CeramicsFor smart and productive machining of super alloys

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Ceramic machiningApplications

Ceramic grades can be applied in a broad range of applications and materials; most often in high speed turning operations but also in grooving and milling operations. The specific properties of each ceramic grade enable high productivity, when applied correctly. Knowledge of when and how to use ceramic grades is important for success.

All ceramic cutting tools have excellent heat and wear resistance at high cutting speeds. Below you can find the most common types of ceramics used in hard and/or difficult to machine materials.

Super alloy materials

Sialon (SiAlON) grades combine the strength of a self-reinforced silicon nitride network with enhanced chemical stability. Sialon grades are ideal for machining heat resistant super alloys (HRSA). CC6060, CC6065

Whisker-reinforced ceramics use silicon carbide whiskers (SiCw) to dramatically increase toughness and enable the use of coolant. Whisker-reinforced ceram-ics are ideal for machining Ni-based alloys. CC670

Other materials

Mixed ceramics are particle reinforced through the addition of cubic carbides or carbonitrides (TiC, Ti(C,N)). This improves toughness and thermal conductivity. CC6050

Silicon nitride ceramics (Si3N4) represent another group of ceramic materials. Their elongated crystals form a self-reinforced material with high toughness. Silicon nitride grades are successful in grey cast iron, but a lack of chemical stability limits their use in other workpiece materials. CC6190, CC6090

Oxide ceramics are aluminium oxide based (Al2O3), with added zirconia (ZrO2) for crack inhibition. This generates a material that is chemically very stable, but which lacks thermal shock resistance. CC620

General limitations of ceramics include their thermal shock resistance and fracture toughness.

Ceramic grades

vc

hex

CC6065

CC6060

CC670

400

300

200

100

00.05 0.1 0.15 0.2

CC670

CC6060CC6065

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Bulk toughness

Programmed direct into corner/plunging

Programmed with roll-in, roll-out of corner

Skin, scale, ovalityHigh quality forging

Pre-machined material

First stage machining – 26 HRC

Intermediate stage machining – 46 HRC

Short tool life – too high cutting temperature

Edge line frittering – too low cutting temperature

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CC670 200 to 300 m/min 2 mm 0.1 to 0.15 mm/rCC6065 200 to 250 m/min 2 mm 0.15 to 0.2 mm/rCC6060 250 to 300 m/min 2 to 3 mm 0.15 to 0.2 mm/r

Grade Cutting speed, vc Cutting depth, ap Feed, fn

Start cutting data recommendations (RNGN 12, RCGX 12) – Inconel 718 (38 to 46 HRC)

Cutting parameters

The speed should be balanced to create enough heat in the cut-ting zone to plasticise the chip but not too high to unbalance the ceramic.

The feed should be selected to give a chip thickness which is high enough to not work-harden the material but not be too high to cause edge frittering.

Higher feeds and depths of cut require a reduction of the cutting speed.

These boundaries will change depending upon the component material hardness and grain size.

Cutting data for turning

Stable conditions and correctly applied application methods and coolant supply are important for best results.

Notch wear resistance

Programming consideration

Material consideration Forging

Application areas for HRSA grades

Ceramic turning

vc

hex

1200

900

600

300

0.025 0.05 0.075 0.1

6060 700 to 1000 m/min 2 mm 0.07 to 0.11 mm/r

Grade Cutting speed, vc Cutting depth, ap Feed, fn

Cutting data for milling

• Grade CC6060 best - no coolant• Conventional milling - zero chip thickness on entry into component• Radial immersion, ae - >70% to give smoothest exit from component

Ceramic milling

Ceramic inserts cutter for roughing super alloys

• Ceramic milling typically runs at 20 to 30 times the speed of carbide, although at lower feed rates (~0.1 mm/tooth), which results in high productivity gains. Due to intermittent cutting, it is a much cooler operation than turning. For this reason, speeds of 700-1000 m/min when milling are adapted, compared with 200–300 m/min for turning.

• Ceramics have a high tendency for notching, which is why round inserts are primarily used to ensure a low entering angle.

• Never use coolant.

• Ceramics have a negative effect on the surface integrity and topography, and are therefore not used when machining close to the finished component shape.

• The primary application for grade CC6060 (sialon) is milling Inconel 718 engine castings and oil drilling equipment, in both cases due to the high metal removal rates.

• Maximum flank wear when using ceramic inserts in HRSA is 1 mm.

