Tech Tip #35 - Tap Coatings
Below are Kennametal’s current recommendations for taps in various materials. They are listed in order of preference. Those in parentheses should be viewed as alternatives, but are not in order of preference.
Maxi #1 is Kennametal’s designation for nitride. Increase SFM by 50% for TiN and TiCN, and 100% for TiAlN.
- Carbon steels 1010, 1045: TiCN, TiN, (oxide, oxide over nitride)
- Alloy steels 4140, 8620: TiCN, TiN (oxide, oxide over nitride)
- Tool steels A2, D2, H13: TiCN, TiN (TiAlN, oxide, oxide over nitride)
- 300 Stainless 304, 316: TiCN, TiN (oxide, oxide over nitride)
- 400 Stainless 414, 440: TiCN, TiN (oxide, oxide over nitride)
- PH Stainless 15-5PH, 17-4PH: TiCN, TiAlN (TiN, oxide, oxide over nitride)
- Cast iron, ductile: TiCN, TiN (oxide, oxide over nitride, Maxi #1)
- Cast iron, gray class 20-50: TiCN, TiN (oxide, oxide over nitride, Maxi #1)
- Aluminum, wrought 1100, 2024: CrN, Maxi #1
- Aluminum, silicon cast 319, 360, 380: (TiCN, Maxi #1) TiN, CrN
- Copper, brass, bronze, zinc, magnesium: CrN, Maxi
- Titanium, pure CP Ti: Maxi #1, CrN
- Titanium, alloy Ti-6AL-4V: Max #1, (TiN, TiCN, TiAlN, CrN)
- Nickel-based alloy monel, Inconel: TiCN, (TiN, TiAlN, CrN) (Maxi #1, oxide, oxide over nitride)
- Iron-based alloy A-286, Incoloy: TiCN, (TiN, TiAlN) (Maxi #1, oxide, oxide over nitride)
- Cobalt-based alloy haynes: TiCN, (TiN, TiAlN, CrN) (Maxi #1, oxide, oxide over nitride)
- Plastics, soft and abrasive: TiCN, (TiN, Maxi #1) CrN
- Graphite: TiCN, (TiN, Maxi #1) CrN