Upload
trinhnhi
View
223
Download
2
Embed Size (px)
Citation preview
A Study of the Effect Of Extrusion Parameters yOn the Properties Of Extruded
Zr-2.5Nb Pressure Tubes
N SaibabaChief Executive
Nuclear Fuel ComplexHyderabad-INDIA
ASTM STP 4th t 7th F b 2013ASTM –STP-4th to 7th Feb 2013
Hot Extrusion is the process by which a block of metal or
HOT EXTRUSIONHot Extrusion is the process by which a block of metal oralloy is reduced in X-section by forcing it to flow through a dieorifice under high pressure and above Recrystallizationorifice under high pressure and above Recrystallizationtemperature. It is used to produce long straight, semi-finishedproducts such as Bars, Solids & Hollow sections & tubes.
Multi axial compression in Extrusion is responsible for veryhigh strain in extrusion.Workability: “Deformation to the point of Fracture” increaseswith increasing mean pressure or hydrostatic pressure
m = (1 + 2 + 3 ) / 3or decreasing relative mean valueor decreasing relative mean value
Mean value = m / Kƒ
STATE OF STRESS IN VARIOUS METALWORKING PROCESSESMETALWORKING PROCESSES
f COMPRESSIVE HYDROSTATIC STRESSES ACT TO CLOSE UP SMALL
PORES OR SEPARATIONS AT THE PHASE INTERFACES AND GENERALLY MAKE THE FRACTURE PROPAGATION
1 2 3> frMAKE THE FRACTURE PROPAGATION
PROCESS MORE DIFFICULT
UNIAXIAL TENSILE TESTROLLING & FORGING
OF BILLETS & INGOTSTENSION
TEST
1 2 3>
UNIAXIAL COMPRESSION TEST
-1/3 1/30
m
Kf
EXTRUSION PROCESS PARAMETERS
• INTRINSIC VARIABLES Temperature of extrusion St i t ( t ll d b R d) Strain rate (as controlled by Ram speed) Strain rate sensitivity
• EXTRINSIC VARIABLES Tooling
Inter dependence Of Principal Variables
gTool geometryTool TemperatureM t i l f t lMaterial of tool
Lubrication Heat loss during transportation of billetHeat loss during transportation of billet
3780T HORIZONTAL EXTRUSION PRESS
Extrusion Data Acquisition
OBJECTIVE OF EXTRUSION SIMULATION STUDYSIMULATION STUDY
To carry out the “Design and Control of Experiments to arrive at the optimisedExperiments to arrive at the optimisedparameters of Billet preheat temp, extrusion speed extrusion ratio toolextrusion speed, extrusion ratio, tool geometry etc.”
• Hit-and-Trial Method :• Hit-and-Trial Method : Expensive Time consuming unreliable.
• Computer simulation : Customizable Safe Inexpensive,
METHODOLOGY OF SIMULATION/ PRINCIPLES OF HYPERXTRUDE
Billet cavity, Die Cavity, Land Cavity & Profile.
HEX 8 l t t ti 8 t HEX‐8 element, aspect ratio 8 to avoid non‐convergence.
Elements across any dimension6. 30° Sector , Axi‐symmetric problem.
Structured Arbitrary Lagrangian Eulerian mesh consisting of 37200 to 39600 elements .
30°HyperXtrudehp‐adaptive FE‐based software;
bi CAD l d i li icombines CAD, solver and visualization tools.Extrusion‐specific interface.Inputs finite element mesh materialInputs finite element mesh, material data, boundary conditions & process parameters
CONSTITUTIVE EQUATIONFlow in Extrusion is modeled as Viscous incompressible flowFlow in Extrusion is modeled as Viscous incompressible flow.
