Product name : ASTM B381 Titanium 45 Degree Socket Weld Elbow
Specifications : ASTM B381 / ASME SB381
Standard : ASME 16.11, MSS SP-79, 83, 95, 97, BS 3799
Size : 1/8″ NB to 4″ NB
Class : 2000 LBS, 3000 LBS, 6000 LBS, 9000 LBS
Type : Socketweld Fittings, Screwed-Threaded Fittings
Wall thickness: SCH5S-SCHXXS
Material: Titanium and titanium alloys

Dimensions 90 Degree/45 Degree Socket Weld Elbows ASME B16.11

Nominal Size		Socket Bore Dia	Bore Dia of Fittings			Socket Wall Thickness						Body Wall			Depth of Socket	Center to Bottom of Socket
DN	NPS	B	D			C						G			J	A
			3000	6000	9000	3000		6000		9000		3000	6000	9000		90°Elbow Tee Cross			45°Elbow
						ave	min	ave	min	ave	min					3000	6000	9000	3000	6000	9000
6	1/8	10.9	6.1	3.2	–	3.18	3.18	3.96	3.43	–	–	2.41	3.15	–	9.5	11	11	–	8	8	–
8	1/4	14.3	8.5	5.6	–	3.78	3.3	4.6	4.01	–	–	3.02	3.68	–	9.5	11	13.5	–	8	8	–
10	3/8	17.7	11.8	8.4	–	4.01	3.5	5.03	4.37	–	–	3.2	4.01	–	9.5	13.5	15.5	–	8	11	–
15	1/2	21.9	15	11	5.6	4.67	4.09	5.97	5.18	9.53	8.18	3.73	4.78	7.47	9.5	15.5	19	25.5	11	12.5	15.5
20	3/4	27.3	20.2	14.8	10.3	4.9	4.27	6.96	6.04	9.78	8.56	3.91	5.56	7.82	12.5	19	22.5	28.5	13	14	19
25	1	34	25.9	19.9	14.4	5.69	4.98	7.92	6.93	11.38	9.96	4.55	6.35	9.09	12.5	22.5	27	32	14	17.5	20.5
32	1 1/4	42.8	34.3	28.7	22	6.07	5.28	7.92	6.93	12.14	10.62	4.85	6.35	9.7	12.5	27	32	35	17.5	20.5	22.5
40	1 1/2	48.9	40.1	33.2	27.2	6.35	5.54	8.92	7.8	12.7	11.12	5.08	7.14	10.15	12.5	32	38	38	20.5	25.5	25.5
50	2	61.2	51.7	42.1	37.4	6.93	6.04	10.92	9.5	13.84	12.12	5.54	8.74	11.07	16	38	41	54	25.5	28.5	28.5
65	2 1/2	73.9	61.2	–	–	8.76	7.62	–	–	–	–	7.01	–	–	16	41	–	–	28.5	–	–
80	3	89.9	76.4	–	–	9.52	8.3	–	–	–	–	7.62	–	–	16	57	–	–	32	–	–
100	4	115.5	100.7	–	–	10.69	9.35	–	–	–	–	8.56	–	–	19	66.5	–	–	41	–	–

Tolerance for ASME Socket Weld Fittings

Dimensions and tolerances shown are as specified in ASME/ANSI B16.11-1991. These agree substantially with BS3799:1974.

This ASME standard covers socket-welding and threaded forged fittings. However, These pipe fittings are characterized as Class 2000, 3000, and 6000 for threaded end fittings and Class 3000, 6000, and 9000 for socket-weld end fittings respectively.

Nominal Diameter		All Fittings		90° 45° Elbow Tee Cross Lateral	Coupling	Half Coupling Reducing insert	Union (Socket and Thread)
		Socket Bore	Water Way Bore	Center To Bottom of Socket	Laying Lengths	Laying Lengths	Length Assem Nominal
DN	NPS	d1	d2	A H	E	F	L
6-8	1/8-1/4	–	–	±0.8	±1.5	±0.8	±1.5
10-20	3/8-3/4	+0.3/0	±0.4	±1.5	±3	±1.5	±1.5
25-50	1-2	–	–	±2	±4	±2	±1.5
65-100	2 1/2-4	+0.4/0	±0.8	±2.5	±5	±2.5	±1.5

Chemical Composition of Titanium and Titanium Alloys

CP Titanium – Commercially Pure Titanium

Titanium CP4 – Grade 1

Commercially Pure Titanium Grade 1 is the softest titanium and has the highest ductility. It has good cold forming characteristics and provides excellent corrosion resistance. It also has excellent welding properties and high impact toughness.

