Seek truth from facts and correctly treat "using aluminum to save copper"

Academician Huang Chongqi pointed out:
1. Because copper and aluminum (aluminum alloy) conductors each have their own characteristics, they cannot be simply replaced or considered a binary choice. Therefore, the principle of "using aluminum to save copper" should be based on facts. Copper should be used for cable products that require copper. For products that can use copper or aluminum as conductors, scientific experiments and successful trials should be conducted before promoting their application. Blindly promoting such products will lead to a decline in product quality and even frequent safety accidents, causing production fluctuations. Some fields or products have already achieved good results after practical verification.
2. "Using aluminum to save copper" is an international trend, but it varies according to national conditions, scientific and technological progress, and application habits, with starts and stops and repeated occurrences. However, the prospect of using aluminum to save copper is generally bright. The decision of whether to use copper, aluminum, or aluminum alloy cables should be made by the end-user's design and users based on the comprehensive economic and technical effects and operational safety and reliability.
3. For cables, "using aluminum to save copper" means that not only are copper and aluminum alloy conductors competitors, but aluminum and aluminum alloys are also competitors, both domestically and internationally. In China, the current application of aluminum alloy conductors in overhead lines or cables is relatively low compared to copper and aluminum conductors, accounting for only a single-digit percentage of the total conductor volume. It is expected that the usage of aluminum and aluminum alloy conductors will reach a double-digit percentage in the future.
Currently, the chaos of "using aluminum to save copper" stems primarily from irresponsible misleading information, which has affected users, disrupted the market, and impacted investment. This has also harmed cable manufacturers. In this regard, we ask Academician Huang Chongqi to provide concise guidance to help relevant parties learn from the lessons and enable the healthy and steady development of "using aluminum to save copper".
Academician Huang said: In summary, there are currently four main problems and four misleading aspects.
Problem 1: False advertising has disrupted the normal and orderly promotion of the application of aluminum and aluminum alloy cables.
Misleading aspect one: Claiming that "aluminum and aluminum alloy cables are energy-saving cables and save more energy than copper cables".
According to the ICA research report (February 2013), comparing the energy consumption of the production and application of primary metal materials: Based on the analysis of unit energy consumption in metal production, the unit energy consumption of primary aluminum is 2.2 times that of cathode copper; considering factors such as comprehensive cross-sectional area, the energy consumption of 1 ton of primary aluminum is still about 10% higher than that of 2 tons of cathode copper; according to the analysis of industry technological progress and development planning, by 2015, the unit energy consumption of primary aluminum will be about 2.8 times that of cathode copper, and the energy consumption of 1 ton of primary aluminum will be about 39% higher than that of 2 tons of cathode copper.
In short, at least in the primary metal material stage, in terms of equivalent comparable energy consumption, copper cables are superior to aluminum cables; under the same conditions, the conductivity of copper is significantly better than that of aluminum and even better than that of aluminum alloys. Therefore, in the application stage, end-users should select the best option based on comprehensive technical and economic effects and safe operation requirements.
Misleading aspect two: In different conditions, false comparative advertising of the performance of copper, aluminum, and aluminum alloy conductors has led to design doubts and affected the reasonable and appropriate selection of cables.
Under the same conditions, the typical conductivity (soft state) is copper (100-102% IACS) > aluminum (63-64% IACS) > aluminum alloy (≥61.0% IACS); under the same conditions, the typical softness (bendability) in the soft state, especially in thin wires, is copper > aluminum > aluminum alloy. After the conductor is made into a cable, its softness (bendability) is also related to the structure of the cable (insulation, armor, etc.). If we compare interlocking armored aluminum alloy cables and steel-tape armored aluminum alloy cables, the former is naturally better; the corrosion resistance of metal conductor materials is closely related to the medium or material it contacts under operating conditions. The operating conditions of overhead bare conductors and cable cores are different and cannot be confused. Generally speaking, the corrosion resistance of pure aluminum is better than that of aluminum alloys. People try to add certain elements to develop corrosion-resistant aluminum alloys, but so far, none have entered industrial applications. In electrical aluminum with relatively low iron and silicon content, adding an appropriate amount of rare earth elements has been shown to improve corrosion resistance in salt spray tests (similar to steel-core aluminum stranded wires erected in coastal areas), but if the aluminum contains higher levels of iron and silicon, the results are reversed. For copper, aluminum, and aluminum alloy cable cores, generally speaking, their corrosion resistance is copper > aluminum > aluminum alloy, but it must be pointed out that if the insulation material contains sulfur, the surface of the copper wire used for cable cores will produce "sticky and black" corrosion products. In this case, the surface of the copper wire needs to be plated with a layer of tin to isolate the sulfur; the corrosion resistance of copper-clad aluminum wire will be accelerated if "pinholes" (exposed aluminum) appear on the surface of the copper wire, leading to embrittlement.
