Presentation on theme: "R. Srinivasan1, B. Cherukuri2, P.K. Chaudhury3"— Presentation transcript:
1 Scaling up of Equal Channel Angular Pressing (ECAP) for the Production of Forging Stock R. Srinivasan1, B. Cherukuri2, P.K. Chaudhury31Professor and 2Graduate Student,Mechanical and Materials Engineering Dept.Wright State University, Dayton OH 454353formerly Chief Metallurgist, Intercontinental Manufacturing/ General Dynamics OTSnow with Orbital Sciences Corporation, Launch Systems Group, 3380 South Price Rd., Chandler AZ 85248Presented at “NanoSPD3” the Third International Conference on Nanomaterialsby Severe Plastic Deformation, Fukuoka, Japan, September 22-26, 2005
2 AcknowledgementsUS Department of Energy, Grant number DE-FC36-01ID14022Institutional partners:Intercontinental Manufacturing/General Dynamics-OTSQueen City Forge (Rob Mayer)Edison Materials Technology Center (Percy Gros, David Swenson)Oak Ridge National Laboratory (S. Viswanathan, Qingyou Han)Travel grant to this conference provided by the Research Council, Wright State University
3 Severe Plastic Deformation (SPD) SPD refers to a “new” class of mechanical deformation processes that imparts large plastic strainsECAE/P, HPT, MAC, FSP, ARB …Strains of the order of 4 or greater have been shown to result in grain refinement to produce ultra-fine grained (UFG) microstructureFine grain (< 10 mm) materials exhibit superplastic behavior at high temperatures and slow strain ratesUltrafine grain (UFG) materials would exhibit superplastic behavior at lower temperature and higher strain rate.
4 Potential Benefits of Ultrafine grain (UFG) Microstructures ProcessingLower secondary forming temperatureLower load or pressure for forging and extrusionIncreased die lifeDecreased tonnage requirement for pressesIncreased material yield in forgingsFewer intermediate steps in forging complex shapesNearer to net shape forgings Reduced machiningImproved machinabilityServiceHigher strength and better fatigue properties with fine microstructureAbility to design lighter components with ultrafine grain materials.
5 ECAP/ECAE Very extensively investigated process Route BC (90 rotation between passes) produces equiaxed submicron size grainsBillet sizes from 10 mm to 50 mm cross section from a variety of materials (several Al alloys, steels, Mg alloys, Ti alloys)G.M. Stoica and P.K. Liaw, JOM pp36-40, March 2001M. Furukawa, et al., in “Ultrafine Grain Materials,” R.S. Mishra ed., TMS, p125, 2000
6 Objectives Scale up the ECAP process Increase cross section to produce “industrial” sizesDemonstrate benefits of using SPD-UFG stock material in hot forgingDecreased forging temperatureImproved hot forging metal flowReduced forging stock sizeEnergy savings
7 Scale-up to Large Cross Section Commercially available AA606112.5, 50, and 100 mm (0.5, 2.0 and 4.0 inch) square cross section bars were annealed (500C, 1hr, FC)ECAP ProcessingRoute Bc with 90, 105 and 120 angle diesChannel SizeChannel AngleChannel LengthFinal Billet SizeAccumulated Strain12.5 mm(WSU)12065 mm12.5 12.5 50 mmUp to 6 passes with ~0.67/pass50 mm(AFRL)90200 mm50 50 150 mmUp to 4 passes with ~1.15/pass100 mm(IMCO/GD)105350 mm100 100 300 mmUp to 4 passes with ~0.89/pass
11 Scale up to Large Cross Section TEM Microstructure (a) 12.5 mm, 4(b) 50 mm, 3.2(c) 100 mm, 3.5