Chemical Composition of CP4 Titanium Grade 1

C	.08 max
Fe	.20 max
H	.015 max
N	.03 max
O	.18 max
Ti	bal

Standards of CP4 Titanium Grade 1

Extrusion	ASME SB-363
Forgings	ASME SB-381
Pipe	ASME SB-337, ASME SB-338
Round Bar/Wire	ASME SB-348, ASTM F-67
Sheet/Plate	ASME SB-265
Tubes	ASME SB-337, ASME SB-338

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Titanium CP3 – Grade 2

Commercially Pure Titanium Grade 2 has moderate strength and excellent cold forming properties. It provides excellent welding properties and has excellent resistance to oxidation and corrosion.

Chemical Composition of CP3 Titanium Grade 2

C	.08 max
N	.03 max
O	.25 max
H	.015 max
Ti	bal
Fe	.30 max

Standards of CP3 Titanium Grade 2

Extrusion	ASME SB-363
Forgings	ASME SB-381
Pipe	ASME SB-337, ASME SB-338
Round Bar/Wire	ASME SB-348, ASTM F-67, AMS 4921
Sheet/Plate	ASME SB-265, AMS 4902
Tubes	ASME SB-337, ASME SB-338, AMS 4942

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Titanium CP2 – Grade 3

Chemical Composition of CP2 Titanium Grade 3

C	.08 max
N	.05 max
O	.35 max
H	.015 max
Ti	bal
Fe	.30 max

Standards of CP2 Titanium Grade 3

Extrusion	ASME SB-363
Forgings	ASME SB-381
Pipe	ASME SB-337, ASME SB-338
Round Bar/Wire	ASME SB-348, ASTM F-67, AMS 4921
Sheet/Plate	ASME SB-265, AMS 4902
Tubes	ASME SB-337, ASME SB-338, AMS 4942

Commercially Pure Titanium Grade 3 is stronger and less formable than Titanium Grades 1 and 2. It is used in Aerospace and industrial applications that require moderate strength. Grade 3 titanium has excellent corrosion resistance.

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Titanium CP1 – Grade 4

Chemical Composition of CP1 Titanium Grade 4

C	.08 max
Fe	.50 max
H	.015 max
N	.05 max
O	.40 max
Ti	bal

Standards of CP1 Titanium Grade 4

Extrusion	ASME SB-363
Forgings	ASME SB-381
Pipe	ASME SB-337
Round Bar/Wire	ASME SB-348, ASTM F-67, AMS 4921
Sheet/Plate	ASME SB-265, AMS 4902
Tubes	ASME SB-338

Commercially Pure Titanium Grade 4 is stronger than CP Grades 2 & 3 – it can be cold formed, but has lower ductility. It has excellent corrosion resistance in a wide variety of environments. Grade 4 titanium is commonly used in Aerospace, Industrial and Medical applications where high strength is needed.

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Titanium Grade 7

Titanium Grade 7 has physical and mechanical properties equivalent to CP3 titanium or Grade 2. It has excellent welding and fabrication properties and is extremely resistant to corrosion especially from reducing acids.

Chemical Composition of Titanium Grade 7

C	.08 max
N	.03 max
O	.25 max
H	.015 max
Pd	.12-.25
Ti	bal
Fe	.30 max

Standards of Titanium Grade 7

Extrusion	ASME SB-363
Forgings	ASME SB-381
Pipe	ASME SB-337
	ASME SB-338
Round Bar/Wire	ASME SB-348
Sheet/Plate	ASME SB-265
Tubes	ASME SB-337，ASME SB-338

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Titanium Grade 11 – CP Ti-0.15Pd

Chemical Composition of Titanium Grade 11

C	.08 max
N	.03 max
O	.18 max
H	.015 max
Pd	.20 max
Ti	bal
Fe	.20 max

Standards of Titanium Grade 11

Tube	ASME SB-338

Titanium Grade 11 is highly resistant to corrosion has similar physical and mechanical properties to Titanium CP Grade 2.

