Kutz M. Handbook of materials selection

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208 SELECTION OF TITANIUM ALLOYS FOR DESIGN

4 MICROSTRUCTURE AND PROPERTIES OF TITANIUM AND ITS

ALLOYS

The grain size, grain shape, and grain boundary arrangements in titanium have

a very signiﬁcant inﬂuence on mechanical properties, and it is the ability to

manipulate the phases/grains present as a result of alloy composition that is

responsible for the variety of properties that can be produced in titanium and its

alloys. Transformed

␤

-phase products in alloys can affect tensile strengths, duc-

tility, toughness, and cyclic properties. To these effects, must be added the basic

strengthening effects of alloy elements.

4.1 Alloy Composition and General Behavior

Alpha alloys usually have high amounts of aluminum that contribute to oxidation

resistance at high temperatures. (

␣

–

␤

alloys also contain, as the principal ele-

ment, high amounts of aluminum, but the primary reason is to control the

␣

phase.) Alpha alloys cannot be heat treated to develop higher mechanical

properties because they are single-phase alloys.

The addition of certain alloy elements to pure titanium provides for a wide

two-phase

␣

plus

␤

region and so enables the resultant alloys to be heat treated

or processed in the temperature range where the alloy is two phase. The two-

phase condition permits the structure to be reﬁned by the

␣

␤

␣

transfor-

mation process on heating and cooling. The process of heating to a high

temperature to promote subsequent transformation is known as solution heat

treatment. By permitting some beta to be retained temporarily at lower temper-

ature, the alloy elements enable optimum control of the microstructure during

subsequent transformation after cooling from the forging or solution heat treat-

ment temperature when the alloys are ‘‘aged’’ (reheated after rapid cooling to

temperatures well below the

␤

transus). The

␣

–

␤

alloys, when properly treated,

have an excellent combination of strength and ductility. They are stronger than

the

␣

or the

␤

-alloys.

The

␤

-alloys are metastable; that is, they tend to transform to an equilibrium,

or balance, of structures. The

␤

-alloys generate their strength from the intrinsic

strength of the

␤

structure and the precipitation of alpha and other phases from

the alloy through heat treatment after processing. The most signiﬁcant beneﬁt

provided by a beta structure is the increased formability of such alloys relative

to the hexagonal crystal structure types (

␣

and

␣

–

␤

Titanium aluminides differ from conventional titanium alloys in that they are

principally chemical compounds alloyed to enhance strength, formability, etc.

The aluminides have higher operational temperatures than conventional titanium

but at higher cost and, generally, have lower ductility and formability.

In addition to alloys, titanium is sold and used in (CP) forms usually identiﬁed

as grades. Pure titanium usually has some amount of oxygen alloyed with it.

The strength of CP titanium is affected by the interstitial (oxygen and nitrogen)

element content. A principal difference among grades is the oxygen (and nitro-

gen) content, which inﬂuences mechanical properties. Small additions of some

alloy elements such as palladium are added for increased corrosion resistance

in certain grades. A summary of the compositions of many commercial and

semicommercial titanium grades and alloys is given in Table 2.

209

Table 2 Some Commercial and Semicommercial Grades and Alloys of Titanium

Designation

Tensile

Strength

(min)

MPa ksi

0.2% Yield

Strength

(min)

MPa ksi

Impurity Limits wt. % (max)

