minor metal elements effects in steel

There are several minor metal elements, like Nickel, Molybdenum, Vanadium, Tungsten, Niobium and Cobalt. Unlike other usual metal or non metal elements, they only occupy little part of the total chemical composition of the final steel or iron product. However, they still play their necessary and different roles in steel. Sometimes only very mall amount can make a big difference to the physical property of steel. 

Nickel can increase the strength of steel while maintaining good plasticity and toughness. Nickel has high corrosion resistance to acids and alkalis, rust and heat resistance at high temperatures. However, as nickel is a relatively scarce resource, other alloying elements should be used to replace nickel-chromium steel. It is very important for manufacturers to detect the Ni content in stainless steel and prevent suppliers from shoddy.

Molybdenum can refine the grain of steel, improve hardenability and thermal strength, and maintain sufficient strength and creep resistance at high temperatures (long-term stress and deformation at high temperatures are called creep). The addition of molybdenum to structural steel can improve mechanical properties. It can also suppress the brittleness of alloy steel due to fire. Adding molybdenum to tool steel can improve redness.

minor metal elements effects in steel

Vanadium is an excellent deoxidizer for steel. The addition of 0.5% vanadium to the steel can refine the grain structure and improve the strength and toughness. The carbide formed by vanadium and carbon can improve the resistance to hydrogen corrosion under high temperature and high pressure.

Tungsten has a high melting point and high specificity, and is an expensive alloying element. Tungsten and carbon form tungsten carbide with high hardness and wear resistance. Adding tungsten to tool steel can significantly improve the red hardness and thermal strength, which can be used as cutting tools and forging dies.

Niobium can refine the grains and reduce the overheating sensitivity and temper brittleness of steel, and improve the strength, but the plasticity and toughness are reduced. Adding niobium to ordinary low-alloy steel can improve the resistance to atmospheric corrosion and hydrogen, nitrogen, and ammonia corrosion at high temperatures. Niobium can improve welding performance. Adding niobium to austenitic stainless steel can prevent intergranular corrosion.

Cobalt is a rare precious metal and is mostly used in special steels and alloys, such as heat-strength steel and magnetic materials.