semi solid metal forming

Pierre Rossouw

02 December 2010

Semi-Solid Metal Forming

© CSIR 2010 www.csir.co.za


• Background

- Organogram of MSM

- Research Focus (ACT)

• SSM Forming

- Background

- CSIR’S Approach

- Current Research

• Casting Alloys

• Wrought Alloys

• Product Development

- Future

Outline

BackgroundMMP Organogram

Powder Metallurgy Technologies

Dr Hilda Chikwanda

Advanced Casting Technologies

Dr Sagren Govender

Engineering Design & AnalysisVacant

Metals & Metals ProcessesDr Willie du Preez

CA AssistanceChristelle Stearn

Mary MojalefaRebecca Myelase(contr)

Quality FacilitationChristelle Stearn

Jeff BensonDr Chris Machio

Dr Lethu ChikoshaMaje Phasha

Sylvester BolokangTafadzwa Mushove

Given LesejaneLerato Raganya (intern)

Pierre RossouwHein MöllerUlyate Curle

Kalenda MutomboSigqibo Camagu

Nonjabuliso MazibukoPeter Malesa

Sam PapoDr Lillian Ivanchev(IC)

William Tefu (contr)

Gary CorderleyLesley Harris

Markus CoetzerFilipe Pereira Danie Wilkins

Martin WilliamsMarius Grobler

David Ntuli (contr)

Primary Processes

Dawie van Vuuren

Ronel LaageShaan OosthuizenGhislain TshilomboEugene Swanepoel

Jaco SwanepoelDewald Terblanche

Danie Snyman

Pro

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MMP LaboratoryMechanical Testing, Metallurgical & High Temperature Materials Testing

Visiting Researchers

Chris McDulingErich GüldenpfennigSuzan Nchabeleng (100%)

Danie Snyman (20%)Dr Wim Richter (20%)

CSIR-CermalabBruce Berger (Ops. Man.)

CSIR-CermalabBruce Berger (Ops. Man.)

Levy Chauke



Advanced Casting

HPDC•New tool materials•Improving net yield•Foundry practice for Al•Development of a VIVC HPDC Machine•Squeeze casting•Near Net shape forming of AlMMCs

SSM•SSM processing of aluminium alloys•Heat treatment of SSM castings•Development of the CSIR-RCS•Near Net shape forming of AlMMCs

Investment Casting

•Titanium(90%)•Counter gravity casting of Aluminium Magnesium alloys(5%)•Near net shape forming of AlMMCs(5%)

Funded by CSIR Parliamentary Grant and LMDN

Funded by DST

Funded by LMDN

Funded by CSIR Parliamentary Grant

BackgroundOverview of Casting Research

1. THIXOFORMING

2. RHEOCASTING

Semi-Solid Metal Forming Background


• High wall thicknesses and different wall thicknesses can be designed

• Low gas porosity due to laminar filling and good airing

• Low solidification porosity due to a high solid fraction proportion (fsolid ~50%)

• Production of thin walled components

• Allows for the casting of wide range of alloys inclusive of highstrength wrought alloys.

• Joining by LASER, MIG or WIG welding possible

• Heat treatment from T0 - T7 possible

• Near netshape or netshape parts production

• Improved tool life

Semi-Solid Metal Forming Background - Potential Benefits


Liquidus temperature

Solidus temperature

LIQUID

SEMI-SOLID

SOLID

•CASTING

•HOT FORMING

•SEMI-SOLID METALCASTING/FORMING

Known since 3000 BC

Known since 3500 BC

Ambient temperature

•COLD FORMINGKnown since 4000 BC

Known since 1973 AD

THIXO RHEO

Globular structureformation

Semi-Solid Metal Forming Background – Thixo VS Rheocasting


SSM FEEDSTOCK

SSM FORMING PROCESS

Semi-Solid Metal FormingBackground- Thixoforming


Disadvantages

• High cost of feedstock material compared to normal foundry alloys

• In order to meet production rates multiple induction heating stations are required which requires high capital expenditure

• The scrap produced cannot be recycled on site and is also devalued significantly

• The feedstock is supplied in specific lengths, which means there would be additional scrap created by off cuts.

