Chemical Elements in Stainless Steel

There are various chemical elements play a important role in stainless steel, different chemical content affect different result, check details of chemical composition in stainless steel grades, and list some elements as following:

Carbon (C)

  • Carbon content increasing,yield point and tensile strength increasing, but ductility and impact resistance down
  • When carbon content exceed 0.23%,welding performance of steel will be not good
  • Carbon content is generally not more than 0.20%
  • High carbon content can also reduce the corrosion resistance of the steel, easy to rust
  • In addition, carbon can increase cold brittleness and aging of steel,like TP304 and TP304L,304L is low carbon 304

Silicon (Si)

  • In the process of making steel,silicon as a reducing agent and oxidizing agent, so containing 0.15 – 0.30% of silicon
  • If silicon content more than 0.50-0.60%,silicon significantly improve elastic limit, yield point and tensile strength,so it is widely used in spring steel
  • Adding 1.0 – 1.2% silicon in the quenched and tempered steel, strength can be increased by 15-20%
  • The combination of Silicon,Molybdenum, Tungsten, Chromium has the effect of improving the corrosion resistance and oxidation resistance
  • Low carbon steel containing silicon 1 – 4%, with a high permeability, used in electrical industry silicon steel sheet
  • Silicon content increasing,reducing the welding of steel

Manganese (Mn)

  • in the process of making steel, manganese is a good agent and desulfurization agent,manganese content in common steel of 0.30 – 0.50%
  • Carbon steel,adding more than 0.70% manganese,not only enough toughness,and have higher strength and hardness, improve steel quenching and performance of thermal processing
  • Manganese content increased, weakened the corrosion resistance of steel, reduce the welding performance. Manganese can improve the strength of steel, increase the manganese content to improve the low temperature impact toughness is good

Phosphorus (P)

in general, phosphorus is a harmful element in steel, increasing the cold brittleness of steel, so that the welding performance deterioration, reduce ductility, so that the cold bending performance. It usually requires the phosphorus content in steel is less than 0.045%, lower requirements for high quality steel.

Sulfur (S)

  • Sulfur in the normal circumstances is also harmful elements. generating heat, reduce ductility and toughness
  • Sulfur on the welding performance is also bad, reducing corrosion resistance. So the sulfur content is less than 0.055%
  • Requirements of high quality steel is less than 0.040%. The addition of 0.08-0.20% to the steel can improve the machinability, often referred to as free-cutting steel

Chromium (Cr)

  • In the structural steel and tool steel, chromium can significantly improve the strength, hardness and wear resistance, but at the same time to reduce ductility and toughness
  • Chromium can improve oxidation resistance and corrosion resistance,so it is an important alloying element of stainless steel

Nickel (Ni)

  • Nickel element can improve the strength of steel, and maintain a good ductility and toughness. Nickel has a higher corrosion resistance to acid and alkali, and has the ability of anti rust and heat resistance at high temperature
  • Improve toughness, so that the steel has a high strength, but also to maintain a good ductility and toughness
  • Nickel can improve the corrosion resistance and low temperature impact toughness
  • Nickel based alloys have a higher thermal performance

Molybdenum (Mo)

  • Molybdenum can make the grain refinement, improve the quenching and thermal properties
  • Under high temperature to maintain sufficient strength and creep resistance (long-term at high temperature under stress, deformation, said creep)
  • Mechanical properties can be improved with the addition of molybdenum in structural steel


  • itanium steel is strong deoxidizing agent,making the internal structure of the steel dense, fine grain size, and reduce the aging sensitivity and cold brittleness
  • Improve the welding performance
  • Adding proper titanium to Austenitic stainless steels,avoiding Intergranular corrosion

Copper (Cu)

  • Copper can improve the strength and toughness, especially to atmospheric corrosion performance
  • Disadvantage is prone to cracking during thermal processing, the copper content more than 0.5% ductility significantly reduced
  • When the copper content is less than 0.50%, no effect on the welding property

Nitrogen (N)

Nitrogen can improve the strength of steel, low temperature toughness and welding.