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Quenching methods for Ti-325 alloy
Engineering Failure Analysis 14 (2007) 1401–1405 www.elsevier.com/locate/engfailanal
Quenching methods for Ti-325 alloy B. Sarrail a, C. Schrupp a, S. Babakhanyan a, K. Muscare a, J. Foyos a, J. Ogren a, P. Stoyanov a, S. Sparkowich a, R. Sutherlin a, R. Clark Jr. b, O.S. Es-Said a,* a
Department of Mechanical Engineering, Loyola Marymount University, One LMU drive, Los Angeles CA 90045, United States b Virginia Western Community College, Roanoke, VA 24038, United States Received 8 April 2006; accepted 18 November 2006 Available online 22 January 2007
Abstract The purpose of this research is to determine the effects of two different cooling procedures on the room temperature mechanical properties of AMS 4943 Ti-325 alloy. The samples were annealed at 1170 °F (632 °C), 1200 °F (649 °C) and 1230 °F (666 °C), half of the samples were water quenched and the other half were furnace cooled to room temperature. The yield strength, ultimate strength and percent elongation as a function of quenching media were determined. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: AMS 4943 Ti-325 alloy or Ti Grade 9; Quenching methods; Mechanical properties
1. Introduction Ti-325, also known as Ti Grade 9, is a near-alpha alloy that is composed of 3 wt% aluminum, 94.5 wt% titanium and 2.5 wt% vanadium. The typical % elongation is between 15% and 29%, the yield strength is between 75 and 84 ksi and the tensile strength is between 90 and 94 ksi. The typical use of this alloy is in tubing in aircraft and engine hydraulic systems, pipes and vessels. It is also used in foil and honey comb applications, sporting equipment such as golf club shafts, bicycle frames and tennis racquets [1,2]. The 3 wt% aluminum in Ti-325 acts as an alpha stabilizer and the 2.5 wt% vanadium acts as a beta stabilizer. This near-alpha alpha–beta alloy is generally used in the cold-worked stress relieved condition. The metal is typically cold worked and partially recrystallized [2]. The purpose of this research was to determine the effects of two different cooling procedures on the room temperature mechanical properties of the AMS 4943 Ti–3Al–2.5V in the fully annealed condition. Furthermore, it was important to investigate if furnace cooling (FC) after annealing will yield the same results as the conventional water quenching (WQ) after annealing. If it does yield the minimum values of 75 ksi in yield strength, 90 ksi in tensile strength and 15% elongation then it will be more economically feasible to use FC methods. The annealing temperatures were 1170 °F (632 °C), 1200 °F (649 °C) and 1230 °F (666 °C) and the *
Corresponding author. Tel.: +1 310 338 2829; fax: +1 310 338 2391. E-mail address: [email protected] (O.S. Es-Said).
1350-6307/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.engfailanal.2006.11.050
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B. Sarrail et al. / Engineering Failure Analysis 14 (2007) 1401–1405
annealing times were 60, 120 and 150 min. The typical heat treatment conditions for annealing this alloy is 1200–1400 °F from 0.5 to 2 h followed by air cooling (AC) [2]. Typical stress relief is at 700–1200 °F for 0.5 to 2 or 3 h followed by AC methods. These temperatures and times were chosen because the base annealing temperature that companies use is 649 °C (1200 °F) for one hour followed by WQ methods. Therefore, this will give a range to investigate the changes in mechanical properties with 30 ° variants in temperature. 2. Experimental procedure In order to determine the mechanical properties of Titanium 325 alloy, traditional tensile samples had to be machined from the tubes. The AMS 4943 alloy was received in the seamless tubing form. The challenge was that the tensile bars should be machined from the pipes to simulate the mechanical tensile properties that the tube will attain after a specific cooling rate. The initial step was to cut the pipes down into five inch long half cylinders with the use of the mill and lathe. Slower speed and heavier cuts were preferred because they maintained lower tool temperatures. Fig. 1 shows the material that needed to be removed in order to make the half cylinders. They were then cut into tensile bars with the EDM Sodick Linear Servo Controller LNIW machine. A layout of different steps and their results is shown in Fig. 2. Once the tensile bars were heat treated (some water quenched and others furnace cooled at different temperatures) they were sanded down to remove the oxidation layer. Finally, tensile testing was conducted with an Instron 4505 machine to determine the tensile mechanical properties. Two tensile bars were evaluated for each data point (see Fig. 3).
