Abstract: The first color penetration testing conducted after the two testing magnetic particle inspection process technology method for surface inspection of diesel engine valve, a separate use of complementary coloring inadequate testing or magnetic particle testing to ensure test quality and reliability.
Key words: diesel engine; valve; surface inspection
1. Cause valve failure and the need for surface inspection
Diesel engine valve in the service process, the downtime caused by failure, resulting in economic losses. Diesel engine valve failure are the following three reasons: First, as the valve can not be reset while the Pistons hit touched off; Second, poor body raw materials (such as surface cracks, inclusions, etc.) caused during the manufacturing process defects (such as forging cracks, stress concentration due to machining marks and microcracks formed in service); third, the body flow by heat stress and heat stress corrosion cracks generated.
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China’s chemical fertilizer industry with the H22-type hydrogen nitrogen over 30 ring compressor valves, valve failure due to become the current outstanding problems in the compressor.
To address this problem, the valve manufacturer for the life of valve failure analysis and statistics, found that many still use the valve was replaced, the main reasons are:
1. Lift limiter valve on the radial block a lot of wear and tear guide so that the valve and the guide block between the gap of about 0.2mm into a 1mm ~ 2mm (see Figure 1), so the valve can not fall after exercise deviates from the correct position of the valve seat sealing surface. Especially high-pressure section of the valve.
Solution: Replace the worn out the lift limiter.
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