Fundamental equations: conservation of mass, momentum and energy· U = 0· U = 0
ρ (U · ) U = · (σ)ρCP U · T = · q + φρCP U T q φ
Where, U is the velocity vector, σ is the total stress tensor, Tis the temperature, ρ is the mass density, CP is the specific heat ofthe fluid at constant pressure, q is the heat flux vector, and φ
The material behavior is specified by the constitutive relations for
p , q , φrepresents internal heat generation rate due to viscous dissipation.
p ythe viscous stress tensor, (τ ) and the heat flux vector (q)
τ = 2µγ;γ = [( U ) + ( U )]T
U is the velocity vector, µ isthe viscosity and k is theγ [( U ) + ( U )]T
q = −k Tthe viscosity, and k is theisotropic thermal conductivityof the material.
APPROXIMATIONS/ASSUMPTIONS
• Constant Ram velocity
• Heat transfer & friction coefficientsoptimization and comparison with p pexperimental ram-force curve
MESHING SCHEME, MODEL COMPONENTS AND BOUNDARY CONDITIONS
Convective heat transfer to container and die, Coulomb friction
Conical Die
Coulomb friction
BilletDieSymmetry
Free Surface
Traction force = 0Convective heat transfer to mandrel, Coulomb
frictionfriction
BOUNDARY CONDITIONS• Convective Heat Transfer boundary: All tool face boundaries areassigned convective heat transfer boundary, i.e., heat removal from thesefaces is through convection.
• Friction Boundary: When shear stress over contact surfaces exceedscritical shear stress, material starts to flow.
I fl B d A t t l it d t t b d• Inflow Boundary: A constant velocity and temperature boundarycondition is assigned at billet ram face.
• Free Surface Boundary: Free surface boundary is assigned at profilesurface. This boundary is assigned an insulated boundary
i.e. q (heat flux) = 0.
• Outflow Boundary: This boundary is assigned to profile face.Outflow Boundary: This boundary is assigned to profile face.Traction forces = 0 (as the extrudate is not pulled out of the die),Displacement 0 (as extrudate is free to expand), Heat Flux = 0
• Symmetric Boundary: This is assigned to symmetric faces.
BOUNDARY CONDITIONS (MATHEMATICAL FORM)(MATHEMATICAL FORM)
Bill t R I t f U U T TBillet-Ram Interface : U = URam ; T = TRam
Billet Container Interface : τ = µσ ; T = TBillet-Container Interface : τS = µσN ; T = TContainer
Die Face : τS = C (U − UTool ) ; T = TContainerS ( Tool ) ; Container
Bearing Surface : τS = C (U − UTool )
Free Surface : σ · n = 0
FLOW BEHAVIOUR DATA FOR ZR-2.5NB ALLOY
Flow Stress (MPa) at Temperature (°C)
ZR 2.5NB ALLOY
StrainStrain
rate (s-1)650 700 750 800 850 900 950
0.001 72.7 50.3 33.5 15.1 13.8 10.9 8.1
0.01 122.3 80.8 61.8 36.5 27.8 18.2 16
0.50.1 143 118.4 75 66.4 44.2 30.2 25.8
1 332.8 180.1 129.7 92.7 60.4 45.7 39.3
10 303.1 234.6 179.6 120.5 88.1 78 70.7
100 286.3 264.1 222.4 151.2 120 100.7 87.3
EXTRUSION PARAMETERS RANGE FOR EXTRUSION SIMULATIONSEXTRUSION SIMULATIONS
• Effect of ram velocity : OD 119 mm, WT 6 mm, billet preheattemperature 815°C, included die angle 90°, fillet radius of 10 mm,
d ti ti 14 44 l iti 1 / 3 / 30 / 47reduction ratio 14.44, ram velocities: 1 mm/s, 3mm/sec, 30 mm/s, 47mm/s, 75 mm/s, 125 mm/s.
• Role of reduction ratio: OD 119 mm, ram velocity 30 mm/s, filletradius of 10 mm, Billet preheat temperature 815°C, included die angle90°, reduction ratios: 6, 8, 10, 12, 14.44, 20.
• Effect of preheat temperature: OD 119 mm, WT 6 mm, ram velocity 30mm/s, included die angle 90°, fillet radius of 10 mm, reduction ratio14.44, billet pre-heat temperatures: 775°C to 855°C at intervals of 10°C.
