What Is Alloy Steel ?

steels are usually divided into the two main categories of high alloy or low alloy. it is commonly accepted that low alloy steels contain up to 8% alloying elements, and anything over 8% falls into the category of high alloy.

common alloying elements of steel.

though not an exhaustive list, these are some of the most popular elements used in alloying steel. it is estimated that approximately 75% of all steel alloys have been created in the last 20 years alone, and development is ongoing. many alloys require heat treatment to develop their required features further. although this list gives some idea of the properties that can be affected by different alloying materials, most alloys will contain two or more elements to create a specific desired effect. a typical example is the 4100 series of chromium-molybdenum alloys, widely used in everything from structural projects to military gear.

aluminium

aluminium is used in relatively small amounts, resulting in a robust and lightweight metal with great corrosion resistance, though depending on the proportions this can come at the cost of increased brittleness and poor shock-resistance.

chromium

a small percentage of chromium in an alloy can increase hardness and toughness, although with some loss of ductility. larger ratios of chromium significantly increase corrosion resistance; stainless steel is the most well-known alloy in this category, with approximately 11% chromium content or higher.

cobalt

cobalt alloys have increased hardness and dramatically improved resistance to scaling at high-temperatures, making them a popular tool steel.  

silicon

silicon is used in small amounts, generally around 3%, to slightly improve strength while increasing magnetism and acting as a highly effective deoxidiser. this makes them useful within electrical applications such as  transformer,  motors, and generators.

manganese

manganese improves both ductility and hardness, reduces brittleness and greatly increases wear and shock resistance. these alloys are the ideal choice for hammering or where the metal will be under stress.

nickel

another deoxidiser, nickel greatly increases corrosion resistance when used in higher proportions. it also improves strength and hardness without compromising on ductility like some alloys.

tungsten

as well as increased strength and hardness, tungsten alloys are primarily used for their impressive heat-resistance with a higher melting point than most steels. this ability to retain toughness under high temperatures makes them ideal for high-speed tools and machinery parts such as drill bits and cutting blades.

vanadium

vanadium alloys are a great all-round choice, with increased tensile strength, toughness, wear-resistance and corrosion-resistance. these are often alloyed with chromium to retain a workable level of formability.