Why does Solid Round Copper Braid turn black?

In the field of electrical conductive components, Solid Round Copper Braid is widely used in assembly due to its excellent ductility and conductivity. Meeting the various physicochemical standards of the product is a fundamental condition for ensuring the stable operation of electrical systems. Once the surface of the finished product shows blackening and deterioration, the conductivity of the component will be significantly reduced, making it unusable for direct installation. The cause must be investigated and the production process optimized. Only after rectification and acceptance can it be released to the market. This type of blackening defect can appear instantly after the annealing process or gradually occur after a period of storage. From a physicochemical perspective, this deterioration phenomenon belongs to the category of metal corrosion reactions. Initially, it is mainly chemical oxidation corrosion. With changes in environmental conditions, electrochemical corrosion easily develops, continuously exacerbating the surface deterioration.

The formation of metal corrosion is influenced by multiple objective conditions. The physicochemical properties of the raw material of Round Pure Copper Braided Strap, the surface condition during processing, the internal metal structure, and residual stress, as well as factors such as the production environment, operating temperature, and deviations in heat treatment parameters, all affect the rate of oxidation and blackening. Copper substrates are chemically reactive; under normal conditions, they react slowly with oxygen in the air to form a dense oxide film on the surface. High-temperature environments further accelerate the oxidation reaction. If production control is lax, the accumulation of various corrosion factors can cause the product surface to gradually turn from light brown to dark black, destroying the product's appearance and conductivity.

To curb blackening defects at the source of production and stabilize the quality of Latching Relay Round Copper Flexible Braid, the primary task is to control the protective gas source during heat treatment, systematically purify the protective gas components, and prevent corrosive media such as oxygen and water vapor from penetrating the annealing tank. When the product completes annealing and enters the air-cooling stage, protective gas is continuously introduced into the tank to maintain a stable internal pressure higher than standard atmospheric pressure. This sealed, inert environment isolates the copper substrate from air contact, reducing the probability of contact between the copper substrate and corrosive gases, thus lowering the probability of oxidation reactions during this critical heat treatment process.

The accompanying post-treatment and mold control are equally crucial in preventing product blackening. After high-temperature annealing, the Round Copper Stranded Braid for Relay undergoes a uniform corrosion-inhibiting treatment, forming a protective thin layer on the metal surface to block moisture and air corrosion. During production inspections, the integrity of the drawing dies is regularly checked; worn or cracked dies are immediately replaced to prevent burrs from scratching the substrate surface and to prevent the accumulation of lubricating oil and impurities in scratches, avoiding long-term residue adhesion that could induce localized corrosion and blackening.

Daily maintenance of the production equipment is also essential. The annealing tank is periodically thoroughly rinsed with high-pressure water, and the inside of the tank is thoroughly dried after rinsing to remove accumulated oil, metal debris, and moisture residue, maintaining a clean and dry heat treatment chamber. In the tank airtightness testing process, nitrogen is used instead of traditional compressed air. The tank is heated to 200°C and continuously vacuumed to remove the humid air and oxidizing impurities mixed in the cavity, thus eliminating various corrosion hazards in the production environment and effectively controlling the blackening defect rate of the Copper Braided Wire.

Based on the above-mentioned standardized production control process, Solid Round Copper Braid strictly implements gas control, corrosion inhibition treatment, and equipment maintenance standards throughout the entire process. From raw material processing to finished product protection, multiple layers prevent oxidation and blackening defects. The finished product has a smooth, rust-free surface, and its conductivity stability and environmental corrosion resistance are superior to conventional products in the industry, making it suitable for various electrical assembly scenarios such as new energy and power distribution equipment. Customers are welcome to inquire about selection and procurement matters at any time.