Machining of nickel base corrosion and temperature resistant alloys
Nickel base corrosion and temperature resistant alloys are classified as moderate to difficult when machining, however these alloys can be machined using conventional production methods at satisfactory rates. During the machining processes these alloys work harden rapidly, generate high heat during cutting, weld to the cutting tool surface and offer high resistance to metal removal because of their high shear strengths. Following are key points that should be considered during machining operations. The actual operating parameters are to serve only as a guide and are not to be taken as absolute values.
Capacity – All nickel alloys can be face-turned and bored on practically any machine. Factors such as speed, feed, depth-of-cut and tooling will be the determining factors that allow you to utilize machinery available for the job. Drilling large holes and tapping require sturdy machinery with plenty of power.
Tooling – Due to the nature of the alloys being worked, tools will tend to dull fairly quick and the need to change tooling or re-sharpen tools will be frequent. Although expensive, C grade inserts should be used whenever possible.
Lubrication/Coolants – Lubricants/coolants are desirable. Good results can be obtained using water-miscible vegetable oil based fluids in CNC equipment and engine lathes. However, tapping and heavy drilling (large diameter or deep-hole drilling) requires a heavy duty, light viscosity petroleum cutting oil. Other facilities may use different lubricants based on trial and error. What works for one shop may not work for another.
Drilling – When using insert drills in CNC machines use the same speeds (SFM) for facing, turning and boring for the specific alloy. Feed rates should be .002” per revolution. When twist drill bits are used, cobalt drills are preferred but high speed steel (HSS) drills will also work as long as you keep the speed slow and steady. Solid carbide drills work well in some applications.
Machining Data
Nickel 200/201, Alloy 400, Alloy 600, Alloy 800H/HT
Suggested starting rates:
| Facing, Turning & Boring | |
| Speed | 50-1050 |
| SFM Depth-of-cut | 0.12” |
| Feed for Roughing | 0.012” – 0.016” |
| Feed for Finishing | 0.010” – 0.012” |
| Drilling | |
| Speed | 20-35 SFM per drill diameter |
| 1/16” Dia. of hole | 1200-2000 RPM |
| 1/8” Dia. of hole | 611-1069 RPM |
| 3/16” Dia. of hole | 408-715 RPM |
| 1/4” Dia. of hole | 305-535 RPM |
| 7/16” Dia. of hole | 173-303 RPM |
| 1/2” Dia. of hole | 152-267 RPM |
| 9/16” Dia. of hole | 136-238 RPM |
| Feed: 0.006” – 0.010” per revolution | |
Machining Data
Alloy B2 & B3
Suggested starting rates:
| Facing, Turning & Boring | |
| Speed | 80-150 SFM |
| Depth of cut | 0.25” |
| Feed for Roughing | 0.006” – 0.008” |
| Feed for Finishing | 0.010” – 0.012” |
| Drilling | |
| Speed | 8-14 SFM per drill diameter |
| 1/16” Dia. of hole | 490-800 RPM |
| 1/8” Dia. of hole | 240-420 RPM |
| 3/16” Dia. of hole | 160-285 RPM |
| 1/4” Dia. of hole | 120-213 RPM |
| 7/16” Dia. of hole | 69-120 RPM |
| 1/2” Dia. of hole | 61-106 RPM |
| 9/16” Dia. of hole | 54-95 RPM |
| Feed: 0.004” – 0.010” per revolution | |
Machining Data
Alloy C-276, Alloy C-22, Alloy K-500
Suggested starting rates:
| Facing, Turning & Boring | |
| Speed | 140-200 SFM |
| Depth of cut | 0.25” |
| Feed for Roughing | 0.006” – 0.008” |
| Feed for Finishing | 0.010” – 0.012” |
| Drilling | |
| Speed | 8-14 SFM per drill diameter |
| 1/16” Dia. of hole | 730-1200 RPM |
| 1/8” Dia. of hole | 365-611 RPM |
| 3/16” Dia. of hole | 245-408 RPM |
| 1/4” Dia. of hole | 183-305 RPM |
| 7/16” Dia. of hole | 104-173 RPM |
| 1/2” Dia. of hole | 91-152 RPM |
| 9/16” Dia. of hole | 81-136 RPM |
| Feed: 0.004” – 0.010” per revolution | |
*The data and information contained in this website has been taken from open literature and is believed to be reliable. The information contained is intended to be used as a guide. Mega Mex does not make any warranty or assume any legal liability for its accuracy, completeness or usefulness.
