General Information for Cast Iron GG25
| Material Group |
K - Cast Iron |
| Sub-Group |
Cast Iron |
| Hardness |
220.0 HB |
| Tensile Strength |
730 [N/mm^2] |
| Machinability Range |
112% |
MACHINABILITY OF GG25 CAST IRON
GG25 is a Grey cast iron material with a mchinability rating of 112% and hardness 220 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 GG25 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 720 - 970 [SFM] / 220 - 295 [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 overhang 490 - 660 [SFM] / 150 - 200 [m/min]
For detailed cutting speed recommendations, check the table below.
Equivalent International Designations for Cast Iron GG25
| Standard |
Name |
| SAE |
A48-35B |
| WNR |
0.6025 |
| DIN |
GG25 |
| BS |
Grade 250 |
| SS |
125-00 |
| ANFOR |
Ft25D |
| UNI |
G25 |
| UNF |
FG25 |
| JS1 |
FC25 |
Chemical Composition for Cast Iron GG25
Sorry, Not Availble for this Material
Cutting Speeds Recomendations for Grey cast iron - Pearlitic/Ferritic
| Application |
Vc (m/min) |
Vc (SFM) |
| Turning |
220-295 |
720-970 |
| Milling |
150-200 |
490-660 |
| Parting |
110-150 |
360-490 |
| Grooving |
150-205 |
490-670 |
| Drilling |
125-165 |
410-540 |
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 GG25
Grade for Milling (Indexable)
Recommended Insert Cutting Edge Geometry for Cast Iron GG25
| 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" |
