Unit 17.4: Tungsten Steel

Introduction

Tungsten steel is an alloy steel containing tungsten as the primary alloying element.
Tungsten increases hardness, high-temperature strength, and wear resistance, making it ideal for cutting tools, dies, and high-temperature applications.

It is important in mechanical engineering where tools and parts must retain hardness at elevated temperatures.

Definition

Tungsten Steel

Tungsten steel is an alloy steel containing carbon (0.5–1.5%) and tungsten (up to 18%), designed to provide high hardness, wear resistance, and strength at high temperatures.

Core Concept Explanation

Tungsten forms stable carbides in steel, which increase hardness and wear resistance.
It retains hardness at high temperatures, known as red hardness, essential for cutting tools.
Tungsten steel is brittle if not tempered properly, but heat treatment can balance hardness and toughness.
Commonly used in tool steels, especially for high-speed cutting tools and dies.

Composition

Element	Percentage
Carbon (C)	0.5 – 1.5 %
Tungsten (W)	2 – 18 %
Chromium (Cr)	0.3 – 1.5 %
Vanadium (V)	0.1 – 0.3 % (optional)
Iron (Fe)	Balance

Tungsten forms hard carbides that provide wear resistance and high-temperature hardness.

Properties / Characteristics

Property	Description
Hardness	Very high, retains hardness at high temperatures
Strength	High tensile strength
Toughness	Moderate (can be low if not tempered)
Wear Resistance	Excellent
Red Hardness	Very good, suitable for cutting at high speeds
Ductility	Low
Heat Treatability	Excellent (quenching & tempering)

Applications in Engineering

Tungsten steel is widely used for cutting and high-temperature resistant tools:

Cutting tools: lathe tools, drills, milling cutters
Dies and punches for metal forming
High-speed steel tools
Industrial knives and shear blades
Components exposed to high-temperature stress

Exam-Focused Points

Tungsten content: 2–18%
Carbon content: 0.5–1.5%
Retains hardness at high temperatures (red hardness)
Properties: High hardness, wear resistance, high-speed cutting capability
Common applications: cutting tools, dies, punches, high-speed steel tools

Common Exam Traps

Confusing tungsten steel with vanadium steel – remember: tungsten → high-temperature hardness, vanadium → toughness & fatigue resistance
Forgetting red hardness property, which is unique to tungsten steel
Assuming high ductility – tungsten steel is brittle if untempered

Example Competitive Exam Questions

Question: What is the typical tungsten content in tungsten steel?
Answer: 2–18%

Question: Which property makes tungsten steel ideal for cutting tools?
Answer: Retains hardness at high temperatures (red hardness)

Question: Give one common application of tungsten steel.
Answer: Lathe cutting tools or milling cutters

Question: Can tungsten steel be heat treated?
Answer: Yes, by quenching and tempering

Quick Revision Summary

Carbon: 0.5–1.5%
Tungsten: 2–18%
Hardness: Very high, retains at high temperatures
Wear Resistance: Excellent
Red Hardness: Very good
Ductility: Low
Applications: Cutting tools, dies, punches, high-speed steel tools