Super Alloy AM 40 (UNS S21900)

Topics Covered

Introduction
Physical Properties
Mechanical Properties
Fabrication and Heat Treatment
     Machinability
     Forming
     Welding
     Forging
     Annealing
     Hardening
Applications

Introduction

Super alloys are metallic alloys that function at high temperature environment where high surface stability and deformation resistance are mainly required. Three major classification of super alloys include iron-base, nickel-base and cobalt-base alloys. Based on its application and composition, nickel-base and cobalt-base super alloys may be cast or wrought. The iron-base super alloys are generally wrought alloys featuring stainless steel technology. Super alloys are commonly forged, rolled to sheet or produced in various shapes. However, highly alloyed compositions are produced as castings. These alloys contain different elements in various combinations in order to achieve the desired result.

The following datasheet explains in detail about super alloy AM 40.

Physical Properties

The physical properties of super alloy AM 40 are given in the following table.

Properties Metric Imperial
Density 7.7 g/cm³ 0.28 lb/in³

Mechanical Properties

The mechanical properties of super alloy AM 40 are displayed in the following table.

Properties Metric Imperial
Poisson’s ratio 0.298 0.298

Fabrication and Heat Treatment

Machinability

Machining of super alloy AM 40 can be performed through resulfurized lubricant, positive feeds and slow speeds. This alloy employs all kinds of machining practices. However, the usage of breakers or curlers is preferred to avoid tough and stringy chips.

Forming

Super alloy AM 40 can be formed using any common forming method. However, springback must be taken into consideration before selecting the appropriate forming method.

Welding

Welding methods such as submerged arc welding, gas metal arc welding and gas tungsten arc welding can be used to weld super alloy AM 40.

Forging

Super alloy AM 40 should be heated to 1093ºC (2000ºF), soaked to equalize and then heated to 1176ºC (2150ºF) before forging.

Annealing

Super alloy AM 40 is annealed at 1038 to 1121ºC (1900 to 2050ºF) followed by quenching in water or air.

Hardening

Super alloy AM 40 can be hardened using cold working method.

Applications

The following are some of the major applications of super alloy AM 40:

  • Fasteners
  • Pipe components
  • Ducting equipment
  • Bellows

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