Before visiting the Mechanical parts Exhibition, let us have a look at the knowledge of valve spring.

In addition to the fabrication defects, the valve spring may suffer from early damage due to improper use. The common reasons are the following.

There are pitting and corrosion pits on the surface of the spring. Due to improper storage, corrosion pits will be formed on the surface of springs. When springs bear large torsion, stress concentration will easily occur at the pits, which will eventually lead to fatigue fracture of springs.

New method for quality inspection of valve spring: the spring is clamped on the Bench Vise and compressed to the minimum length, so that there is no gap between the ring and the ring as far as possible, and kept for 48 hours. If there is a defect on the surface of the spring, it will break after such compression treatment. This is because the internal stress of the spring is highly concentrated near the defect, causing the spring to break.

The strength of valve spring can be identified by contrast method. The specific method is: first, an old valve spring will be inspected in series with a new valve spring, and the middle is separated by a steel gasket. Then adding a certain pressure on a valve spring to observe the degree of compression of the old and new springs. If the old spring is not strong enough, it must be pressed down at this time.