Dry goods: the copper strip production knowledge that metal people must collect! Copper strip is a very common metal component, which is often seen in electrical components, lamp caps, battery caps, buttons, seals, connectors and other places. It is mainly used for conducting electricity, conducting heat, corrosion-resistant equipment, etc. There are six areas for copper strip production, namely, smelting area, laboratory, cutting area, hot rolling area, water washing area and rolling area. Today's article mainly talks about the copper strip production process and the solutions to some common problems, such as discoloration and shear indentation.

Production process flow of copper strip:

1. Embryo making: according to the predetermined production target, different amounts of zinc blocks are added to the waste copper material to make copper raw materials of different specifications.

2. Assay: in order to ensure the production of both qualified and economic finished products, the accuracy of assay results is particularly important. The responsibility of the laboratory is to quickly and accurately report the test results to the smelter according to the copper blocks submitted for inspection.

3. Cutting: the complete copper strip is pulled by the lifting rope, placed stably on the special cutting table, cut by the cutting wheel saw, and then the uneven surface of the copper strip is polished and smoothed by the copper strip washing machine, which is conducive to the flatness and smoothness of the copper strip surface processed in the later stage.

4. Hot rolling: the cut copper strip is heated at 1000 ℃ and then hot rolled to form a copper strip with a thickness of about 2.3cm.

5. Water washing: after the blooming process, each copper block must go through the sealing furnace and water washing again to avoid affecting the quality of the finished product due to the existence of surface impurities. The water washing area is divided into two types of water tanks according to different acidity. The high concentration is 6-8 degrees, and the low concentration is 3-5 degrees.

The medium red patches on the surface of copper bars and strips can be washed away by the acid solution in the water washing tank, while the dark red patches can be removed by the iron fine brush during the water washing. After this series of treatment, the copper strips obviously shine the inherent luster of copper. Similarly, if there are still red patches and red patches during rolling, it is still necessary to repeat the water washing step. During water washing, regularly check the acidity in the water tank and add acid in time to avoid insufficient water washing due to low acid content.

6. Plate rolling: the plate rolling area is divided into 180 primary rolling and 110 intermediate rolling according to the wheel roll. According to the different sizes of various wheels and rollers, the copper strip hot rolled and forged in the sealing furnace is processed from rough to fine through the above two steps.

Solutions to common problems of copper strip:

1. Solution to copper strip discoloration

(1) Control the acid concentration during pickling. When the oxide layer on the surface of annealed copper strip is washed off, the high acid concentration has no significance. On the contrary, the high concentration makes it difficult to wash away the residual acid attached to the surface of the copper strip, and accelerates the pollution of the cleaning water, resulting in the high concentration of residual acid in the cleaning water, which makes the cleaned copper strip easier to change color. Therefore, when determining the concentration of the acid washing solution, the principle should be followed: on the premise that the oxide layer on the surface of the copper strip can be cleaned, the concentration should be reduced as much as possible.

(2) Control the conductivity of pure water. Control the conductivity of pure water, that is, control the content of chlorine ions and other harmful substances in pure water. Generally, the conductivity is controlled at 50 μ It is safer below s/cm.

(3) Control the conductivity of hot cleaning water and passivator. The increase of conductivity of hot cleaning water and passivator mainly comes from the residual acid brought in by the running copper strip. Therefore, under the condition of ensuring the quality of pure water for cleaning, control the conductivity, that is, control the amount of residual acid. According to many experiments, the conductivity of hot cleaning water and passivator are respectively controlled at 200 μ Below s/cm is safe.

(4) Ensure that the copper strip is dry. The winding outlet of the air cushion furnace shall be partially sealed, and the dehumidifier and air conditioner shall be used in the local sealing device to control the humidity and temperature during copper strip winding within a certain range.

(5) Passivate with passivator. At present, most copper processing plants use benzotriazole (BTA) (molecular formula: c6h5n3) as passivator. Practice has proved that it is a convenient, economical and practical passivator. When the copper strip passes through BTA solution, the oxide film on the surface reacts with BTA to form a dense complex, which protects the copper substrate.

2. Solution of copper strip shear indentation

In order to prevent the indentation of the cutting edge, the reasonable outer diameter difference between the round knife and the rubber stripping ring should be selected according to the thickness and hardness of the strip; The hardness of the rubber stripping ring shall meet the use requirements of the cut strip; When the width of the cut strip is small, the thickness of the round knife shall be reasonably selected to increase the width of the rubber stripping ring.

Source: tongxinbao