• Effect of fillet radius: OD 119 mm, WT 6 mm, ram velocity 30 mm/s,yincluded die angle 90°, billet preheat temperature 815°C, reduction ratio14.44, fillet radii: 1 mm, 5 mm, 10 mm, 20 mm.
OPTIMIZATION OF CONVECTIVE HEAT TRANSFER COEFFICIENT (W/m2 .K)
3000 CONSTANT FRICTION COEFFICIENT VALUE OF 0.1
2000
2500
)
1500
2000
Forc
e (T
on)
Conv. 10Conv. 100Conv. 250
1000Ram
F Conv. 500Conv. 750Conv. 1000
0
500DAS_Total Force
00 100 200 300 400 500
Ram Travel (mm)
OPTIMIZATION OF FRICTION COEFFICIENT
2500 CONSTANT HEAT TRANSFERVALUE OF 100 W/m2 K
2000
n)
VALUE OF 100 W/m2 .K
1500
Forc
e (T
on
DAS_Total Force
Friction 0.01
Friction 0 1
500
1000
Ram
F Friction 0.1
Friction 0.5
Friction 0.7
0
500 Friction 0.9
0 100 200 300 400 500
Ram Travel (mm)
OPTIMIZATION OF CONVECTIVE HEAT TRANSFER AND FRICTION COEFFICIENTS
2500
3000
AGREEMENT OF SIMULATED LOAD PROFILES AND EXPERIMENTAL LOAD
2000
2500
ons)
AND EXPERIMENTAL LOADOptimized values: 100 W/m-2 /K and 0.1
1500
Forc
e (T
o
Shop Floor Data
1000
Ram
F
p47mm/s_500W/m-2/K_FrCoef0.0147mm/s_100W/m-2/K_FrCoef0.147mm/s_100W/m-2/K_FrCoef0.947mm/s_50W/m-2/K_FrCoef0.14 / 0 / 2/ C f0 9
50047mm/s_50W/m-2/K_FrCoef0.9
00 50 100 150 200 250 300 350 400
Ram Displacement (mm)
SCHEMATIC GEOMETRY OF EXTRUSION SETUPDETAILS OF THE EXTRUSION MODEL
Billet
Fillet Radius
Tube WT
Length of the billet 450mm
Fillet Radius 10mmBillet OD
TUBE
semi Die Angle Land length 6 mm
Profile length 10mm
225TUBE ID
Billet O.D 225mm
Tube O.D 119 mm
Tube I D 107 mmTube I.D 107 mm
Sector modeled 30°Average no. of elements 38000elements
No. of element layers in Radial direction
15
fNo. of elementlayers along circumferential direction
20
TYPICAL TEMPERATURE CONTOURS
Location of highest
temperature
EFFECT OF RAM VELOCITY ON EXTRSUION LOAD
2300
2500Peak Ram Force
EXTRSUION LOAD
2100
2300
ns)
Steady State Ram Force
1700
1900
Forc
e (To
n
1300
1500
Ram
F
900
1100
9000 20 40 60 80 100 120 140
Ram Velocity (mm/s)
EFFECT OF RAM VELOCITY ON CROSS SECTIONAL TEMPERATURE DISTRIBUTION
960
980LETE 960
980LETEa bRAM VELOCITY RAM VELOCITY
900
920
940
960
atur
e (
C)
TE
900
920
940
atur
e (
C)
TEa bRAM VELOCITY20mm/sec
RAM VELOCITY47mm/sec
820
840
860
880
Tem
pera
820
840
860
880
Tem
pera
20mm/s 47mm/s
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)980 LE
980LE
/ 47mm/s
920
940
960
e (
C)
LETE
900
920
940
960
re (
C)
LETEc d RAM VELOCITY
125mm/secRAM VELOCITY
75mm/sec
840
860
880
900
Tem
pera
tur
840
860
880
900Te
mpe
ratu
r
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)
75mm/s 125mm/s
EFFECT OF LOWER RAM VELOCITY ON LEADING AND TRAILING END TEMPERATURE PROFILES
(AT FILLET REGION)
RAM VELOCITY1mm/sec
RAM VELOCITY3mm/sec
1 mm/s 3 mm/s
2700Peak Ram
EFFECT OF EXTRUSION RATIO ON EXTRUSION LOAD
2300
2500Force
Steady State Ram Force
