How to fix the cracks inside the cast steel gate valve by welding

Before we use the cast steel gate valve for the first time, it is necessary to check whether the cast steel gate valve is qualified or not. However, many people do not know how to troubleshoot in the testing process. Today we will introduce it to you.

Ⅰ. Structural characteristics and advantages of cast steel gate valve

  • (1) The cast steel gate valve has a reasonable design, reliable sealing, smooth channel and small flow resistance coefficient.
  • (2) The gate plate and valve seat sealing surface of cast steel gate valve are made of iron-based alloy surfacing welding or Stellite cobalt-based hard alloy surfacing welding, which has good wear resistance, high-temperature resistance, corrosion resistance, scratch resistance, and long service life.
  • (3) It adopts a wedge-type elastic gate or rigid wedge-type single gate structure, the rolling bearings are installed in medium and large diameters. It has a flexible switch that is easy to open and close.
  • (4) The valve stem of the cast steel gate valve has good corrosion resistance, abrasion resistance and wear resistance after tempering and surface nitriding treatment.
  • (5) It can adopt various piping flange standards and flange sealing surface types to meet various engineering needs and user requirements.
  • (6) The valve body of the cast steel gate valve is complete, and the packing and gasket can be reasonably selected according to the actual working conditions or user requirements, and can be applied to various pressure, temperature and medium working conditions.

Ⅱ. Do internal cracks of the cast steel gate valve need to be repaired by welding?

First of all, we need to test the pressure in water to detect test whether it is qualified or not. Sometimes, we will find some small cracks in the valve body that will affect the use effect of the cast steel gate valve. Therefore, it is necessary to fix these small cracks by welding.

When there is water inside the cast steel gate valve, it cannot be welded if the water inside is not cleaned out first. Also, this welding method is difficult because you have to completely drain the water before welding. It is best to use vertical seam welding due to its thicker welding part. In addition, the amount of cast steel gate valves on the market is very small. For a steel component, there is no cracking after welding.

It is also worth noting that normal welding rods can be used when welding between cast steel and normal carbon steel (such as low-carbon steel). Stainless steel must be matched with welding rods.

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ZECO Valve is established in 1991, as a professional industrial valve manufacturer and water valve manufacturer in Shanghai, China.