Halnn BN-S20 grade CBN inserts are recommended for milling high manganese steel parts with hardness over 45HRC. High manganese steel has excellent wear resistance but is difficult to machine due to its high hardness. CBN inserts, especially Halnn's BN-S20 grade, can mill high manganese steel without chipping or collapsing when encountering hard spots, unlike coated carbide or ceramic tools. A case study showed Halnn BN-S20 grade CBN inserts achieved a tool life 12 times longer, with 2 times the cutting speed and higher feed rate compared to traditional carbide tools when milling a high manganese steel crushing cone.

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Halnn BN-S20 grade CBNinserts for milling High Manganese
Steel parts
Ⅰ,The characteristics of High Manganese Steel and how to mill High
Manganese Steel parts
The surface hardness of high manganese steel is greatly improved after
solution treatment or work hardening HB300～HB400 can be achieved under
low impact load, and HB500～HB800 can be achieved under high impact load.
The surface hardened layer can reach a depth of 10 to 20 mm depending on
the impact load. The hardened layer of high hardness resists abrasive wear.
High manganese steel has excellent anti-wear performance under the
condition of strong impact abrasive wear, so it is often used in mining, building
materials, thermal power and other mechanical equipment to make wear parts.
Due to the high hardness of high manganese steel itself, coupled with work
hardening, it is more difficult to mill high manganese steel. Currently, the tool
materials on the market include traditional carbide tools, coated carbide tools,
ceramic tools and CBN inserts. Among them, traditional carbide tools are
suitable for processing workpieces with hardness below HRC40 due to their
low hardness. The hardness and performance of coated carbide tools are
higher than those of uncoated traditional carbide tools, but the surface coating
is wear resistant. The layer is thinner, and when it encounters a hard spot, a
chipping may be generated. After the surface wear layer collapses, the
performance is the same as that of the uncoated traditional carbide tool, and
the tool cost is high; the ceramic tool does not need to say it is very well aware
of the brittleness, can only be used in the finishing process of small amount of
cutting depth and feed rate; for high manganese steel with large margin, it is
recommended to choose CBN inserts, especially Halnn superhard BN-S20
grade CBN inserts can not only mill high-manganese steel, but also cut it
intermittently. It will not collapse when it encounters hard spots.

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As a well-known tool company in the industry with CBN inserts solutions, Halnn
Superhard has been continuously developing with its customers' value,
providing high-quality, high-performance CBN inserts that can quickly meet
increasingly diverse needs. Since its inception, it has accurately grasped the
changing pulse of the times and has enjoyed a high reputation in the academic
field of CBN insertss by virtue of its long-term cultivation of accumulated
technical strength and cutting-edge technological development capabilities.
The following is a brief introduction to the cutting parameters and actual cases
of Halnn BN-S20 grade CBN inserts milling high manganese steel.
Ⅱ, Halnn BN-S20 grade CBN inserts milling high manganese steel
cutting parameters and actual cases
Recommended cutting parameters and CBN grade
Workpieces
materials
Cutting speed
Vc（m/min）
Cutting depth
ap(mm)
Feed rate
Fr（mm/r)
Recommended
CBN grade
High
Manganese
Steel parts
（Hardness：≥
45HRC）
50-150(Roughing) 1-10 0.15-0.7
BN-S20
60-25（Finishing） ≤1 0.05-0.35
The following is a practical case of Halnn BN-S20 grade CBN inserts milling
high manganese steel Crushing Cone
Halnn BN-S20 grade CBN inserts milling high manganese steel Crushing Cone
Workpieces material: high
manganese steel Crushing Cone
Tool type: BN-S20;
Cutting parameters: ap = 2.5mm,
Fr = 0.2mm/r,
Vc = 135m/min.
Processing method: dry cutting;

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Tool materials Tool life Feed rate(Fr) Cutting speed(Vc)
Halnn BN-S20 grade CBN inserts 12pcs/edge 0.2mm/r 135m/min
A brand of carbide tools 1pcs/edge 0.15mm/r 35m/min
Machining effect: Halnn BN-S20 grade CBN inserts compared with traditional carbide tool
(as shown above): the cutting speed is 2 times that of traditional carbide tool, and the feed
rate is also higher than that of traditional carbide tool. In this case, the single-edge life of
the Halnn BN-S20 grade CBN tool is 12 times that of the traditional carbide tool.
Ⅲ,Summary
With the continuous development of modern technology, more and more
high-hardness and difficult-to-machine materials appear in the machine shop.
In order to obtain good workpiece size and precision while ensuring economic
benefits, machine manufacturers are always looking for high processing
efficiency. For cutting tool materials, as long as they are advancing with the
times, continuously develop high-quality, high-hardness, high-efficiency tool
materials or tool grades to occupy the tool market and promote the
development of machinery manufacturing industry.