AISI 4340 Alloy Steel is a heat treatable and low alloy steel containing chromium, nickel and molybdenum. It has high toughness and strength in the heat treated condition. It is mainly used in power transmission gears and shafts, aircraft landing gear, and other structural parts.

Размеры
Круглый прокат горячей прокатки: диам. 16–300 мм
Круглый прокат кованный: диам. 150–1200 мм
Круглый прокат холодной вытяжки: диам. 6–30 мм
Лист горячекатаный: 10–150 × 2000–2300 мм
Кованый блок: 150–1000 × 200–1900 мм

Технические условия поставки
EAF+LF+VD, Hot Rolled or Forged or Cold Drawn, Annealed or Q+T, Black or Machined surface, UT SEP1921 Class3 C/c or D/d

Применение
This low-alloy steel finds many applications where high strength, plasticity required such as large and important parts requiring hardening and tempering as heavy load axle for heavy machinery, axle with diameter over 250mm for steam turbine, axle of rotor wing for helicopter, axle of turbo and turbine blade and heavy load transmission part for jet engine, fasteners and gear for crank axle. It’s also used for rotor spindle and blade where temperature over 400ºC. It can be used as important part with special properties after nitriding and ultrahigh strength steel after low tempering isothermal quenching.