特黄免费,激情九月婷婷,毛片不卡视频操逼,久久综合色婷婷,美女18毛片九区,国产高清视频免费最新在线,四虎免费黄色网站

    Damage to natural and man-made damage to two. In the open and close over we will have scratches, bumps, crushing and other damage to the sealing of multistage pump. Between the two sealing surface, mechanical damage. Under the action of high temperature and high pressure atomic interpenetration exudation, adhesion phenomenon. When moving between the two sealing surfaces, the adhesion at pull tear easily. Multi-stage pump sealing surface roughness is high, this phenomenon is more easily occur.

    The media activities of the multi-stage pump sealing surface wear, flushing, cavitation. Medium fine-grained pelagic sealing surface resistance to offend, cause local damage, high speed direct media activities flushing sealing surface, cause local damage, mixed media and local vaporization, the bubble burst produced angry impulse sealing surface, causing local damage. Medium erosion combined with chemical erosion alternation, the sealing surface erosion will be strong.

    Contact between the sealing surface, the sealing surface and the closure of the valve body and the concentration of media exposure and poor, poor concentration of oxygen causes, will have a potential difference, causing electrochemical erosion, occurs in the anode side of the sealing surface erosion. However, the sealing surface near the media does not produce current in the case, media directly with the sealing surface chemical reaction, the formation of the chemical erosion. , erosion of the sealing surface.

    Sealing surface processing quality is not good, mainly expressed crack, hole and inclusion defects in the sealing surface. Because the welding and heat treatment specification improper selection and welding and heat treatment process control caused by the sealing surface hard through the high or low, because the selection of wrong or heat treatment caused by improper sealing surface hardness uneven, no corrosion, mainly because of the welding process, metal bottom blowing up the dilute seal surface alloy composition caused by the course.