Short tool life – too high cutting temperature

Edge line frittering – too low cutting temperature

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application

Negative inserts require up-milling

Please observe that negative inserts require up-milling while positive inserts prefer down-milling

Programming considerations when using turn milling technique – the center line of the insert must be on the centre line of the component.

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Ceramic milling

Tool: Competitor, Sandvik Coromant high-feed cutter S-R120R-051C6-12X4Insert: Competitor, Sandvik Coromant carbide RNGN 12 07 00-E

Cutting speed vc (m/min): 38 800Feed per tooth fz (mm): 0.71 0.13Table feed vf (mm/min): 600 2000Cutting depth ap (mm): 0.7 1.5Cutting width ae (mm): 46 44.1Metal removal rate Q (cm3/min): 19.3 132.3

Results:A total of 42 hours of cutting time was saved per year, and the productivity increased by 469%.

Sandvik Coromant’s Sialon grades CC6060 and CC6065 and the whisker ceramic CC670 complement a strong ceramic insert programme both for turning and milling.

Tool: Competitor, Sandvik Coromant Solid holder Adaptor: C8-SL70-LF-051 Holder: SL70-CRDCL-50-12Insert: RC… RCGX 12 07 00E Coated carbide Ceramic grade CC6060

Cutting speed vc (m/min): 50 275Feed per tooth fz (mm): 0.2 0.25Cutting depth ap (mm): 2.5 2.5Metal removal rate Q (cm3/min): 25 172Tool life per insert edge (min): 10 5

Results:By using the ceramic insert grade CC6060 in combination with trochoidal turning the machining time for the pocketing operation was reduced from 63 hours down to 13 hours i.e. a saving of 50 hours machining time per component! Additional the No of insert edges used is reduced from 380 to 160 per component.

Ceramic turning

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Cases

Product offer for super alloys

CNGN

DNGN

RNGN

SNGN

TNGN

RPGN

RCGX

RPGX

TPGN

General inserts turning/ milling

12

15

9, 12, 15, 19, 25

9, 12, 15, 19

16, 22

6, 9, 12

6, 9, 12

6, 9, 12

11, 16

ISO

4

4

3, 4, 5, 6, 8

3, 4, 5, 6

3, 4

2, 3, 4

2, 3, 4

2, 3, 4

2, 3

ANSI

CSGX

150.23

Grooving

6, 9, 12

X

ISO

2, 3, 4

X

ANSI

6060 6065 670

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

6

CNGN

DNGN

SNGN

TNGN

RNGN

CNGN

DNGN

SNGN

TNGN

RCGN

RNGN

CSGX

RCGX

150.23 RPGN

RNGN

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oman

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SL7

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For round T-Max P ceramic inserts with positive or negative basic-shape and without hole.

Internal turning T-M

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boring

bar

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Gauge inserts

For T-Max P ceramic and CBN inserts with negative basic-shape, without hole.

External turning

Applications

Holders for inserts with hole

Turning

7

Dia 40 mm

Dia 50 mm

Dia 50 - 80 mm

Dia 36 - 44 mm

Dia 36 - 54 mm

Dia 20 - 32 mm

Dia 25 - 40 mm

Dia 32 - 50 mm

RNGN 12

RPGN 06

RPGN 09

RPGN 12

Cyl

indr

ical

sha

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Cor

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Arb

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Applications

Milling

Head office: AB Sandvik Coromant SE-811 81 Sandviken, Swedenwww.sandvik.coromant.com E-mail: info.coromant@sandvik.com

C-2929:61 ENG/01 © AB Sandvik Coromant 2010.12

Sandvik Coromant Total ceramic grade offer

CC650

CC6050

GC1690

CC6060

CC6190 CC6090

CC620

CC6065

CC670

Oxide ceramic for high speed finishing of grey cast iron in stable and dry conditions.

Mixed ceramic for light, continuous finishing in hardened materials.

Mixed ceramic for high speed finishing of grey cast irons and hardened materials, and for semi-finishing operations in HRSA with low toughness demands.

Whisker ceramic with excellent toughness for turning, grooving and milling of Ni-based alloys. Can also be used for hard part turning in unfavourable conditions.

Silicon nitride grade for rough to finish turning and high speed dry milling of cast iron, perlitic nodular cast irons and hardened cast irons.

Coated silicon nitride grade for light roughing to finish turning of cast iron.

Sialon grade for optimized performance when turning pre-machined HRSA in stable conditions. Predictable wear due to good notch wear resistance.

Particle reinforced Sialon for turning operations in HRSA that demand tough inserts.

www.sandvik.coromant.com, www.aero-knowledge.com