NC HFeO

Nominal Composition, wt. %

Al Sn Zr Mo Others

Unalloyed grades

ASTM grade 1 240 35 170 25 0.03 0.08 0.015 0.20 0.18 — — — — —

ASTM grade 2 340 50 280 40 0.03 0.08 0.015 0.30 0.25 — — — — —

ASTM grade 3 450 65 380 55 0.05 0.08 0.015 0.30 0.35 — — — — —

ASTM grade 4 550 80 480 70 0.05 0.08 0.015 0.50 0.40 — — — — —

ASTM grade 7 340 50 280 40 0.03 0.08 0.015 0.30 0.25 — — — — 0.2Pd

ASTM grade 11 240 35 170 25 0.03 0.08 0.015 0.20 0.18 — — — — 0.2Pd

␣

and near-

␣

alloys

Ti–0.3Mo–0.8Ni 480 70 380 55 0.03 0.10 0.015 0.30 0.25 — — — 0.3 0.8Ni

Ti–5Al–2.5Sn 790 115 760 110 0.05 0.08 0.02 0.50 0.20 5 2.5 — — —

Ti–5Al–2.5Sn–ELI 690 100 620 90 0.07 0.08 0.0125 0.25 0.12 5 2.5 — — —

Ti–8Al–1Mo–1V 900 130 830 120 0.05 0.08 0.015 0.30 0.12 8 — — 1 1V

Ti–6Al–2Sn–4Zr–2Mo 900 130 830 120 0.05 0.05 0.0125 0.25 0.15 6 2 4 2 0.08Si

Ti–6Al–2Nb–1Ta–0.8Mo 790 115 690 100 0.02 0.03 0.0125 0.12 0.10 6 — — 1 2Nb, 1Ta

Ti–2.25Al–11Sn–5Zr–1Mo 1000 145 900 130 0.04 0.04 0.008 0.12 0.17 2.25 11 5 1 0.2Si

Ti–5.8Al–4Sn–3.5Zr–0.7Nb–0.5Mo–0.35Si 1030 149 910 132 0.03 0.08 0.006 0.05 0.15 5.8 4 3.5 0.5 0.7Nb, 0.35Si

␣

–

␤

alloys

Ti–6Al–4V

900 130 830 120 0.05 0.10 0.0125 0.30 0.20 6 — — — 4V

Ti–6Al–4V–ELI

830 120 760 110 0.05 0.08 0.0125 0.25 0.13 6 — — — 4V

Ti–6Al–6V–2Sn

1030 150 970 140 0.04 0.05 0.015 1.0 0.20 6 2 — — 0.7Cu, 6V

Ti–8Mn

860 125 760 110 0.05 0.08 0.015 0.50 0.20 — — — — 8.0Mn

Ti–7Al–4Mo

1030 150 970 140 0.05 0.10 0.013 0.30 0.20 7.0 — — 4.0 —

Ti–6Al–2Sn–4Zr–6Mo

1170 170 1100 160 0.04 0.04 0.0125 0.15 0.15 6 2 4 6 —

Ti–5Al–2Sn–2Zr–4Mo–4Cr

b,c

1125 163 1055 153 0.04 0.05 0.0125 0.30 0.13 5 2 2 4 4Cr

Ti–6Al–2Sn–2Zr–2Mo–2Cr

1030 150 970 140 0.03 0.05 0.0125 0.25 0.14 5.7 2 2 2 2Cr, 0.25Si

Ti–3Al–2.5V

620 90 520 75 0.015 0.05 0.015 0.30 0.12 3 — — — 2.5V

Ti–4Al–4Mo–2Sn–0.5Si 1100 160 960 139

0.02 0.0125 0.20

4 2 — 4 0.5Si

210

Table 2 (Continued )

Designation

Tensile

Strength

(min)

MPa ksi

0.2% Yield

Strength

(min)

MPa ksi

Impurity Limits wt. % (max)

NC HFeO

Nominal Composition, wt. %

Al Sn Zr Mo Others

␤

alloys

Ti–10V–2Fe–3Al

a,c

1170 170 1100 160 0.05 0.05 0.015 2.5 0.16 3 — — — 10V

Ti–13V–11Cr–3Al

1170 170 1100 160 0.05 0.05 0.025 0.35 0.17 3 — — — 11.0Cr, 13.0V

Ti–8Mo–8V–2Fe–3Al

b,c

1170 170 1100 160 0.03 0.05 0.015 2.5 0.17 3 — — 8.0 8.0V

Ti–3Al–8V–6Cr–4Mo–4Zr

a,c

900 130 830 120 0.03 0.05 0.20 0.25 0.12 3 — 4 4 6Cr, 8V

Ti–11.5Mo–6Zr–4.5Sn

690 100 620 90 0.05 0.10 0.020 0.35 0.18 — 4.5 6.0 11.5 —

Ti–15V–3Cr–3Al–3Sn 1000

145

965

140

0.05 0.05 0.015 0.25 0.13 3 3 — — 15V, 3Cr

1241

180

1172

170

Ti–15Mo–3Al–2.7Nb–0.2Si 862 125 793 115 0.05 0.05 0.015 0.25 0.13 3 — — 15 2.7Nb, 0.2Si

Mechanical properties given for the annealed condition; may be solution treated and aged to increase strength.

Mechanical properties given for the solution-treated-and-aged condition; alloy not normally applied in annealed conditions.

Semicommercial alloy; mechanical properties and composition limits subject to negotiation with suppliers.

Primarily a tubing alloy; may be cold drawn to increase strength.

Combined O

⫹ 2N

⫽ 0.27%.

