High strength and hardness, yet not much of toughness?

In everyday language, terms like strength, hardness, and toughness may seem similar, but when it comes to engineering, particularly in the context of materials mechanics, what do these terms truly signify?

The concepts of strength, hardness, and toughness are distinct mechanical properties of materials, and they don't always go hand in hand. It's crucial to understand the differences between these properties:

1. Strength: Strength is the ability of a material to withstand an applied load without deformation or failure. It's essentially a measure of how much force a material can endure before breaking or yielding. A strong material can withstand a large amount of force without deforming or fracturing.

2. Hardness: Hardness, on the other hand, is a measure of a material's resistance to surface deformation, typically through indentation or scratching. It quantifies a material's ability to withstand wear and abrasion. Hard materials can resist penetration from other objects or materials. For example, Hardox® wear plate is the world's leading abrasion-resistant (AR) steel. Hardox® is hard through and through, from the surface deep down to its core, giving you extended service life and high productivity in the most challenging environments. Read more: https://www.ssab.com/en/brands-and-products/hardox

3. Toughness: Toughness is the ability of a material to absorb energy and deform plastically before fracturing. It's a measure of how much energy a material can absorb before it ruptures. Tough materials can take a lot of deformation and energy absorption before failing.

Now, here's why a strong, hard metal may not be tough:

Imagine a brittle material, such as some ceramics or certain high-carbon steels. These materials can be very strong and hard, meaning they can withstand a lot of force and resist surface deformation. However, they lack toughness. When subjected to a sudden impact or a load beyond their capacity to deform plastically, they tend to fracture suddenly, without much warning. In other words, they are strong and hard but not tough.

Conversely, some materials like ductile metals (e.g., mild steel, copper, or aluminum) may not be exceptionally hard, but they are tough. They can deform significantly before breaking, absorbing a considerable amount of energy in the process. So, they might not be as strong or hard as some other materials, but they are tough.

Genuine Hardox® steel is both hard and tough

Hardness ensures outstanding wear resistance, while toughness enables easy bending and forming of the steel plate. Hardox® wear plate can withstand high-impact forces without permanent deformation.

Genuine Hardox® wear plate combines hardness for exceptional wear resistance and toughness for workshop versatility and structural wear steel performance.

Scan the QR code below or click here to see an animation on the SSAB website showing how Hardox® wear plate can take high-impact forces without denting. "When a heavy object hits the plate the

force is distributed and doesn’t leave any permanent deformation.

The absence of reinforcements makes the container stronger since the plate can flex and absorb the blow "[1].

More details at :

https://www.ssab.com/en/brands-and-products/hardox/genuine

References:

[1] https://www.ssab.com/en/brands-and-products/hardox/genuine