Titanium is a new type of bai metal. The performance of titanium is related to the content of impurities such as carbon, nitrogen, hydrogen, and oxygen. The purest titanium iodide contains no more than 0.1% dao, but its strength and plasticity are low. high. The performance of 99.5% industrial pure titanium is: density ρ=4.5g/cubic centimeter, melting point is 1725℃, thermal conductivity λ=15.24W/(mK), tensile strength σb=539MPa, elongation δ=25%, section Shrinkage ψ=25%, elastic modulus E=1.078×105MPa, hardness HB195.

1. High strength
The density of titanium alloy is generally about 4.51g/cm3, which is only 60% of steel. The density of pure titanium is close to that of ordinary steel. Some high-strength titanium alloys exceed the strength of many alloy structural steels. Therefore, the specific strength (strength/density) of titanium alloy is much greater than that of other metal structural materials. See Table 7-1, which can produce parts with high unit strength, good rigidity and light weight. The aircraft’s engine components, skeleton, skin, fasteners and landing gear all use titanium alloys.

2. High thermal intensity
The service temperature is several hundred degrees higher than that of aluminum alloy. It can still maintain the required strength at medium temperature. It can work for a long time at a temperature of 450~500℃. These two types of titanium alloys are still very high in the range of 150℃~500℃. Specific strength, while the specific strength of aluminum alloy decreases significantly at 150°C. The working temperature of titanium alloy can reach 500℃, while that of aluminum alloy is below 200℃.

3. Good corrosion resistance
Titanium alloy works in moist atmosphere and seawater medium, its corrosion resistance is far better than stainless steel; it is particularly resistant to pitting corrosion, acid corrosion, and stress corrosion; it is resistant to alkali, chloride, chlorine organic substances, nitric acid, sulfuric acid It has excellent corrosion resistance. However, titanium has poor corrosion resistance to media with reducing oxygen and chromium salts.

4. Good low temperature performance
Titanium alloys can still maintain their mechanical properties at low and ultra-low temperatures. Titanium alloys with good low temperature performance and extremely low interstitial elements, such as TA7, can maintain a certain degree of plasticity at -253°C. Therefore, titanium alloy is also an important low-temperature structural material.

5. High chemical activity
Titanium has high chemical activity, and produces strong chemical reactions with O, N, H, CO, CO2, water vapor, ammonia, etc. in the atmosphere. When the carbon content is greater than 0.2%, it will form hard TiC in the titanium alloy; when the temperature is higher, it will also form a TiN hard surface layer when it interacts with N; when the temperature is above 600℃, titanium absorbs oxygen to form a hardened layer with high hardness ; Increase in hydrogen content will also form an embrittlement layer. The depth of the hard and brittle surface layer produced by absorbing gas can reach 0.1~0.15mm, and the degree of hardening is 20%~30%. Titanium also has a high chemical affinity and is easy to adhere to the friction surface.

6. Low thermal conductivity
The thermal conductivity of titanium λ=15.24W/(m.K) is about 1/4 of nickel, 1/5 of iron, and 1/14 of aluminum. The thermal conductivity of various titanium alloys is about 50% lower than that of titanium. The elastic modulus of titanium alloy is about 1/2 of that of steel, so it has poor rigidity and is easy to deform. It is not suitable to make slender rods and thin-walled parts. The springback of the processed surface during cutting is very large, about 2~3 of stainless steel. Times, resulting in severe friction, adhesion, adhesive wear on the flank of the tool.

Comparison table of commonly used titanium and titanium alloy grades in various countries

Numbering China


International standard ISO USA


Russia TOCT France






  1 TA1 Grade1 GradeF1 BT1-00 T40 Ti1 Level 1
  2 TA2 Grade2 GradeF2 BT1-0 T40 Ti3 Level 2
  3 TA3 Grade4A/4B GradeF3 BT1-0 T40 Ti4 Level 2
  4 TA4 Grade3 GradeF4 BT1-0 T40 Ti4 Level 3
  5 TC4 TiAl6v4 GradeF5 BT6 TA6V TiAl6V4 YATB640
  6 TC11 BT9


Material Name Chinese standard USA standard
Titanium and titanium alloy sheet GB/T3621 ASTM B265
Titanium and titanium alloy bars GB/T2965 ASTM B348
Titanium and titanium alloy tube GB/T3624 ASTM B337
Titanium and titanium alloy tubes for heat exchangers and condensers GB/T3625 ASTM B338
Titanium and titanium alloy strips and foils GB/T3622 ASTM B265
Titanium and titanium alloy cakes and rings GB/T16598 ASTM B381
Titanium and titanium alloy wire GB/T3623 ASTM B863

Titanium and titanium alloy processed materials for surgical implants




Commonly used titanium and titanium alloy grades and chemical composition(GB/T 3620.1-2007)

Alloy grade Chemical composition group Main ingredients/%
Ti Al Sn Mo V Cr Fe Mn Zr Pd
Chinese standard USA standard Russia standard Janpan Standard
TA1ELI Industrial pure titanium
TA1 GR1 BT1-0 TP270 Industrial pure titanium
TA1-1 GR1 BT1-00 Industrial pure titanium ≤0.20
TA2ELI Industrial pure titanium
TA2 GR2 TP340 Industrial pure titanium
TA3ELI Industrial pure titanium
TA3 GR3 TP450 Industrial pure titanium
TA4ELI Industrial pure titanium
TA4 GR4 TP550 Industrial pure titanium
TC4ELI Ti-6Al-4VELI 5.5~6.5 3.5~4.4
TC4 GR5 BT6 TAP6400 Ti-6Al-4V 5.5~6.75 3.5~4.5
TA9 GR7 TP340Pb Ti-0.2Pd 0.12~0.25
TA9-1 GR11 Ti-0.3Pd 0.12~0.26
TA18 GR9 OT4-B TAP3250 Ti-3Al-2.5V 2.0~3.5 1.5~3.0
TA10 GR12 Ti-0.3Mo-0.8Ni 0.2~0.4
Main ingredients/% Impurities, not more than/%
Ni Cu Nb Si B Fe C N H O Other elements
single total
0.1 0.03 0.012 0.008 0.1 0.05 0.2
0.2 0.08 0.03 0.015 0.18 0.1 0.4
≤0.08 0.15 0.05 0.03 0.003 0.12 0.1
0.2 0.05 0.03 0.008 0.1 0.05 0.2
0.3 0.08 0.03 0.015 0.25 0.1 0.4
0.25 0.05 0.04 0.008 0.18 0.05 0.2
0.3 0.08 0.05 0.015 0.35 0.1 0.4
0.3 0.05 0.05 0.008 0.25 0.05 0.2
0.5 0.08 0.05 0.015 0.4 0.1 0.4
0.25 0.08 0.03 0.012 0.13 0.1 0.3
0.3 0.08 0.05 0.015 0.2 0.1 0.4
0.3 0.08 0.03 0.015 0.25 0.1 0.4
0.2 0.08 0.03 0.015 0.18 0.1 0.4
0.25 0.08 0.05 0.015 0.12 0.1 0.3
0.6~0.9 0.3 0.08 0.03 0.015 0.25 0.1 0.4

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