Are lock nuts and washers used on the process piping?

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We have a project that requires lock nuts and washers; we haven’t used them before. Could someone who is familiar with it explain? In what situations is it generally used? I checked the description on Baidu, and it says that 1. The lock nut’s main functions are to prevent loosening and to resist vibration. For special occasions. Lock nuts generally self-lock through friction. There are those with nylon rings, those with a neck closure, and those equipped with metal relaxation devices. They all belong to the effective torque type. First, superior vibration resistance: When the threads are tightened, the thread profile of the bolt’s shank fits tightly into the 30° wedge-shaped surface of the nut, causing it to be secured in place. The normal force exerted on this wedge-shaped surface is at a 60° angle to the bolt’s axis, rather than 30°. As a result, the normal force generated when tightening a locknut is much greater than that of a regular standard nut, giving it excellent vibration resistance and locking capabilities. Second, it has strong wear resistance and shear resistance: the 30° bevel at the bottom of the nut’s thread flanks allows the locking force of the nut to be distributed evenly across all the thread flanks. Thanks to this even distribution of compressive forces across the thread surfaces, the nut is able to effectively counteract problems such as thread wear and shear deformation. Third, it has good reusability: extensive use has shown that anti-loosening nuts maintain their locking force even after being tightened and loosened repeatedly, preserving their original locking capability. 2. Ordinary nuts tend to loosen over time. Its wear resistance, seismic resistance, and reusability are all much worse than those of lock nuts. I took a look at GBT 5649-2008 on lock nuts and washers for pipe fittings – it’s described quite simply there as well.