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Titanium Based Alloys

Titanium Grade 5 – Titanium 6Al-4V

Chemical Composition of Titanium Grade 5/Titanium 6Al-4V

C	.08 max
N	.05 max
O	.20 max
H	.0125 max
V	3.50 – 4.50
Al	5.50 – 6.75
Fe	.25 max
Ti	Remaining

Standards of Titanium Grade 5/Titanium 6Al-4V

Extrusion	AMS 4936
	MIL-T-81556
Forgings	AMS 4920/4928
	AMS4967
	BMS 7-247 (P.Q.)
	BMS 7-269 (B.A.)
	BMS 7-348
	MIL-F-83142A Comp. 6
	MIL-T-9046
	MIL-T-9047
Round Bar/Wire	AMS 4928
	AMS 4965
	AMS 4967
	ASME SB-348
	DMS 1570
	MIL-T-9047
Sheet/Plate	ASME SB-265
	AMS 4905
	AMS 4911
	BMS 7-347 (P.Q.)
	DMS 1592
	MIL-T-9046

Titanium Grade 5 alloy is the most commercially available of all titanium alloys. It offers an excellent combination of high strength and toughness. Grade 5 titanium has good welding and fabrication characteristics.

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Titanium Grade 6 – Titanium 5Al-2.5Sn

Chemical Composition of Titanium Grade 6/Titanium 5Al-2.5Sn

C	.08 max
N	.05 max
O	.20 max
H	.0175 – .020 max
Sn	2.0 – 3.0
Al	4.0 – 6.0
Fe	0.50 max
Ti	Remaining

Standards of Titanium Grade 6/Titanium 5Al-2.5Sn

Extrusion	MIL-T-81556
Forgings	AMS 4924
	AMS 4966
	ASME SB-381
	MIL-F-83142A
	MIL-T-9046
	MIL-T-9047
Round Bar/Wire	AMS 4926
	AMS 4924
	AMS 4956
	AMS 4976
	ASME SB-348
	MIL-T-9047
Sheet/Plate	AMS 4910
	ASME SB-265
	MIL-T9046
	MIL-T9046

Titanium Grade 6 alloy offers good weldability, stability and strength at elevated temperatures.

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Titanium Grade 9 – Titanium 3Al-2.5V

Chemical Composition of Titanium Grade 9/Titanium 3Al-2.5V

C	.08 max
N	.03 max
O	.15 max
H	.015 max
V	2.0 – 3.0
Al	2.50 – 3.50
Fe	.25 max
Ti	Remaining

Standards of Titanium Grade 9/Titanium 3Al-2.5V

Forgings	ASME SB-381
Pipe	ASME SB-337
Round Bar/Wire	ASME SB-348
Sheet/Plate	ASME SB-265
Tubes	AMS 4943
	AMS 4944
	ASME SB-338

Titanium Grade 9 has medium strength that falls between Grade 4 and Grade 5. It has excellent corrosion resistance and is used in Aerospace and Industrial applications. Grade 9 Titanium can be used at higher temperatures than Grades 1 through 4. Grade 9 titanium has good cold rolling properties.

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Titanium Grade 12 – Ti-0.3-Mo-0.8Ni

Chemical Composition of Titanium Grade 12

C	.08 max
N	.03 max
O	.25 max
H	0.15 max
Ni	0.6 – 0.9
Ti	bal
Fe	.30 max

Standards of Titanium Grade 12

Tubes

ASME SB-338

This Titanium Grade 12 alloy is similar to Titanium Grades 2 and 3 except that Titanium Grade 12 has 0.3% molybdenum and 0.8% nickel. This offers enhanced corrosion resistance.

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Titanium Grade 19 – Titanium Beta C

Chemical Composition of Titanium Grade 19/Titanium Beta C

Ti	bal
C	.05 max
N	.03 max
O	.12 max
H	.02 max
Cr	5.5 – 6.5
Mo	3.5 – 4.5
Pd	.04 – .08
V	7.5 – 8.5
Al	3.0 – 4.0
Fe	0.3 max
Zr	3.5 – 4.5

Standards of Titanium Grade 19/Titanium Beta C

Titanium Grade 19 has very high strength and can be heat treated. It offers good resistance to stress and corrosion.

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Titanium Grade 23 – Titanium 6Al-4V ELI

Chemical Composition of Titanium Grade 23/Titanium 6Al-4V ELI

Ti	bal
C	.08 max
N	.03 max
O	.13 max
H	.0125 max
V	3.5 – 4.5
Al	5.5 – 6.5
Fe	0.25 max

Standards of Titanium Grade 23/Titanium 6Al-4V ELI

Extrusion	MIL-T-81556
	Forgings
	AMS 4930
	MIL-F-83142A
	MIL-T-9046
	MIL-T-9047
Round Bar/Wire	AMS 4930
	AMS 4931
	AMS 4956
	ASME SB-348
	ASTMF136
	MIL-T-9047
Sheet/Plate	MIL-T-9046
	AMS 4907
	ASME SB-265
	ASTM F136

Titanium Grade 23 is similar to Grade 5 but has lower oxygen, nitrogen and iron. It has better ductility and fracture toughness than Titanium Grade 5.

