And thereby settlement for embrittlement was suggested as follows: activation with acidic salt instead of pickling for degreased products.

The test is used to detect surface iron contamination, i. e., iron salt residue from pickling, iron tool scratches on the stainless steel surface, iron deposits at weld areas, and iron oxides.

There exist some unassailable problems in traditional chrome tanning, such as low exhaustion of chrome, salt pollution from pickling, and time-consuming process, etc.