How to prevent the titanium plate joint welds from being corroded?

Titanium plates are prone to erosion corrosion and impact corrosion in certain corrosive media with high flow rates and variable flow rates. Therefore, when designing the flow rate for handling such media, it is necessary to control it below the critical flow rate; or set protective baffles at the areas prone to erosion or impact corrosion and avoid flow rate changes.

To avoid or reduce the galvanic corrosion that occurs when the titanium plate comes into contact with other metals, the following measures are usually taken:

a) Add completely isolated insulating materials between the two metals to avoid the formation of a corrosion cell;

b) Avoid the formation of a corrosion cell with a large cathode and a small anode between the two metals;

c) Increase the distance between different metals and change their positions;

d) Use cathodic protection, etc.

To prevent the splicing welds of the titanium plate from being corroded, the following measures can be taken:

a) On the structure, try to eliminate gaps and stagnant areas. For example, use welding instead of bolted connections or riveting; use butt welding joints instead of spot welds and lap joints; improve the flow state of the solution in the titanium equipment to avoid dead corners and stagnant areas;

b) Select materials resistant to gap corrosion or surface-treated materials at the gaps. For example, use TA9, TA10 titanium alloys with better gap corrosion resistance instead of industrial pure titanium; applying coatings, oxidation, and anodizing treatments on the titanium surface can also improve its resistance to gap corrosion;

c) Use special forms and compositions of gasket materials to improve the environment for gap corrosion, etc.

Depending on the medium, the galvanic corrosion of titanium can be divided into two types: The first type of medium, such as salt solutions, nitric acid, acetic acid, and seawater, titanium originally has excellent corrosion resistance in these media. However, if it is combined with another metal and when the titanium surface has an oxide film, it acquires an inert property, causing it to become the cathode in the galvanic cell and the other metal to form the anode, resulting in galvanic corrosion. The second type of medium, such as hydrochloric acid, sulfuric acid, and oxalic acid, titanium can be in either active or passive state in these media. If it comes into contact with other metals, it may either increase the corrosion rate of titanium or increase the corrosion rate of other metals.