Electrolytic tinplate quality standards
Electrolytic tinplate three cans, canned food and canned food sealed containers. In recent years, the annual consumption of about 40 to 600,000, electrolytic tinplate three cans manufacturing industry, since 1978, the introduction of the first resistance welding production equipment, 20 years, due to the rise of domestic equipment factory, and a large number of the introduction, So far the country has about 600 cans production lines, rated capacity of 25 billion / year. Production capacity is far more than the actual demand, therefore, many production lines can not start, disorderly competition is inevitable.
The rapid growth of quantity, of course, reflects the progress of our society, but this is too fast growth, often accompanied by lack of understanding of the inherent quality of the product, a lot of production technology staff on the quality of empty cans, With the naked eye can be observed, with a simple test can identify the level. But the core quality of all empty cans is corrosion-resistant, that is, for the food or drink it wraps, it is not only leaked, not corrupt, and only as little as possible the corrosion (the existence of "corrosive" Domestic food regulations within the limits), to do this is not easy. Every year, the quality of canned food and beverage and its empty cans is only sent to me for technical testing of the ruling, not less than dozens of cases, some even hundreds of years, which should cause the attention of the whole industry. We can only from the "corrosion-resistant" point of view to understand the succession of each step of the canning process, the meaning of each indicator of the printing process and the most important quality of the quality of the tank material can be said to really grasp the The quality of empty cans.
The quality of the empty cans depends on the quality of the cans and the level of the cans. The cost of an empty cans is 60% to 80% of the material cost. It is mainly the value of electrolytic tinplate. Therefore, the quality and standard of electrolytic tinplate are correctly understood. Is the basis of understanding of cans, is one of the main key success or failure.
First, electrolytic tinplate is a high-tech product
As canned food and beverage packaging materials, electrolytic tinplate as a result of the use of that line of scrapped, to people illusion is: it is not worth attention, in fact, absurd, because:
1. For the manufacture of electrolytic tinplate steel, in the smelting, which requires a variety of residual metal and non-metallic impurities in the type, nature and content, must be strictly controlled, its control methods, indicators and detection methods, China has not yet Complete mastery.
2. In the subsequent operation of hot rolling, cold rolling, successive cleaning, quenching and tempering, leveling and other operations and control, may cause (or affect) the quality of electrolytic tinplate, and many of these problems , And most are not thoroughly understood.
3. In the cleaning, tinning, melting, passivation, oiling and other tin plating process, the number of related technical topics in most of our tinplate mill, but the initial grasp, far from handy. An electrolytic tinplate cold rolling production line, the length of more than 1000m, it rolled 1.5 to 1.7m wide strip plate, the plate out of the speed of 30m / s (this is only moderate speed), the thickness of its products, mostly In the range of 0.25 ~ 0.17mm (90 years, the United States and Japan developed countries can easily roll out the thickness of 0.14 ~ 0.75mm thin plate), this high-speed, high precision (the thickness of the average error of not more than 4%) , Strong power, high power equipment, the surface finish of its products, need to reach the mirror, which of course is high technology.
Second, electrolytic tinplate is a complex technology products
Said electrolytic tinplate is a complex technology products, it can be detected from the factory when the technical indicators to explain, first of all:
1. Analysis of steel-based components, including: carbon, copper, chromium, molybdenum, nickel, silicon (Si), manganese (Mn), phosphorus (P), sulfur (S) and other elements of at least 8 residual analysis , As well as other metal, non-metallic inclusions content determination;
2. Metallographic examination: the organizational structure, carburizing body, purity, grain size and alloy layer of the structural test a total of 5;
3. Mechanical performance test: the hardness, cup protrusion value, tension, rebound, aging, bending, roughness, thickness of 8;
4. Corrosion resistance (intrinsic quality) detection: the thickness of the tin layer, alloy layer thickness, oxide layer, passivation layer, the amount of oil film measurement, AT C (alloy tin current), I SV (iron dissolution) , PLV (acid lag time), T CS (grain size), anti-vulcanization, weldability, adhesion, health inspection and other 13;
5. Sheet shape inspection: straight angle, sickle bend, side wave, wave, warping and other five tests. More than 40 of the above test, the product factory, should be carried out according to different frequencies, we can see that the quality of electrolytic tinplate connotation, more than the general imagination.