Important Indicators of Enamel Quality Inspection
The quality inspection of enamel is an important part of judging the quality of enamel products. It has several dimensions of inspection, such as enamel thickness, adhesion, impact resistance, thermal shock resistance, pressure test, acceptable total area ofenamel defects and other Chemical properties, etc. The following is the detailed content of enamel quality inspection. If you have any other questions, welcome to communicate with us:
1. The thickness of the enamel: The thickness of the enamel is related to the process used. Whether a single-layer or double-layer enamel process is used, the thickness of the enamel should be between 0.15-0.5mm, and the porcelain layer should be uniform and continuous. The thickness of the enamel is generally measured with a small hand-held instrument. The thickness measurement should take the average value of more than 10 data, and the measurement data should include the inner liner and the liner cover. If it does not meet the requirements, it will be rated as unqualified.
2. Adhesion: The adhesion of enamel is a very important indicator to measure the quality of enamel. In the case of a destructive test, it is required that no metal surface is exposed, but there must still be enamel covering the metal surface. The adhesion strength of a good enamel process can reach 100N/mm³, and the commonly used inspection method is hammering.
3. Impact resistance: 10N impact force is applied to the enamel test piece, and the area of enamel damage on the surface of the test piece does not exceed f1.5mm.
4. Thermal shock resistance:
The test method for thermal shock resistance is to repeat the enamel product 5 times, from 200 ℃ to 15 ℃, and then observe whether there is visible damage on the surface. The test must use 3 specimens with an area of more than 100cm².
5. Pressure test: After the water heater is filled with hot water, pressurize it to a pressure of at least 1.3xP (P is the operating pressure). Pressurization from 0 to P should not be less than 15 seconds, from P to test pressure, no more than 5 seconds, and the test pressure should be maintained for at least 15 minutes. The whole process is repeated twice, and if the water heater can withstand 12 bar pressure, it is rated as passable.
6. The total area of acceptable enamel defects: hidden defects: only allowed to exist at the edges and welds, and the distance between the hidden defects and the good welds on the edge should not be greater than 2mm, and the hidden defects on the surface of the enamel per square meter The total area shall not exceed 20cm².
Defects: The total area of hidden defects per square meter of enamel surface shall not be greater than 7cm².
There are also other chemical properties, such as boiling water resistance, acid resistance, physiological harmlessness (enamel enamel can not contain harmful substances to human beings, and there are certain requirements for harmful substances such as lead, cadmium, arsenic, antimony, etc., which are precipitated from enamel into water) .