How to test the zinc coating thickness of DX51D+Z steel coils?
A: Commonly used methods include fluorescent X-ray testing (non-destructive testing) and gravimetric analysis. The gravimetric method requires removing the zinc coating with hydrochloric acid, calculating the zinc coating weight based on the weight difference before and after removal, and then converting this to the thickness, conforming to the requirements of GB/T 1839-2008 standard.
What are the characteristics of the substrate material of DX51D+Z steel coils?
A: The substrate is mostly low-carbon aluminum-killed steel with low carbon content, possessing good stamping and bending forming properties, suitable for processing needs in home appliances, construction, and other fields.
What are the main applications of DX51D+Z steel coils?
A: Widely used in building roofs, walls, and supports; air conditioner side panels and washing machine door panels in home appliances; automotive body parts and chassis components; and also as a substrate for color-coated steel sheets.
What are the common surface quality grades of DX51D+Z steel coils?
A: Common grades include FB (Flawless Finish). FB grade allows for minor defects such as slight scratches. Different grades correspond to different surface finishes and are suitable for products with different appearance requirements.
What are the reasons for zinc layer peeling off DX51D+Z steel coils?
A: Reasons include substrate surface oxidation, contamination of the cold rolling emulsion, improper annealing furnace atmosphere, low aluminum content in the zinc pot, insufficient strip entry temperature, or inadequate reduction stage.