Also solution treated and aged using an alternative aging temperature (480⬚C, or 900⬚F)

Source: From Titanium: A Technical Guide, 2nd ed., ASM International, Materials Park, OH 44073-0002, 2001, p. 8.

5 EFFECTS OF ALLOY ELEMENTS 211

4.2 Strengthening of Titanium Alloys

Desired mechanical properties such as yield or ultimate strength density (strength

efﬁciency), perhaps creep and creep-rupture strength, as well as fatigue-crack

growth rate, fracture toughness, and manufacturing considerations such as weld-

ing and forming requirements, are extremely important. They normally provide

the criteria that determine the alloy composition, structure (

␣

–

␤

,or

␤

), heat

treatment (some variant of either annealing or solution treating and aging), and

level of process control selected or prescribed for structural titanium alloy ap-

plications.

By introducing atoms, phases, grain boundaries, or other interfaces into tita-

nium, the movement of imperfections that cause deformation to occur is inhib-

ited. Modiﬁcation of composition and microstructure enables titanium alloys to

be strengthened signiﬁcantly. Final strength is a function of composition and the

various deformation processes used to form and strengthen alloys. It is quite

important for the alloy selector to have a realistic understanding of the strength-

ening process in titanium alloys as the properties of titanium and its alloys can

be modiﬁed considerably not only by chemistry modiﬁcation but also by proc-

essing.

The titanium alloys derive their strength from a ﬁneness of microstructure

produced by transformation of crystal structures in grains from

␤

␣

, plus

dispersion of one phase in another as in the case of precipitation of

␣

-phases

from retained

␤

in metastable beta alloys. The ﬁne structure produced by trans-

formations can often be martensitic in nature, as temperatures on the component

being produced are reduced during cooling from deformation processing or so-

lution treatment. The reader may recall that martensitic structures are produced

in steels (and in other systems) and can create very strong and hard alloys.

Martensitic reactions are found in titanium alloys; they are not as effective as

those in steels at causing hardening but do bring about microstructure reﬁne-

ments and thus strength improvements in titanium alloys. Fine dispersions in the

alloys usually are produced by ‘‘aging’’ through reheating and holding at an

intermediate temperature after prior forging and heat treatment processing.

5 EFFECTS OF ALLOY ELEMENTS

Alloy elements generally can be classiﬁed as

␣

stabilizers or

␤

stabilizers. Alpha

stabilizers, such as aluminum, oxygen, and nitrogen increase the temperature at

which the

␣

-phase is stable. On the other hand, beta stabilizers, such as vana-

dium and molybdenum, result in stability of the

␤

-phase at lower temperatures.

The transformation temperature from

␣

plus

␤

or from

␣

to all

␤

is known as

the

␤

transus temperature. The

␤

transus is deﬁned as the lowest equilibrium

temperature at which the material is 100%

␤

. The

␤

transus is critical in defor-

mation processing and in heat treatment, as described below. By reference to

the

␤

transus, heat treatment temperatures can produce speciﬁc microstructures

during the heat treatment process. See, for example, the amount of

␣

-phase that

can be produced by temperature location relative to the

␤

transus for Ti–6Al–

4V as shown in Fig. 4.

5.1 Intermetallic Compounds and Other Secondary Phases

Intermetallic compounds and transient secondary phases are formed in titanium

alloy systems along with microstructural variants of the traditional

␤

- and

␣

212 SELECTION OF TITANIUM ALLOYS FOR DESIGN

Fig. 4 Phase diagram that predicts the results of heat treatment or forging practice.

(From Titanium: A Technical Guide, 1st ed., ASM International, Materials Park,

OH 44073-0002, 1988, p. 51.)

phases. The more important secondary phases, historically, have been

␻

and

␣

2, chemically written as Ti

Al. Omega phase has not proven to be a factor in

commercial systems using present-day processing practice. Alpha-2 has been

considered to be a concern in some cases of stress–corrosion cracking. Alloys

with extra-high aluminum (favoring

␣

-2) were found to be prone to stress–

corrosion cracking. Most present interest in

␣

-2 centers on its use as a matrix

for a high-temperature titanium alloy. Another phase more likely to succeed as

a high-temperature alloy matrix is

␥

TiAl, mentioned previously. Gamma-phase

is not a factor in the property behavior of conventional titanium alloys.

5.2 Mechanical and Physical Properties

Titanium is a low-density element (approximately 60% of the density of steel

and superalloys) that can be strengthened greatly by alloying and deformation

processing. The physical and mechanical properties of elemental titanium are

given in Table 3. Titanium is nonmagnetic and has good heat-transfer properties.

