Thoughts on the Development of Special Steel in my country

3. Timely guide and support the second round of investment in the development of modern electric furnaces in my country
my country’s modern electric furnace steelmaking began in 1993 at the “Contemporary Electric Furnace Process and Electric Furnace Engineering Problem Seminar” held by the former Ministry of Metallurgy and Shanghai in 1993 (hereinafter referred to as the first Shanghai meeting). Thanks to the guidance of government departments at all levels and support for iron and steel enterprises to make a round of investment in modern electric furnace processes, and relying on the introduction of advanced foreign modern electric furnace process technologies, a number of “three in one” or “four in one” advanced electric furnace processes have been built in our country.
It is precisely because of the completion, commissioning, production, and overproduction of this batch of advanced modern electric furnace processes that the proportion of electric furnace steel in my country was once declining from 1993 to 2000, and it was out of the trough between 2000 and 2003. , There has been a rebound, by about 2%. At this stage, the growth rate of electric furnace steel is higher than the growth rate of national steel and converter steel, as shown in Table 2.
Why is the electric furnace steel growing so rapidly at this stage? The rapid development of the national economy is the driving force. The development of electric furnaces is driven by GDP growth. However, if there is no investment, the country does not build a batch of modern electric furnace processes, and the rapid development of electric furnace steel is impossible of. Of course, the introduction of equipment alone is not enough. The creative and hard work of the vast majority of electric furnace workers in our country has enabled my country to reach the international advanced level in terms of electric furnace smelting process, technical and economic indicators, and theoretical research. International leadership.
However, my country is currently in a stage where the proportion of electric furnace steel has been declining for the second time since 1990. Due to the release of converter steel production capacity caused by my country’s large investment in converter processes in the previous stage, my country’s converter steel output has increased substantially. The annual growth rate has reached 27%, and the potential tapping and release caused by the first round of investment in electric furnace steel has been nearly saturated, and the annual growth rate has been greatly reduced. It was 6.7% in 2004. The growth rate of converter steel is much higher than that of electric furnace steel. It has dropped by 2 percentage points in a year, and it is estimated that this will continue in 2005 and 2006.
The decline in the proportion of electric furnace steel is not conducive to the sustainable development of the steel industry, and it is not conducive to my country’s transformation from a large steel country to a strong steel country. It deserves attention. In my opinion, the state should promptly guide and support the second round of investment in the development of modern electric furnace processes in my country.
Table 2 The growth rate of electric furnace steel in my country and the world from 2001 to 2003
Steel growth rate = (steel output of the current year-steel output of last year) / steel output of last year * 100%
The state has already stipulated that a large number of backward small blast furnaces, small converters, small electric furnaces, and ground steel should be eliminated. However, the production capacity of small blast furnaces, small converters, and small electric furnaces under 10 tons still account for a large proportion of the “Eleventh Five-Year Plan”. During the period, according to the principle of “shut down a batch in accordance with laws and regulations, treat squeezed a few differently, increase the size of the small and eliminate a batch, replace and rebuild a batch of the same amount”, comprehensively use various methods to make the backward production capacity exit the market as soon as possible. I believe it will receive the expected results. Here I want to talk more about the issue of revising the national standard of steel.
In the current development of my country’s electric furnace steelmaking and the elimination of outdated production capacity, in addition to the country’s promulgation of relevant policies and regulations, it is also technically necessary to promptly revise certain steels, such as the national standards for construction steels that are used in a large and wide range, and firstly support relevant formulations. And revision of national standards. Second, relevant national standards must be formulated and revised in a timely manner.
According to the research results of the 973 project “Major basic research on new generation steel materials”, the cleanliness of steel has an important impact on the microstructure and properties of steel. It is recommended to modify the relevant steels, especially the ferrite + pearlite types that are widely used. Steel cleanliness standards, such as standards for sulfur, phosphorus, and non-metallic inclusions, formulate standards for nitrogen and oxygen in steel. Because steel midflow and dissolved oxygen have a significant effect on the mechanical properties of steel, it is necessary to produce newly developed super steels The standard of the original traditional steel cannot be used. The total oxygen content in steel should be required. If the total oxygen content of steel is required to be <=50ppm, and the sulfur content is <=100ppm, some equipment and processes that represent backward production will naturally be eliminated because the steel produced fails to meet this requirement. Advanced converter process and electric furnace process are easy to reach. It may be difficult to “upgrade the large ones and eliminate the small ones” because the backward production capacity can still produce low-end products according to traditional standards and compete with advanced processes for cost.
