simulation of 3d metal forming pocesses of axi-symmetric products …€¦ · simulation of 3d...

SKF Engineering & Research Centre

Simulation of 3D metal forming pocesses of axi-symmetric

products

FENET MeetingNovember 13, 2001

Wiesbaden, GermanyGerrit-Jan Dop


3D process to manufacture axi-symmetric product

• axi-symmetric billet• fully 3D process• axi-symmetric product

• Orbital Forming• Ring Rolling


Orbital Forming


Orbital Forming (2)


Some examples of rings


From steel to tube & rings (1)


Radial and Radial-Axial ring rolling


Schematic overview of a Radial-Axial Ring Rolling machine


OVAKO's Radial/Axial Ring Mill #9

• manufacturer : Wagner (Germany)• axial force 125 ton• radial force 125 ton• data-logger feature (99 channels)• speeds and forces are calculated

based on billet and final geometry, using the RollTech program

• both king roll and cones are driven (mandrel motor is not installed)


OVAKO's open die hot Ring Rolling Processes

HOT RING ROLLING

ODWidth [mm]

Mass[kg]

Capacity[rings/h]

machining allowance

tolerance[mm]

RM 7;die rolling mill

130~27030~90

1~7 400~820 3.0 1.0

RM 8;radial rolling mill

150~38040~130

5~19 300~500 4.5~7.0 1.7~3.0

RM 4;radial-axial rolling mill

230~65075~230

15~70 40~70 5.0~8.0 2.0~3.6

RM 9;radial-axial rolling mill

300~300050~530

50~2500 10.0~44.0 4.0~21.0

COLD RING ROLLING

80 0.0301


Hot Ring Rolling• 1150 deg. cent.• +low process forces (comp. to cold/warm)• -inclusions originating from ingot not broken

up• -high costs in re-heating• -big tolerances and allowances• -problems with porosity (porosity increases if

hydrostatic pressure becomes negative during the process)

• -forming of laps • -geometrical defects


Cold Ring Rolling• preferred solution • +less waste• +no costs in re-heating• +finer micro-structure• +inclusions more broken-up• +better fatigue properties• - higher process forces• -limited product size• -cracks on OD• -problems with filling of die


Process defects

Porosity during blankingPorosity during blanking

Geometric defectsGeometric defects


Warm Ring Rolling

• <730 deg. centigrade• lower process forces than in cold RR• used for medium sized rings• less energy consumed in re-heating

compared to hot RR


Why are Ring Rolling problems so difficult to solve

• many contact changes (40 revs)• friction driven process• many small increments of plastic work• (almost) rigid body mode at start of

process• small contact zone vs. large workpiece• fully coupled thermo-mechanical

problem


FEA codes that were considered

• MARC & MARC/Autoforge• DEFORM• Forge3• ABAQUS/Standard• ABAQUS/Explicit


Selection criteria

• able to simulate one case in less than 2 days on $50.000 hardware

• good GUI, preferably in terms of process design engineer

• stable and user friendly code• open code ; experts and R&D people must be

able to add to the code• preferably one code for all metal forming

applications• vendor with good reputation and world wide

support network


ABAQUS ANIMATION FILES

• radial-axial ring rolling : temperatures

• radial-axial ring rolling : Equivalent plastic strain

• radial ring rolling : temperatures• radial ring rolling : Equivalent plastic

strain


Shape of the cross section of the formed ring (1)



Theoretical rolled dimension [mm]

Abaqus/Explicit dimension [mm]

OD 161.3 159.24

ID 126.0 124.8

Draceway 133.7 132.5

Width 38.3 38.28


Radial force on the mandrel


ComparisonCPU Time GUI

Gui in process terms

Stable and user friendly

open code world wide support

MARC/ Autoforge

45 days yes --+

++ ++

Deform * yes n.a. n.a. +

Forge/3 15 days yes ++++

+ +

ABAQUS/Standard

45 days can be custom.

+++

+ ++

ABAQUS/Explicit

2 days can be custom.

+++

+ ++


Conclusionsboth Forge/3 and ABAQUS/Explicit are capable of simulating the Ring Rolling process,it is a matter of "time invested in setting up the modelling" that determines the quality of the result ( to a large extent ),the implicit FEA codes ( MARC/Autoforge, Forge2/3, DEFORM, ABAQUS/Standard) take too long to solve the Ring Rolling simulation, even on very fast hardware,ABAQUS/Explicit is the only code that was investigated that yields results that are acceptable at first sight and within computational times that allow for case studies and optimisationby means of analysis,Expecting analysis with a precision of well below 0.5 [mm] (on the diameter) for rings with a diameter of 150 [mm] seems unrealistic,However the influence on the final product of changes in geometry and process parameters can be studied efficiently. These semi qualitative answers can be used to optimise the product and process.


Frequently experienced FEA related difficulties

• loss of volume due to arbitrary re-meshing

• exceeding max. limit on available stress-strain data

• almost rigid body motions at process start-up

• numerical instabilities (contact algorithm?)

• validation data

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