Its coefﬁcient of thermal expansion is somewhat lower than that of steel’s and

less than half that of aluminum.

Titanium’s modulus can vary with alloy type (

␤

vs.

␣

) and processing from

as low as about 93 GPa (13.5

⫻ 10

psi) up to about 120.5 GPa (17.5 ⫻ 10

psi). For reference, titanium alloy moduli on average are about 50% greater than

the moduli for aluminum alloys but only about 50%–60% of the moduli for

steels and nickel-base superalloys. Titanium alloys can have their crystals ori-

5 EFFECTS OF ALLOY ELEMENTS 213

Table 3 Physical and Mechanical Properties of Elemental Titanium

Atomic number 22

Atomic weight 47.90

Atomic volume 10.6 W / D

Covalent radius 1.32 A

First ionization energy 158 kcal / g-mol

Thermal neutron absorption 5.6 barns / atom

cross section

Crystal structure

• Alpha: close-packed,

hexagonal

ⱕ882.5⬚C (1620⬚F)

• Beta: body-centered, cubic

ⱖ882.5⬚C (1620⬚F)

Color Dark gray

Density 4.51 g / cm

(0.163 lb/ in.

)

Melting point 1668

 10⬚C (3035⬚F)

Solidus/ liquidus 1725

⬚C

Boiling point 3260

⬚C (5900⬚F)

Speciﬁc heat (at 25

⬚C) 0.518 J / kg ⬚K (0.124 Btu / lb  ⬚F)

Thermal conductivity 9.0 Btu / h ft

⬚F

Heat of fusion 440 kJ / kg (estimated)

Heat of vaporization 9.83 MJ / kg

Speciﬁc gravity 4.5

Hardness HRB 70 to 74

Tensile strength 35 ksi min

Modulus of elasticity 14.9

⫻ 10

psi

Young’s modulus of elasticity 116

⫻ 10

N/m

16.8 ⫻ 10

lbf/ in.

102.7 GPa

Poisson’s ratio 0.41

Coefﬁcient of friction 0.8 at 40 m / min

(125 ft / min)

0.68 at 300 m / min

(1000 ft / min)

Speciﬁc resistance 554

␮

⍀  mm

Coefﬁcient of thermal expansion 8.64

⫻ 10

⫺

/⬚C

Electrical conductivity 3% IACS (copper 100%)

Electrical resistivity 47.8

␮

⍀  cm

Electronegativity 1.5 Pauling’s

Temperature coefﬁcient of

electrical resistance

0.0026/

⬚C

Magnetic susceptibility 1.25

⫻ 10

⫺

3.17 emu / g

Machinability rating 40

Source: From Titanium: A Technical Guide, 1st ed., ASM International, Ma-

terials Park, OH 44073-0002, 1988, p. 11.

ented by processing such that a texture develops. When that happens, instead of

the usual random orientation of grains leading to uniformity of mechanical prop-

erties, a nonuniform orientation occurs and leads to a greater range of values

than expected. By appropriate processing, it should be possible to orient wrought

titanium for optimum elastic modulus at the high end of the modulus values

quoted above. Although textures can be produced, processing that leads to di-

214 SELECTION OF TITANIUM ALLOYS FOR DESIGN

Table 4 Relative Advantages of Equiaxed and Acicular

Microstructures

Equiaxed

Higher ductility and formability

Higher threshold stress for hot-salt stress corrosion

Higher strength (for equivalent heat treatment)

Better hydrogen tolerance

Better low-cycle fatigue (initiation) properties

Acicular

Superior creep properties

Higher fracture-toughness values

Source: From Titanium: A Technical Guide, 1st ed., ASM In-

ternational, Materials Park, OH 44073-0002, 1988, p. 168.

rectional grain or crystal orientation similar to directional solidiﬁcation in cast-

ings or directional recrystallization in oxide dispersion strengthened alloys is not

practical in titanium alloy systems.

5.3 Effects of Processing

Properties of titanium alloys generally are controlled by variations of the proc-

essing (including heat treatment) and are modiﬁed for optimum fatigue resistance

by surface treatments such as shot peening. Process treatments can produce

either acicular or equiaxed microstructures in most titanium alloys if phase trans-

formations from

␣

␤

␣

or related phases are permitted to occur. Micro-

structures have been identiﬁed that show

␣

as acicular or equiaxed and with

varying amounts of

␣

-phase. The platelike or acicular

␣

produced by transfor-

mation from

␤

-phase has special aspects as far as properties are concerned. Table

4 shows the relative behavior of equiaxed versus platelike alpha. No one

microstructure is good for all applications.