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Titanium 6Al-6V-2Sn – Titanium 6-6-2

Titanium 6-2-4-2 has excellent strength, stability, and creep resistance to temperatures as high as 550 °C.

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Titanium 6Al-2Sn-4Zr-2Mo – Titanium 6-2-4-2

Titanium 6Al-6V-2Sn is a two-phase, Alpha Beta Alloy. It is usually used in the annealed or solution treated and aged conditions. It’s a heat treatable, high strength alloy with lower toughness and ductility than Titanium Grade 5 (6Al-4V) and it’s difficult to weld. Cold forming of Titanium 6Al-6V-2Sn is difficult because of its high strength and the large amount of spring-back that results. This grade can be welded by the inert gas shielded, fusion welding process but the heat effected area will have less ductility and toughness than the parent material. The hardness of Titanium 6-6-2 is approximately Rockwell C 36-38. This grade is primarily used for airframe and jet engine parts, rocket engine cases and ordinance components. Please call us to determine our minimum item quantity.

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Titanium 6Al-2Sn-4Zr-6Mo – Titanium 6-2-4-6

Titanium 6Al-2Sn-4Zr-6Mo is an Alpha-Beta Alloy and it’s generally regarded as the workhorse alloy of the titanium industry. The alloy is fully heat-treatable in section sizes up to one inch and is used up to approximately 400°C (750°F). Since it is one of the most commonly used alloys (over 70% of all alloy grades melted are a sub-grade of Ti-6-4,) its uses span many aerospace engine and airframe components. Titanium 6Al-2Sn-4Zr-6Mo is also used in lots of non-aerospace applications such as marine, offshore and power generation industries. This Alpha-Beta Alloy combines good corrosion resistance and strength with weldability and fabricability. The alloy is generally available in bar form and it’s typically used in deep sour well applications. This alloy can be hot or cold formed. Please call us to determine our minimum item quantity.

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Titanium 8Al-1Mo-1V – Titanium 8-1-1

Titanium 8Al-1Mo-1V is a near Alpha Alloy that was primarily designed for use at elevated temperatures – up to 455 degrees centigrade. It offers the highest modulus and lowest density of all Titanium alloys. It has good creep strength and it’s weldable by the inert gas fusion and resistance-welding processes. Titanium 8Al-1Mo-1V is used in the annealed condition for such applications as airframe and jet engine parts that demand high strength, superior creep resistance and a good stiffness-to-density ratio. The machinability of this grade is similar to that of Titanium 6Al-4V. Please call us to determine our minimum item quantity.

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Titanium 10V-2Fe-3Al

Titanium 10V-2Fe-3Al is a Titanium Beta Alloy. It is harder and stronger than many titanium alloys. This Titanium is a heat treatable alloy, it’s weldable and it’s easily formed. Titanium 10V-2Fe-3Al is an all Beta Alloy and is more difficult to machine than most titanium alloys. The chief problems include flank wear, spring-back and chip control. Because of these characteristics, positive rake chip grooves in combination with light hones on the cutting edge are advantageous. Please call us to determine our minimum item quantity.

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Titanium 15V-3Cr-3Sn-3Al

This Metastable-Beta Alloy is used primarily in sheet metal form. It is age-hardenable and highly cold-formable. Titanium 15V-3-3-3 is often used to replace hot-formed Titanium Grade 5 (6Al-4V) sheet. It can also be produced as foil and is an excellent alloy for castings. For aerospace applications, this grade is often specified as AMS 4914. Please call to determine the minimum item quantity.

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Titanium Alpha Alloys

Commercially pure titanium and alpha alloys of titanium are non-heat treatable and have very good welding characteristics.

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Titanium Beta Alloys

Titanium Beta or near Beta Alloys are:

• Fully heat treatable Generally weldable
• Capable of high strengths Possess good creep resistance up to intermediate temperatures
• In the solution treated condition, excellent formability can be expected from Beta Alloys

Titanium Beta Alloys are ideal for sporing applications. Common Titanium Beta Alloys include:

Ti3Al8V6Cr4Mo4Zr

ASTM Grade 19
Ti-3Al-8V-6Cr-4Mo-4Zr

AMS 4983, 4984, 4987
Ti-10V-2Fe-3Al

ASTM Grade 21
Ti-15Mo-3Nb-3Al-2Si

AMS 4914
Ti-15V-3Cr-3Sn-3Al

The Metastable Titanium Beta Alloys are heat treatable by solution treatment and ageing. Fully stable beta alloys can only be annealed.

