This document discusses processing techniques for automotive gears after heat treatment. It describes how gears made of materials like 20CrMoTi and 40Cr undergo blanking, forging, normalizing, machining, carburizing, quenching, and other processes. After heat treatment, the gears need to be finished to the required specifications using cutting tools. CBN tools are recommended for gears harder than HRC 45, with solid CBN tools suitable for gears over HRC 50. The document provides details on Halnn's three grades of CBN tools for automotive gear finishing.

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CBN inserts for finishing automotive gears after heat
treatment
Automobile gear material and processing technology
The automobile gears are subjected to the heat treatment process
to obtain better performance.The gears are used as the
transmission and speed adjustment of the power in the mechanical
device,which not only plays an important role in the
automotive industry, but also consumes a considerable amount.
Processing technology of automobile gear
Processing technologyof gearbox gear 20CrMoTimaterial:
blanking-forging-normalizing-machining-carburizing-quenching low
temperature tempering-shotting-grinding-assembly.
Parts Material
Automotive gearbox gears, Drive axle
drive gears, Drive differential gears
20CrMoTi, 20CrMo
Automotive crankshaft timing gears 45、40Cr 、35SiMn
Automotive starter gears 15Cr, 20Cr, 20CrMo,
15CrMnM, 20CrMnTi.

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Processing technologyof automobile crankshaft 40Crmaterial:
blanking-forging-normalizing-roughing-surface hardening and
tempering-finishing.
Performance and hardness of automobile gear after heat treatment
Performance:1 high bending fatigue strength and contact fatigue
strength (anti-fatigue pitting); 2 tooth surface has high hardness
and wear resistance; 3 gear core has enough Strength and
toughness.
Hardness: 120CrMnTi material, 20CrMo gear after heat treatment
tooth surface hardness: 58-64HRC, core hardness: HRC32-45; 235,
40, 45 heat treatment hardness 149-179HB,340Crsteelheat
treatment hardness 207-241HB;
How to choose the cutting tools for Processing technology of automobile gear
After the heat treatment, the automotive gears need to be finished,
and the required dimensions and precisionof the drawings are
obtained. Therefore, it is very important to select the tool material to
finishing gear.

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The selectionof suitable high-quality tools not only brings the
completionof automotive gear parts, but also greatly improves
work efficiencyand saves processing costs.
At present, the cutting tools that can be used for finishing
automotive gears according to their hardness have traditional
carbide tools, ceramic tools and CBN tools.
automotive
gears
hardness
Cutting tool type Reasons
Below HRC45
Traditional carbide
tool
The hardness of the carbide tool itself is
low,machining high-hardness automobile
gears may cause severe wear or failure
of machining.
Above HRC45 Ceramic tools
&CBN tools
Ceramic tools have good
thermochemical stability, but less than
the toughness and hardness of CBN
tools
Above HRC50 Halnn CBN tools
Halnn CBN tools use non-metal
(ceramic) as a binder, which increases
the toughness compared with the
traditional CBN tool. not only high
hardness, wear resistance and impact
resistance, but also machining accuracy.
high,
Halnn has developed three CBN tools for finishing automotive
gears, namely BN-H10 grade CBN tools,BN-H20 grade CBN tools

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and BN-S20 grade CBN tools Among them, BN-H10 grade and
BN-H20 grade belong to welded grade CBN tools, the BN-S20
grade belongs to the solid CBN tools.
The specific cutting parameters are shown in the table below.
It is divided by hardness: BN-S20 grade CBN tools >BN-H10
grade CBN tools >BN-H20 grade CBN tools ; divided by toughness:
BN-S20 grade CBN tools >BN-H20 grade CBN tools >BN-H10
grade. CBN tools
CBN
geade
Processing
conditions
Cutting depth
ap (mm)
Feed rate
Fr (mm / r)
Cutting speed
Vc (m/min)
BN-H10 Continuous
cutting
0.2 0.1 180
BN-H20 Semi-interrupted
cutting
0.25 0.1 120
BN-S20 Strong interrupted
cutting
2.5 0.12 90