5.4 Hydrogen (in CP Titanium)

The solubility of hydrogen in

␣

titanium at 300⬚C (572⬚F) is about 8 at. % (about

0.15 wt. %, or about 1000 ppm by weight). Hydrogen in solution has little effect

on the mechanical properties. Damage is caused by hydrides which form. Upon

precipitation of the hydride, the ductility suffers. Hydrogen damage of titanium

and titanium alloys, therefore, is manifested as a loss of ductility (embrittlement)

and/or a reduction in the stress intensity threshold for crack propagation. Figure

5 shows the effect of hydrogen on reduction of area, a measure of ductility.

No embrittlement is found at 20 ppm hydrogen, which corresponds to about

0.1 at. % of hydrogen. Other data shows that, independent of the heat treatment,

this low a concentration has little effect on the impact strength (a different

measure of embrittlement). However, as little as 0.5 at. % hydrogen (about 100

atom ppm) can cause measurable embrittlement. Slow cooling from the

␣

re-

gion—e.g. 400

⬚C (752⬚F)—allows sufﬁcient hydride to precipitate to reduce the

impact energy. The only practical approach to control the hydrogen problem is

to maintain a low concentration of the element. As a result, CP titanium will

usually have a maximum allowable hydrogen content of about 0.015 wt. %

(about 100 ppm by weight). For example, for the grades of commercially pure

5 EFFECTS OF ALLOY ELEMENTS 215

Fig. 5 Ductility of alpha titanium versus test temperature, showing embrittling effects

of hydrogen. (From Titanium: A Technical Guide, 1st ed., ASM International,

Materials Park, OH 44073-0002, 1988, p. 161.)

titanium, the level is about 0.01%. Hydrogen also can have a potent effect on

titanium alloy properties.

5.5 Oxygen and Nitrogen (in CP Titanium)

Oxygen and nitrogen have a signiﬁcant effect on strength properties. As the

amount of oxygen and nitrogen increases, the toughness decreases until the

material eventually becomes quite brittle. Embrittlement occurs at a concentra-

tion considerably below the solubility limit. The allowed oxygen content is

higher than the allowed nitrogen content. Yield and ultimate strengths increase

as oxygen (and nitrogen) levels go up. The higher strengths in CP titanium

grades come from higher oxygen levels. Oxygen (and nitrogen) can have a potent

effect on titanium alloy properties as well.

5.6 Mechanical Properties of Titanium Alloys

The grain size, grain shape, and grain boundary arrangements in titanium have

a very signiﬁcant inﬂuence on mechanical properties, and it is the ability to

manipulate the phases/grains present as a result of alloy composition that is

responsible for the variety of properties that can be produced in titanium and its

alloys. Transformed

␤

-phase products in alloys can affect tensile strengths, duc-

tility, toughness, and cyclic properties. To these effects must be added the basic

strengthening effects of alloy elements.

Interstitial elements are those elements such as oxygen that are signiﬁcantly

smaller than the titanium atom and so may dissolve in the titanium phase crystal

lattice as solid solutions without substituting for titanium atoms. Of course, some

interstitial elements also may form second phases with titanium. As is the case

for comparable-size elements, interstitial elements may have a preference for

216 SELECTION OF TITANIUM ALLOYS FOR DESIGN

one phase over another in titanium. As indicated above, a signiﬁcant inﬂuence

on mechanical behavior of CP titanium is brought about by hydrogen, nitrogen,

carbon, and oxygen, which dissolve interstitially in titanium and have a potent

effect on mechanical properties. These effects carry over to titanium alloys in

varying degrees.

The ELI (extra-low interstitial) levels speciﬁed for some titanium alloys im-

plicitly recognize the effect of reduced interstitials on ductility. ELI-type material

is used for critical applications where enhanced ductility and toughness are pro-

duced by keeping interstitials at a very low level. Hydrogen is always kept at a

low level to avoid embrittlement, yet there still remains concern about the most

reasonable level to specify in both CP and alloyed titanium to protect against

embrittlement but keep manufacturing cost low.

Although data are not provided here for grain size effects on titanium grades,

it is generally accepted that ﬁneness of structure (smaller particle size, grain

size, etc.) is more desirable from the point of view of TYS in metallic materials.

The UTS is not particularly affected by grain size, but ductility as represented

by elongation or reduction in area generally is improved with smaller grain sizes.

