8 Methods for Inspecting the Quality of Zinc Alloy Die Casting

Intuitive judgment

The surface quality of zinc alloy die-casting parts can be analyzed with the naked eye. The patterns, air marks, shrinkage, deformation, cold separation, lack of flesh, discoloration, and color spots can be visually seen. The inspection can also be carried out based on a high-power magnifying glass enlarged by 5 times.

Specification inspection

1) Use a vernier caliper to check the thickness and diameter of zinc alloy die casting.

2) Use CMM to check the shape specifications and hole position specifications of the zinc-alloy die casting.

3) Check the diameter with a standard inspection rod.

Composition analysis

The composition of zinc alloy dies casting was analyzed by spectroanalyzer and atomic absorption meter, especially the composition of impurity elements that would affect the defects such as cracks, inclusions, and hard grains. Judge whether the aluminum alloy material is in line with the regulations.

Metallographic analysis and inspection

A metallographic microscope and scanner transmission electron microscope was used to analyze the structure of the defective substrate and identify the defects such as cracks, inclusions, hard grains, and holes in the die casting of zinc alloy. In metallography, contractions show irregular edges and dark inner cavities, while vents show smooth edges and bright inner cavities.

camera housing zinc die casting part

X-ray examination

The use of radiation with strong transmission ability, according to the tested zinc alloy die casting, effect the photographic film so that it has a different level of light induction. Then the photographic film takes the defect of the projector image, from which it can judge the location of the defect, appearance, size, and spread.

Ultrasonic test

Ultrasound is the frequency of sound waves that vibrate beyond 2000Hz. Internal defects in zinc-alloy die casting are detected using ultrasound to create reflective surface conditions as it passes from one substance to another. Ultrasonic detection can also accurately measure zinc alloy thickness through die casting and material analysis.

Fluorescence test

The ultraviolet light emitted by liquid mercury quartz lamps is used to excite the optical material and emit visible light to analyze the small discontinuous defects on the surface of zinc alloy die casting, such as cold separation and cracks. Put the clean zinc alloy die casting into the fluorescent liquid tank, make the fluorescent liquid penetrate the casting surface, remove the casting, and dry the casting coated with image powder. When a mercury lamp inspected the casting, obvious fluorescence occurred at the defect. According to the brightness level, the size of the defect can be judged:

Coloring test

A simple, reasonable, convenient, and convenient defect inspection method composed of detergent, penetrant, and imaging agent. You can buy a set of “DPT-5 coloring infiltration flaw detection agents” from the sales market around Xiangyu metal materials, a total of 3 cans, and you can carry out a defect inspection. The way:

1) Clean the surface of zinc alloy die casting with detergent first.

2) Spray paint the surface of the casting with red penetrant liquid and keep it wet for about 5-10min.

3) Wipe off the unnecessary penetrant on the surface of the casting, and then clean up with detergent or tap water.

4) Spray painting imaging agent if there are cracks, and loose holes on the die-casting surface, then the absorbent agent is precipitated on the surface under the effect of the imaging solution, and the corresponding position shows red. Still, there is no red on the surface without defects.

5) AC pressure test

Used to check the high density of casting. Method 1: The working fixture clamps the casting to show the tightness. The incoming air is compressed and permeated into the water storage tank. Observe whether there are bubbles in the water to measure. Generally, the entering air is compressed under 2 atmospheric pressures, and the soaking time is 1-2min; with 4 atmospheric pressure, the infiltration time is shorter. The experimental working pressure should exceed the specified pressure of the casting by 30%-50%.

6) Flexible photoconductivity test

It consists of electronic, optical contact, camera, TV picture display screen, visual guide, and special lamp source to constitute excellent inspection equipment. The contacts can be rotated for bone joints and returned to transport high-pixel, panchromatic, real-time images. Xiangyu metal materials can intuitively view the internal defects of zinc alloy die casting according to the TV image.

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