1900
2100
(Ton
s)
1700
1900
m F
orce
(
1300
1500Ram
900
1100
9000 5 10 15 20 25
Reduction Ratio
EXTRUDATE PROFILES AT DIFFERENT REDUCTION RATIOS
EFFECT OF EXTRUSION RATIO ON TEMPERATURE PROFILES BETWEEN LE AND TE OF EXTRUSION
(AT FILLET REGION)(AT FILLET REGION)
980LE 980
LE
900
920
940
960
re (
C)
TE
900
920
940
960
re (
C)
LETERR=6 RR=20
840
860
880
900
Tem
pera
tu
840
860
880
900
Tem
pera
tur
800
820
0 5 10 15 20
Distance from ID (mm)
800
820
0 1 2 3 4 5
Distance from ID (mm)
RR = 6 RR = 20
EFFECT OF EXTRUSION RATIO ON TEMPERATURE GRADIENTS ACROSS THE SECTION
200
160
180
200m
m)
RR6
RR20
120
140
ent (
C/m
80
100
e G
radi
e
20
40
60
pera
ture
-20
0
20
Tem
-200 0.2 0.4 0.6 0.8 1
% Wt Away from ID
2900
EFFECT OF PREHEAT TEMPERATURE ONEXTRUSION LOAD
2500
2700
2900 Peak Ram Force
Steady State Ram Force
2100
2300
2500
Tons
)
1700
1900
2100
m F
orce
(T
1300
1500
1700
Ram
900
1100
1300
900770 780 790 800 810 820 830 840 850 860
Preheat Temperature (oC)
960
980LETE 960
980LETEa b
EFFECT OF PREHEAT TEMPERATURE ON CROSS SECTIONAL TEMPERATURE DISTRIBUTION
900
920
940
960
ture
(C
)
TE
900
920
940
960
ture
(C
)
TE
820
840
860
880
Tem
pera
t
820
840
860
880
Tem
pera
t
8 °C 80 °C800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)980
LE 980LEd
785°C 805°C
900
920
940
960
re (
C)
LETE
920
940
960
re (
C)
LETEc d
840
860
880
900
Tem
pera
tur
840
860
880
900
Tem
pera
tur
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)
825°C 855°C
2700Peak Ram
EFFECT OF DIE FILLET RADIUS ON RAM FORCE
2300
2500Force
Steady State Ram Force
2100
2300
Tons
)
1700
1900
m F
orce
(T
1300
1500Ram
900
1100
9000 5 10 15 20 25
Fillet Radius (mm)
960
980LETE 960
980LETE
a b
EFFECT OF DIE FILLET RADIUS ON CROSS SECTIONALTEMPERATURE DISTRIBUTION
900
920
940
960
ture
(C
)
TE
900
920
940
960
ture
(C
)
TE
820
840
860
880
Tem
pera
t
820
840
860
880
Tem
pera
t
1 5800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)980
LE980
LEd
1 mm 5 mm
920
940
960
re (
C)
LETE
920
940
960
re (
C)
LETEc d
840
860
880
900
Tem
pera
tur
840
860
880
900
Tem
pera
tur
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)
800
820
0 1 2 3 4 5 6 7
Distance from ID (mm)
10 mm 20 mm
Zr‐2 5Nb Alloy Pressure TubeZr 2.5Nb Alloy Pressure Tube Produced With Modified Route
Fabrication Routes550 di M lti I t
Forging to
350mm dia Melted Ingot 550 mm dia Melting Ingot
Extrusion to
I stage forging to 350mm diaForging to
230mm diaExtrusion to
230mm diaII stage forging to 230mm dia
quenching(1000C/30min)
Extrusion to119mm OD x 6mm WT(8150 C)
Extrusion to133mm OD x 9mm WT(8000 C)
Ist pilgering to 119mm OD x 6mm WT
( )(8150 C)( )(8000 C)
Stress relieving at 480C/3hStress relieving
at 480C/3hp g g
Final pilgering to 112 8mm OD 103 4mm ID
Annealing (550C/6h)
