Transcript Damaged Area Under Pouring Hole Nitrided H13 Shot Sleeve

STUDIES ON SHOT SLEEVE BEHAVIOR DURING USE TO
IMPROVE ITS LIFE
Stationary Platen
Ejector Platen
Ladle
Hydraulic Cylinder
Die Cavity
Shot Sleeve
Shot
Sleeve
Plunger
Plunger
Cover Die
Ejector Box
Ejector Die
Steel Shot Sleeves – Modes of Failures
Wash-out
progressive loss of material because of
corrosion and erosion
Soldering
adhesion and buildup of aluminum to the
surface of the shot sleeve
Deformation
temperature gradients between bottom and
top of the shot sleeve cause uneven
thermal expansion
Gross Cracking
caused by thermal shock or severe
jamming of the plunger tip
Thermal Fatigue Cracking
surface cracking caused by repeated
thermal stress/strain
Heat Loss
rapid heat extraction can cause premature
solidification
Damage Flow
Soldering
Plunger tip sticking
Wash-out
Distortion
Plunger/sleeve
damage
Aluminum blow by
Uneven friction
Sleeve rupture
Sleeve and Plunger
Replacement
Basic Schematic of the Experimental Facilities
Ladle
Funnel
Cylinder
Sleeve
Furnace
Experimental Facilities
Experimental Facilities (another view angle)
Timing of Operation
Ladle
Ladle
Cycle time 36 seconds
Filling, 14 sec
Arm Advancement, 7 sec
Ladle
Pouring, 4 sec
Plunger
Injection, 4 sec
Arm Retracting, 11 sec
Ladle
Plunger
Tip Retracting
Lubrication
Shot Sleeve/Plunger Tip
Design for Accelerated Testing of Nitrided Shot Sleeve
Under pour hole area
Design for Accelerated Testing of Shot Sleeves with (TiAl)N PVD
Coating, Stellite #6 Insert and Thermal Sprayed Molybdenum
Coating
Under pour hole area
Shot Sleeve Failure – Damaged Area Under Pouring Hole
Nitrided H13 Shot Sleeve - Temperature Measurement Under The
Pouring Hole
Shot sleeve and plunger tip were both nitrided H13
> 1000 °F
0.060”
0.060”
Nitrided H13 Shot Sleeve Temperature Measurement
0.060”
0.060”
Pressure in Hydraulic Cylinder During Operation
1000
End of stroke
Pressure [psi]
800
600
Beginning of stroke
400
`
Soldering Area
200
always happens when soldering occurs
0
0
1
2
3
4
Time [sec]
5
6
7
Schematic of the Washout/Soldering Testing Arrangement
Cavity
Test Pins
Plunger
Shot Sleeve
Al jet from slit
ca. 70 in/sec
Schematic Diagram of the Accelerated Test Die
Molten Aluminum
Shot sleeve
Gate
Test pin Die cavity
Plunger
Test Pin, Test Pin Location and Casting Design
Pin location
Test pin
Casting
Ф5
5
19
30
5
Biscuit Runner Gate
Ф10
10
Effect of Coating on Washout by Pin Testing
0.14
H13-Base
Nitrided H13
0.12
Weight Loss of Pin(g)
H13-Base
(TiAl)N nano LUMENA Coating
0.10
0.08
0.06
(TiAl)N PVD Multilayer Coated H13
0.04
Nitrided H13
0.02
0.00
0
30
60
90
120
Shot Number
150
180
210
240
Washout Resistance of Slected Materials by Pin Testing
0.14
0.12
Weight Loss [g]
0.1
0.08
0.06
0.04
0.02
0
H-H13
50 shots
Mo based
Ti based
W based
100 shots
100 shots
100 shots
Damage Evolution on Nitrided H13 Sleeve
600 shots
1000 shots
1600 shots
2200 shots
The Mechanism of Soldering and Wash-out in Nitrided H13
Nitrided Layer
• Soldering initiates by intermetallic
formation at aluminum-steel interface
• Wash-out takes place by iron dissolution
at aluminum -intermetallic interface
H13 substrate
x 100
• Both processes involve diffusion of
aluminum and iron across the interfaces
Aluminum
Intermetallic
H13 substrate
x 50
x 200
Damage Depth of Nitrided H13 Sleeve - Longitudinal Section
Through the Area Under Pouring Hole
Shot Sleeve
Original ID surface
0.50"
initial
Soldered
Aluminum
0.33"
final
Thermocouple Hole
Steel
TiAlN PVD Coating
- Inert in molten aluminum
- Relatively thick coating (10-12 mm)
- Thermal conductivity similar with steel’s
- Very high hardness/strength
- Very low steel-coating friction coefficient
Stellite 6 Welded Insert
- Lower solubility in molten
aluminum than Fe
- Wear resistant
- Thermal expansion and
conductivity similar with steel’s
- High hardness/strength
Welded plug
Steel plug with Stellite 6 weldment about 6 mm
Methods For Improving the Shot Sleeves
Stellite 6 Welded Insert
Note: Dimensions are in inch.
Molybdenum Thermal Sprayed Coating
- Very low solubility in molten aluminum
- Thicker than TiAlN PVD (~250 mm)
- High thermal conductivity
Pouring hole
- Good hardness/strength
- Very good thermal fatigue properties
Molybdenum thermal
sprayed coating (250 mm)
Depth of Damage vs. Number of Cycles
5
Nitrided H13
Nitrided H13
TiAlN coated
Depth of Damage [mm]
4
Stellite 6 insert
Molybdenum
thermal spray
3
2
Stellite 6 insert
TiAlN coated
1
Molybdenum thermal spray
0
0
200
400
600
800
1000
1200
1400
1600
Number of Cycles at Maximum Temperature
1800
2000
Area of Damage vs. Number of Cycles
400
Nitrided H13
350
Area of Damage [mm 2]
Stellite 6 insert
300
250
200
Nitrided H13
150
TiAlN coated
TiAlN coated
Stellite 6 insert
100
50
Molybdenum thermal spray
Molybdenum
thermal spray
0
0
200
400
600
800
1000
1200
1400
1600
Number of Cycles at Maximum Temperature
1800
2000
CONCLUSIONS
1. The molybdenum coating provided the very best material for
avoiding damage to the shot sleeve steel. The molybdenum held up
longer than any other material. With an improved bond, the
molybdenum coating would have lasted for a longer period of time.
2. The hard coating (TiAlN PVD) performed excellent manner as long
as the coating was maintained. However, its thickness was limited to
about 10 microns (0.01 mm). After this coating wore off, the
behavior was that of the nitrided H13.
3. Stellite 6 material showed considerable wear under the action of the
molten aluminum alloy; cracking occurred in the weldment. The
wear is the result of solubility of cobalt in molten aluminum.
4. The nitrided coating of the H13 provided some assistance to
withstanding the wearing and soldering effect on the H13 shot
sleeve.
Acknowledgements
This research work is supported by DOE funds provided
through by Casting Metals Coalition program. The NADCA
and the members of Die Materials Committee in that
Association approved this work and provided background.
The appreciation of this group of people is hereby
acknowledged.