News | Chongqing Steel Successfully Hot-Rolled Ultra-Thin 800MPa Grade Ultra-High-Strength Steel

Recently, Chongqing Steel’s hot rolling production line delivered exciting news — the first successful rolling of 700L-D grade products with 800MPa level and 3.0×1500mm specifications! All 14 slabs were smoothly processed into finished products, with key quality indicators accurately met on the first try. This is not only a technological breakthrough but also a significant step forward for Chongqing Steel in ultra-high-strength steel ultra-thin rolling, further strengthening its capabilities in the high-end automotive steel market.

Challenging “Micron-Level” Precision

Ultra-high-strength steel with a tensile strength of 800MPa means each square millimeter can withstand 80 kilograms of tension; the 3.0mm ultra-thin specification is comparable to the thickness of a magazine. When “ultra-high strength” meets “ultra-thin,” the rolling difficulty increases geometrically — heavy load on the rolling mill, challenging shape control, narrow process window, and every parameter must be precisely controlled to the “micron level” and monitored to the “second.”

“Like performing surgery, every step must be just right; a tiny deviation can lead to a thousand miles of difference,” said Xu Shaoxu, head of the technical team. For this rolling, the team started an “all-process attack” from the moment the contract was signed. Heating temperature, rolling passes, force parameters, model self-learning… every step was repeatedly simulated.

“Data is our ‘battle map.’ We must optimize every parameter to the best,” said Chen Qihua, a core technical staff involved in parameter debugging. The team stayed on-site at the rolling mill, comparing data, optimizing models — “even a 0.1% deviation could affect the final quality, so we prefer to recalculate ten times rather than overlook any detail.”

On-Site Success: One Shot, One Success!

On the day of rolling, the production line atmosphere was tense yet orderly. Technical staff stayed by the control station, working closely with operators, eyes fixed on the data streams bouncing on the screens.

“Temperature fluctuations, adjust cooling parameters!” “Thickness stable, maintain set values!”

Each instruction was precisely communicated, from final rolling temperature to coiling temperature, from thickness control to surface quality. Every critical point had technical personnel “on site.” Ultimately, the final rolling temperature hit an 87.5% accuracy rate, coiling temperature 94.7%, and thickness 95% — three “high accuracy rates” that resulted in a solid “one-shot success.”

Breakthrough Begins with Every Steel Piece

The products successfully rolled this time include multiple ultra-thin specifications such as 3.0mm, 3.2mm, 3.7mm, and 4.0mm, fully demonstrating the high-precision capabilities accumulated over long-term operation of the hot rolling line. This is not only a technological breakthrough but also a reflection of systemic strength. “High-precision operation of the production line gives us the confidence to tackle high-end varieties,” said Li Xiaosong, assistant to the head of the rolling mill. This success not only verified Chongqing Steel’s mass production capacity in ultra-high-strength, ultra-thin steel but also laid a solid foundation for capturing the high-end automotive steel market.

From “Dare Not Roll” to “Dare to Roll,” Chongqing Steel has achieved not just process optimization but a self-breakthrough from zero to one. We will continue to deepen process improvements and technological innovation, constantly pushing the boundaries of product specifications. With better products and more robust technology, we will inject strong momentum into the company’s high-quality development.

Editor-in-Chief | Zhang Kaibin

Editor | Tao Beibei

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