Super Alloy Pyrotool 7 (UNS N07718)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Other Designations
Fabrication and Heat Treatment
     Machinability
     Forming
     Welding
     Forging
     Hot Working
     Cold Working
     Annealing
     Aging
Applications

Introduction

Super alloy Pyrotool 7 is a high-strength, corrosion resistant, and high-temperature resistant nickel-chromium alloy. It can be effectively utilized at cryogenic temperatures and also in air up to 704°C (1300°F). The alloy can be readily worked and age-hardened.

The following sections will discuss in detail about super alloy Pyrotool 7.

Chemical Composition

The chemical composition of Pyrotool 7 is outlined in the following table.

Element Content (%)
Nickel, Ni + Cobalt, Co 52.5
Chromium, Cr 19
Niobium, Nb + Tantalum, Ta 5.25
Molybdenum, Mo 3
Titanium, Ti 1
Aluminum, Al 0.6
Carbon, C 0.05
Iron, Fe Remainder

Physical Properties

The physical properties of Pyrotool 7 are tabulated below.

Properties Metric Imperial
Density 8 g/cm3 0.29 lb/in3
Melting point 1326°C 2420°F

Other Designations

Equivalent materials to Pyrotool 7 are provided below.

AMS 5663 GE B14H89 PWA 1009 SPS M637
AMS 5662 DIN 2.4688 GE B50TF15 PWA 1033
AMS 5597 DIN 2.4668 GE B50TF14 SPS M275
AMS 5596 ASTM B670 GE B50 TF69 RBO 170-153
AMS 5590 ASTM B637 GE B50 TF14 PWA 1010
AMS 5589 AMS 5832 AMS 5664  

Fabrication and Heat Treatment

Machinability

Super alloy Pyrotool 7 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 Pyrotool 7 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 Pyrotool 7 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 1121-926°C (2050-1700°F).

Hot Working

Hot working can be performed in the temperature range of 1121-898°C (2050-1650°F). In case hot working temperatures fall below 898°C (1650°F), it is essential to reheat the alloy.

Cold Working

Pyrotool 7 can be cold formed using all the standard tools.

Annealing

Pyrotool 7 can be solution annealed at 1037°C (1900°F) and rapidly air cooled.

Aging

This super alloy can be annealed at 982°C (1800°F) and aged at 718°C (1325°F) for 8 h. Then furnace cooled to 621°C (1150°F) and held at that temperature for 10 h, which is followed by air cooling. This treatment provides the highest room temperature strength and excellent rupture properties.

Applications

Super alloy Pyrotool 7 is used in many application areas as listed below:

  • Rams
  • Rings
  • Liners
  • Mandrels
  • Holders
  • Forging dies
  • Extrusion dies
  • Dummy blocks
  • High-temperature tooling
  • Cryogenic storage tanks
  • Gas turbine hot section components.

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