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Titanium Alpha-Beta Alloys

Titanium Alpha Beta alloys are heat treatable and most of them are also weldable. The typical properties of Titanium Alpha Beta Alloys are:

• Medium to high strength levels;
• High temperature creep strength is not as less than most alpha alloys;
• Limited cold forming but hot forming qualities are normally good;

The most commonly used Titanium Alpha Beta Alloy is Ti 6Al-4V. Titanium 6Al-4V has been developed in many variations of the basic formulation for numerous and widely differing applications.

Other Titanium Alpha Beta Alloys include: 6Al-4V-ELI 6Al-6V-2Sn 6Al-2Sn-4Zr-2Mo 3Al-2.5V 8Mn

Physical Properties of Titanium and Titanium Alloys

The physical properties of titanium and its alloys are summarised in Table 1, from which it can be seen that there is little variation from one alloy to another. For example, coefficients of thermal expansion range from 7.6×10-6 K-1 to 9.8×10-6 K-1.

Table 1. Physical properties of titanium and titanium alloys.

Alloy		Density (g.cm-3)	Melt Range (°C±15)	Spec. Heat (J.g-1.K-1)	Elec. Resist. (µΩ.cm)
Commercially Pure	ASTM Grade 1	4.51	1670	0.54	56
Commercially Pure	ASTM Grade 2	4.51	1677	0.54	56
Commercially Pure	ASTM Grade 3	4.51	1677	0.54	56
Commercially Pure	ASTM Grade 4	4.54	1660	0.54	61
Ti-3%Al-2.5%V	ASTM Grade 9	4.48	1704	–	124
Ti-0.8%Ni-0.3%Mo	ASTM Grade 12	4.51	–	0.54	51
Ti-3%Al-8%V-6%Cr-4%Zr-4%Mo	Beta C	4.81	1649	–	–
Ti-15%Mo-3%Nb-3%Al-0.2%Si	Timetal 21 S	4.90	–	0.49	135
Ti-6%Al-4%V	ASTM Grade 5	4.42	1649	0.56	170
Ti-2.5%Cu	IMI 230	4.56	–	–	70
Ti-4%Al-4%Mo-2%Sn-0.5%Si	IMI 550	4.60	–	–	160
Ti-6%Al-6%V-2%Sn		4.54	1704	0.65	–
Ti-10%V-2%Fe-3%Al		4.65	1649	–	–
Ti-15%V-3%Cr-3%Sn-3%Al		4.76	1524	0.50	147
Ti-8%Al-1%Mo-1%V		4.37	1538	–	198
Ti-11%Sn-5%Zr-2.5%Al-1%Mo	IMI 679	4.84	–	–	163
Ti-5.5%Al-3.5%Sn-3%Zr-1%Nb-0.3%Mo-0.3%Si	IMI 829	4.54	–	–	–
Ti-5.8%Al-4%Sn-3.5%Zr-0.7%Nb-0.5%Mo-0.3%Si	IMI 834	4.55	–	–	–
Ti-6%Al-2%Sn-4%Zr-2%Mo		4.54	1649	0.42	191
Ti-6%Al-2%Sn-4%Zr-6%Mo		4.65	1635	–	–
Ti-6%Al-5%Zr-0.5%Mo-0.2%Si	IMI 685	4.45	–	–	–
Ti-6%Al-3%Sn-4%Zr-0.5%Mo-0.5%Si	Ti 1100	4.50	–	–	180

Table 1 (cont.). Physical properties of titanium and titanium alloys.