Regarding cleanliness, I think that the “limit” is difficult to quantify in the understanding of “limit cleanliness” and “economic cleanliness”. It can only determine the level that can be achieved under current circumstances, but this level should not be the “limit” The level that may be reached in different periods is different, and the “economy” is also relative and developing. “Economic cleanliness” should be to meet the performance requirements of advanced steel materials, which can be achieved under the current equipment and process conditions, and achieve a cleanliness that does not increase the cost too much. According to this understanding, the above-mentioned total oxygen content <=50ppm and sulfur content<=100ppm can be determined as the “economic cleanliness” of 400MPa grade ferrite + pearlite under current conditions. The threshold value of “economic cleanliness” is also the standard stipulation. If it is not set properly, it may objectively extend the life of backward equipment and technology, create a situation of coexistence and competition between backward and advanced, and affect the speed of elimination of backward production capacity and advanced steel. The popularization and application of materials, especially when our country is not completely high-quality and high-priced. It is the original intention of the “major basic research on a new generation of steel materials (973 project)” to replace 200MPa traditional steel with advanced steel materials with a yield strength of 400MPa.
At present, my country’s scrap steel and electricity are still in short supply. This is the actual difficulty in developing modern electric furnace steelmaking. Why I still think that the state should promptly guide and support the second round of funding for the development of modern electric furnace processes. There are two main considerations:
(1) It takes a certain time for investment to form production capacity
After the 1993 “Contemporary Electric Furnace Process and Electric Furnace Engineering Problem Symposium”, under the guidance and support of governments at all levels, various iron and steel enterprises made the first round of investment in the development of modern electric furnace processes, and newly built about 40 modern electric furnaces over 60 tons. It took about 8 to 10 years for these electric furnaces to inspect, declare, approve, establish projects, negotiate, sign contracts, construct, put into production, reach production, and exceed production, and reached a peak in 2003.
(2) From 2010 to 2015, my country’s scrap steel and electricity supply situation will undergo major changes, which is conducive to the development of electric furnaces
First of all, due to the state’s efforts to build energy resources, the power shortage situation will be changed. At present, some companies have already dropped their electricity prices for production.
In terms of steel scrap, the amount of steel scrap used in steelmaking in China will increase significantly. There are two reasons: first, China’s self-produced steel scrap and processed steel scrap will increase due to the large total steel output. Depreciation of steel scrap will have a payback period of 15 years. The steel produced after 1996 has begun to be recycled for steelmaking. After this time, the amount of domestically produced steel has exceeded 100 million tons per year, and the amount of depreciated steel scrap will also increase; second, the country has decided to eliminate outdated steel before 2010 Steel production capacity, the eliminated small converters, small electric furnaces, and ground strip steel are calculated at 100 million tons. At least 20 million tons of scrap can be used for advanced converter and electric furnace processes. If there is more scrap, the price will be reduced.
With the development of the domestic economy, the demand for steel materials will not decrease. If 100 million tons of backward steel production capacity is eliminated, the part of their production will be gone. The lack of steel will come from there. First, it is produced by the converter process, such as by On the premise of eliminating outdated production capacity at the same time, the newly-built and advanced steel joint enterprise produces but consumes limited scrap steel, because its own production capacity will not reach 100 million tons, and the scrap steel addition ratio is only 8%. Based on China China’s national conditions and investment intensity make it impossible to build many pilot enterprises. Another is that companies that already have small converters eliminate small converters and build large converters with the same capacity. I think this measure is not appropriate from the viewpoint of sustainable development. If we start now to consider the second round of investment in the development of modern electric furnaces in my country, from 2010 to 2015, the second round of investment in the new modern electric furnace process may be a good time for the electric furnace process to take advantage of its advantages.
Fourth, the electric furnace process to produce high-quality plain steel is the correct way for the electric furnace factory to get out of the predicament
At present, my country’s scrap steel and electricity are still in short supply. The cost of electric furnace steel is higher than that of converter steel of the same variety. It is a fact that electric furnace steel plants are difficult to produce. What is the road for electric furnace steel plants to get out of the predicament? I think it is electric furnace process to produce high-quality plain steel. The right way for the factory to get out of the predicament.
