General Information for Cast Iron GG40
| Material Group |
K - Cast Iron |
| Sub-Group |
Cast Iron |
| Hardness |
250.0 HB |
| Tensile Strength |
810 [N/mm^2] |
| Machinability Range |
90% |
MACHINABILITY OF GG40 CAST IRON
GG40 is a grey cast iron material with a machinability rating of 90% and hardness 250 HB.
Grey cast iron is the most brittle cast iron sub-group. It is the easiest to machine and produces tiny chips even when using a flat insert without a chip breaker.
In cast iron, the material standards also define the allowed hardness range, and hardness is the top-ranking factor affecting the machinability ratings. For example, nodular cast iron is known to be harder to machine compared with grey cast iron. However, if a grey cast iron alloy has a hardness of 300HB is will have lower machinability than nodular cast iron with 200HB.
Cast iron is very brittle and produces short chips. Therefore, there is no need for a sharp cutting edge, and a strong geometry with a large honing or K-land is the best choice..
SUMMARY:
For general Turning of Cast Iron GG40 at stable conditions use a grade with a very hard substrate and CVD coating.
In case you are running at a cutting speed that is lower than 490 SFM (150 m/min), it is better to use a grade with a Very Hard substrate and PVD coating.
For general Milling use a grade with a semi hard substrate and CVD coating.
For detailed carbide grades recommendations, check the table below.
Recommended Cutting speed range for turning at stable conditions is 570 - 790 [SFM] / 175 - 240 [m/min].
Consider using CBN inserts. Although they cost more than twice, they enable increasing the cutting speed by 2-4 times (relative to carbide).
Recommended Cutting speed range for milling with stable clamping and short overhang390 - 520 [SFM] / 120 - 160 [m/min]
For detailed cutting speed recommendations, check the table below.
Equivalent International Designations for Cast Iron GG40
| Standard |
Name |
| SAE |
A48-55B |
| WNR |
0.6040 |
| DIN |
GG40 |
| BS |
Grade 400 |
| SS |
140-00 |
| ANFOR |
Ft40D |
Chemical Composition for Cast Iron GG40
Sorry, Not Availble for this Material
Cutting Speeds Recomendations for Grey cast iron GG40
| Application |
Vc (m/min) |
Vc (SFM) |
| Turning |
175-240 |
570-790 |
| Milling |
120-160 |
390-520 |
| Parting |
90-120 |
300-390 |
| Grooving |
120-165 |
390-540 |
| Drilling |
100-135 |
330-440 |
Important! The speed estimation is given for an ideal situation:
- Most suitable carbide grade
- Stable tool clamping
- Stable workpiece clamping
- Good quality raw material
- A short overhang of the cutting tool.
- Nominal hardness of the material.
- etc.
Recommended Carbide Grades for Cast Iron GG40
Grade for Milling (Indexable)
Recommended Insert Cutting Edge Geometry for Cast Iron GG40
| Honing Size |
0.05-0.10 mm / 0.002-0.004" |
| Rake Angle |
0° -0° |
| Land Angle |
Negative |
| Land Width |
0.30-0.40 mm / 0.012-0.016" |