Fig. 1. Material that needs to be removed to make the half cylinder.
Fig. 2. Layout of the different steps and results.
B. Sarrail et al. / Engineering Failure Analysis 14 (2007) 1401–1405
Fig. 3. Samples after furnace annealing and cleaning.
Yield Strength vs. Annealing Time (Water Quenched)
Yield Strength (ksi)
a 120 110 100 90 80 70 60 50 40
Temperature (˚F)
1170 1200 1230
60
120
150
Annealing Time (min)
b Ultimate Strength (ksi)
UltimateStrength vs. Annealing Time (Water Quenched) 120 110 100 90 80 70 60 50 40 60 120 150 Annealing Time (min)
%Elongation
c
%Elongation vs. Annealing Time (Water Quenched)
Temperature (˚F)
1170 1200 1230
Temperature
20
(˚F)
15
1170
10
1200
5
1230
0 60
120
150
Annealing Time (min)
Fig. 4. Data analysis of water quenched samples for (a) yield strength, (b) ultimate strength, and (c) % elongation.
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B. Sarrail et al. / Engineering Failure Analysis 14 (2007) 1401–1405
3. Results and discussion 3.1. Water quenched samples Fig. 4a indicates that the yield strength values decrease as the annealing temperature increases within 60, 120 and 150 min of annealing time. A similar relationship can be found within the ultimate strength values as the annealing temperature increases, Fig. 4b. There is no evident correlation between the % elongation values due to the increase in the annealing temperature, Fig. 4c. With the increase in the annealing time on the other hand, the yield strength and ultimate strength values show a slight overall decrease when keeping the temperature constant, Fig. 4a and b. Within the % elongation values there is no evident correlation with the increase in time and there is significant scatter in the data, Fig. 4a. 3.2. Furnace cooled samples Fig. 5a–c show that there is no evident relationship within the yield strength, the ultimate strength and the % elongation values due to the increase in the annealing temperature for the furnace cooled samples.
Yield Strength (ksi)
a
Yield Strength vs. Annealing Time (Furnace Cooled) Temperature (˚F)
120 110 100 90 80 70 60 50 40
1170 1200 1230
60
120
150
Annealing Time (min)
b Ultimate Strength (ksi)
Ultimate Strength vs. Annealing Time (Furnace Cooled) Temperature (˚F)
120 110 100 90 80 70 60 50 40
1170 1200 1230 60
120
150
Annealing Time (min)
c
%Elongation vs. Annealing Time (Furnace Cooled) Temperature (˚F)
%Elongation
20 15
1170
10
1200
5
1230
0 60
120
150
Annealing Time (min)
Fig. 5. Data analysis of furnace cooled samples for (a) yield strength, (b) ultimate strength, and (c) % elongation.
B. Sarrail et al. / Engineering Failure Analysis 14 (2007) 1401–1405
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Table 1 Method satisfaction for minimum values of 75 ksi yield strength, 90 ksi ultimate strength and 15% elongation Annealing temperature (°F)
Annealing time (min)
Water quenched samples Are all properties above minimum requirements?
Properties below minimum requirements
Furnace cooled samples Are all properties above minimum requirements?
Properties below minimum requirements
1170 1170 1170 1200 1200
60 120 150 60 120
Yes Yes No Yes Yes
– – % elongation – –
No Yes Yes Yes No
1200 1230 1230 1230
150 60 120 150
Yes Yes No No
– – Y.S. Y.S.
