RTI Proprietary Information
Reducing Titanium Cost
by Continuous Casting
K.O. Yu, M.P. Jacques and S.R. Giangiordano
RTI International Metals, Inc.
Titanium 2011
International Titanium Association Annual Meeting
October 2-5, 2011, San Diego, CA
Titanium 2011 October 2-5, 2011
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Introduction
• Existing Titanium Production Technology
* Batch type ingot making processes – VAR, PAM and EBM
* Large ingots need multiple hot working operations
* High energy consumption, yield loss, processing time
and production cost
• RTI Titanium Continuous Casting
* Based on mature PAM technology
* 5 patents, 2011 R&D 100 Award, 2010 NorTech Innovation Award
* Continuous process to make small diameter ingots
* Input stock for making castings, extrusions, bars and fasteners
* Lower energy consumption, yield loss, processing time and
production cost
• Status report for products made from round ingots
Titanium 2011 October 2-5, 2011
3
PAM (Plasma Arc Melting)
Process and Product
Copper
Crucible
Feeder
Pool Surface
Depression
Hearth
Solid
Skull
Continuously
Cast Ingot
Plasma Plume
Liquid
Pool Plasma Torch
13” x 34” x 80” Ti-64 Slab
15” Ø x 200” Lg Ti-64 Ingot
RTI Proprietary Information Titanium 2011 October 2-5, 2011
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Schematic of PAM
Continuous Casting Process
Torch Temper-
ature
Sensor
Hearth
Glass
Container
Roller
Roller
Ingot
Ingot
Cutting
Torch
Casting
Mold
Heating
Coils
Ingot
Titanium ConCast
Process 20K lbs. 8-inch Ingots
Cast in One Campaign
RTI PAM H2
3-Torch
Furnace
Titanium 2011 October 2-5, 2011
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8-inch Diameter Ingot
Exiting Furnace during
Campaign
Glass Coated 8.25”
Diameter Ingot
Guide Rollers
Furnace Chamber
5 Titanium 2011 October 2-5, 2011
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Advantages of PAM ConCast
1. ConCast is a productivity enhancement from existing,
mature PAM technology
2. Flexible use of input materials
3. Ingots sized to reduce/eliminate hot working steps
4. Reduce processing time and improve productivity
5. Reduce delivery time and cost from conventional 2X
VAR processing route
Titanium 2011 October 2-5, 2011
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Products made from
ConCast Ingots
Sponge PAM
Single
Melt
Scrap
Chips
Machining
Conditioning
Round
Billets
Slabs
Extruded Shapes/Tubes
Rolled Bars/Fasteners
Rolled Plates/Sheets
Investment Castings Casting
Electrodes
Rolled Rings
Titanium 2011 October 2-5, 2011
7
RTI Proprietary Information
ConCast Ti-64 Alloy
Chemistry
8
Heat # &
Individual
ingot #
Trans. H2
ppm O2 % N % C % AI % V % Mo % Cr % Cu % Fe % Si % Sn % Mn %
Y
ppm
B
ppm Ni Zr
X10-5424-01
Edge
25
0.163 0.005 0.014 6.15 4.07 0.002 0.012 0.008 0.189 0.011 0.014 0.006 3 5 0.006 0.000
Mid-radius 0.168 0.006 0.013 6.04 4.03 0.001 0.011 0.014 0.187 0.011 0.01 0.005 2 4 0.006 0.000
Center 0.162 0.005 0.012 5.99 3.97 0.001 0.011 0.008 0.184 0.009 0.008 0.004 1 3 0.005 0.000
X10-5424-02
Edge
25
0.171 0.005 0.016 6.19 4.20 0.002 0.012 0.006 0.180 0.010 0.016 0.006 2 6 0.006 0.000
Mid-radius 0.176 0.006 0.016 6.16 4.03 0.001 0.012 0.006 0.186 0.010 0.012 0.005 2 5 0.006 0.000
Center 0.171 0.006 0.013 6.13 3.99 0.002 0.012 0.006 0.179 0.010 0.010 0.006 2 5 0.006 0.000
X10-5424-02
Edge
24
0.176 0.006 0.016 6.06 4.06 0.002 0.012 0.008 0.189 0.010 0.014 0.006 3 6 0.006 0.000
Mid-radius 0.177 0.005 0.014 6.01 3.99 0.001 0.012 0.006 0.185 0.010 0.012 0.006 2 5 0.006 0.000
Center 0.176 0.006 0.013 6.07 4.01 0.001 0.012 0.007 0.180 0.010 0.012 0.005 2 5 0.006 0.000
X10-5424-03
Edge
19
0.175 0.005 0.014 6.14 4.23 0.001 0.010 0.004 0.177 0.010 0.015 0.004 1 3 0.004 0.000
Mid-radius 0.170 0.005 0.015 6.22 4.27 0.001 0.011 0.004 0.185 0.010 0.017 0.005 1 3 0.005 0.000
Center 0.167 0.005 0.024 6.22 4.30 0.002 0.013 0.006 0.185 0.010 0.002 0.007 3 6 0.007 0.000
X10-5424-03
Edge
22
0.181 0.005 0.013 6.16 3.88 0.001 0.100 0.004 0.160 0.009 0.007 0.004 1 3 0.004 0.000
Mid-radius 0.177 0.006 0.02 6.18 3.96 0.001 0.100 0.004 0.160 0.009 0.009 0.004 1 3 0.004 0.000