Alloy		Therm. Cond. (W.m-1.K-1)	Therm. Exp. Co-eff 0-100°C (10-6 K-1)	Therm. Exp. Co-eff 0-300°C (10-6 K-1)	Beta Transus (°C±15)
Commercially Pure	ASTM Grade 1	16.3	8.6	9.2	888
Commercially Pure	ASTM Grade 2	16.3	8.6	9.2	913
Commercially Pure	ASTM Grade 3	16.3	8.6	9.2	921
Commercially Pure	ASTM Grade 4	16.3	8.6	9.2	949
Ti-3%Al-2.5%V	ASTM Grade 9	7.6	–	7.9	935
Ti-0.8%Ni-0.3%Mo	ASTM Grade 12	22.7	9.5	–	888
Ti-3%Al-8%V-6%Cr-4%Zr-4%Mo	Beta C	8.4	9.4	9.7	793
Ti-15%Mo-3%Nb-3%Al-0.2%Si	Timetal 21 S	7.62	4.4	4.9	785
Ti-6%Al-4%V	ASTM Grade 5	7.2	8.8	9.2	999
Ti-2.5%Cu	IMI 230	16.0	9.0	9.1	895
Ti-4%Al-4%Mo-2%Sn-0.5%Si	IMI 550	7.9	8.8	9.2	975
Ti-6%Al-6%V-2%Sn		7.2	9.0	9.4	946
Ti-10%V-2%Fe-3%Al		–	–	9.7	796
Ti-15%V-3%Cr-3%Sn-3%Al		8.1	–	9.7	760
Ti-8%Al-1%Mo-1%V		6.5	8.5	9.0	1038
Ti-11%Sn-5%Zr-2.5%Al-1%Mo	IMI 679	7.1	8.2	9.3	950
Ti-5.5%Al-3.5%Sn-3%Zr-1%Nb-0.3%Mo-0.3%Si	IMI 829	–	9.45	9.77	1015
Ti-5.8%Al-4%Sn-3.5%Zr-0.7%Nb-0.5%Mo-0.3%Si	IMI 834	–	10.6	10.9	1045
Ti-6%Al-2%Sn-4%Zr-2%Mo		6.0	9.9	–	996
Ti-6%Al-2%Sn-4%Zr-6%Mo		7.1	9.4	10.3	932
Ti-6%Al-5%Zr-0.5%Mo-0.2%Si	IMI 685	4.8	9.8	9.5	1025
Ti-6%Al-3%Sn-4%Zr-0.5%Mo-0.5%Si	Ti 1100	6.6	8.8	9.5	804

Density

The density of an alloy is dependent upon the amount and density of the alloying constituents. For example, an alloy containing aluminium as an alloying element is likely to be substantially lighter than one containing an appreciable amount of tin. Generally, beta alloys are heavy because they contain alloying constituents such as molybdenum which has a relatively high density. Where weight is important, it may be worthwhile to compare specific properties of alloys, e.g. the specific strength.

Strength

In Table 2 the specific strengths of some titanium alloys are compared with those of other structural metals.

Table 2. Strength of some titanium alloys at room temperature, normalised by density, compared with other structural metals.

Material		Yield Str/Density (x106N.m.kg-1)	Tensile Str/Density (x106N.m.kg-1)	107 Cycle Fatigue Str/Density (x106N.m.kg-1)
Commercially Pure	ASTM Grade 2	78	107	54
Ti-6%Al-4%V	ASTM Grade 5	206	226	135
Ti-6%Al-2%Sn-4%Zr-2%Mo		202	223	123
Ti-4%Al-4%Mo-2%Sn-0.5%Si	IMI 550	225	247	136
Ti-10%V-2%Fe-3%Al		264	282	155
Maraging Steel		170	202	121
FV 520 B Steel		153	165	105
13% Cr Stainless Steel		95	105	68
18/8 Stainless Steel		68	75	40

Thermal Conductivity

The thermal conductivity of all titanium alloys is relatively low for a metal, although recent work has indicated that the value for commercially pure titanium is actually 21.6 W m-1.K-1, about 32% higher than the value quoted in Table 1. The titanium alloys generally have even lower thermal conductivities than the commercially pure material.

Electrical Resistivity

As may be expected from this, electrical resistivity is relatively high. Specific heat does not show any obvious trend, ranging from about 400 to 600 J.kg-1.K-1.

Magnetic Properties

Commercially pure titanium and all the titanium alloys are non magnetic. The permeability of commercially pure titanium is 1.00005-1.0001 at 955 H.m-1.

Elastic Modulus

Values of elastic (Young’s) modulus typically range from 80 to 125 GPa, but this depends to some extent on the working process used to produce the material and on the directionality of the test material. There is, however, a general tendency for high aluminium containing materials to have a somewhat higher modulus than other alloys.

Poissons Ratio

It is difficult to give a reliable value for Poisson’s ratio for titanium alloys since anisotropy leads to small differences in both elastic and shear moduli which, when taken together to calculate Poisson’s ratio can lead to values varying from 0.287 to 0.391 for annealed ASTM Grade 5 (Ti-6%Al-4%V) sheet. However, the generally accepted value for commercially pure titanium is 0.36 and that for ASTM Grade 5 is 0.31.

