A powerful deoxidizer and nitride former. In small amounts, can serve as a powerful, inexpensive grain refiner (i.e., restricts Austenitic grain growth). Can improve toughness, especially at low temperatures.
Strongly increases hardenability by suppressing Ferrite precipitation during transformation from Austenite during heat treatment. Effective in very small amounts (less than 0.003% B). Also reduces the brittleness of hardened steel by positively influencing the transformation from Ferrite to Austenite to Martensite Structure. Especially effective in steels with lower carbon content (e.g., C=0.27%) that tend to transform inertly, Boron strongly improves the transformation process.
The principal element responsible for hardness in steel, due to the formation of Fe3C upon cooling through the Transformation Temperature, when Gamma Iron (Austenite) decomposes into Alpha Iron (Ferrite) + Fe3C (Iron Carbide). Increases tensile strength in steels. Ductility generally decreases as C increases, but this effect can often be offset with proper heat treatment. Weldability decreases as C increases. Excess oxygen usage may be required to remove excess C (takes furnace time).
A strong carbide former that improves wear resistance and somewhat increases resistance to softening during tempering. Improves hardenability depth. Promotes the response of steel containing Cr to the effects of carburizing heat treatment. In combination with even very low P, Sn, As, or Sb contents, Chromium and Ni-Cr alloy steels are particularly susceptible to 'temper embrittlement' (loss of ductility when tempering or slow cooling in the range 700-1100 F). When Cr > 4%, corrosion resistance greatly improves (responsible for corrosion resistance in Stainless Steels). Not readily oxidized from the bath; requires high temperatures, increased heat time, and slag volume. Makes steel oil and air hardenable.
A strong carbide former with a high effect on hardenability. Improves control of heat treatment by inhibiting the formation of certain microstructures (e.g., Pearlite). Can improve high-temperature corrosion resistance, toughness, and fatigue properties. Expensive. Vanadium (V) and Molybdenum (Mo) both influence better toughness and have the same negative influence as Cr. They are mostly used as fragility compensators in high-carbon steels like D2 or, in extreme cases, in 440V steel.
Extremely reduces the critical cooling temperature and increases hardenability. Yield strength, tensile strength, and durability increase with increasing Mn content. Also has a positive impact on forging and weldability and increases through hardening.
Improves hardenability. Reduces distortion in heat treating. Permits the use of milder quenching media. Improves weldability, plasticity, and fatigue properties. Improves toughness, especially at low temperatures. Improves corrosion resistance.
Phosphorus (P) and Sulfur (S): These elements are necessary intrusions caused by the metallurgic process. They are undesirable, and their content should be less than 0.025%.
Phosphorus (P) and Sulfur (S): These elements are necessary intrusions caused by the metallurgic process. They are undesirable, and their content should be less than 0.025%.
An element (like Mn) contained in every kind of steel since iron ore already has a certain amount. In content up to 0.5%, it has a positive influence on mechanical properties and helps perform hot forming of steel. Si deoxidizes and increases durability and strongly increases elasticity. Only steel with more than 0.40% is called silicon steel.
Forms extremely hard, stable carbides. Used almost exclusively in High-Speed and other tool steels (requiring wear resistance and high hot hardness). Very expensive. Used in the manufacture of High-Speed Tool Steel but otherwise almost never used due to extremely high cost.
Vanadium (V) and Molybdenum (Mo) both influence better toughness and have the same negative influence as Cr. They are mostly used as fragility compensators in high-carbon steels like D2 or, in extreme cases, in 440V steel. V is an effective grain refiner (i.e., restricts Austenitic grain growth). Strong carbide and nitride former (improves abrasion resistance). Improves yield strength, toughness, and hot hardness. Strongly increases resistance to softening during tempering. Expensive.
