Dec 17 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
Machinability
Forming
Welding
Heat Treatment
Forging
Hot Working
Cold Working
Annealing
Applications
Introduction
Super alloys or high performance alloys contain a number of elements in a variety of combinations to achieve a desired result. These alloys are ideal for use at high temperatures and severe mechanical stress , and also in cases where high surface stability is needed. Super alloys provide good creep and oxidation resistance.
Strengthening of super alloys is performed by work hardening, solid-solution hardening, and precipitation hardening methods.
Nimonic PE16™ is Ni-Cr-Mo alloy with lower nickel content, and belongs in the high temperature and high strength alloy group. It is a not an expensive alloy. The aluminum and titanium present in this alloy makes it precipitation hardenable by heat treatment.
The following datasheet will provide more details about Nimonic PE16™.
Chemical Composition
The following table shows the chemical composition of Nimonic PE16™.
|
Element |
Content (%) |
|
Nickel, Ni |
42-45 |
|
Iron, Fe |
31 |
|
Chromium, Cr |
15.5-17.5 |
|
Molybdenum, Mo |
2.80-3.80 |
|
Cobalt, Co |
2 |
|
Titanium, Ti |
1.10-1.30 |
|
Aluminum, Al |
1.10-1.30 |
|
Silicon, Si |
0.50 |
|
Copper, Cu |
0.50 |
|
Manganese, Mn |
0.20 |
|
Carbon, C |
0.040-0.080 |
|
Zirconium, Zr |
0.020-0.040 |
|
Sulfur, S |
0.015 |
|
Boron, B |
0.0050 |
Physical Properties
The physical properties of Nimonic PE16™ are outlined in the following table.
|
Properties |
Metric |
Imperial |
|
Density |
8.02 g/cm³ |
0.290 lb/in³ |
|
Melting point |
1310-1355°C |
2390-2471°F |
Mechanical Properties
The mechanical properties of Nimonic PE16™ are provided below.
|
Properties |
Metric |
Imperial |
|
Tensile strength (precipitation hardened, value at room temperature) |
900 MPa |
131000 psi |
|
Yield strength (@strain 0.200%, precipitation hardened, value at room temperature) |
450 MPa |
65300 psi |
|
Elongation at break (precipitation hardened) |
28% |
28% |
Thermal Properties
The thermal properties of Nimonic PE16™ are given below.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@21-100°C/69.8-212°F) |
13.8 µm/m°C |
7.67 µin/in°F |
|
Thermal conductivity |
11.72 W/mK |
81.34 BTU in/hr.ft².°F |
Fabrication and Heat Treatment
Machinability
Traditional machining methods that are used for iron-based alloys can be used for Nimonic PE16™. This alloy can be work-hardened during machining. Before cutting is performed, it is recommended that heavy duty machining equipment and tooling be used so as to reduce chatter or work-hardening of the alloy. During high speed operations such as grinding, turning, or milling, water-based coolants are preferred. The use of heavy lubricants while drilling, tapping, broaching or boring is recommended.
Forming
Nimonic PE16™ has good ductility and can be easily formed using all the conventional methods. This alloy is stronger than regular steel; hence it requires a more powerful equipment to complete the forming process. It is recommended that heavy-duty lubricants be used while cold forming. At the end of this process all traces of lubricant has to be cleaned off to prevent embrittlement.
Welding
Nimonic PE16™ can be welded using traditional welding methods. Some of the commonly used methods are shielded metal-arc welding, gas metal-arc welding, submerged-arc welding, and gas-tungsten arc welding. It is recommended that matching alloy filler metal should be used and that the weld beads should be slightly convex. Before the welding process begins, the surface to be welded should be cleaned and should be free from oil, paint or crayon stains.
Heat Treatment
Nimonic PE16™ has to be solution annealed at 1038°C (1900°F) for 4 h and then air cooled. This process is repeated twice at 799°C (1470°F) for 2 h and air cooled, and at 699°C (1290°F) for 16 h and air cooled, so as to complete the precipitation hardening process.
Forging
Nimonic PE16™ can be forged at 1176-968°C (2150-1775°F).
Hot Working
Nimonic PE16™ can be hot worked at 1176-954°C (2150-1750°F).
Cold Working
Cold working can be performed using standard tooling. It is better to avoid using plain carbon tool steels for forming as they cause galling. To minimize galling and provide a neat finish, soft die materials containing bronze and zinc alloys are recommended. However, the life of the die is short. Likewise, heavy duty lubricants should be used to reduce galling in all forming operations.
Annealing
Nimonic PE16™ can be solution annealed at 1038°C (1900°F) for 4 h and then air cooled.
Applications
Nimonic PE16™ is mainly used in high temperature oxidizing applications, especially in cases where strength at temperature is a primary requirement, e.g. industrial furnace components or gas turbine hot sections.