The Effect of Temperature on the Physical Properties

The effect of temperature on the physical properties of commercially pure titanium is given in Table 3. The alloys follow a similar pattern although the thermal conductivity tends to increase more at elevated temperature, most of the alloys showing increases of 60 to 80% between ambient and 500°C. Other properties follow more closely the trends for commercially pure titanium.

Table 3. Effect of temperature on the physical properties of comeercially pure titanium.

Temp. (°C)	Therm. Exp. Co-eff 20-T°C (x10-6K-1)	Therm. Cond. (W.m-1.K-1)	Elec. Resist. (µΩ.cm)	Spec. Heat (J.g-1.K-1)	Magnetic Suscept. (x10-6)	Elastic Mod. (GPa)
20	–	17	0.48	0.50	3.4	110
100	7.6	16	0.65	0.55	3.5	101
200	8.9	15	0.83	0.58	3.6	92
300	9.5	15	1.00	0.595	3.7	85
400	9.6	15	1.15	0.605	3.9	78
500	9.7	15	1.29	0.615	4.0	72
600	–	16	1.41	–	–	–

Tensile Strength

The tensile strength of titanium and its alloys at ambient temperature ranges from 240 MPa for the softest grade of commercially pure titanium to more than 1400 MPa for very high strength alloys. Proof strengths vary from around 170 to 1100 MPa according to grade and condition. Details are given in Table 4.

Table 4. Guaranteed properties of titanium alloys.

Alloy		0.2% Proof (MPa)	Tens. Str. (MPa)	Fatigue Limit (% of Tens. Str)	Elong. (%)	Red. Of Area (%)	Elastic Modulus (GPa)
Commercially Pure	ASTM Grade 1	172	241	50	25	35	103
Commercially Pure	ASTM Grade 2	276	345	50	20	35	103
Commercially Pure	ASTM Grade 3	379	448	50	18	35	103
Commercially Pure	ASTM Grade 4	483	552	50	15	30	104
Ti-3%Al-2.5%V	ASTM Grade 9	483	621	–	15	–	91
Ti-0.8%Ni-0.3%Mo	ASTM Grade 12	345	483	–	18	25	103
Ti-3%Al-8%V-6%Cr-4%Zr-4%Mo	Beta C	1104	1172	–	6	19	103
Ti-15%Mo-3%Nb-3%Al-0.2%Si	Timetal 21 Sa	750	792	–	10b	–	74
Ti-6%Al-4%V	ASTM Grade 5	828	897	55-60	10	20	114
Ti-2.5%Cu	IMI 230	400	540	–	16	35	–
Ti-4%Al-4%Mo-2%Sn-0.5%Si	IMI 550	959	1104	50-60	9	38	114
Ti-6%Al-6%V-2%Sn		966	1035	50-60	8	15	–
Ti-10%V-2%Fe-3%Al		1104	1241	50	–	–	103
Ti-15%V-3%Cr-3%Sn-3%Al		966	1000	–	7	–	103
Ti-8%Al-1%Mo-1%V		828	897	–	10	20	117
Ti-6%Al-5%Zr-0.5%Mo-0.2%Si	IMI 685	990	850	–	6	–	125
Ti-6%Al-2%Sn-4%Zr-2%Mo		862	931	50-60	8	–	114
Ti-6%Al-2%Sn-4%Zr-6%Mo		1069	1172	–	10	20	114
Ti-5.5%Al-3.5%Sn-3%Zr-1%Nb-0.3%Mo-0.3%Si	IMI 829	820	960	50	10	–	120
Ti-5.8%Al-4%Sn-3.5%Zr-0.7%Nb-0.5%Mo-0.3%Si	IMI 834	910	1030	–	6	–	120

a = Solution treated, b= typical value

At elevated temperatures each grade of titanium exhibits characteristic tensile properties. The alloy grades, particularly the high strength materials, retain both proof and tensile strengths up to much higher temperatures than the commercially pure grades. This is shown clearly in Figures 1 and 2. Ductility normally increases with increasing temperature, as shown in Figure 3. However, there is a slight irregularity with the commercially pure grades in that ductility increases consistently up to a temperature of between 200°C and 300°C but thereafter decreases until at 400 to 450°C values are very similar to those at room temperature.

Figure 1. Typical values of tensile strength for titanium and its alloys

Figure 2. Typical values of proof stress for titanium and its alloys.

Figure 3. Typical elongation values for titanium and its alloys.

