Prokat yog'i va boshqa yog'li dog'lar folga yuzasida qoladi, tavlanishdan keyin turli darajada folga yuzasida hosil bo'ladi, yog'li dog'lar deyiladi.
Yog 'dog'larining asosiy sabablari: alyuminiy folga prokatidagi yog'ning yuqori darajasi, yoki prokat moyining noto'g'ri distillash diapazoni; alyuminiy folga prokat yog'ida mexanik yog 'infiltratsiyasi; noto'g'ri tavlanish jarayoni; excessive oil on the surface of the product during rolling; The slitting tension is too large, causing the aluminum foil roll to be too tight.