• During reheating oxidation of the billet surface occurs therefore dies have to be designed to remove oxides during the forming process.

• During reheating there are liquid metal losses from the billet prior to casting.

Semi-Solid Metal FormingBackground- Thixoforming


High Pressure Die Casting

Liquid Metal Semi-solid metal with round grain structure

Cool Transfer

Semi-Solid Metal FormingBackground- Rheocasting


Advantages Disadvantages Cost of material same as standard casting alloys

Semi-solid state achieved direct from liquid.

Oxidation reduced – reduced oxide entrapment.

Reduced loss of metal during reheating.

SSM scrap can be recycled in house.

Hydrogen Absorption

Process consistency

Semi-Solid Metal FormingBackground- Rheocasting



• 2000 – 2002 Rheo-casting process Developed and patented

• 2003 – 2005 Development of industrial prototype –CSIR funded

• 2006 – 2010 - Development of the CSIR-RCS - SSM forming of Al alloys- Heat treatment - Development of component for SSM forming- Established Research Infrastructure- Commercialisation of CSIR-RCS

Semi-Solid Metal FormingBackground- SSM Forming Research in SA

SSM Research at the CSIRGoal


To provide the total SSM product solution to the prospective client

• Process Development•RCS•HPDC

•Material•Alloy•Heat treatment•Material property

•Product•Customer specification•Product design•Die design•Product qualification•Lifeing


SSM Research at the CSIRApproach

Overview of SSM research• Development of the CSIR-RCS for

commercialisation• SSM processing of cast and wrought

aluminium alloys• Heat treatment• Corrosion• Mechanical properties• Product development


SSM Research at the CSIRResearch Areas


SSM Research at the CSIRInfrastructure

130 Ton Shot Controlled HPDC Machine

CSIR – RCS Lab Prototype


Dosing Furnace

630 Ton LK shot control die casting machine

Industrial scale prototype of CSIR SSM billet machine



Other Cast Wrought MMC

Pure Al A356 2024 SiCp/Al

Al-12Si F357 6082

A206 6004

A201 6005

7075

7150

7278

SSM Research at the CSIRAlloys Processed

SSM Processing of Casting

Alloys



A356, F; Etched F357; F; Etched

A356, T6; Etched

SSM Research at the CSIRMicrostructure of SSM formed A356 & F357

F357, T6; Etched


Alloy YS /MPa UTS /MPa Elongation /%

A201-T6(Low Mn)

297 407 13.4

A356-T6(0.35% Mg)

261 317 6.7

F357-T6(0.62% Mg)

312 355 6.0

Note: The properties presented are very dependent on composition and heat treatment process applied.

SSM Research at the CSIRTensile properties obtained for Casting Alloys


SSM Research at the CSIRInfluence of Mg on Tensile properties of A356/F357 Alloys


30

40

50

60

70

80

90

100

110

120

130

0 1 10 100

t at 180oC (h)

VH

N

6082: 0NA6082: 120NA6004: 0NA6004: 120NAA356: 0NAA356: 120NA

SSM Research at the CSIRHeat Treatment of Cast and Wrought Alloys


SSM Processing of Wrought

Alloys


7075 with no TiB2; F; Etched 7075 with medium TiB2; F; Etched

7075 with high TiB2; F; Etched

SSM Research at the CSIRMicrostructure of SSM formed GR 7075


no TiB2; T6; Etched

SSM Research at the CSIRMicrostructure of SSM formed GR 7075

7075 with medium TiB2; T6; Etched

7075 with high TiB2; T6; Etched


• Tensile test results; T6


no TiB2 467 513 3.2

medium TiB2 458 516 4.5

high TiB2 453 516 5.3

Minimumspecification 455 531 7.0

SSM Research at the CSIRTensile properties obtained for GR 7075


• Tensile results relative to minimum specification; T6

Alloy YS /% UTS /% Elongation /%

no TiB2 103 97 46

medium TiB2 101 97 64

high TiB2 100 97 76

SSM Research at the CSIRTensile properties obtained for GR 7075


• Microstructure: 2024

F T6(Etched)

