Alkaline washing of titanium alloy rods is easy to catch fire, especially alkali washing of titanium sheets is more likely to catch fire. The chemical activity of the titanium alloy rod in the lye, when alkaline washing in the lye containing an oxidant, the overall lye temperature is too high or the local temperature is too high are the reasons for the burning of titanium. Studies have shown that due to the potential difference between the titanium and steel tools in the lye, there is a galvanic effect. When titanium and steel are in contact, galvanic current is formed, and the smaller the contact point, the greater the current and the excessive contact. The current density causes local overheating so that the titanium alloy rod often starts to burn from the contact point of these two metals.
In order to prevent and reduce the ignition of titanium alloy rods during alkaline washing, the following measures can be taken:
1. Selection of qualified alkaline washing liquid components;
2. Strictly control the temperature of lye;
3. Insulate the alkali washing frame with high-temperature resistant coating or high temperature resistant insulating gasket. For example, if a stainless steel alkaline cleaning frame is used, ceramic strips or ceramic pieces can be placed to separate the titanium material from the steel frame, which can also avoid fire.
In the alkaline washing process of titanium alloy rods, the lye is continuously taken away or evaporated by the workpiece, so it is necessary to supplement the lye and adjust it in a timely manner to keep the composition of the lye relatively stable. During alkaline washing, insoluble oxide scale slag settles on the bottom of the tank, which affects the good thermal conductivity of the tank, and the gap caused by the precipitation makes the steel tank prone to electrochemical corrosion, which greatly shortens its service life. Therefore, the sediment should be cleaned up in time. The use of a movable tank bottom to collect slag is a common method. When it is necessary to eliminate sediments, just hang the bottom of the movable tank.
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