Final pilgering to 112.8mm OD 103.4mm ID
Autoclaving at 4000C/36 hrs
PROCESS FLOW SHEET FOR Zr‐2.5%NbPRESSURE TUBES FOR 700 MWe PHWR REACTORS
M j P i St A d V i bl
Vacuum Melted Ingots (550mm OD)
Major Processing Stages And Variables Affecting Metallurgical Characteristics
•Forging Temperature
1st Radial forging to 350mm Diameter logs
2nd Radial forging to 230mm Diameter Rods
Forging Temperature•Forging strain rate•Forging pass schedule
Machining, Expansion, Beta quenching, Machining
Bl k E i
•Ram Velocity•Extrusion Ratio•Preheating Temperature
ad a o g g to 30 a ete ods
Blank Extrusion
Vacuum Stress relieving
•Die Profile( Fillet Radius)
Pilgering to final size of 112.8 mm OD X 103.4 mm ID
UT ET Di i l Vi l I ti
• Temperature uniformity in vacuum furnace
• Variation in the cold work UT, ET, Dimensional, Visual Inspection
Autoclaving
CHANGES IN SPECIFICATIONS
CHEMISTRYElement 540 MWe 700 MWe
Nb 2.4‐2.8 % 2.5‐2.8 %
O 900‐1300 ppm 1100‐1400 ppmO 900 1300 ppm 1100 1400 ppm
Fe < 650 ppm (impurity) 900‐1300 ppm (alloying element)
C < 125 ppm (impurity) 40‐80 ppm (alloying element)
Other impurity limits remain same for 540 and 700 MWe pressure tubes
METALLURGICAL PROPERTIES
Description 540 MWe 700 MWe
Other impurity limits remain same for 540 and 700 MWe pressure tubes
Microstructure Radial ~0.3 micron Radial ~0.3 micron
Axial ~ 5‐10 micron Radial : Transverse: Axial ~ 1:5:50
Texture Ft: 0.5 to 0.6 Ft: 0.6 to 0.7Texture
Fr: 0.3 to 0.4 Fr: 0.25 to 0.35
Fl </=0.1 Fl </= 0.1
Other parameters like dislocation density hydride orientation parameters areOther parameters like dislocation density, hydride orientation parameters aresimilar for 540 and 700 MWe pressure tubes
Extruded microstructure formicrostructure for high and low E.R extruded blankextruded blank
Fig. 1 Bright field TEM g gmicrographs of pressure tube blanks extruded with different extrusion ratios; (a) leading end and (b) trailing end ( ) g ( ) g
of tube extruded with ER 7.3:1, (c) leading end and (d) trailing end o
(b) f tube extruded with ER ( )12.75:1.
Final autoclaved microstructure for two stage and single stage pilgered tube
Fig. (a) and (b) SEM micrographs of leading and trailing ends of pressure tube single extrusion-, tube blank extrusion with low ER (7.3:1), double pass pilgering with intermediate annealing followed by autoclaving,(c) and (d) double radial forged- extruded (12.75:1), single pass pilgered,
Final autoclaved microstructure formicrostructure for
two stage and single stagesingle stage pilgered tube
Fig. 3 Bright field TEM micrographs; (a) leading and (b) trailing end of pressure tubemanufactured through double pass pilgering with intermediate annealing, (c) leading and (d)trailing end of pressure tube manufactured through single pass pilgering.