Hardness

The absorption of oxygen into a titanium surface when the material is heated causes an increase in hardness of the surface layer. Grinding and polishing can have a similar effect on metallurgical samples and it is for this reason that hardness values can be misleading. However, the hardness of titanium, if interpreted correctly, can be a useful measurement for the following purposes:

• Hardness can be used to give a rough indication of the identity of a grade of titanium alloy;

• Comparison of hardness before and after annealing can be used to estimate the degree of work hardening initially present or the completeness of annealing depending upon the circumstances;

• For certain alloys the relationship between hardness and tensile strength is known. A hardness measurement can therefore be used to give an indication of local mechanical properties, for example, a fragment of a failed component, or alternatively to check the success of a heat treatment.

Figure 4 illustrates the approximate relationship between the hardness of commercially pure titanium and its tensile strength.

Figure 4. Approximate relationship between hardness and tensile strength for commercially pure grades of titanium.

Creep

There is little published information on the creep properties of commercially pure titanium, mainly because current applications have not normally required detailed knowledge of this property. Generally, creep values for the material to 0.1% plastic strain in 100,000 hours are approximately 50% of the tensile strength at temperatures up to 300°C.

Design codes for chemical plant allow the use of tensile information for equipment operating at up to 150°C, and this covers most of the current uses of commercially pure titanium in the chemical industry. At temperatures above this, titanium is normally used as a lining supported by steel. Chemical plant design codes also refer to stress rupture values and information on these is given in Figures 5 and 6.

Figure 5. 10,000 hour stress rupture curves for commercially pure titanium sheets (Larson-Miller interpolation).

Figure 6. 100,000 hour stress rupture curves for commercially pure titanium sheets (Larson-Miller interpolation).

Clearly, some applications require the use of material having a good resistance to creep and titanium alloys have been developed over the years to fulfil this requirement. They generally fall into three main categories:

• Alpha-beta alloys. These contain sufficient beta stabilising elements to allow some beta phase to be retained at room temperature. They are heat treated in the alpha-beta phase field and their structure consists of primary alpha and transformed beta. The maximum operating temperature under creep conditions for these materials would normally be 300-450°C;

• Near alpha alloys heat treated in the alpha-beta phase field. By optimising alpha and beta stabilising elements, alloys have been developed which have improved creep resistance at temperatures in the range 450-500°C;

• Near alpha alloys heat treated in the beta phase field. A significant further improvement in creep properties is obtained by heat treating near alpha alloys in the beta phase field and such materials are suitable for use at up to 600°C.

Fatigue

The high cycle fatigue strengths of titanium alloys are generally good in comparison with their tensile strengths. Although the S-N fatigue curves do not show a sharp knee as they do with some metals, they tend to flatten out at about 107 cycles and the fatigue limit thus defined is between 40 and 60% of the tensile strength. The effect of notches is less than could be expected from the stress concentration factors and fatigue crack propagation rates, and residual static strengths of cracked samples compare favourably with those of steels and aluminium alloys. Comparison of specific fatigue strengths of titanium alloys with other high strength materials is included in Table 2.

As with other materials, the fatigue properties of titanium vary with surface finish, notched specimen tests giving substantially lower values than those with unnotched samples. Thus, care is required in design and manufacture to avoid stress concentrators. Poor surface finish, sharp sectional transitions, unblended radii and corners are conditions that should be avoided.

The low cycle fatigue properties of titanium alloys are of relevance to rotating components in aircraft applications. Most data have been generated under constant load, zero minimum stress conditions where it has been established that the fatigue strength of the alloys is closely related to strength and ductility.

Fracture Toughness.

The toughness of titanium alloys is dependent upon strength, composition, microstructure and texture, which properties are interrelated. However, in general terms, the toughness of titanium alloys varies inversely with strength in the same way as that of steels or aluminium alloys. For example, the plain strain fracture toughness of the alpha-beta alloys drops from a value of between 60 and 100 MPa.m-½ at proof stress levels of 800 MPa, to 20 to 60 MPa.m-½ at proof stress levels of 1200 MPa. In general, the heat treatments that are normally used with titanium were originally developed to give optimum tensile properties rather than to improve fracture toughness. However, it has been established that for certain alpha-beta alloys it is possible to increase fracture toughness significantly by simple changes in heat treatment procedure or by a minor variation in alloy chemistry, for example, by reducing the oxygen level in the Ti-6%Al-4%V alloy to produce the extra low interstitial (ELI) grade. Such improvements are generally only associated with small decreases in tensile and fatigue strengths. Other alloy types such as the beta heat treated near alpha alloys have better fracture toughness levels than the alpha-beta types.

From: www.iom3.org