Corrosion at the welds of on-site welding equipment
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Given the difficulties and costs associated with transportation, many devices need to be welded on-site. I remember that welds are areas prone to corrosion. For equipment that is welded on-site like this, how should the welds be treated after welding?
After cleaning with 10% dilute hydrochloric acid or acid pickling passivation paste, rinse thoroughly with high-pressure water.
Welding stress has not been eliminated, or there are welding defects
In the case of stress corrosion cracking, the best solution is effective heat treatment. However, it is often difficult to ensure the quality of heat treatment in the field, as issues such as uneven heating, unstable temperature retention, and difficulty in controlling the cooling rate can arise. For low-alloy high-strength steels, a hardness test after heat treatment can be used to assess its effectiveness. In the case of corrosion-induced thinning, the best approach is to improve the quality of the materials used, or to add linings, apply anti-corrosion paint, or use thermal spraying for more effective protection.
If the goal is merely to improve corrosion resistance, anti-corrosion materials can be applied, such as ordinary anti-corrosion paint; for applications where higher levels of corrosion resistance are required, polymer composite materials can be considered.
It depends on what material and medium are involved; in most cases, it’s sufficient to polish the surface until it’s smooth. The welding materials and welding process have an impact on corrosion
The welding requirements on site must also be carried out in accordance with the design specifications; the welding processes used are those that have been evaluated and proven to be effective. Post-welding treatments are also to be done in compliance with welding codes and standards – heat treatment, if required, must be performed on site, as must acid cleaning and passivation, among other procedures, all of which must be carried out as specified in the design.