ThePipingMart Blog Metals Hardness of Alloy Steels – An Overview

Hardness of Alloy Steels – An Overview

Exploring the Hardness of Alloy Steels

If you are looking for a strong yet highly malleable metal, alloy steel is a great option. Alloy steels are composed of various elements to improve their properties, and this combination allows them to be used in a wide range of applications. Each alloy has its unique hardness level, but how do you determine which is right for your project? Let’s explore the hardness levels of different alloy steels to help you make an informed decision.

Alloy 20 Hardness

Alloy 20 (also known as Carpenter 20Cb-3®) is a nickel-iron-chromium austenitic stainless steel developed for maximum corrosion resistance. Its chemical composition includes nickel (20% min.), chromium (17-19%), molybdenum (2-3%), and iron (balance). This composition gives it excellent corrosion resistance against sulfuric acid, chlorides, and other industrial chemicals. The hardness level of Alloy 20 is measured at between 213 HBW and 241 HBW on the Rockwell C scale.

4140 Alloy Steel Hardness

4140 alloy steel has been around since its invention in 1940 by William S. Hackett. This low-alloy steel offers users good mechanical properties such as strength, toughness, wear resistance, and fatigue strength. It also offers excellent weldability and machinability due to its low carbon content. On the Rockwell C scale, 4140 alloy steel has a hardness rating between 241 HBW and 269 HBW, depending on heat treatment methods used during production.

Alloy 825 Hardness Alloy 825 is an austenitic nickel-iron-chromium alloy with excellent corrosion resistance in both reducing and oxidizing environments due to its high chromium content. It also contains molybdenum for additional strength at high temperatures and titanium for increased protection from chloride pitting corrosion. The hardness level of Alloy 825 ranges from 212 HBW to 278 HBW on the Rockwell C scale, depending on the heat treatment processes used during manufacturing.


After exploring some common alloy steels and their respective hardnesses on the Rockwell C scale, you can now decide which type will work best for your project based on its characteristics and performance needs. Remember that each type of alloy steel has different characteristics that can affect its performance when exposed to various elements or conditions—so choose wisely! With the right information, you can now confidently select which alloy best suits your project’s needs.

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