Is it a corrosion pit or a defect in the raw material itself?

If the defect occurs on the inner wall of the tube, the first thing to consider is the possibility of pitting, as the media involved in the operation of the heat exchanger may have a corrosive effect on duplex steel materials. Pitting corrosion is primarily a form of localized accelerated corrosion caused by the reaction between chemical components in the medium (such as chloride ions) and the metal pipe wall. If the pits have a regular shape and are concentrated in a specific area, they are more likely to be caused by corrosion. Defects in raw materials generally refer to issues that arise when the material does not meet certain standards during the manufacturing process, such as inclusions and pores; these are usually distributed evenly on the surface or within the material. To determine the specific situation, it is possible to further examine the morphological characteristics of the defect; methods such as metallographic analysis or chemical analysis can be used to determine whether it is a material issue or pitting caused by subsequent use. At the same time, check the operating environment and the properties of the chemical media to see if there are any substances with extremely strong corrosive properties. .

Okay, thank you. A few more pipes with internal leaks were opened up yesterday, and the internal problems are basically the same.

As can be seen from the image, the corrosion pits are caused by the effects of the production medium. An analysis should be conducted based on usage conditions and materials.