A freshly cast, glowing red steel billet measuring 165mm x 165mm x 12 meters emerges from the continuous caster. It undergoes processing through 18 rolling mills—roughing, intermediate, and finishing stands—navigating each stage successfully before splitting into two streams that enter the cooling bed. At 9:00 AM on February 9, stepping into the direct-rolling rebar production line at the Steel Rolling Plant of Maanshan Iron & Steel Group's Changjiang Steel, one is met with a scene of vigorous production activity.
"Today, we are rolling 25-millimeter specification rebar using a double-splitting process," explained Ren Yuanbao, the operating supervisor of the Double-Bar Area at the Steel Rolling Plant. "From billet to finished product, from the first rolling stand to the cooling bed, it takes just 34 seconds." This production line, converted from furnace-rolling to direct-rolling in 2023, has achieved remarkable speed and high efficiency.
The shift from furnace-rolling to direct-rolling eliminates the heating furnace step, reducing gas consumption and preventing billet scaling. This change saves over 150 yuan per billet. Over the past two years, Changjiang Steel has upgraded and constructed three direct-rolling production lines. The foundation laid by these upgrades aims for lean and efficient operations.
The high efficiency demonstrated in those 34 seconds stems from continuous technical refinement. Through ongoing optimization of pass design and rolling processes, and by quantifying and reducing slot-changing and mold-changing times, these activities are now controlled within 15 minutes and approximately 60 minutes, respectively. Continuous improvements in direct-rolling technology and the splitting process have significantly increased the rolling line speed.
Ren Yuanbao noted, "The overall speed has increased by about 2 meters per second compared to before the optimizations and now operates stably at 12.5 meters per second."
The high efficiency seen in those 34 seconds also results from tight collaboration. "We work closely with the steelmaking and continuous casting processes, precisely coordinating slot and mold changes with the rhythm of molten steel production and ladle changes to minimize billet waiting time and ensure smoother production," Ren Yuanbao said.
Furthermore, this high efficiency is driven by the strong morale of the workforce. Changjiang Steel adheres to a performance principle of "value creators sharing in value," implementing an innovative "piece-rate" performance pay system at the grassroots level. By breaking down operational accounting into smaller units and simulating an internal market, profits are calculated separately. This differentiated assessment and compensation system, where performance directly impacts earnings, has fully stimulated the creativity and initiative of front-line employees.
This year, facing the target of reducing the rolling cost per ton of steel by another 20 yuan, Ren Yuanbao acknowledges significant challenges. "By benchmarking against industry leaders, we have identified gaps. But these gaps represent room for improvement. This year is the company's 'Lean Management Year.' We will continue striving, saving every second, pursuing excellence, further reducing consumption, improving yield rates, minimizing equipment failures, and charging towards the cost-reduction target," Ren Yuanbao stated.
Behind him, another glowing red billet began its 34-second journey.