Super Alloy 21-4N Valve Steel

Topics Covered

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

Introduction

Super alloys or high performance alloys have an ability to function at temperatures above 540ºC(1000ºF) with deformation resistance and high surface stability. As they have good oxidation and creep resistance, super alloys can be commonly forged, rolled to sheet or produced in various shapes. Iron-base, nickel-base and cobalt-base alloys are the major types of super alloys. Nickel-base and cobalt-base super alloys may be cast or wrought based on its composition or application. The iron-base super alloys are generally wrought alloys, that can be strengthened by precipitation hardening, work hardening and solid-solution hardening.

The following datasheet provides a detailed description of super alloy 21-4N valve steel.

Chemical Composition

The following table shows the chemical composition of super alloy 21-4N valve steel.

Elements Content (%)
Chromium, Cr 21
Manganese, Mn 9
Nickel, Ni 3.88
Carbon, C 0.53
Silicon, Si 0.25 max

Physical Properties

The physical properties of super alloy 21-4N valve steel are given in the following table.

Properties Metric Imperial
Density 7.7 g/cm³ 0.278 lb/in³

Mechanical Properties

The mechanical properties of super alloy 21-4N valve steel are displayed in the following table.

Properties Metric Imperial
Tensile strength 950-1200 MPa 13778-17404 psi
Modulus of elasticity 215 GPa 31183 ksi
Elongation 8% 8%
Reduction 10% 10%
Hardness 32 32

Fabrication and Heat Treatment

Machinability

Super alloy 21-4N valve steel can be machined similar to that of the standard 18-8 stainless steels.

Forming

Forming of super alloy 21-4N valve steel can be performed at 950 to 1100ºC (1742 to 2012ºF).

Tempering

Super alloy 21-4N valve steel can be tempered at 730 to 780ºC (1346 to 1436ºF)

Hardening

Super alloy 21-4N valve steel can be hardened at 1140 to 1180ºC (2084 to 2156ºF) and then water quenched.

Applications

Super alloy 21-4N valve steel is widely used in the manufacture of automotive valve.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Submit