Jul 30 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Forging
Welding
Annealing
Hardening
Applications
Introduction
Super alloys, also referred to as high performance alloys, perform excellently in high temperature environments. They are widely used in many industrial sectors.
Super Alloy HPA 50 is an austenitic, nitrogen strengthened steel alloy. It has corrosion resistance that is similar to grade 316 stainless but possesses greater strength. It can be readily fabricated and remains non-magnetic even after rigorous forming operations. It has excellent yield strength.
The following sections will discuss in detail about super alloy HPA 50.
Chemical Composition
The chemical composition of super alloy HPA 50 is outlined in the following table.
|
Element |
Content (%) |
|
Chromium, Cr |
20.5 - 23.5 |
|
Nickel, Ni |
11.5 - 13.5 |
|
Manganese, Mn |
4-6 |
|
Molybdenum, Mo |
1.5 - 3 |
|
Silicon, Si |
1 max |
|
Nitrogen, N |
0.2 - 0.4 |
|
Vanadium, V |
0.1 - 0.3 |
|
Niobium, Nb |
0.1 - 0.3 |
|
Carbon, C |
0.06 max |
|
Phosphorus, P |
0.04 max |
|
Sulfur, S |
0.03 max |
|
Iron, Fe |
Remainder |
Physical Properties
The physical properties of super alloy HPA 50 are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
7.7 g/cm3 |
0.28 lb/in3 |
Other Designations
Equivalent materials to super alloy HPA 50 are listed below:
|
ASTM A193 (B8R, B8RA) |
ASTM A240 (XM-19) |
ASTM A249 (XM-19) |
ASTM A312 (XM-19) |
ASTM A403 (XM-19) |
|
ASTM A182 (XM-19) |
ASTM A194 (B8R, B8RA) |
ASTM A269 (XM-19) |
ASTM A336 (XM-19) |
ASTM A412 (XM-19) |
|
ASTM A479 (XM-19) |
ASTM A580 (XM-19) |
ASTM A813 (TP XM-19) |
ASTM A276 |
DIN 1.3964 |
Fabrication and Heat Treatment
Machinability
Super alloy HPA 50 can be machined using the common processes. Slow speeds, generous quantity of resulfurized lubricant and constant feeds are essential for machining this alloy. The speeds and feeds can match that of stainless grades 316 or 317. the chips tend be tough and stringy and it is recommended that curlers or breakers are used.
Forming
Super alloy HPA 50 can be formed using any of the conventional methods. The springback tends to be greater for this alloy than with standard austenitics and hence care should be to provide appropriate forming forces. It is recommended that process annealing be performed to remove stresses caused by this alloys' high work hardening rate. In case of intermediate annealing, this alloy has to be heated to 1065°C (1950°F).
Forging
Forging of super alloy HPA 50 can be performed by heating to 1093°C (2000°F), soaking to equalize, and then heating to 1176°C (2150°F). This process should be followed by annealing so as to regain optimum corrosion resistance.
Welding
Welding of super alloy HPA 50 can be performed using all the traditional welding methods such as gas tungsten arc, gas metal arc and submerged arc methods. It is recommended that a filler matching the higher alloy material should be selected to provide optimum results. Pre-heating is not required with this material.
Annealing
Annealing of this material can be performed by soaking at 1037-1121°C (1900-2050°F) and then rapidly quenching in air or water.
Hardening
Super alloy HPA 50 hardens only by cold work.
Applications
Super alloy HPA 50 is used in the following application areas:
-
Super alloy HPA 50 is mainly used in applications requiring high strength and corrosion resistance such as marine hardware, boat shafting, fasteners, valves, and pumps.