Carbon (C) carbon is the main element in steel. With the increase of carbon content in steel, the strength and hardness of steel at room temperature advance, but the plasticity, toughness and welding energy are low Therefore, the carbon content of steel for pressure bearing components of boiler is generally 0.1% ~ 0.25%.

Manganese (Mn) manganese can improve the normal temperature strength, hardness and wear resistance of steel. When the content is high, the welding stress increases Manganese can advance the strength of steel at high temperature and short time, but it has no obvious effect on the strength and creep limit.

Molybdenum (Mo) and chromium (Cr) both molybdenum and chromium can advance the strength of steel Chromium has obvious effects on the high temperature structure stability function of Qianjin steel - resistance to pearlite spheroidization, graphitization and high temperature oxidation And can advance corrosion resistance However, the steel with high chromium content has strong sensitivity to welding cracks and large temperature difference stress Molybdenum has obvious impregnation on the strength height of forward steel Molybdenum has graphitization direction, chromium can be added to prevent disease, and chromium embrittlement can be prevented by molybdenum. The coexistence of the two can possibly advance the comprehensive function of steel.

Vanadium (V) vanadium can advance high temperature microstructure stability in steel and offset the adverse effect of chromium on welding function.

Titanium (Ti) can improve the strength of steel and the welding function of steel in alloyed steel.

Tungsten (W) tungsten can improve the strength and high temperature hardness of steel.

Silicon (Si) can improve the strength, wear resistance and oxidation resistance of steel When it coexists with chromium, it can advance the ability of high temperature oxidation resistance and corrosion resistance in flue gas.

Niobium (Nb) niobium has the same impregnation as titanium, and can advance steel with thermal strength.

Boron (B) the prominent impregnation of boron is the hardenability of Qianjin steel In heat-resistant steel, the thermal strength and plasticity of steel can be improved.