Before the reform and opening up ‚ the only hot strip rolling mill in China was Angang 1700 semi-continuous rolling mill, which the former Soviet Union built in the early years of the founding of the People’s Republic of China.
Technical Starting Point: Lagging Behind International Standards
In the 1970s, WISCO introduced a 3/4 continuous 1700 hot tandem mill from Japan. However, the technical level of this equipment fell significantly short compared to international standards.
Post-Reform Development: Modern Hot Tandem Mills Begin
After China’s reform and opening up, Baosteel took the lead by introducing the 2050 hot tandem mill. This marked the beginning of large-scale construction of modern hot rolling lines in China, initially relying heavily on foreign technology.
Advanced Technology Imported from Germany and Japan
At that time, China imported cutting-edge technologies from Germany, including furnace combustion control, automatic gauge control (AGC), continuous variable crown (CVC), automatic width control (AWC), tension control, accelerated cooling (ACC), and full computer control systems. Later, Baosteel 1580 and Angang 1780 introduced hot rolling technologies from Japan’s Mitsubishi, such as PC mills, width-variable presses, free-program rolling, and online rolling control.
Absorption and Mastery of Core Technologies
Through technical negotiations, joint design, collaborative manufacturing, and practical applications, Chinese steelworkers gradually digested and absorbed the imported technologies. This laid the foundation for mastering the core technologies of hot continuous rolling and initiating independent innovation.
Initial Breakthrough: Angang’s First Independent Integration
In 2000, Angang upgraded its original 1700 mill and pioneered short-process slab production technology, becoming the first in China to independently integrate a hot tandem rolling line. In 2005, a new 2150ASP line was built and transferred to Jinan Steel, followed by the ASP1700 hot rolling mill project.
Collaborative Innovation: Nationwide Equipment Integration
Design institutes, universities, research organizations, and heavy equipment manufacturers worked together to build a number of fully integrated domestic hot rolling lines, including Xinjiang Baiyi 1700, Titian 1780, Laisteel 1500, Rizhao 2150, and Ningbo 1780. These efforts marked a leap in China’s independent integration capabilities.
Continuous Innovation: Advanced Technologies and Products
Chinese steelworkers independently developed key innovations such as VCL roll shape control, UFC+ACC cooling systems, oxide scale control, and high-efficiency production methods. These supported the production of internationally competitive steel grades like X70, X80 pipeline steel, and fine-grain high-strength steels.
Following Global Trends: Compact Short-Process Lines
At the turn of the century, China followed international trends and introduced 11 compact-process hot rolling lines, including CSP and FTSR. Based on this, extensive research was conducted on the mechanical properties and strengthening mechanisms of short-process steel.
Chinese Characteristics: Development of Specialized Products
Based on imported technology, China developed production processes suited to local conditions. These technologies enabled the production of various advanced steels. They include high-strength container steel, micro-alloyed steels, and dual-phase steel. Cold-rolled base materials and electrical steel were also developed. These achievements contributed greatly to global thin slab casting and rolling technology.
Remarkable Achievements: China Leads the World
By the end of 2008, China had built 57 hot rolling mills. Their total capacity exceeded 168 million tons.China had emerged as the most advanced country in hot continuous rolling technology.
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