Machining Stainless Steel Tool Geometry
Tool geometries are similar for both austenitic and ferritic grades and the summarized below for HSS:
Drilling:
Cutting edge angel ± 135°, point angel ± 138°, lip relief angle varies from 16° for 3mm diameter to 8° for 25mm diameter.
Reaming
Rake angle 3° to 8°, margin width 0.125 to 0.35mm, relief angles primary 4° to 6°, secondary double primary chamfer angle 30° to 35°, chamfer relief angle 4° to 5°, helix angle ± 7°, lead angle ± 2°.
Tapping:
Straight fluted for > 12mm holes, spiral fluted for smaller holes hook/rake angle 15° to 20°, back relief angle 10°, chamfer angle/length plug taps 9° to 10° (3.5 to 4.5 threads) taper taps 4° to 5°, (8 to 10 threads).
Die Threading:
Rake angle 20° to 30°, throat angle 20° to 25°, face angle 1.5°.
Single Point Turning:
Back rake angle ferritics 5°, austenitic 0°, side rake angle ferritics 8°, austenitics 10° to 15°, end relief, side relief and end cutting edge angles all 5°.
Form Turning:
Back rake angle 4° to 10°, end relief angles 7° to 10°, side relief and clearance angles 1° to 5°.
Cut Off Tools
Back rake angle 6° to 10°, end relief angle 7° to 10°, side relief angle 2° to 3°, end cutting edge angle 10° to 15° for small diameters and shallow cuts, decreasing to 5° for larger diameters.
Cutting Fluids
Sulphurised, chlorinated or sulphur-chlorinated mineral oils and emulsifiable oils are used. In cases of high pressure the latter must contain sulphonated or chlorinated additions.
Cleaning
After machining it is essential to remove the cutting fluid and degrease the workpiece. This is usually done with conventional degreasing agents or solvents. In situations where the workpiece has been subjected to excessive heating or where maximum corrosion resistance is required, it may be necessary to passivate and/or pickle and passivate. If this is required refer to the section on post Fabrication Treatment.
Related References:
1. Free Machining Stainless Steel
2. Machinability Table of Metals
3. Machining Stainless Steel Tool Geometry
4. Machining Machinability of Stainless Steel
5. General Principles of Machining Stainless Steel
6. Influence of Stainless Steel on Machinability
Cutting - Sawing | Hand Hacksawing | Shearing | Abrasive Cutting | Thermal Cutting
Hot Rolling - Hot Rolling Process | Hot Rolling Application | Types of Hot Rolling Mill | Hot Rolled Steel Tube | History
Cold Rolling - Physical metallurgy | Degree of cold work | Cold Rolling Stainless Steel | Manufacturing Process
Foil rolling | Rolling Mill | Steel Mill | Production methods | Recycling of Steel | Modern Steelmaking | Contemporary Steel
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