Introduction
Super alloys or high performance alloys are used in environments with very high temperature above 540ºC (1000ºF) where deformation resistance and high surface stability are chiefly required. They have good oxidation and creep resistance. Cobalt-base, nickel-base and iron-base alloys are the three major types of super alloys. The iron-base super alloys are generally wrought alloys provided with stainless steel technology. Nickel-base and cobalt-base super alloys may be cast or wrought based on its composition or application. Super alloys can be generally forged, rolled to sheet or produced in different shapes. Highly alloyed compositions are formed as castings. They can be strengthened using hardening techniques like work hardening, solid-solution hardening and precipitation hardening.
HASTELLOY(r) G30(r) alloy is corrosion resistant and has the ability to oxidize acids.
The following sections will provide a detailed description of HASTELLOY(r) G30(r) alloy.
Chemical Composition
The following table shows the chemical composition of HASTELLOY(r) G30(r) alloy.
| Element |
Content (%) |
| Nickel, Ni |
43 |
| Chromium, Cr |
28.0-31.5 |
| Iron, Fe |
13-17 |
| Cobalt, Co |
5 |
| Molybdenum, Mo |
4-6 |
| Tungsten, W |
1.50 - 4 |
| Manganese, Mn |
1.50 |
| Copper, Cu |
1 - 2 .40 |
| Silicon, Si |
0.8 |
| Phosphorous, P |
0.040 |
| Carbon, C |
0.030 |
| Sulfur, S |
0.020 |
Physical Properties
The physical properties of HASTELLOY(r) G30(r) alloy are given in the following table.
| Properties |
Metric |
Imperial |
| Density |
8.22 g/cm³ |
0.297 lb/in³ |
| Melting point |
1371ºC |
2500ºF |
Mechanical Properties
The mechanical properties of HASTELLOY(r) G30(r) alloy are given in the following table.
| Properties |
Metric |
Imperial |
| Tensile strength |
1096 MPa |
159000 psi |
| Yield strength (@0.2%) |
1000 MPa |
145000 psi |
| Modulus of elasticity (plate heat treated to 1177°C, rapid quenched) |
202 GPa |
29300 ksi |
| Elongation at break (in 50.8 mm) |
12% |
12% |
| Reduction of area |
57% |
57% |
| Hardness, Brinell (converted from Rockwell C hardness) |
304 |
304 |
| Hardness, Knoop (converted from Rockwell C hardness) |
326 |
326 |
| Hardness, Rockwell C |
32 |
32 |
| Hardness, Vickers (converted from Rockwell C hardness) |
316 |
316 |
Thermal Properties
The thermal properties of HASTELLOY(r) G30(r) alloy are given in the following table.
| Properties |
Metric |
Imperial |
| Thermal expansion co-efficient (@30-316ºC/86-601ºF) |
14.4 µm/m°C |
8 µin/in°F |
| Thermal conductivity |
10.2 W/mK |
70.8 BTU in/hr.ft2.°F |
Other Designations
Equivalent materials to HASTELLOY(r) G30(r) alloy are the following:
ASTM B366
ASTM B581
ASTM B582
ASTM B619
ASTM B622
DIN 2.4603
Fabrication and Heat Treatment
Machinability
HASTELLOY(r) G30(r) alloy can be machined using conventional techniques employed for iron based alloys. The quality of the alloy can be improved with the utilization of water-base coolants. Heavy duty machining tools and equipment can be used prior to cutting in order to reduce chattering or work-hardening of the alloy.
Forming
HASTELLOY(r) G30(r) alloy can be formed through conventional forming methods.
Welding
Welding of HASTELLOY(r) G30(r) alloy is performed through commonly used welding techniques like gas tungsten arc welding, shielded metal-arc welding, metal-arc welding and submerged-arc welding. However, an alloy filler metal that suits this alloy should be used.
Heat Treatment
HASTELLOY(r) G30(r) alloy is capable of being annealed. However, this alloy must be solution-annealed after hot forming in order to restore its resistance to corrosion.
Forging
As HASTELLOY(r) G30(r) alloy has good ductile property, it can be forged easily.
Cold Working
HASTELLOY(r) G30(r) alloy can be cold worked using standard tooling methods. As plain carbon steels produce galling, they are not preferred for forming HASTELLOY(r) G30(r) alloy. Galling can be minimized with the help of heavy duty lubricants.
Annealing
HASTELLOY(r) G30(r) alloy can be annealed at 1177ºC (2150ºF) followed by rapid cooling of air and water quenching.
Hardening
HASTELLOY(r) G30(r) alloy can be hardened by cold working.
Applications
The following are the major applications of HASTELLOY(r) G30(r) alloy:
Chemical process equipment
Reheater tubes
Pump components
Agitator blades
Reboilers in nuclear waste reprocessing.
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