1, the electrochemical corrosion. Stainless steel valve surface accumulating the attachments contain other metal elements or heterogeneous metal dust particles, in the humid air, condensate and stainless steel fixtures between the two together into a micro-battery, causing the electrochemical reaction, valves, protective film damage. 2, stainless steel valve surface adhesion organic juice, oxygen in the water, the Guangzhou Kaiheng Valve Co., constitute organic acids, acids long is the corrosion of the metal surface. 3, stainless steel valve surface adhesion containing acid, alkali, salts, can cause localized corrosion. 4, in the air pollution (such as those containing sulfides, carbon dioxide, nitrogen oxide atmosphere), Shanghai and Shanghai Valve Manufacturing Co., Ltd., the case of condensed water to form sulfuric acid, nitric acid, acetic acid solution point, causing chemical corrosion. Above may cause damage to the stainless steel surface protection film cause rust. Check valve pressure test method Test status: Lift check valve axis in the horizontal position and vertical; swing check valve and valve channel axis approximately parallel to the axis in the horizontal position. Strength test, Suzhou Watts Valve Co., Ltd., the introduction of the test medium to a predetermined value from the inlet end and the other end closed, body and bonnet look no leakage in compliance. Tightness test test medium is introduced from the outlet end, check the sealing surface at the inlet end, packing and gaskets at no leakage in compliance. Tianjin Tanggu valve limited liability company, the Hong Kong valves (online consultation), the valve provided by the Dongguan Science and Technology Co., Ltd., the Hong Kong valve. Valve Co., Ltd., Dongguan Ming Kong (www.gdmgfm.com) is Dongguan, butterfly leaders, over the years, the company implement the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Ming Kong valve leadership with the staff warmly welcome all inquiries negotiations to create a better valve out of Hong Kong in the future.