ZC7/HC4For continuous machining | Ceramic for machining materials 30 - 70 HRC

Significant cost savings for high hardness materials

Machines a wide range of hardened materials

Real tool cost reductions by replacing CBN
ZC7: Ideal for hardened materials from 30 - 62 HRC
HC4: Ideal for hardened materials from 55 - 70 HRC


  • High hot hardness and low plasticity at high temperature ranges make them ideal for finishing of hardened materials
  • Significant tool cost reductions are achieved by replacing CBN
  • Inserts with a wiper flat or a chipbreaker are available to further improve machining efficiency

Tooling application

Hardened material
Continuous finish turning hardened materials 30-70HRC

Grade & Speed recommendation chart

Cutting conditions

Scroll the table →

Grade Material Operation type Machining Cutting speed (m/min) Feed(mm/rev) DOC(mm) DRY WET
ZC7 Hardened material (HRC30-62) Turning
Continuous machining
Finishing 40 - 200 - - -
HC4 Hardened material (HRC55-70)

Recommended Depth of cut and Feed rate

Corner R DOC (㎜) Feed (㎜ /rev)
R0.4 0.15 0.05 ~ 0.08
R0.8 0.3 0.08 ~ 0.10
R1.2 0.4 0.10 ~ 0.13
R1.6 0.5 0.13 ~ 0.16
Round insert 2.0 0.16 ~ 0.25

Grade application map

CBN's low hardness reduces its wear resistance
Ceramic has superior wear resistance vs. CBN machining under HRC55

Inserts with a wiper flat or a chipbreaker are available

Effect of Wiper Flat on Cutting Edge
[ Cutting conditions ]
Vc=100m/min  F=0.1㎜/rev  ap=0.5㎜
Using a ZC7 insert with AG-chipbreaker improves surface finish and reduces machine down-time due to chip taggling. This results in increased productivity.
[ Cutting conditions ]
SCM415 - carburized HRC50  vc=150m/min f=0.2㎜/rev  ap=0.2㎜

Case study

Material :
Carburized steel
Cutting speed :
Feed :
Coolant :
ZC7 ( 4 corner )

70 pcs / corner

Competitor’ CBN ( 2 corner )

50 pcs / corner

ZC7 achieved longer tool life per corner and significantly reduced tool costs with 4 corners compared to the compeitor's 2 corner CBN.
Industrial part
Material :
Cutting speed :
Feed :
Coolant :

50pc/month - stable machining

Competitor’ CBN

50 pcs/month - unstable machining

ZC7 machined the same number of parts as the competitor's CBN.
ZC7 performance was much more stable and significantly reduced tool costs for the customer.

Tool lineup

View Catalog Information

Please check product catalog for tooling lineup