In high-temperature environments (>200â), 42CrMo chromium-molybdenum alloy steel (such as A193 B7) should be used. It can withstand temperatures up to 480â and has a tensile strength of âĨ860 MPa.
Extremely cold environments (<-50â) recommend A320 L7 material with nickel-chromium-molybdenum composite strengthening.
The wedge-shaped lock washers (such as the Nord-Lock system) are used. The geometric structure with a slope angle greater than the thread rise angle is adopted to prevent vibration loosening. The radial fine teeth form indentations on the contact surface.
The creep vibration test is used to verify anti-loosening performance and is applicable to scenarios with dynamic loads such as wind turbine towers and ship decks.