Casting die

8/12/2019 Casting die

1/41

Introduction to Die Casting(VEDCME600)

DaimlerChrysler Corporation

Chassis & Powertrain Materials Engineering

Presented by

Cast Metals Engineering & Prototyping

Larry Kopka - Sr. Specialist Materials Eng.

Ph: 776 - 7473, E-mail: [email protected]

Randy Beals - Materials Eng.

Ph: 776 - 7478, E-mail: [email protected]


2/41

DIE CASTING - DIE ALLOYS

QUALITIES REQUIRED FOR DIE STEELS:

EXHIBIT GOOD TOUGHNESSRESISTANCE TO CRACKING

RESISTANCE TO WEAR I EROSION

RESISTANCE TO HEAT CHECKING

HIGH THERMAL CONDUCTIVITY

LOW THERMAL EXPANSION

RESISTANCE TO OXIDATIONGOOD THERMAL SHOCK RESISTANCE

REASONABLE COST

MOST POPULAR DIE STEELS USED FOR PRODUCTION

CHROMIUM BASED - USED FOR ALUM & MAG DIE CASTING:

H-13 / OTHERS: H-11, H-12, CROMO-N, QRO 80M, &ORVAR M SUPREME

LOW CARBON STEEL - USED FOR ZINC, LEAD, &

TIN DIE CASTING:

P-20, P-21, SAE 1020 & MARAGING STEELS


3/41

Introduction to Die Casting

Larry KopkaDCX Materials Engineering

Agenda Die Casting Process

Equipment, Operation, Process Parameters

Die Casting Defects/ Trouble Shooting

DaimlerChrysler Materials Engineering

Process Control Requirements for Die Cast

Structural Components


4/41

Die Casting Design Considerations

Case Studies of DCX Die Cast Components

Problems, Failure Analysis Die Casting Supplier - Process Control

Introduction to Die Casting

Larry KopkaDCX Materials Engineering

Agenda


5/41


6/41


7/41


8/41


9/41

MOST POPULAR DIE STEELS USED FOR PROTOTYPING

P-20, P-21, & SAE 1020

DIE HEAT TREATMENTS

AUSTENITIZE / QUENCH / TRIPLE TEMPER TO Rc 45-52STRESS RELIEF

DIE SURFACE HARDENING HEAT TREATMENTS

CARBURIZING, CARBO-NITRIDING, NITRIDING,

TUFFTRIDING, & IONITRIDING

DIE CASTING - DIE ALLOYS


10/41


11/41


12/41


13/41

Curve of Plunger Travel vs. Time


14/41

Curve of Plunger Pressure vs. Time


15/41


16/41

SLOW SHOT SPEED SYSTEM (1 ST. EVENT)

SLOW SHOT PHASE INITIATES THE MOVEMENT OF THE

LIQUID ALLOY METAL BY THE PLUNGER.SLOW SHOT CYCLE IS COMPLETED WHEN PLUNGER

HAS COVERED POUR HOLE & SHOT SLEEVE IS FILLED.

SLOW SHOT SPEED IS "CRITICAL" - PROPER SLOW SHOT

INSURES MINIMUM AIR ENTRAPMENT IN LIQUID METAL.

FAST SHOT SPEED SYSTEM (2ND. EVENT)FAST SHOT PHASE COMPLETELY FILLS DIE CAVITY

RAPIDLY TO INSURE LIQUID METAL DOES NOT SOLIDIFY

BEFORE FILLING DIE CAVITY.

INTENSIFICATION SPEED SYSTEM (3RD. EVENT)

PLUNGER TIP CONTINUOUSLY APPLIES INCREASED

PRESSURE TO MINIMIZE POROSITY - STUDIES SHOW

ONLY MARGINAL RETURNS.


17/41


18/41


19/41


20/41


21/41


22/41


23/41


24/41


25/41


26/41


27/41

DIE CASTING DEFECTS

POROSITY (GAS):

ENTRAPPED SPHERICAL INTERNAL VOIDS / PORES CONTAINING GAS (HYDROGEN). GASPOROSITY IS CAUSED BY THE ENTRAPMENT OF AIR FROM TURBULENCE DURING CAVITY

FILL, THE SOLUTION OF HYDROGEN GAS IN THE MOLTEN ALLOY (ABSORPTION FROM HIGH

HUMIDITY, MOISTURE IN LUBRICANTS, LACK OF DEGASSING OF MOLTEN ALLOY, MOISTURE

ON ALLOY INGOTS, ETC.). GAS POROSITY MAY BE ELIMINATED BY PRE-HEATING (DRYING)

INGOTS, DEGASSING THE MOLTEN ALLOY, CONTROL OF LUBRICANT APPLICATION /

DRYING, USE OF COVER GAS, VENTING DIE CAVITY, GATING CHANGES, OR IMPLEMENTINGVACUUM SYSTEMS TO REMOVE AIR FROM DIE CAVITY PRIOR TO FILL.

