Cold Work Hardening Characteristics of 0Cr20Ni18Mo6CuN(254SMO) Steel
0Cr20Ni18Mo6CuN(254SMO) Steel is a highly alloyed austenitic stainless steel which is designed for extreme corrosion resistance and high strength. This alloy contains 21.5%-23.5% of chromium, 17.5%-19.5% of nickel, 6%-6.5% of molybdenum and 0.1%-0.4% of copper and nitrogen. It offers an excellent combination of corrosion resistance, strength and toughness at extremely high temperatures, making it an ideal material for a wide range of applications, such as chemical and process industries, heat exchangers, power generation and off shore oil and gas fields.
Cold work hardening is an important physical parameter which affects the performance of 0Cr20Ni18Mo6CuN(254SMO) Steel. It is the process in which austenitic stainless steel has its surface subjected to strain hardening and/or cold working which increases its strength and hardness. This is usually seen in the form of work hardening during fabrication or manufacturing when cold forming of the material is carried out.
Cold working or cold forming of 0Cr20Ni18Mo6CuN(254SMO) Steel reduces its ductility, increases strength and hardness as well as decreases its corrosion resistance. Cold forming of this alloy yields an associated work hardening hardening of the surface layer which is usually around 300HV and increases at increasing forming depths. As cold forming increases, the alloy’s corrosion resistance typically decreases which is clearly visible in the addition of nickel and chrome levels.
Heating of 0Cr20Ni18Mo6CuN(254SMO) Steel can help to restore its ductile properties and corrosion resistance, however some work hardening will remain even after heat treatment. The cold work hardening of 0Cr20Ni18Mo6CuN(254SMO) steel is essentially a result of two phenomena which are lattice reconstruction and dislocation accumulation. The cold work hardening of this alloy can be summarized as follows:
• The cold work hardening of this alloy increases with increasing cold working strain.
• It increases with increasing material temperatures.
• It increases with decreasing strain rates.
• Cold work hardening of the material is reduced by annealing.
• Its surface layer is hardened and its tensile strength is increased with cold forming.
• Its work hardening depth increases with increases in forming depth.
• Cold work hardening is accompanied by a decrease in corrosion resistance.
• Cold working can cause the material’s surface to develop cracks and pits which need to be repaired.
In conclusion, 0Cr20Ni18Mo6CuN(254SMO) Steel possesses excellent cold work hardening characteristics and is widely used in a variety of industries due to its superior corrosion resistance, strength and tough qualities. Its cold forming process reduces its ductility, increases its strength and hardness, but produces a decrease in corrosion resistance. The cold work hardening depth increases with increasing non-homogeneous forming depth. It is usually seen in the form of work hardening during fabrication or manufacture when the material is subjected to cold working. The surface layer is hardened and its tensile strength is increased with cold forming. Lastly, the cold work hardening of this alloy can be reduced by annealing.