Yes No Yes Yes
Y.S., % elongation – – – U.T.S., Y.S. % elongation – % elongation – –
Furthermore, when increasing the annealing time there is also no correlation within the yield strength values and within the ultimate strength values, Fig. 5a and b. The % elongation values, however, show a slight overall increase with the increase in the annealing time when keeping the annealing temperature constant, Fig. 5c. 3.3. Discussion From Table 1, it appears that water quenched samples yield adequate results not only in the standard method (1200 °F/60 min) but also at annealing temperatures of 1170 °F for 60 or 120 min, 1200 °F for 60, 120 or 150 min and 1230 °F for 60 min. The % elongation values for the water quenched samples annealed at 1170 °F for 150 min are below the minimum value. Additionally, the yield strength values for the samples annealed at 1230 °F for 120 and 150 min are also below the minimum value. The tensile values of the furnace cooled samples show above the minimum required property values for the samples annealed at 1170 °F for 120 and 150 min, 1200 °F for 60 and 150 min and 1230 °F for 120 and 150 min. Overall, the strength values were slightly higher in the water quenched samples with less scatter in the data. 4. Conclusions The water quenched samples met or exceeded the minimum requirements at 1200 °F for all durations, at 1170 °F (60 and 120 min) and at 1230 °F for 60 min. The furnace cooled samples met or exceeded the minimum requirements at 1700 °F (120 and 150 min), at 1200 °F (60 and 150 min) and at 1230 °F (120 and 150 min). The water quenched samples appear to have less variation in the strength and the % elongation values as compared to the furnace cooled samples. Acknowledgement This work was funded by the National Science Foundation, Research Experience for Undergraduates Program; Grant number EEC-0353668, Ms. Esther Bolding is the program manager. References [1] Forney Clyde E, Steven E. Meredith, Ti–3Al–2.5V Seamless Tubing Engineering Guide. Washington: Sandvik Special Metals Corporation; 1990. Pgs 5,16. [2] Matthew J. Donachie, Titanium: a technical guide, ASM International. 2000;1, 159, 160.
Quenching methods for Ti-325 alloy B. Sarrail a, C. Schrupp a, S. Babakhanyan a, K. Muscare a, J. Foyos a, J. Ogren a, P. Stoyanov a, S. Sparkowich a, R. Sutherlin a, R. Clark Jr. b, O.S. Es-Said a,* a
Department of Mechanical Engineering, Loyola Marymount University, One LMU drive, Los Angeles CA 90045, United States b Virginia Western Community College, Roanoke, VA 24038, United States Received 8 April 2006; accepted 18 November 2006 Available online 22 January 2007
Abstract The purpose of this research is to determine the effects of two different cooling procedures on the room temperature mechanical properties of AMS 4943 Ti-325 alloy. The samples were annealed at 1170 °F (632 °C), 1200 °F (649 °C) and 1230 °F (666 °C), half of the samples were water quenched and the other half were furnace cooled to room temperature. The yield strength, ultimate strength and percent elongation as a function of quenching media were determined. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: AMS 4943 Ti-325 alloy or Ti Grade 9; Quenching methods; Mechanical properties
1. Introduction Ti-325, also known as Ti Grade 9, is a near-alpha alloy that is composed of 3 wt% aluminum, 94.5 wt% titanium and 2.5 wt% vanadium. The typical % elongation is between 15% and 29%, the yield strength is between 75 and 84 ksi and the tensile strength is between 90 and 94 ksi. The typical use of this alloy is in tubing in aircraft and engine hydraulic systems, pipes and vessels. It is also used in foil and honey comb applications, sporting equipment such as golf club shafts, bicycle frames and tennis racquets [1,2]. The 3 wt% aluminum in Ti-325 acts as an alpha stabilizer and the 2.5 wt% vanadium acts as a beta stabilizer. This near-alpha alpha–beta alloy is generally used in the cold-worked stress relieved condition. The metal is typically cold worked and partially recrystallized [2]. The purpose of this research was to determine the effects of two different cooling procedures on the room temperature mechanical properties of the AMS 4943 Ti–3Al–2.5V in the fully annealed condition. Furthermore, it was important to investigate if furnace cooling (FC) after annealing will yield the same results as the conventional water quenching (WQ) after annealing. If it does yield the minimum values of 75 ksi in yield strength, 90 ksi in tensile strength and 15% elongation then it will be more economically feasible to use FC methods. The annealing temperatures were 1170 °F (632 °C), 1200 °F (649 °C) and 1230 °F (666 °C) and the *
Corresponding author. Tel.: +1 310 338 2829; fax: +1 310 338 2391. E-mail address: [email protected] (O.S. Es-Said).
