General Information for Stainless Steel 420
| Material Group |
M - Stainless Steel |
| Sub-Group |
Martensitic Stainless Steel |
| Tensile Strength |
750-950[N/mm^2] |
| Machinability Range |
45% |
MACHINABILITY OF 420 STAINLESS STEEL
Stainless steel 420 is a martensitic (magnetic) stainless steel alloy with 12.5% chromium, 0.2% carbon and a machinability rating of 45%.
The amounts of carbon (Range 0.1-1.2%) and chromium (10-15%) are the main factors that affect the machinability of martensitic stainless materials.
More carbon ==> More strength, but lower machinability and less corrosion resistance
More chromium ==> More corrosion resistance, but lower machinability
Due to its low carbon content stainless steel 420 has high toughness, and therefore it is very malleable. The main challenge to machining it (relative to other martensitic stainless alloys) is breaking the chips. Therefore, it is recommended to select a sharp cutting edge with a tight chip breaker. For this reason, inserts that are designed for arsenic stainless alloys (Such as 304 and 316) will work well also on stainless steel 420.
SUMMARY:
For general turning of Stainless Steel 420 at stable conditions use a grade with a semi hard substrate and thin CVD coating.
In case you are running at a cutting speed that is lower than 390 SFM (120 m/min), it is better to use a grade with a Semi Hard substrate and PVD coating.
For general milling, use the grade with a semi-hard substrate and thin PVD coating.
For detailed carbide grades recommendations,check the table below.
Recommended cutting speed range for turning at stable conditions is 540 - 740 [SFM] / 165 - 225 [m/min].
Recommended cutting speed range for milling with stable clamping and short over hang is 340 - 460 [SFM] / 105 - 140 [m/min]
For detailed cutting speed recommendations, check the table below.
Equivalent International Designations for Stainless Steel 420
| Standard |
Name |
| SAE |
420 |
| WNR |
1.4021 |
| DIN |
X20Cr13 |
| BS |
420S37 |
| SS |
2303 |
| ANFOR |
Z20C13 |
| UNI |
X20Cr13 |
| UNF |
F.5261 |
| JS1 |
SUS420J2 |
Chemical Composition for Stainless Steel 420
| Element |
Amount |
| Chromium (Cr) |
12.5% |
| Manganese (Mn) |
1.00% |
| Nickel (Ni) |
1% |
| Silicon (Si) |
1.00% |
| Carbon (C) |
0.2% |
| Phosphorus (P) |
0.04% |
| Sulfur (S) |
0.04% |
Cutting Speeds Recomendations for Stainless Steel 420
| Application |
Vc (m/min) |
Vc (SFM) |
| Turning |
165-225 |
540-740 |
| Milling |
105-140 |
340-460 |
| Parting |
65-90 |
210-300 |
| Grooving |
100-135 |
330-440 |
| Drilling |
50-65 |
160-210 |
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 Stainless Steel 420
Grade for Milling (Indexable)
Recommended Insert Cutting Edge Geometry for Stainless Steel 420
| Honing Size |
0.03-0.05 mm / 0.001-0.002" |
| Rake Angle |
9°-11° |
| Land Angle |
Positive |
| Land Width |
0.20-0.30 mm / 0.008-0.012" |