Ductility is a measure of toughness, but toughness is not normally at issue in

CP titanium grades. Another measure of toughness is Charpy impact strength.

Chemistry and minimum tensile properties for various speciﬁcations for CP and

modiﬁed titanium grades at room temperature are given in Table 5.

Elevated temperature behavior of titanium grades has been studied, but tita-

nium grades are not customarily used at high temperatures. The near-

␣

–

␤

alloys are the preferred materials where high-temperature mechanical properties

are desired. With allowance for grain size effects and possible minor chemistry

variations, cast CP titanium materials should behave in much the same way as

wrought.

Alpha Alloys

Alpha alloys such as Ti–5Al–2.5Sn, Ti–6Al–2Sn–4Zr–2Mo ⫹ Si and Ti–8Al–

1Mo–1V (see Table 2) are used primarily in gas turbine applications. Ti–8Al–

1Mo–1V alloy and Ti–6Al–2Sn–4Zr–2Mo

⫹ Si are useful at temperatures

above the normal range for the workhorse

␣

–

␤

alloy, Ti–6Al–4V. Ti–8Al–1Mo–

1V and Ti–6Al–2Sn–4Zr–2Mo

⫹ Si alloys have better creep resistance than

Ti–6Al–4V, and creep resistance is enhanced with a ﬁne acicular (Widmanstat-

ten) structure. In its normal heat-treated condition, Ti–6Al–2Sn–4Zr–2Mo

⫹ Si

alloy actually has a structure better described as

␣

–

␤

Alpha and near-

␣

alloys therefore are usually employed in the solution an-

nealed and stabilized condition. Solution annealing may be done at a temperature

some 35

⬚C (63⬚F) below the

␤

transus temperature while stabilization is com-

monly produced by heating for8hatabout 590

⬚C (1100⬚F). These alloys are

more susceptible to the formation of ordered Ti

Al, which promotes stress–

corrosion cracking (SCC).

Alpha–Beta Alloys

The most important titanium alloy is the

␣

–

␤

alloy, Ti–6Al–4V. This alloy has

found application for a wide variety of aerospace components and fracture-

critical parts. With a strength-to-density ratio of 25

⫻ 106 mm (1 ⫻ 10

in.),

217

Table 5 CP and Modiﬁed Ti: Minimum Room Temperature Tensile Properties for Various Speciﬁcations

Designation

Chemical Composition (% max)

CONFe

Tensile Properties

Tensile Strength

MPa ksi

Yield Strength

MPa ksi

Minimum

Elongation

(%)

JIS Class 1 — 0.15 0.05 0.20 275–410 40–60 165

ASTM grade 1 (UNS R50250) 0.10 0.18 0.03 0.20 240 35 170–310 25–45 24

DIN 3.7025 0.08 0.10 0.05 0.20 295–410 43–60 175 25.5 30

GOST BT1-00 0.05 0.10 0.04 0.20 295 43 — — 20

BS 19-27t / in.

— — — 0.20 285–410 41–60 195 28 25

JIS Class 2 — 0.20 0.05 0.25 343–510 50–74 215

ASTM grade 2 (UNS R50400) 0.10 0.25 0.03 0.30 343 50 275–410 40–60 20

DIN 3.7035 0.08 0.20 0.06 0.25 372 54 245 35.5 22

GOST BTI-0 0.07 0.20 0.04 0.30 390–540 57–78 — — 20

BS 25-35t / in.

— — — 0.20 382–530 55–77 285 41 22

JIS Class 3 — 0.30 0.07 0.30 480–617 70–90 343

ASTM grade 3 (UNS R50500) 0.10 0.35 0.05 0.30 440 64 377–520 55–75 18

ASTM grade 4 (UNS R50700) 0.10 0.40 0.05 0.50 550 80 480 70 15

DIN 3.7055 0.10 0.25 0.06 0.30 460–590 67–85 323 47 18

ASTM grade 7 (UNS R52400) 0.10 0.25 0.03 0.30 343 50 275–410 40–60 20

ASTM grade 11 (UNS R52250) 0.10 0.18 0.03 0.20 240 35 170–310 25–45 24

ASTM grade 12 (UNS R53400) 0.10 0.25 0.03 0.30 480 70 380 55 12

Unless a range is speciﬁed, all listed values are minimums.

Only for sheet, plate, and coil.

Source: From Materials Property Handbook—Titanium, ASM International, Materials Park, OH 44073-0002, 1994, p. 224.