POROSITY (SHRINKAGE):

IRREGULAR SHAPED INTERNAL VOIDS / PORES WHICH DO NOT CONTAIN GAS AND FORM

IN HEAVY SECTIONS DURING SOLDIFICATION. SHRINKAGE IS CAUSED BY THERMAL

CONTRACTION AND INADEQUATE FEEDING OF MOLTEN METAL DURING SOLIDIFICATION.SHRINKAGE POROSITY MAY BE ELIMINATED BY REDESIGN TO ELIMINATE THICK WALL /

BOSS SECTIONS, ETC., PROVIDING BETTER FEEDING OF MOLTEN METAL (VIA GATES, RIBS ),

PROVIDING GREATER ALLOY FLUIDITY (HIGHER ALLOY TEMPERATURE), INCREASING

INJECTION / INTENSIFICATION PRESSURE AND ADJUSTING CASTING PARAMETERS.


28/41

DIE CASTING DEFECTS

COLD SHUTS:

COLD SHUTS ARE "CRACK - LIKE " NON - FUSED OR LAPPED AREAS THAT APPEAR ON THE

SURFACE OF A CASTING. COLD SHUTS ARE THE RESULT OF TWO STREAMS OF LIQUID

MOLTEN METAL MEETING AND FAILING TO UNITE OR METALLURGICALLY BOND. COLD

SHUTS MAY BE

CAUSED BY COLD DIES, LOW POURING TEMPERATURE (SUPER HEAT), SLOW SHOT SPEED,

INADEQUATE FEEDING/GATING, LOW CASTING INJECTION PRESSURE, ETC. COLD SHUTSMAY BE ELIMINATED BY INCREASING INJECTION PRESSURE, INCREASING THE POURING

TEMPERATURE, INCREASING DIE TEMPERATURES, PROVIDING BETTER DIE DESIGN

(LARGER GATES, ADDITION OF RIBS FOR FEEDING, ETC.)

MISRUNS / NON-FILL:

A IRREGULARITY OF THE CASTING SURFACE CAUSED BY INCOMPLETE FILLING OF THEMOLD CAVITY DUE TO LOW POURING TEMPERATURE, GAS BACK PRESSURE FROM

INADEQUATE VENTING OF DIE CAVITY, INADEQUATE GATING, COLD DIE CAVITY, ETC.


29/41

DIE CASTING DEFECTS

CRACKS / HOT TEARS:

A CRACK IS A FLAT INTERNAL FREE SURFACE (FRACTURE) OR OPENING. CRACKS MAY BE

CAUSED BY INTERNAL STRESS DEVELOPED AFTER SOLIDIFICATION (HOT CRACK) OR BY

STRESSES DUE TO SHRINKAGE - RESTRAINT (HOT TEARS) AS THE METAL CONTRACTS AND

THE HOT STRENGTH IS EXCEEDED DURING SOLIDIFICATION. HOT TEARS MAY BE

ELIMINATED BY MINIMIZING RESTRAINT VIA ADDING RIBS TO DISTRIBUTE STRESSES,PROVIDING GENEROUS RADII (LOWER STRESS CONCENTRATION Kt), DECREASING

HOLDING TIME TO EJECT CASTING FROM DIE, CHANGE DIE CASTING PARAMETERS, SUCH

AS, DIE TEMPERATURE, DIRECTION OF METAL FLOW AND MOST IMPORTANTLY CHANGING

DIE CASTING DESIGN. DESIGN CHANGES RELATED TO MULTIPLE / COMPLEX RIB

JUNCTIONS AND THICK BOSS / THIN RIB - WALL TRANSITIONS ARE VERY EFFECTIVE IN

ELIMINATING RESTRAINT CRACKING.


