CuNi1铜镍电阻合金熔炼工艺

Core Viewpoint - The CuNi1 copper-nickel resistance alloy is crucial in various industries due to its high-temperature oxidation resistance, good conductivity, and stable resistance characteristics. The focus is on establishing a reasonable smelting process to ensure the precision and consistency of the alloy's resistance [2]. Group 1: Technical Parameter Analysis - The optimal smelting temperature for CuNi1 is set between 1300 and 1350°C, following the ASTMB170 standard to ensure adequate fusion of liquid copper and nickel [3]. - The flux content should be controlled within 2%, and the aluminum high-tin concentration should avoid inclusions. The smelting time is recommended to be between 45 and 60 minutes to eliminate pores and inclusions, enhancing material uniformity [3]. - The finished product's resistance value must meet industry standards, specifically within the range of 1.1Ω/mm² ± 0.05Ω/mm², reflecting its conductive properties. The material density should be around 8.9g/cm³, as density variations directly impact resistance stability and conductivity [3]. Group 2: Misconceptions in Material Selection - A common misconception is the blind pursuit of low prices, which can lead to neglecting material purity and impurity control, potentially resulting in unstable resistance and reduced corrosion resistance [4]. - Sole reliance on LME or Shanghai Nonferrous Metals data without considering the supplier's material source and certification can be misleading [4]. - Strict control of nickel content is often overlooked; even minor differences in nickel content (e.g., 98% vs. 99%) can significantly affect resistance values and thermal stability, particularly in high-precision applications [4]. Group 3: Challenges and Controversies in Smelting Process - A key controversy in the smelting process is the duration of the holding time. Some factories prefer to extend the holding time to ensure complete alloy uniformity, but excessive smelting time can lead to grain coarsening, reducing thermal stability [5]. - Maintaining an optimal operation window of around 45 minutes is essential to ensure sufficient fusion without causing grain growth, which has become a focal point of industry discussions [5]. - Adhering to international standards (e.g., ASTMB170) and domestic standards (e.g., GB/T25189) in setting process parameters can effectively mitigate production variations. Each step of the process should consider LME copper prices (currently around $7000 per ton) and market dynamics from Shanghai Nonferrous Metals to adjust input quantities and avoid raw material waste or supply risks [5].