Super Alloy 21-2N Valve Steel (UNS K63017)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Fabrication and Heat Treatment
Machinability
Forming
Tempering
Hardening
Applications

Introduction

Super alloys are metallic alloys used at high temperatures above 540ºC (1000ºF) where high surface stability and deformation resistance are mainly required. Three major classes of super alloys include iron-base, nickel-base and cobalt-base alloys. The iron-base super alloys are generally wrought alloys with stainless steel technology. Nickel-base and cobalt-base super alloys may be cast or wrought based on its composition or application. Super alloys are commonly forged, rolled to sheet or produced in various shapes. However, highly alloyed compositions are produced as castings.

The following datasheet provides a detailed description of super alloy 21-2N valve steel.

Chemical Composition

The following table shows the chemical composition of super alloy 21-2N valve steel.

Elements Content (%)
Chromium, Cr 20.35
Manganese, Mn 8.5
Nickel, Ni 2.13
Carbon, C 0.55
Molybdenum, Mo 0.50 max
Silicon, Si 0.25 max

Physical Properties

The physical properties of super alloy 21-2N valve steel are given in the following table.

Properties Metric Imperial
Density 7.7 g/cm³ 0.2878 lb/in³

Mechanical Properties

The mechanical properties of super alloy 21-2N valve steel are displayed in the following table.

Properties Metric Imperial
Tensile strength 900-1150 MPa 13053-16679 psi
Modulus of elasticity 215 GPa 31183 ksi
Elongation 8% 8%
Reduction 10% 10%
Hardness 28 28

Fabrication and Heat Treatment

Machinability

Super alloy 21-2N valve steel can be machined similar to that of the standard 18-8 stainless steels.

Forming

Forming of super alloy 21-2N valve steel can be performed at 950 to 1100ºC (1742 to 2012ºF).

Tempering

Super alloy 21-2N valve steel can be tempered at 730 to 780ºC (1346 to 1436ºF)

Hardening

Super alloy 21-2N valve steel can be hardened at 1140 to 1180ºC (2084 to 2156ºF) and then water quenched.

Applications

Super alloy 21-2N valve steel finds its application in the manufacture of automotive valve.

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