30/41

INCLUSIONS ("DIRT") / DROSS:

INCLUSIONS ARE PARTICLES OF FOREIGN MATERIAL (DROSS, SLAG, MOLD

MATERIAL, REFRACTORIES) TERMED "EXOGENOUS" OR INHERENT INCLUSIONS

TERMED "INDIGENOUS" (OXIDES, SILICATES, SULFIDES, ETC.) IN A METALLIC

MATRIX. INCLUSIONS MAY BE INHERENT IN THE CAST ALLOY INGOT, ORPRESENT DUE TO INADEQUATE ALLOY REFINING PROCESSES, INTRODUCED

DURING RECYCLING, OR DURING THE CASTING PROCESS (INADEQUATE

DROSSING, DEGASSING, ETC.).

DIE CASTING DEFECTS


31/41


32/41


33/41


34/41


35/41


36/41


37/41


38/41


39/41

CHRYSLER MATERIALS ENGINEERING REOUIREMENTS FOR


40/41

CHRYSLER MATERIALS ENGINEERING REOUIREMENTS FOR

PROCESS CONTROL OF DIE CAST STRUCTURAL COMPONENTS

SPECIFICATION/ENGINEERING DRAWING REOUIREMENTS:

THE APPROPRIATE CHRYSLER MATERIAL (MS) & PROCESSING (PS)

SPECIFICATIONS FOR THE SPECIFIC MAGNESIUM, ALUMINUM, OROTHER DIE CASTING ALLOYS MUST BE DESIGNATED ON THE

ENGINEERING DRAWING. A LISTING OF SOME FOLLOWS:

MAGNESIUM SPECIFICATIONS:

MS-9231 (HIGH DUCTILITY MAGNESIUM DIE CASTING ALLOYS)

MS-2413 (MAGNESIUM DIE CASTING ALLOYS)MS-10675 (MAGNESIUM ALLOY INGOT FOR DIE CASTING)

ALUMINUM SPECIFICATIONS:

MS-2410 (ALUMINUM DIE CASTING ALLOYS)

MS-3495 (ALUMINUM ALLOY INGOT FOR DIE CASTING)

PROCESS SPECIFICATIONS:

PS-I0ll (RADIOGRAPIC INSPECTION OF CASTINGS)PS-8335 (PENTAGON-CRITICAL VERIFICATION SYMBOL)

PS-5190 (DIE CASTING PROCESS CONTROL)

THE ENGINEERING DRAWING WILL DESIGNATE THE CRITICALLY

STRESSED ZONES OF THE COMPONENT AS DESIGNATED BY PS-8335

AND DETERMINED BY FEA, ENDURANCE TESTS, STATIC & DYNAMIC

(SLED, DROP TOWER, ETC.) LOAD TESTS.


41/41

STANDARD CASTING / REFERENCE RADIOGRAPHIC FILMS:

AFTER OPTIMIZATION OF DIE CASTING PROCESS PARAMETERS,

CHRYSLER MATERIALS ENGINEERING WILL X-RAY A MINIMUM OF

TWELVE (12) CASTINGS TO ESTABLISH A "STANDARD CASTING". THE

"STANDARD CASTING" WILL BE SELECTED AND AGREED TO BY

CHRYSLER PRODUCT / PLATFORM ENG., MAT'LS ENG., QUALITY

ASSURANCE, PURCHASING & THE DIE CASTING / 1ST TIER SUPPLIER.

THE "STANDARD CASTING" AND RELATED RADIOGRAPHIC FILM

STANDARDS WITH DESIGNATED CRITICAL ZONES, WILL BE USED FOR

X-RAY / FLUOROSCOPIC INSPECTION OF PRODUCTION CASTINGS BY

THE DIE CASTING SUPPLIER. THE QUANTITY AND FREQUENCY OF

CASTINGS INSPECTED FOR PRODUCTION CONTROL WILL BE

ESTABLISHED BY CHRYSLER ENG & QUALITY ASSURANCE, BASED ON

CRITICALITY AND SAFETY RELATED REQUIREMENTS.

PRE-PRODUCTION VALIDATION:A DESIGNATED QUANTITY OF INITIAL PRODUCTION CASTINGS

(USUALLY 100-300 PCS) DEPENDING ON COMPONENT CRITICALITY &

SAFETY RELATED REQUIREMENTS WILL BE X-RAYED AND COMPARED

TO THE "STANDARD CASTING" / FILM STANDARDS AGREED UPON.

Documents

Casting die