What limitations does alloy structural steel have in harsh service environments?

Alloy structural steel only contains low chromium content, so its natural anti-corrosion capacity is weak. It rusts rapidly in seawater, acid mist or humid coastal environments without protective coating. Its sustained service temperature is limited below 500°C; long-term exposure above this threshold leads to strength decline and creep deformation. It also cannot withstand severe chemical corrosive media. These shortcomings restrict its use from anti-corrosion and ultra-high-temperature equipment, requiring surface painting, galvanizing or other protective treatments for outdoor and marine structural applications.