Laminated Steel Plate Defects

Of structural defects under loads active during operation.

Laminated steel plate defects. These are i the major or most severe defects which result in scraping or rejection of castings ii intermediate defects which permit salvaging of castings through necessary repairs and iii minor defects which can be easily repaired. Laminations are an imperfection in a steel or alloy resulting from blisters seams foreign material and or scratches on an ingot or billet that are not repaired during the rolling process. This defect was the primary cause of the boiler failure. Plate lamination defect is one of the primary processing discontinuity that originates during hot or cold forming processes and is considered as a serious metal plate defect.

There are in general three broad categories of defects in the foundry cast steel products. Here are some common flat roll steel defects we watch out for. The laminated plate was determined to be defective for use as a furnace tube. When the fabricator trims the plate laminar imperfections can occur within the body of a plate or at the edges.

All the metals contain discontinuities at micro and macro levels. Bare spots galvanized coated bare spots result when coating fails to adhere leaving the substrate exposed. A weld joint is considered a serious metal plate defect when packed with a corrosive product when there are gaps in the continuous weld such as in spot welds or when the weld is weakened to the point that it fails under finger. While checking a welder test piece it was found that a 12 mm steel plate is having clear lamination.

However even mid plate laminations may appear as edge laminations when the fabricator strips out a flange or web. These defects were latent at the time that the boiler was manufactured. Indeed they were latent. Most commonly seen is external corrosion rust due to dampness see also coating skips 7 2 2.

1 can ut test in all condition read this defects. These discontinuities when above the acceptance level are termed as defects.