Production Improvements of ALD Vacuum Carburizing vs Conventional Atmosphere Carburizing

LPC Loads & ResultsLPC Loads & Results

Production Improvements of ALD Vacuum Carburizing

vs Conventional Atmosphere Carburizing

(with various Load Examples and Results)


Sprocket Sample

Material: Powdered Metal0.4%C, 0.5%Cr, 0.5%Mn, 0.5%Mo (AISI 4142 Equivalent)

Number of parts: 288Total Weight: 440kg (970 lbs)Quench media: HeliumQuench pressure: 20 BarCase Depth: 0.35 mm (min)Surface Carbon: 1.0%(wt)Surface Hardness: 700 HV1 (min)


Sprocket Sample

0

0,2

0,4

0,6

0,8

1

1,2

0 0,2 0,4 0,6 0,8 1 1,2

distance from surface [ mm ]

carb

on

co

nte

nt

[ w

eig

ht

- %

]

sprocket 3609

200

300

400

500

600

700

800

0,0 0,2 0,4 0,6 0,8 1,0


hard

nes

s [

HV

0.1

]

1: journal

2: tooth

pretrialsprocket 11

2Carbon Profile

Hardness Profile


Bevel Gear Sample

Material: 16MnCr5Number of Parts: 198Weight per part: 1.39 kgTotal Weight: 410 kg (900 lbs)Quench Media: HeliumQuench Pressure: 20 BarCase Depth: 0.40mm (min)Core Hardness: 311 HV1Surface Hardness: 700 HV1 (min)


Bevel Gear Sample

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0 0,2 0,4 0,6 0,8 1 1,2 1,4distance from surface [ mm ]

carb

on

co

nte

nt

[ w

eig

ht

- %

]

1: cd = 0,4 - 0,6 mm

2: cd = 0,6 - 0,8 mm

C2H2

T = 930 °C16MnCr51

2

200

300

400

500

600

700

800

0,00 0,20 0,40 0,60 0,80 1,00 1,20 1,40


har

dn

ess

[ H

V 1

]

1: root

2: flank

3: tip

1

23

T = 930 °Ct = 98 min20 bar He16MnCr5

Carbon Profile

Hardness Profile


Hardness ProfileDiesel Nozzle Sample

Material: 16MnCr5Number of Parts: 4000

Total Weight 480kg (1060 lbs)Quench Medium: NitrogenQuench Pressure: 20 BarCase Depth: .060mm (min)Core Hardness: 450 HV1Surface Hardness: 770 HV1 (min)

Injector Detailed Presentation


Hardness profiles of a nozzle

400

450

500

550

600

650

700

750

800

0 0,2 0,4 0,6 0,8 1

distance from the surface [ mm ]

hard

ness

[ H

V 1

]

1: seat inside

2: shaft inside

3: shaft outside

1

2

3

Hardness Profile - Diesel Nozzle Sample


Blind Hole PerformanceBlind Hole Performance


Material: 25MoCr4Largest Size: 16“Dia x6“ HWeight: ~90 lb/ea. (maximum)Heat Treating Process: LPC with 20-Bar Helium Quench

Mixed Load Sample


200

300

400

500

600

700

800

900

0.0 0.5 1.0 1.5 2.0 2.5depth in mm

Har

dnes

s in

HV

10

sample #1(top) flank

sample #1 root

sample #2 (bottom) flank

sample #2 root

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2

depth in mm

carb

on c

onte

nt in

%

C-Profile

Case Hardness: 60-63 HRC

Core Hardness: 34-38 HRC

Case Depth: 1.40 mm (flank)

Mixed Load Sample

Hardness Profile


Hardness Comparison ofOil-quenched vs. Helium-quenched Samples

Mixed Load Sample

Hardness in HRC Oil QuenchBefore tempering

Oil QuenchAfter Tempering

Helium QuenchedAfter Tempering

Core hardness 33.2 - 34.0 29.5 - 33.2 34.0 – 35.0

Hardness at root 35.4 – 37.1 34.5 – 37.7 35.0 – 38.3

LPC Loads & Results

• Effective Case Depth: 0.045/0.065"• 25 to 35 per load (4/tray conventional)

• 7.6 hrs LPC vs. 9.75 hrs conventional

• To get acceptable distortion Modified loading pattern

Modified quench parameters Changed part temperature before quench

010203040506070

0 50 100 150 200 250Depth (0.001")

HR

C

Pitch (LPC) Root (LPC)Pitch (conventional) root (conventional)

Hub Gears

LPC Loads & Results

• Effective Case: 0.045/0.065"• 55 to 84 per load (20/tray conventional)• 5.25 hrs LPC vs. 9.75 hrs conventional carburizing

0

10

20

30

40

50

60

70

0 50 100 150 200

Depth (0.001")

HR

C

Pitch Root

Helical Side Gears

LPC Loads & Results

• Effective Case Depth: 0.045/0.065"• 128 pieces per load (25/tray conventional

carburizing)• 5.25 hrs LPC vs. 9.75 hrs conventional carburizing

0

10

20

30

40

50

60

70

0 50 100 150

Depth (0.001")

HR

C

Pitch Root

Drive Pinions

LPC Loads & Results

• Effective Case Depth: 0.045/0.065"• 365 / load (80/tray conventional)• 5.0 hrs LPC vs. 9.75 hrs conventional carburizing• To get acceptable spider arm distortion

loading pattern had to be modified

0

10

20

30

40

50

60

70

0 50 100 150Depth (0.001")

HR

C

Pitch Root

Differential Spiders

LPC Loads & Results

Product

#of parts / fixture Carburizing time (hours)

ALD Vacuum Carburizing

Conventional atmosphere Carburizing

ALD Vacuum Carburizing

Conventional Atmosphere Carburizing

Hub Gears 25 to 35 4 7.6 9.75

Diff Spiders 365 80 5.0 9.75

Drive Pinion

128 25 5.25 9.75

Helical Gears

55 to 84 20 5.25 9.75

Production Improvement

LPC Loads & Results

Parts: Chain for Conveyors

Material: 21Mn5 (carburizing)

15CrNi6 (case hardening)

Spec.: ECD (550 HV) / CD (0,35%C) =

1,0 to 3,0 mm

Surface-C: 0,75-0,80 %C (21Mn5)

Surface Hardness: min. 800 HV (15CrNi6)

Process: HT-Vacuum Carburizing: 1050°C

Gas quenching: 20 bar He

Load: 600x750x1000 (WxHxL in mm)

600 - 1000 kg gross

System: ModulTherm 3 + 2(2008)

Capacity: 7.000 kg per day in average

SOP: October 2007

High-Temp LPC of Chains

LPC Loads & Results

0

6

12

18

24

30

36

42

0 0,5 1 1,5 2 2,5 3

EHT (550HV) in mm

Be

ha

nd

lun

gs

da

ue

r in

h

950°C - Direkthärtung

1050°C - Einfachhärtung

1050°C - Direkthärtung

Tot

al t

rea

tmen

t tim

e in

hr

Effective case depth (550HV) in mm

1740F direct hardening

1920F single hardening

1920F direct hardening

High-Temp LPC of Chains

Production Improvements of ALD Vacuum Carburizing vs Conventional Atmosphere Carburizing

Documents