Alloy Steel vs. Stainless Steel

Alloy steel is a metal consisting mainly of iron but which includes small amounts of other elements such as: carbon, chromium, manganese, molybdenum, nickel, silicon, tungsten, or vanadium. These elements are added to alter the physical properties of the steel to improve such things as hardness, strength, or corrosion resistance. Alloy steel is often used in applications that require high strength, such as construction or manufacturing.

Stainless steel is a specific type of alloy steel that contains a relatively large proportion of chromium. The added element gives this metal its distinctive shine and corrosion resistance. Stainless steel is often used in kitchenware, medical equipment, or exposed architectural elements. Stainless steel is more resistant to corrosion than most other steel alloys, but it is often not as strong. This article will further compare alloy steel vs. stainless steel in terms of their properties and applications to give you a better understanding of which one might be best for your next project.

What is Alloy Steel?

Alloy steel is a catch-all category for steel materials that contain one or more alloying elements (a substance added to another material to improve its properties). All basic steel consists of iron and a small amount of carbon. The most common additional alloying element is chromium, which gives steel corrosion-resistant properties. Other elements that can be used to alloy steel include: manganese, molybdenum, nickel, titanium, tungsten, and vanadium. The properties of alloy steel depend on the specific elements that are added to it. For example, chromium increases the hardness, wear resistance, and toughness of steel while manganese increases its ductility, hardenability, and wear resistance.

For more information, see our guide on All About Alloy Steel.

What is Stainless Steel?

Stainless steel is a type of alloyed steel that contains at least 10.5% chromium, making it highly resistant to corrosion. The added chromium makes it an ideal material for a wide range of applications, from cookware to medical equipment. Its unique properties make it a popular choice for consumers and businesses alike. It is important to note that there are also different grades of stainless steel, each with its own set of properties.

What Are the Properties of Alloy Steel?

Table 1 highlights the properties of Alloy Steel:

Does mild steel rust?

Because stainless steel is alloyed with chromium, this metal has a much higher corrosion resistance than mild steel. The chrome in the stainless reacts with the oxygen in the air producing a natural ‘chromium oxide’ protective skin on the surface of the metal which means that as long as this layer is undamaged, the metal is naturally corrosion resistant. Different stainless steel grades contain different elements to make them more suitable for different environments, such as a marine environment. Mild steel on the other hand does not have this chromium oxide protective layer and so the iron present reacts with the moisture in the air to produce iron oxide or ‘rust’. Mild steel therefore requires further processing such as galvanising in order to give it a protective surface.