Jul 18 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Forging
Hot Working
Cold Working
Annealing
Applications
Introduction
Super alloy VLX800H is a slightly modified version of Incoloy 800 with the 800H grade possessing higher creep and rupture strength. This modification is possible because of the closely controlled carbon content and modified heat treatment.
The following sections will discuss in detail about super alloy VLX800H.
Chemical Composition
The chemical composition of super alloy VLX800H is outlined in the following table.
|
Element |
Content (%) |
|
Nickel, Ni |
30 - 35 |
|
Chromium, Cr |
19 - 23 |
|
Manganese, Mn |
1.5 max |
|
Silicon, Si |
1 max |
|
Copper, Cu |
0.75 max |
|
Aluminum, Al |
0.15 - 0.6 |
|
Titanium, Ti |
0.15 - 0.6 |
|
Carbon, C |
0.05 - 0.1 |
|
Sulfur, S |
0.015 max |
|
Iron, Fe |
Remainder |
Physical Properties
The physical properties of super alloy VLX800H are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
7.9 g/cm3 |
0.287 lb/in3 |
|
Melting point |
1371°C |
2500°F |
Other Designations
Equivalent materials to super alloy VLX800H are provided below:
-
ASTM B163
-
ASTM B407
-
ASTM B408
-
ASTM B409
-
ASTM B514
-
ASTM B564
-
DIN 1.4876
-
DIN 1.4958
Fabrication and Heat Treatment
Machinability
Super alloy VLX800H can be machined using the common processes applied to iron based alloys. This alloy does work-harden during machining and displays higher strength and "gumminess" unlike steels. It is recommended that heavy duty machining equipment and tooling should be used to reduce chatter or work-hardening of the alloy.
Any commercial coolants can be used during the machining operations; however water-based coolants are recommended for high-speed operations such as milling, turning, or grinding. Similarly, heavy lubricants are ideal for tapping, broaching, drilling, or boring.
Forming
Super alloy VLX800H can be formed using any of the conventional methods as it is very ductile. Powerful equipment is required to perform forming operations as this alloy is strong. It is recommended that heavy-duty lubricants be used while performing cold forming. It is important to clean all traces of lubricant after forming.
Welding
Welding of super alloy VLX800H can be performed using all the traditional welding methods. Matching alloy filler metal should be used. In case that is not available, it is advised that the nearest alloy closest to the chemical composition be used. The weld beads should be slightly convex, and preheating is not required. Surfaces to be welded have to be clean and free from oil, paint or crayon marking.
Forging
Forging should be performed in the temperature range of 1204-982°C (2200-1800°F).
Hot Working
Hot working can be performed in the temperature range of 1204-871°C (2200-1600°F).
Cold Working
Super alloy VLX800H can be cold formed using all the standard tools except for plain carbon tool steels as they produce galling.
Annealing
Super alloy VLX800H can be annealed at 1176°C (2150°F) and then air cooled.
Applications
Super alloy VLX800H is used in the following application areas:
-
Piping for petrochemical plants
-
Heaters and heat exchangers that are used in prolonged high temperature environments.