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.
Parts
|
Material
|
Automotive gearbox gears, Drive axle drive gears,
Drive differential gears
|
20CrMoTi, 20CrMo
|
Automotive crankshaft timing gears
|
45、40Cr 、35SiMn
|
Automotive starter gear
|
15Cr, 20Cr, 20CrMo, 15CrMnM, 20CrMnTi.
|
Processing technology of automobile gear
Processing technology of gearbox gear 20CrMoTi material: blanking-forging-normalizing-machining-carburizing-quenching
+low temperature tempering-shotting-grinding-assembly.
Processing technology of automobile crankshaft 40Cr material: 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, 340Cr steel heat 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 precision of the drawings
are obtained. Therefore, it is very important to select the tool material to finish the car gear.
The selection of suitable high-quality tools not only brings the completion of automotive gear parts, but also greatly improves work
efficiency and 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,
machininghigh-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
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.
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
|
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