Jul 8 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Annealing
Forging
Hot Working
Cold Working
Applications
Introduction
Titanium mixed with other chemical elements such as molybdenum, aluminum, nickel, and zirconium produces a wide range of titanium alloys.
Grade 12 Ti 0.3 Mo 0.8 Ni is a commercially pure wrought alloy. This alloy has excellent strength at high temperatures coupled with excellent weldability and crevice corrosion resistance.
The following sections will discuss in detail about grade 12 Ti 0.3 Mo 0.8 Ni alloy.
Chemical Composition
The chemical composition of grade 12 Ti 0.3 Mo 0.8 Ni alloy is outlined in the following table.
|
Element |
Content (%) |
|
Nickel, Ni |
0.6 - 0.9 |
|
Iron, Fe |
0.3 max |
|
Molybdenum, Mo |
0.2 - 0.4 |
|
Oxygen, O |
0.25 max |
|
Carbon, C |
0.08 max |
|
Nitrogen, N |
0.03 max |
|
Hydrogen, H |
0.015 max |
|
Titanium, Ti |
Remainder |
Physical Properties
The physical properties of grade 12 Ti 0.3 Mo 0.8 Ni alloy are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
4.50 g/cm3 |
0.163 lb/in3 |
|
Melting point |
≤ 1660°C |
≤ 3020°F |
Mechanical Properties
The following table shows mechanical properties of grade 12 Ti 0.3 Mo 0.8 Ni alloy.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
550 MPa |
79800 psi |
|
Yield strength |
380 MPa |
55100 psi |
|
Poisson’s ratio |
0.37 |
0.37 |
|
Elastic modulus |
105 GPa |
15200 ksi |
|
Shear modulus |
45.0GPa |
6530 ksi |
|
Elongation at break |
12 % |
12 % |
|
Hardness, Brinell |
180 - 235 |
180 - 235 |
|
Hardness, Knoop |
222 |
222 |
|
Hardness, Rockwell C |
11 |
11 |
|
Hardness, Vickers |
209 |
209 |
Thermal Properties
The thermal properties of grade 12 Ti 0.3 Mo 0.8 Ni alloy are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@0.000-100°C/32-212°F) |
8.60 µm/m°C |
4.78 µin/in°F |
|
Thermal conductivity |
19 W/mK |
132 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to grade 12 Ti 0.3 Mo 0.8 Ni alloy are as follows:
-
ASTM B265 (12)
-
ASTM B337 (12)
-
ASTM B338 (12)
-
ASTM B348 (12)
-
ASTM B381 (F-12)
Fabrication and Heat Treatment
Machinability
Grade 12 Ti 0.3 Mo 0.8 Ni alloy can be machined using slow speeds, right quantity of coolant flow and high feed rates. High-speed tools should be used for tooling this alloy and the recommended tool types are tungsten carbide designations C1-C4 or cobalt based.
Forming
Grade 12 Ti 0.3 Mo 0.8 Ni alloy can be hot or cold formed.
Welding
Weldabilty of grade 12 Ti 0.3 Mo 0.8 Ni alloy is rated as excellent.
Annealing
For annealing grade 12 Ti 0.3 Mo 0.8 Ni alloy, the material has to be heated to 732-816°C (1350-1500°F), held for 2 h followed by air cooling. In case of intermediate stress relieving, the material has to be heated to 538-649°C (1000-1200°F) and held for 1 h followed by air cooling.
Forging
Rough forging can be performed at 871°C (1600°F) and completed at 788-843°C (1450-1550°F)
Hot Working
Hot working enhances the overall ductility of the material.
Cold Working
Cold working features of this material is same as that of austenitic stainless steel. Post-work annealing is recommended to re-attain favorable performance properties.
Applications
Grade 12 Ti 0.3 Mo 0.8 Ni alloy is used in the following application areas:
-
Pumps
-
Valves
-
Heat exchangers
-
Pipes and fittings
-
Chemical processing
-
In high temperature chemical manufacturing equipment
-
Marine and airframe components
-
In medium reducing or variable oxidizing-reducing media - containers