For Low-Alloy Steel

Low alloy steel


1.Base metal

Definition: Main metal of low alloy steel is iron, and the total of the other metal is/or less than 5%. Low alloy steel by composition includes heat resistant steel, low temperature service steel, atmospheric corrosion resistant steel, and high tensile steel. By usage, structure, tool, special application.


Heat resistant low alloy steel includes carbon(C), chromium(Cr), molybdenum(Mo), tungsten(W), vanadium(V), niobium(Nb), boron(B), and remain tensile strength, anti-creep or corrosion under high temperature. 


Low temperature service steel includes nickel(Ni), minor molybdenum(Mo), minor vanadium(V), and remain impact resistance and ductility under low temperature. 

 Atmospheric corrosion resistant steel includes chromium(Cr), nickel(Ni), copper(Cu), or minor vanadium(V) for resist the pitting corrosion on the surface.


Low temperature service steel includes manganese(Mn), chromium(Cr), minor molybdenum(Mo), nickel(Ni) to enhance strength for structures, tools, modules, and bearings. 



2.Welding methods and features

Welding methods of low alloy steel is the same as mild steel and high tensile steel. Heat input, temperature control, diffusible hydrogen reducing are the main points. 


There is possibly internal stress on the beads because of the adding alloy, especially for the heat resistant steel. Post heat treatment is necessary to eliminate the stress.