The application of China lead die casting and zinc die casting is still very extensive. We can see their traces whether in daily life or on the streets. However, since they are all die-casting parts, the problem of surface bubbles cannot be avoided.
One of the reasons for the blistering of die castings is intergranular corrosion. Zinc alloys are harmful impurities contained in the composition: lead, cadmium, and tin will accumulate at the grain boundaries and cause intergranular corrosion. The metal matrix is ​​broken due to intergranular corrosion and electroplating Accelerated this scourge, the parts affected by intergranular corrosion will expand and lift the coating, causing blistering on the surface of the casting. Especially in a humid environment, intergranular corrosion will cause the casting to deform, crack, or even break.
Another reason is cracks, such as water lines, cold barrier lines, and hot cracks.  Water pattern and cold barrier pattern are when the molten metal is in the filling process, the molten metal that enters first contacts the mold wall to solidify prematurely, and then the molten metal cannot be fused with the solidified metal layer, forming a stack at the butt of the casting surface Streaks and streaks are defects. The water mark is generally shallow on the surface of the casting; while the cold barrier may penetrate into the casting.
Thermal cracking: (1) When the casting thickness is uneven, stress will be generated during solidification;  (2)   ejected prematurely, the metal strength is insufficient;  (3) the force is uneven during ejection; (4) excessively high mold temperature causes crystal Coarse grains;  (5)  harmful impurities exist. The above factors may cause thermal cracking. 
When there are water marks, cold barrier marks, and hot cracks in the die casting, the solution will penetrate into the cracks during electroplating, and it will be converted into steam during baking, and the pressure will lift the electroplated layer to form blisters.
However, China zinc die casting manufacturer or other manufacturers are aware of the existence of this problem, and believe that in the production process, the probability of occurrence of this problem will only become smaller and smaller. www.chinaweilong.cn