Problem 2: Misleading investment has further expanded the already oversupply of mid-to-low-end products in the cable industry. This may help alleviate the oversupply of electrolytic aluminum (upstream), but it has also created problems with the oversupply of cable products (downstream).
Misleading aspect three: The media continuously reprints reports that the application of aluminum alloy cables abroad has reached 80-90%, exaggerating the huge market potential.
According to a research report by the ICA International Copper Association (October 2013), their research on the major world power cable markets in North America and Europe shows that the basic conclusion is that the amount of conductors used in power cables produced worldwide each year, including equipment cables, industrial cables, building cables, power system cables, and bare conductors (BOHC, overhead conductors), is 23.12 million tons of copper equivalent (2012), with copper accounting for 42.6%; while power cables, only including industrial and power system cables, use 7.01 million tons of copper equivalent (2012), with copper accounting for 50.6%. The report uses copper equivalent for calculation, i.e., 1 ton of aluminum is equivalent to 2 tons of copper; the classification method used in the report is different from that in China, but it can be used for reference.
Europe is a region that uses a significant amount of aluminum, including aluminum alloys for overhead conductors. Approximately 51.5% of the aluminum used is in cables and overhead lines, with 74% allocated to overhead conductors (including aluminum alloys) and 26% to cables. For easier recall, the weight ratio of aluminum to copper conductors is approximately 3:7. In Europe, only aluminum, not aluminum alloys, is used for conductors in power cables. Currently, the primary applications of 8000 series alloys are in North America and China. In North America, 8000 series aluminum alloys are only used in low-voltage building cables; According to a September 2013 report by CRU (the UK-based commodity research firm): (1) In 2012, the consumption of aluminum-core insulated power cables increased by 6.4%, showing the strongest growth among metal-insulated cables, but the net increase was not significant; (2) Aluminum-core cables are most commonly used in India and least used in Japan. In terms of conductor weight, 36.8% of power cables globally used aluminum conductors, with Japan having the lowest market share at only 4.3%, while India's market share reached 85%. Aluminum-core cables are mainly used in power transmission, while copper-core cables are still predominantly used in industrial power cables. (3) Despite high copper prices, the substitution process for aluminum has not been rapid. The proportion of aluminum-core power cables only increased by 9% in 7 years, from 28% in 2004 to 37% in 2011. (4) The application of overhead insulated cables in power transmission has become increasingly significant (the structure of this cable mainly consists of aluminum conductors or steel-core aluminum stranded wire plus insulation). In 2012, China's aluminum consumption for this purpose reached 170,000 tons.
Misconception Four: It has been reported that a certain company has invested in several factories producing rare-earth high-strength aluminum alloy cables in several regions, with a total investment of tens of billions of yuan. In a few years, the output value of each newly built enterprise could reach 10 billion yuan; some reports even claim that "the aluminum alloy cable market in China is expected to develop rapidly in the next 5 years, forming a market scale exceeding 200 billion yuan."
Currently, there is a frenzy of investment in aluminum alloys within and outside the cable industry. Some say there are 100 companies, others say 200, with various claims. This has led to interaction between the government and enterprises, with the government aiming for GDP growth and enterprises seeking government land approvals and bank loans.
The cable industry's biggest concern now is overcapacity and how to ensure the quality of aluminum alloy cable products, preventing the market from being ruined. There are already instances of aluminum cables being sold as aluminum alloy cables to obtain higher profits. This warrants caution!
Even for the largest cable manufacturers in China, achieving an annual output value of 10 billion yuan for aluminum alloy cables within a few years is unrealistic and only serves to deceive uninformed investors. If the market size of aluminum alloy cables in China reaches 200 billion yuan in the next 5 years, this would represent 16% of the entire industry's output value in 2012? A single aluminum alloy cable product achieving such a high output value is simply a fantasy.
