Technical progress of straight seam steel pipe rolling:
1) Increase the thermal charging temperature and thermal charging ratio: Increasing the thermal charging temperature and thermal charging ratio is an important measure for energy saving and emission reduction, and has attracted much attention. At present, the average hot charging temperature in my country is 500-600°C, and the highest temperature can reach 900°C; the average hot charging ratio is 40%, and the production line reaches more than 75%. The hot charging rate of the 1780mm hot strip rolling mill in Fukuyama Works of Japan Steel Tube is 65%, the direct rolling rate is 30%, and the hot charging temperature reaches 1000°C; , The hot charging rate is 28%. In the future, my country should increase the hot charging ratio of continuous casting slabs above 650 °C, and strive to save energy by 25% to 35%.
2) Various heating technologies of the heating furnace: heating technologies include regenerative heating, automatic combustion control, combustion of fuel with low calorific value, low oxidation or non-oxidation heating technology, etc. According to statistics, more than 330 steel rolling heating furnaces in my country have adopted regenerative combustion technology, and the energy saving effect can reach 20% to 35%. Energy consumption can be further reduced by optimizing combustion. This requires work on the use of low-calorific-value fuels, increasing the application of blast furnace gas and converter gas. The low-oxidation heating technology of atmosphere control and the non-oxidation heating technology of gas protection are important measures to reduce oxidation burning loss and increase yield. The technology even eliminates the need for pickling. At present, the oxide scale produced in the steel rolling heating process is 3-3.5kg/t, and the annual loss is estimated to be about 1.5 million tons of steel (about 7.5 billion yuan); according to calculations by European scholars, the cost of pickling is 15-20 Euros/ton t, if it can be used to reduce pickling and acid consumption, it will have a significant effect on protecting the environment and reducing the pressure of waste acid treatment.
3) Low-temperature rolling and rolling lubrication technology: Some domestic high-speed wire manufacturers have adopted low-temperature rolling technology, and their average furnace temperature has reached 950°C, and the lowest has dropped to 910°C. The power has been designed and manufactured according to the rolling temperature of 850°C. The total energy consumption of low-temperature rolling is reduced by about 10% to 15% compared with conventional rolling. According to the statistics of the hot rolling plant of Kashima Iron Works, Japan, reducing the billet temperature by 8°C will save energy by 4.2kJ/t, and the energy saving effect is 0.057%. However, low-temperature rolling has strict requirements on the uniformity of billet heating temperature, and the temperature difference over the entire length of a 130-150mm billet should not be greater than 20-25°C. Rolling lubrication technology can reduce rolling force by 10% to 30%, reduce power consumption by 5% to 10%, reduce iron oxide scale by about 1kg/t, thereby increasing yield by 0.5% to 1.0%, and can also reduce pickling acid The consumption is about 0.3～1.0kg/t. Many domestic rolling mills have successfully applied it to the production of stainless steel and electrical steel, with excellent results. In the future, while vigorously promoting rolling lubrication, we should strengthen the research and development of environmentally friendly rolling lubrication media, lubrication technology and recycling technology.
4) Controlled rolling and cooling technology and its equipment: Controlled rolling and cooling technology is an indispensable means for energy saving, high-performance products and production. Representative steel materials such as DP steel, TRIP steel, TWIP steel, CP steel, AHSS steel, UHSS steel, other pipeline steel, building structure steel, grain steel, and heat-free steel are all produced by controlled rolling and controlled cooling technology. Controlled rolling and controlled cooling technology is not only based on the new development of physical metallurgy, but also benefits from new technology and equipment, such as high-pressure rolling mills that can achieve low temperature and high pressure, ultra-compact rolling mills, and ultra-fast cooling ( UltraFastCooling), – Online Accelerated Cooling (Super-OLAC) device, reducing and sizing machine equipment, etc. In the future, the development of controlled rolling and controlled cooling technology will strongly rely on new technical equipment. This is an important feature of the development of controlled rolling and controlled cooling technology, which needs to be paid attention to.
Post time: Mar-09-2023