At present, the production characteristics of copper bars in China are short process, high yield, and environmentally friendly. There are some common problems in the manufacturing process of copper bars:

1. Problem with the pole

The oxygen content exceeds the standard, and even there are pores (oxygen content f oxygen free copper ≤ 10ppm)

Coarse and loose grainsCold shut and surface cracks

Surface oxidation (temperature above 100 ℃ forms black copper oxide, temperature above 180 ℃ forms orange red cuprous oxide, temperature above 400 ℃ accelerates oxidation, and oxidation rate increases with increasing humidity)

2. Problems with soft volleyball

Surface and internal bubbles

Scratches and oxidation

Narrow edge cracks (large soft fill defects)

3. Problems with hard copper bars

Copper bar oxidation (orange or black)

Uneven size of copper bars

Surface defects (spots, pits, scratches, color differences, and defects) of copper bars

4. Tin coating issues

Blackening of tin coating (oxidation of Sn coating)

Measures to improve the quality of copper bars

1. Measures for improving the quality of copper rods

Purify raw materials and auxiliary materials, reduce oxygen content (remove copper beans and copper green; screen and dry charcoal and graphite sheets; dry utensils)

During smelting, copper should not be exposed at the furnace mouth, and charcoal should be covered in place (≥ 10-15cm) to reduce oxygen content

Regularly clean the slag hanging at the furnace mouth to reduce inclusions

Control the temperature and temperature fluctuation of copper liquid, reduce oxygen content, avoid eliminating looseness and cold insulation (≤ 1150 ℃), high temperature, high gas content, low temperature, and poor fluidity

Strictly control the rod making process, control the temperature of the cooling water in the crystallizer (the inlet temperature should not be higher than 30 ℃, and the difference in inlet and outlet water temperature should be controlled within 10-15 ℃), pressure, flow rate, and rod speed to prevent the occurrence of hollow rods, coarse grains, loose structures, and oxidation

Occasional spot checks (oxygen content analysis, or 820 ℃) × 20 min annealing,)

Copper liquid deoxygenation treatment and grain refinement treatment

2. Measures for improving the quality of soft discharge

Eliminate bubbles, control the oxygen content and surface state (oxidation, oil stains, dust, and water stains) of oxygen free copper rods; It is strictly prohibited to bring in gas during the extrusion process (damage to the surface of the copper rod, leakage of cooling water from the extrusion wheel, damage and wrinkling of the copper clad area in the groove of the extrusion wheel, and waste material brought into the extrusion wheel)

Eliminate scratches, polish the surface of the extrusion mold, and ensure the smoothness of the sizing belt; Varying the extrusion speed to remove the oxide attached to the sizing strip

Eliminate oxidation, increase cooling speed, add 3-8% alcohol to the coolant, or use lubricating agent liquid+water

Narrow edge cracks improve metal fluidity (cavity preheating in place, 700-800 ℃ × 10 minutes, appropriately lengthen the length of the mold sizing belt to increase the extrusion driving force,

Optimize extrusion parameters, control recrystallization, and refine grain size

3. Measures for improving the quality of copper bars

Control the unevenness of the thickness of the copper busbar soft busbar to reduce the bending deformation of the hard copper busbar

Water soluble stretching oil lubricates the stretching mold (reduces scratches and scratches, improves smoothness and accuracy)

After stretching, let it stand for a period of time before stacking to avoid oxidation (if the temperature is higher than 100 ℃, black copper oxide will form;)

Standardized packaging (reducing bumps and static electricity during transportation)

Improvement of drawing molds and lubrication cooling fluid, as well as automated testing

4. Improvement of tin coating quality

Control the purity of Sn

Strengthen the cold and hot water cleaning treatment of electroplating tin

Improve storage environment, seal after tin plating and drying

New requirements for adding anti oxidation film copper bars

Solve the issue of adding furnace feed

Reducing the Contact Resistance of Copper Bars

New Technology for Developing High Conductivity and High Extension New Copper Bars and Copper Bars

Copper liquid degassing and impurity removal technology

Grain Refinement Technology for Copper Rod and Copper Strip

Copper bar bright technology

Anti oxidation Technology of Copper Bar Tin Plating Layer

Surface passivation treatment technology for copper bars

Article source: Internet