Question 3: The patent application issue for rare-earth high-strength aluminum alloy conductor materials by individual companies.
The main points of contention in this issue are:
(1) The application of rare earth elements in electrical aluminum and aluminum alloys is not a new technology; it has been used nationwide for over 30 years and is still in use. The Shanghai Cable Research Institute has received first, second, and gold awards and invention patents from the Ministry of Machinery Industry, the National Ministry of Science and Technology, and the Shanghai Science and Technology Expo in 1981, 1985, 1990, 1991, 1997, and 2006, respectively.
(2) The application of rare earth elements in electrical aluminum and aluminum alloys is merely a processing method in the manufacture of wire and cable conductors, similar to adding iron or boron, not the creation of a specialized alloy.
(3) For overhead lines using aluminum and aluminum alloy wires, due to the high requirements for strength and conductivity, domestically produced aluminum materials generally had high silicon content in the past, making them unsuitable for overhead conductors. Adding a small amount of iron can increase strength, and adding a small amount of rare earth elements for optimization can increase conductivity. This can be considered an effective solution; the technical threshold for aluminum alloy wires used in cable cores is relatively low, and they are soft wires, so conductivity is not a problem, and the strength requirements are not high, especially since domestically produced aluminum raw materials now generally have lower silicon content. In fact, when formulating the national standard for "aluminum alloy wires for cable conductors," six participating wire and cable manufacturers submitted test samples. Verification and comparative tests conducted under the same conditions at the Shanghai Cable Research Institute showed that the mechanical properties, conductivity, and creep resistance of aluminum alloy wires with added rare earth elements were not superior to those without added rare earth elements; they merely met the standard requirements. Therefore, the newly formulated "Aluminum Alloy Wires for Cable Conductors (GB Standard)" and "Rated Voltage 0.6/1KV Aluminum Alloy Conductor Cross-linked Polyethylene Insulated Cable Standard (NB Standard)" do not specifically mention rare-earth high-strength aluminum alloy wires.
(4) For aluminum alloy wires used in wire and cable cores, in order to improve their creep resistance and benefit cable connection safety, Alcoa and Southwire Company added higher amounts of iron to aluminum, obtaining patents in the 1960s and establishing the 8000 series standard in the 1980s, which is still in use today. Historically, there is a lesson to be learned: decades ago, when China's rare earth optimization and comprehensive processing technology was widely promoted and applied in the production of electrical aluminum conductors (also applicable to aluminum alloy conductors), a leader in the original Ministry of Electric Power responsible for overhead transmission lines proposed establishing a standard for rare-earth aluminum conductors, aiming to control and monopolize this business for personal gain. After communication with the cable industry regarding the reasons for non-acceptance, this proposal was abandoned. Later, some manufacturers in the market did not add rare earth elements but sold them at high prices as rare-earth aluminum conductors. In short, whether or not to establish a standard should not depend on the will of officials but on scientific principles and market allocation mechanisms.
Question 4: Promoting "using aluminum to save copper" seems enthusiastic on the manufacturing side due to profit incentives, but lukewarm on the application side, and in fact, both sides lack sufficient preparation.
"Using aluminum to save copper" is an international trend, but it is not a "rapidly advancing" phenomenon that is artificially created, but rather a "gradual" process that requires "technical preparation" and "market preparation."
Regarding electrical aluminum and aluminum alloys, the foundation for electrical aluminum is currently relatively good, but it took about 10 years to develop and stabilize its application; electrical aluminum alloys, especially aluminum alloys for overhead conductors (which have a higher technical threshold than aluminum alloys for cable conductors), are still in their early stages of development. To date, only a handful of domestic companies can achieve stable production. This involves the pace of equipment modernization and process stability.
From the perspective of the application side, the most important concerns are the connection and safe and reliable operation of aluminum and aluminum alloy cables used at different voltage levels, as this involves technical, economic, and social responsibilities. Therefore, the credibility of the application of this product is involved. In order to expand the application, the application side must solve the technical issues of connection and its spare parts (aluminum-aluminum, copper-aluminum connection spare parts), as well as the problems of construction and personnel training. Of course, the relevant standards and specifications must also be gradually introduced based on sufficient argumentation, through practice and summarization.