FABRICATION ROUTE &STAGE
LOCATION ASPECT RATIO length thickness
Comparison of Morphology of Alpha grains in Various Routes
Double pilgeredEx P2 Leading 1:4:30 8-10 0.1-0.3
Trailing 1;5:45 6-11 0.1-0.3
F 1 P 2 Leading 1:4:35 5-12 0 2-0 4F 1 P 2 Leading 1:4:35 5-12 0.2-0.4Trailing 1:5:40 8-13 0.1-0.3
F2 P2 Leading 1:4:35 7-14 0.2-0.4Trailing 1;5;45 8-13 0.2-0.45
Si l il dSingle pilgeredEx P1 Leading 1:6:60 10-14 0.2-0.5
Trailing 1:5:50 12-19 0.1-0.4F1P1 Leading 1:6:55 12-18 0.2-0.4
Trailing 1:5:45 14-22 0.1-0.4F2P1 Leading 1:5:50 14-21 0.2-0.5
Trailing 1:5:60 12-20 0.2-0.6F1R2 Leading 1:10:50 20-30 0.5-0.6
Trailing 1:10:55 22-30 0.5-0.55
R1R2 Leading 1:10:65 25-30 0.4-0.5
Trailing 1:10:70 25-32 0.35-0.45
Canadian 1:5:60 10-25 0.2-0.4Note: Double pilger route results in small grain length and width and low A.R.
Double forge route with radial forging show thicker grain, highest AR and large lengthForged route shows uniform structure R1R2 shows best uniformity in microstructure
TEXTURE RESULTS OF AUTOCLAVED PRESSURE TUBES PRODUCED FROM DIFFERENT ROUTES (Leading End)
Fabrication Route and stage FR FT FA FT ‐FRDouble pass pilgered
ExP2 (standard NFC route) 0.33 0.59 0.08 0.25PF1P2 0.34 0.62 0.04 0.28PF12P2 0 38 0 67 0 07 0 29PF12P2 0.38 0.67 0.07 0.29
Single pass pilgered
ExP1 0.27 0.68 0.05 0.40PF1P1 0.27 0.68 0.05 0.42PF12P1 0.27 0.72 0.05 0.45PFIR2P1 0.29 0.68 0.04 0.39R1R2P1 0.26 0.68 0.06 0.42
High FT and High FT-FR values with Single pass pilgering.High FT and High FT FR values with Single pass pilgering.Highly reproducible texture in single pass pilgered tubes. Independent of the primary hot working process.
Texture: Variation between the ends
Fabricate Route FR FT FA FT ‐FR
d 0 29 0 61 0 10 0 32EX1P1
Leading 0.29 0.61 0.10 0.32
Trailing 0.28 0.66 0.06 0.38
PF1P1Leading 0.27 0.68 0.05 0.41
PF1P1Trailing 0.26 0.71 0.03 0.45
PF12P1Leading 0.26 0.69 0.05 0.43
lTrailing 0.25 0.69 0.06 0.44
PF1R2P1Leading 0.27 0.68 0.05 0.41
Trailing 0.26 0.70 0.04 0.44
R1R2P1Leading 0.26 0.68 0.06 0.42
Trailing 0.28 0.68 0.04 0.40
Note: Primary deformation with extrusion shows higher variation in texture
TEXTURE (Autoclaved)
TUBE ENDFr Ft Fl
0.25‐0.35 0.6‐0.7 <0.1
Average# 0.29 0.67 0.05
O 0 29 0 68 0 03O 0.29 0.68 0.03
Std. Deviation
# 0.01 0.02 0.01
O 0.02 0.02 0.01
Maximum# 0.32 0.69 0.07
O 0.32 0.71 0.07
# 0 26 0 62 0 03Minimum
# 0.26 0.62 0.03
O 0.26 0.64 0.02
Mechanical Properties RT at 300C
RoutesRT at 300 C
UTS(KSI)
YS(KSI)
% EL UTS(KSI)
YS(KSI)
% EL
SPECIFICATION (540 MWe PHWR) ‐ <85 ‐ 67 (min) 47 (min) 14 min)
Double pilgeredExP2 (standard NFC route) 111.6 79.8 18.1 78.6 56.9 22.0PF1P2 114.4 81.4 18.0 76.4 57.4 18.0PF1P2 114.4 81.4 18.0 76.4 57.4 18.0PF12P2 (550mm new chem) 112.4 76.5 10.6 75.1 57.3 16.9
Single pilgeredExP1 106 7 78 7 18 0 72 9 61 4 18 4ExP1 106.7 78.7 18.0 72.9 61.4 18.4PF1P1 106.8 76.3 20.0 72.7 54.6 21.3PF12P1(550mm new chem) 119.1 86.0 15.5 80.5 62.8 19.1PF1R2 (550 h )PF1R2 (550mm new chem) 110.0 80.0 14.7 78.7 59.2 20.2R1R2 (550mm new chem) 115.0 89.0 16.0 84.3 62.8 20.7
N R1R2 d F1R2 h i b h dNote: R1R2 and F1R2 showing best strength and ductility values at high temp
