Coating thickness detection:
The magnetic thickness measurement method or metallographic microscope method is used to detect the weight and uniformity of the double-sided coating according to the GB/T 13912 standard. The thickness of the zinc layer directly affects the anti-corrosion life. The requirement for building materials is ≥60g/㎡, and the requirement for automotive plates is 90-180g/㎡. Insufficient thickness will lead to a decrease in anti-corrosion performance, and excessive thickness will affect processing and forming.
Adhesion test:
The coating bonding strength is evaluated through a bending test (T-bend test). After bending the sample 180°, observe the zinc layer shedding. The T-bend grade is required to reach 0T-2T (no cracks). Insufficient adhesion will cause the coating to peel off during stamping, affecting the subsequent coating process.
