Hualing's super-hard diamond tools, specifically CDW010 and CDW025 materials, are employed. Both materials are fabricated using carefully selected artificial diamond microcrystals sintered under high temperature and pressure. Additives added during sintering enhance the tools’ hardness, toughness, and bending strength, offering a novel approach to machining composite brake discs.

Overall, Hualing’s commitment to innovation ensures that their tools consistently deliver superior performance across diverse applications, meeting the evolving needs of modern rail transit systems.