High temperature mechanical properties (300C) (averaged) of autoclaved pressure tubes made from
g g( g ) p
double radial forged ingot
ROUTE SAMPLEUTS YS % Elongation
67 KSI (MIN) 47 KSI (MIN) 14
PF1R2 P1LE 78.7 59.2 20.23
TE 81.6 62.8 21.30
R1R2P1LE 84.3 62.8 20.70
TE 85.4 62.3 20.86
Note: Mechanical properties of leading and trailing end are nearly the same
MECHANICAL PROPERTIESMECHANICAL PROPERTIES: : Variation along the length of the pressure Variation along the length of the pressure tubestubes
(RT - YS: 85ksi(max))(HT UTS 68k i( i ) YS 47k i( i ) %El 12% ( i ))
Mechanical Room temperature High temperature (314C)
(HT - UTS: 68ksi(min), YS: 47ksi(min), %El: 12% (min))
properties Leading end Trailing end Leading end Trailing end
UTS (ksi) 102‐118 (115) 106‐118 (113) 70‐78 (84) 68‐80 (85)
YS (ksi) 71‐85 (89) 78‐85 (81) 50‐58 (63) 50‐59 (62)
% Elongation 16‐20 (16) 14‐19 (18) 17‐21 (21) 16‐20 (21)
Data in Red is from the previous trial
Observations: • RT Mech props: trailing end is showing slightly higher strength and lower ductility• HT Mech props: Both ends are showing nearly similar strength and ductility • Last trial mech props are also lying in the same range
Summary
• Grain shape: Both alpha and beta are lamaller and beta phase is Microstructure
continuous
• Grain Morphology: Av. length =40m, width 5m thickness ~0 7m (from SEM measurements) 0 3-0 7 m ( from TEM)0.7m (from SEM measurements) 0.3 0.7 m ( from TEM) Aspect ratio=1:5:50
• No appreciable difference in leading and trailing microstructure.• Tube to tube variation in microstructure was not significant.
Texture• Av. Ft =0.69; Ft-Fr = 0.36 nearly same at both ends. Variability inAv. Ft 0.69; Ft Fr 0.36 nearly same at both ends. Variability in
texture values is very low.
Summary Of TEM Observations
• Alpha and beta grains were lamellar.• Beta was continuousBeta was continuous.• Alpha thickness varying from 0.3 to 0.7 microns• No appreciable difference in leading and trailing• No appreciable difference in leading and trailing
microstructure.• Tube to tube variation in microstructure was not• Tube to tube variation in microstructure was not
significant.
Effect of Ram Velocity:
Summary of Simulation Studies
Effect of Ram Velocity: Lower ram velocities resulted in appreciable temperature loss at
tailing end thus giving rise to more leading end to tailing end variation higher ram velocities were found to increase the variation across theg
thickness. Simulations showed that peak force of extrusion is stronger function
of the ram velocity than the steady state force.
Effect of Reduction Ratio Higher reduction ratios resulted in increasing the temperature
di t th thi k d t i d t i di t t digradients across the thickness due to increased strain gradients at dieprofile side.
Effect Of Preheat TemperatureSimulations indicate that using of higher preheat temperature willSimulations indicate that using of higher preheat temperature willhave beneficial effect in terms of overall homogeneity.
Effect of Die fillet RadiusFrictional heating at the die profile was found to be moreFrictional heating at the die profile was found to be more
substantial than the temperature drop due to mandrel chilling effect.
Th k YThank You