Center 0.178 0.006 0.012 6.24 3.96 0.001 0.011 0.005 0.171 0.010 0.011 0.005 1 4 0.005 0.000
AMS 6945A ≤150 ≤0.20 ≤0.05 ≤0.08 5.5-6.75 3.5-4.50 ≤0.30 ≤50
Titanium 2011 October 2-5, 2011
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2 x VAR ConCast Ingot
Sponge, Bulk Scrap Sponge, Small Scrap, Turnings
Make Compacts Make Compacts
Weld Electrode
1st VAR
2nd VAR PAM
1st Billet
2nd + Billet
3rd Billet
GFM Forging
Machining Machining
Final Billet Final Billet
Current production Continuous casting provides
process advantages to PAM
Long lead time Short lead time
Comparison of Processing Steps for Extrusion Billet Production Processes
9 Titanium 2011 October 2-5, 2011
Extrusions from Concast Billets
Extrusions made from
ConCast Billets
10
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Back End Macrostructure of X10-5422-07 T7
Extrusion Ratio: 33.8, 2190F
11
ST-Macro/micros
T- Macro/micros L-Macro/micros
1 Inch
L2BL (L-direction)
L2BST (ST-direction)
1 Inch
L2BT (T-direction)
Titanium 2011 October 2-5, 2011
Product Heat
Treatment Test
Direction UTS (ksi)
0.2% YS (ksi)
% Elongation
% RA C(T) Fracture
Toughness (ksi √inch)
First Trial Ratio 18.81
Temperature 2130⁰F
Production heat treated
L 141.7 128.5 11 25.5 78.8
L 142.1 128.1 11 26
2nd Trial Ratio 33.8
Temperature 2140⁰F Back End
As extruded + Lab heat treatment
L 142 128.5 13.5 30.5 79
Ratio 33.8 Temperature 2190⁰F
Back End
Production heat treated
L 139 123 13 25.5 75.5
Extrusion from Wrought Billet
L 143 127 14 26
Minimum Value as per AMS 4935H spec
L 130 120 10 20
Mechanical Properties of L Shaped Ti-6Al-4V
Extrusions made from ConCast Ingots
12 Titanium 2011 October 2-5, 2011 RTI Proprietary Information
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Bars Rolled from
ConCast Billets
2”
1.5”
1”
0.5”
Titanium 2011 October 2-5, 2011
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Photomicrographs of Ti-6Al-4V
Bars Rolled from ConCast Ingot,
Transverse Direction
0.5” Ø, 98% Reduction, = 8.32 1” Ø, 94% Reduction, = 5.55
1.5” Ø, 86% Reduction, = 3.92 2” Ø, 75% Reduction, = 2.78
14 Titanium 2011 October 2-5, 2011
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Photomicrographs of Ti-6Al-4V
Bars Rolled from ConCast Ingot,
Longitudinal Direction
0.5” Ø, 98% Reduction, = 8.32 1” Ø, 94% Reduction, = 5.55
1.5” Ø, 86% Reduction, = 3.92 2” Ø, 75% Reduction, = 2.78
15 Titanium 2011 October 2-5, 2011
Product % +
Reduction UTS (ksi)
0.2% YS (ksi)
% Elongation
% RA
0.5" Ø 98 152.0 142.0 14.7 43
1" Ø 94 143.0 134.0 15.5 42.5
1.5" Ø 86 145.2 135.3 14 36
2” Ø 75 144.0 134.0 14.5 36.5
MMPDS Data (AMS 4928)* 135-140 125-131 10 25
Longitudinal Mechanical Properties of the Ti-6Al-4V Bars Rolled from ConCast Ingots
*Range includes bar sizes from 0.5”-2” Ø
Heat treatment: 1350F anneal for 2 hours and rotary straightened
16 RTI Proprietary Information Titanium 2011 October 2-5, 2011
50
60
70
80
90
100
110
120
130
140
150
100 1,000 10,000 100,000 1,000,000 10,000,000 100,000,000
Maxim
um
Str
ess
, ksi
Fatigue Life, Cycles
Fatigue Life of Smooth ConCast Bar Specimens
(Mean Stress = 0 ksi, 0.5" and 2" Bars)
ConCast 0.5" diameter Bar ConCast 2" diameter bar MMPDS Data
The fatigue life of the smooth ConCast bars at this mean stress level
is comparable to or better than MMPDS data 17
RTI Proprietary Information Titanium 2011 October 2-5, 2011
0
10
20
30
40
50
60
70
80
10000 100000 1000000 10000000 100000000
Maxim
um
Str
ess
, ksi
Fatigue Life, Cycles
ConCast 0.5" diameter Bar ConCast 2" diameter Bar MMPDS Data
Fatigue Life of Notched (Kt=2.43) ConCast Bar Specimens
(Mean Stress=0 ksi, 0.5” and 2” Bars)
The fatigue life of notched ConCast bars at this mean stress level is comparable to MMPDS data
18 RTI Proprietary Information Titanium 2011 October 2-5, 2011
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Summary
Titanium 2011 October 2-5, 2011
• Continuous casting is an effective way to reduce
the cost of certain types of titanium products
• Mechanical properties of castings, extrusions and
bars made from ConCast ingots meet specification
requirements
• Efforts for commercialization of ConCast products
are in progress