1350-6307/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.engfailanal.2006.11.050
1402
B. Sarrail et al. / Engineering Failure Analysis 14 (2007) 1401–1405
annealing times were 60, 120 and 150 min. The typical heat treatment conditions for annealing this alloy is 1200–1400 °F from 0.5 to 2 h followed by air cooling (AC) [2]. Typical stress relief is at 700–1200 °F for 0.5 to 2 or 3 h followed by AC methods. These temperatures and times were chosen because the base annealing temperature that companies use is 649 °C (1200 °F) for one hour followed by WQ methods. Therefore, this will give a range to investigate the changes in mechanical properties with 30 ° variants in temperature. 2. Experimental procedure In order to determine the mechanical properties of Titanium 325 alloy, traditional tensile samples had to be machined from the tubes. The AMS 4943 alloy was received in the seamless tubing form. The challenge was that the tensile bars should be machined from the pipes to simulate the mechanical tensile properties that the tube will attain after a specific cooling rate. The initial step was to cut the pipes down into five inch long half cylinders with the use of the mill and lathe. Slower speed and heavier cuts were preferred because they maintained lower tool temperatures. Fig. 1 shows the material that needed to be removed in order to make the half cylinders. They were then cut into tensile bars with the EDM Sodick Linear Servo Controller LNIW machine. A layout of different steps and their results is shown in Fig. 2. Once the tensile bars were heat treated (some water quenched and others furnace cooled at different temperatures) they were sanded down to remove the oxidation layer. Finally, tensile testing was conducted with an Instron 4505 machine to determine the tensile mechanical properties. Two tensile bars were evaluated for each data point (see Fig. 3).
Fig. 1. Material that needs to be removed to make the half cylinder.
Fig. 2. Layout of the different steps and results.
B. Sarrail et al. / Engineering Failure Analysis 14 (2007) 1401–1405
Fig. 3. Samples after furnace annealing and cleaning.
Yield Strength vs. Annealing Time (Water Quenched)
Yield Strength (ksi)
a 120 110 100 90 80 70 60 50 40
Temperature (˚F)
1170 1200 1230
60
120
150
Annealing Time (min)
b Ultimate Strength (ksi)
UltimateStrength vs. Annealing Time (Water Quenched) 120 110 100 90 80 70 60 50 40 60 120 150 Annealing Time (min)
%Elongation
c
%Elongation vs. Annealing Time (Water Quenched)
Temperature (˚F)
1170 1200 1230
Temperature
20
(˚F)
15
1170
10
1200
5
1230
0 60
120
150
Annealing Time (min)
Fig. 4. Data analysis of water quenched samples for (a) yield strength, (b) ultimate strength, and (c) % elongation.
1403
1404
B. Sarrail et al. / Engineering Failure Analysis 14 (2007) 1401–1405
3. Results and discussion 3.1. Water quenched samples Fig. 4a indicates that the yield strength values decrease as the annealing temperature increases within 60, 120 and 150 min of annealing time. A similar relationship can be found within the ultimate strength values as the annealing temperature increases, Fig. 4b. There is no evident correlation between the % elongation values due to the increase in the annealing temperature, Fig. 4c. With the increase in the annealing time on the other hand, the yield strength and ultimate strength values show a slight overall decrease when keeping the temperature constant, Fig. 4a and b. Within the % elongation values there is no evident correlation with the increase in time and there is significant scatter in the data, Fig. 4a. 3.2. Furnace cooled samples Fig. 5a–c show that there is no evident relationship within the yield strength, the ultimate strength and the % elongation values due to the increase in the annealing temperature for the furnace cooled samples.