SSM Research at the CSIRMicrostructure of SSM Processed Wrought Alloys



F T6(Etched)




2024-T6 351 385 5.1

Spec. min. 345 427 5.0

6082-T6 341 365 3.6

Spec. min. 260 310 10.0

7075-T6 467 513 3.2

Spec. min. 455 531 7.0

SSM Research at the CSIRTensile properties obtained for Wrought Alloys


Tensile results relative to minimum specification

Alloy YS /% UTS /% Elongation /%

2024-T6 102 90 102

6082-T6 131 118 36

7075-T6 103 97 46

SSM Research at the CSIRTensile properties obtained for Wrought Alloys


SSM HPDC High Purity Aluminium

SSM Research at the CSIRMicrostructure of SSM Processed High Purity Al


Conventional Eutectic (No SSM Processing)

Eutectic Rheo-processed and HPDC

SSM Research at the CSIRMicrostructure of SSM Processed Al-Si Eutectic Alloy

• SSM Castings - Produced using the Industrial Scale HPDC Cell

• CSIR-RCS• Dosing Furnace• LK 630 ton shot controlled HPDC machine

- Alloy - A356

• Main Objective:- Demonstrate process consistency


SSM Research at the CSIRSSM HPDC of a Brake Calliper

Surface Liquid Segregation





50

70

90

110

130

150

0 2 4 6 8 10 12 14 16 18 20

Depth (mm)

VH

NFT4 (540-1)T4 (540-6)T5 (180-4)T5 (170-6)T6(540-1,20NA,180-4)T6(540-6,20NA,170-6)

Hardness profiles through a cross section of SSM-HPDC brake calipers


Original componentComponent redesigned for SSM forming

SSM Research at the CSIRProduct Development Case Study – Engine Mounting Bracket


X-ray Analysis of a Casting



Mechanical Properties

Summary of Mechanical Properties from Selected Castings

Condition HB YS, MPa

UTS, MPa

A, %

F 71.2 104.3 180.0 5.2 T4 84.0 144.3 255.4 13.3 T6 109.7 255.5 315.2 5.38 T5 91.6 194.0 262.3 4.7

Minimum requirements

85 167 275 1.5

Tensile samples were machined from this section


• Partner interest after initial discussions:- Component is identified- Al-alloy of wrought composition- Must meet minimum requirements of the customer

- Mechanical properties- Cost

- Partner to specify other applicable material properties

• Intent:- Willing to apply CSIR-RCS technology if successful - Create manufacturing facility with jobs in South Africa

(Localisation)

SSM Research at the CSIRProduct Development – New Opportunities


CSIR-RCS: Large scale (2)

Preliminary Work

• Component: Engine mounting bracket- Commercial 7075 (~ 150 kg furnace); A356- Rheo-processing parameters (pouring & SSM temp.)- HPDC shot parameters (velocity profile & intensification)� X-ray evaluation (defects)� Heat treatments (apply knowl. from plates)� Mechanical properties (compare with knowl. from plates)

• Aim:Preparation of niche component production

SSM Research at the CSIRProduct Development – New Opportunities


• Product development for client• SSM forming of high strength wrought alloys• Optimisation of heat treatments• Alloy development• Develop data base of mechanical properties

- Tensile- Fatigue- Fracture

• Evaluation surface properties- Corrosion- Coatings


SSM Research at the CSIRFuture Work


[email protected]@[email protected]

semi solid metal forming

Documents

process csir

rcs csir

lmdn csir

rheocasting csir

csir goalto

forming process

csirrcs ssm

bcambient temperature