There is no sand hole in aluminum alloy die casting, and the defects of aluminum alloy die casting mainly include pinhole, blowhole, shrinkage cavity, slag hole and slag blowhole. From the appearance, it should be a pinhole.
Generally, visual inspection (experienced inspectors) will be conducted on site, and the problematic parts will be cut off for observation. Observe with a magnifying glass. If the effect is not good, observe it with a microscope.
Extended data:
The accelerant, fluoride, Mn2+, Ni2+, Zn2+ and PO4 were studied in detail by means of SEM, XRD, potential-time curve and film weight change.
And Fe2+ on the phosphating process of aluminum. The results show that guanidine nitrate has the characteristics of good water solubility, low dosage and fast film formation, and is an effective accelerator for aluminum phosphating. Fluoride can promote film formation, increase film weight and refine grains.
Mn2+ and Ni2+ can obviously refine the grain, make the phosphating film uniform and compact, and improve the appearance of the phosphating film. When the concentration of Zn2+ is low, no film or film difference can be formed. With the increase of Zn2+ concentration, the weight of the film increased. The content of PO4 has a great influence on the weight of phosphating film, which increases PO4. This content increases the weight of phosphating film.
Pinholes are caused by too much hydrogen in the alloy liquid, which is dispersed in the tissue and is as big as a needle tip. Preventive measures: 1. Raw materials should be inspected; Strengthen mold exhaust and adjust the process reasonably.
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