Pneumatic valve is how to corrode, because you don't know this at six o 'clock?

pneumatic valve pneumatic valves are corrosion is one of the main reasons for failure, there are several kinds of form, or causes of corrosion, generally can be divided into six forms of corrosion. Corrosion is the waste through natural way for metal into their ore. Corrosion of chemical emphasizes the basic corrosion reaction MM + electronic, which M is metal and M is the metal cation, as long as the metal ( M） Keep electronic, he is still a metal. Otherwise it will corrode. Physical strength has most of the time effect of physics and chemistry can let pneumatic valve failure. There are many common varieties of corrosion, the main is overlapping. Is due to the mechanism of corrosion on the metal surface to form a thick corrosion protective membrane. Corrosion types include:

when two different metals are in contact and exposed to corrosive fluids and electrolytes, form a galvanic cell, increase the anode a corrosion current. Corrosion is usually near the local contact. To reduce corrosion can be implemented by using the method of dissimilar metal plating.

high temperature corrosion

in order to predict the effects of high temperature oxidation, we need to check whether the data) Metal composite,) Atmosphere of) Temperature, and) The exposure time. But, is known to all, most of the light metals ( Those are lighter than their oxide) Form a protective oxide layer, with the passage of time more and more thick, it will fall off. There are other forms of high temperature corrosion including vulcanization, carburization, etc. Crevice corrosion



this kind of situation is happened in the gap, gap hindered the diffusion of oxygen, high and low oxygen zone, to form the solution concentration difference. Especially fitting or weld defects may appear narrow aperture, the slit width ( In generally. ~。 mm） Enough to make into the electrolyte solution, makes the metal inside the seam and seam metal short-circuit galvanic cell, and strong corrosion in the seam local corrosion. Pitting



when the coating is damaged or corrosion product layer decomposition, is to produce local corrosion or pitting occurred. Membrane rupture anode and without rupture of membrane and corrosion products as cathode, actually has set up a closed circuit. In the presence of chloride ions, some stainless steel easy to pitting. Corrosion occurs in the metal surface or rough areas, because the uniformity. Intergranular corrosion


intergranular corrosion occurs for a variety of reasons. Results were almost the same metal grain boundary, the destruction of the mechanical properties. Without proper heat treatment or contact sensitization - ° Fahrenheit temperature of intergranular corrosion of austenitic stainless steel is influenced by many etchant ( –°C） 。 This kind of situation can be eliminated by annealing and quenching ° F ( °C） The low carbon stainless steel ( c - 。 max） Or stable niobium and titanium. Friction corrosion


from wear and fracture of physical force, through protective corrosion of dissolved metals. Effect mainly depends on the power and speed. Too much vibration or metal bending can also have similar results. Cavitation is a common form of corrosion pump, stress corrosion cracking of high tensile stress and corrosive atmosphere will cause metal corrosion. Under static load is tensile stress on the surface of the metal than the yield point of the metal, the corrosion effect of stress concentration area, the results show that for a local corrosion. Alternately in the metal corrosion and to establish a high stress concentration parts, to avoid the corrosion can be eliminated by early stress annealing, or choose the proper alloy materials and design. Corrosion fatigue we usually relate static stress and corrosion.

stress can lead to corrosion cracking, and cyclic loading will lead to corrosion fatigue. Fatigue corrosion in the corrosive conditions than fatigue limit. Surprisingly, these two kinds of corrosion exist at the same time, a greater harm. This is why, in under the action of alternating stress, we will use the best anti-corrosion measures.