The survival of an enterprise must pay attention to economic benefits. Profit is the lifeline of an enterprise. The author once proposed a simple formula for calculating the benefits or benefits of an enterprise, namely, benefit = (product selling price-cost)/time. This time can be the smelting cycle. Profit represents the benefit of a furnace of steel, which can be used to theoretically calculate the smelting cycle; the time can also be a year, and the profit is the annual benefit. From this formula, it can be seen that to improve the efficiency of enterprises, the production of high value-added products with high prices is the key, and cost reduction is an effective measure. In addition, there must be a scale, and the total amount of high value-added products produced in a year is too small. , The efficiency will not be good. my country’s Xingcheng Special Steel and Wuyang Steel Plants account for a large proportion of their high value-added products and are large in scale, and their economic benefits are still very good.
For the smelting process of the electric furnace process, high value-added products have different meanings depending on time and place. The author once wrote an article in “Metallurgical Management” 2006 Issue 8 to discuss several types of electric furnace steels that are currently profitable in my country. This article focuses on further discussion Let’s look at the problem of producing high-quality plain steel from electric furnaces.
On the whole, the proportion of special steel in the entire steel production and the proportion of electric furnace steel is small. The proportion of special steel in the world is only less than 15% of the total steel output, while the proportion of electric furnace steel is about 1/3; The proportion of special steel in my country is less than 8% of total steel output. Although the proportion of electric furnace steel is very low, it was estimated to be around 13% in 2005. In fact, while domestic and foreign electric furnaces are producing special steel, they are also producing general steel. High-quality plain steel, the United States does not produce 200MPa-grade rebar, while the plain steel produced by electric furnaces in China is mostly high-quality carbon steel (mainly medium and high carbon steel).
The modern electric furnace process is used to produce 400MPa grade ferrite + pearlite type steel. If the total oxygen content is less than 0.0050% and the sulfur content is less than 0.010% in the standard, it will be able to replace the current argon blowing, The same kind of small converter steel, small electric furnace steel, and ground bar steel (the total amount of these three types of steel may exceed 100 million tons). Practice shows that the modern electric furnace process can successfully produce ferrite + pearlite type steel with an os of 400MPa under the above standard conditions.
In terms of technical measures to reduce costs, it is still necessary to persist in developing modern electric furnace smelting technology with shortening the electric furnace smelting cycle as the core. Adding part of the molten iron smelting and adopting a concentrated beam oxygen lance to strengthen oxygen supply are two important technical measures.
There is an optimal molten iron ratio for smelting with electric furnace and partial molten iron. The best molten iron ratio calculated with the shortest smelting cycle is related to the average oxygen supply intensity. When the oxygen supply intensity increases, the optimal molten iron ratio increases.
At present, some enterprises use more than 80% molten iron, do not supply electricity, and use electric furnaces as converters. This is understandable from the perspective of enterprises, but it is not appropriate from the perspective of resource consumption, environmental protection, and sustainable development, because electric furnaces The oxygen consumption, productivity (smelting cycle), gas recovery and other indicators of the chemical process are not as good as the converter, and the inherent advantages of the electric furnace compared with the converter are gone.
V. About the establishment method of the Chinese Society of Metals
The China Metal Society has two branches, steelmaking and special steel, and several academic committees (three-level societies) under each. In the special steel branch, there was originally a special steel smelting academic committee, which was later divided into an electric furnace committee and a special smelting and out-of-furnace refining academic committee, which was less active. The Steelmaking Branch has also established the Electric Furnace Academic Committee and the Out-of-furnace Refining Academic Committee. As electric furnaces and converters show more and more commonalities, converters can produce special steel, and electric furnaces can also produce general steel. Therefore, they participated in the Special Steel Branch Electric Furnace Committee and Out-of-furnace Refining Committee, Special Steel Electric Furnace Committee and Special Melting and Out-of-furnace Refining Committee The activities organized by the enterprises are basically the same, causing a certain degree of duplication and confusion. It is recommended that the Chinese Society of Metals adjust the steelmaking branch, which includes the converter, electric furnace, special smelting, and external refining society committees, and the ferroalloy branch, the continuous casting branch, and the refractory The branch is jointly responsible for the smelting of general steel and special steel, and the special steel branch is responsible for metal materials. In fact, superalloys, precision alloys, etc. have been or will be separated from the special steel branch to become a secondary branch, and the institutional settings of the society are being adjusted.