Yield Strength (ksi)
a
Yield Strength vs. Annealing Time (Furnace Cooled) Temperature (˚F)
120 110 100 90 80 70 60 50 40
1170 1200 1230
60
120
150
Annealing Time (min)
b Ultimate Strength (ksi)
Ultimate Strength vs. Annealing Time (Furnace Cooled) Temperature (˚F)
120 110 100 90 80 70 60 50 40
1170 1200 1230 60
120
150
Annealing Time (min)
c
%Elongation vs. Annealing Time (Furnace Cooled) Temperature (˚F)
%Elongation
20 15
1170
10
1200
5
1230
0 60
120
150
Annealing Time (min)
Fig. 5. Data analysis of furnace cooled samples for (a) yield strength, (b) ultimate strength, and (c) % elongation.
B. Sarrail et al. / Engineering Failure Analysis 14 (2007) 1401–1405
1405
Table 1 Method satisfaction for minimum values of 75 ksi yield strength, 90 ksi ultimate strength and 15% elongation Annealing temperature (°F)
Annealing time (min)
Water quenched samples Are all properties above minimum requirements?
Properties below minimum requirements
Furnace cooled samples Are all properties above minimum requirements?
Properties below minimum requirements
1170 1170 1170 1200 1200
60 120 150 60 120
Yes Yes No Yes Yes
– – % elongation – –
No Yes Yes Yes No
1200 1230 1230 1230
150 60 120 150
Yes Yes No No
– – Y.S. Y.S.
Yes No Yes Yes
Y.S., % elongation – – – U.T.S., Y.S. % elongation – % elongation – –
Furthermore, when increasing the annealing time there is also no correlation within the yield strength values and within the ultimate strength values, Fig. 5a and b. The % elongation values, however, show a slight overall increase with the increase in the annealing time when keeping the annealing temperature constant, Fig. 5c. 3.3. Discussion From Table 1, it appears that water quenched samples yield adequate results not only in the standard method (1200 °F/60 min) but also at annealing temperatures of 1170 °F for 60 or 120 min, 1200 °F for 60, 120 or 150 min and 1230 °F for 60 min. The % elongation values for the water quenched samples annealed at 1170 °F for 150 min are below the minimum value. Additionally, the yield strength values for the samples annealed at 1230 °F for 120 and 150 min are also below the minimum value. The tensile values of the furnace cooled samples show above the minimum required property values for the samples annealed at 1170 °F for 120 and 150 min, 1200 °F for 60 and 150 min and 1230 °F for 120 and 150 min. Overall, the strength values were slightly higher in the water quenched samples with less scatter in the data. 4. Conclusions The water quenched samples met or exceeded the minimum requirements at 1200 °F for all durations, at 1170 °F (60 and 120 min) and at 1230 °F for 60 min. The furnace cooled samples met or exceeded the minimum requirements at 1700 °F (120 and 150 min), at 1200 °F (60 and 150 min) and at 1230 °F (120 and 150 min). The water quenched samples appear to have less variation in the strength and the % elongation values as compared to the furnace cooled samples. Acknowledgement This work was funded by the National Science Foundation, Research Experience for Undergraduates Program; Grant number EEC-0353668, Ms. Esther Bolding is the program manager. References [1] Forney Clyde E, Steven E. Meredith, Ti–3Al–2.5V Seamless Tubing Engineering Guide. Washington: Sandvik Special Metals Corporation; 1990. Pgs 5,16. [2] Matthew J. Donachie, Titanium: a technical guide, ASM International. 2000;1, 159, 160.