12 Scale up to Large Cross Section Forging Studies Materials UsedECAP50-mm, 90 die angle, 3 and 4 passes100-mm, 105 die angle 4 passesConventional extruded stockFine-grain cast stock – an alternative source for fine grained stockHot ForgingSmall forging – 50 mm ECAP, Extruded stock, and Fine-grain cast stockComplex forging – 50 mm ECAP and Extruded stockLarge forging – 100 mm ECAP and Extruded stockForging done at Intercontinental Mfg. (IMCO)/General Dynamics
13 Scale up to Large Cross Section Forging Studies ~ 125 mm~ 100 mmAft cargo door latch forging“Small forging”Landing gear door bracket“Complex forging”
14 Scale up to Large Cross Section Forging Studies Forged at 315°C (600°F) 100% stock sizeForged at 370°C (700°F) 85% stock50-mm 3-pass ECAPConventional ForgingExtruded StockForged at 450°C (840°F)Fine Grain Cast StockForged at 443°C (830 °F)50% reduction in the flash
15 Scale up to Large Cross Section Forging Studies Defect ground off before second hitFirst HitSecond Hit50-mm 4-pass ECAP forgedat 360°C (680°F)Extruded stock forged at410°C (770°F)
16 Scale up to Large Cross Section Forging Studies 150-mm6-inch100 mm 4-pass ECAP315°C (600°F) 90% stock sizeConventional extruded stock427°C (800°F) 100% stock size50% reduction in material scrapped in the trimmed flash
17 Potential Energy Savings Time to reach temperature d
18 Potential Energy Savings Furnace gas consumption
19 Potential Energy Savings Weighted Energy Savings FC600316700371800427880471
20 Scale-up to Large Cross Section Potential Energy Savings during Forging lb/yearUS Aluminum Forging2.60E+08Current Scrap1.11E+08Reduced Scrap5.57E+07Energy (BTU/year)Current ConsumptionProjected SavingHeating4.68E+111.54E+11Remelting2.45E+111.23E+11Dross1.11E+11Total9.58E+113.88E+11Projected saving40.53%Assumptions130 forging plants with an average production of 2 million lb/yrAssume material yield is 70%SPD billets reduce scrap by 50%~1800 BTU/lb for heating forging billet~2200 BTU/lb for melting aluminum4% loss as dross, with energy content of 55,000 BTU/lbData from Dr. Qingyou Han, ORNL
21 Scale-up to Large Cross Section Potential Energy Savings during Forging Kg/yearUS Aluminum Forging1.18E+08Current Scrap5.06E+07Reduced Scrap2.53E+07Energy (J/year)Current ConsumptionProjected SavingHeating4.94E+141.63E+14Remelting2.59E+141.29E+14Dross1.18E+14Total1.01E+154.10E+14Projected saving40.53%Assumptions130 forging plants with an average production of 910,000 kg/yrAssume material yield is 70%SPD billets reduce scrap by 50%~4200 kJ/kg for heating forging billet~5100 kJ/kg for melting aluminum4% loss as dross, with energy content of 128,000 kJ/kg
22 Scale-up to Large Cross Section Response to T6 Heat Treatment Solutionize 521C (970F) 3 hrQuenchHold at RT for 36 hrAge 177C (350F) up to 8 hr
23 Scale-up to Large Cross Section Properties of Forged Parts Stock MaterialForging Temp.As Forged HardnessREAs ForgedGST6 UTSMPa (Ksi)T6 YSMPa(Ksi)T6 Elong.%T6GS2-inch 3P ECAE/P393°C 740°F145.8 mm320(46.5)297(43.1)15.831 mm4-inch 4PECAE/P315°C600°F31319 (46.2)17.7Extruded460°C 860°F20 mm305 (44.2)283 (41.0)16.232 mmFine Grain Cast416°C 780°F1350 mm282 (40.9)275 (39.8)19.7243 mmMinimum Specifications262 (38)242 (35)7.0Properties and microstructure are as good or better than conventional materials
24 SummaryECAP can be scaled up to produce “industrial” size billets and used as forging ingotsSPD AA-6061 has “lived” up to the anticipated benefitsLower forging temperaturesDecreased material usageUp to 40% saving in energy used for forgingFaster heat treatment after forgingProperties and microstructure same or better than conventional materials.