What is "ultra-pure iron" with a purity of up to 99.9992%?

More than 2,500 years ago, pre-Qin craftsmen gazed upon molten copper and tin, writing "Six Elements of Metal" in the *Kaogongji* (Record of Trades), thus forging the solemnity of bronze ritual vessels and the sharpness of weapons. Through changing times, the spirit of craftsmanship remains constant. From the ancient philosophy of "examining the curves and shapes to refine the five materials" to the continuous emergence of new materials such as ultra-pure iron, perovskite, and carbon fiber, China's materials industry is growing rapidly from its millennia-old fertile soil, moving towards a new technological frontier. The first industrial culture program, *The Record of Chinese Trades*, jointly produced by China Media Group and the Ministry of Industry and Information Technology, will launch its new materials episode on CCTV-1 (China's main channel) at 8:00 PM on November 2nd, with an exclusive online premiere on CCTV Video.

The Wisdom of the Five Materials:

From "Examining Curves and Shapes" to "Mastering the Skill"

When our ancestors "examined curves and shapes to refine the five materials"—metallurgy for tools, leather for leather, jade for gifts, clay for pottery, and wood for carts—this philosophy of creation, respecting the properties of materials, has been passed down through generations.

This episode vividly recreates the scene of bronze smelting in the pre-Qin period through the audio-visual performance "The Examination of Craftsmen: The Six Elements of Bronze."

The craftsmen precisely grasped the timing of adding tin—when the tin was "fully refined," they used a precise ratio of copper and tin to cast the solemnity of bells and tripods, the sharpness of axes and hatchets, the toughness of weapons and halberds, the power of large blades, the sharpness to cut arrows, and the luster of fire-making mirrors—different objects, different materials, and their functions are closely linked to the ratio of tin.

The relentless pursuit of the finest materials has given rise to countless legends: from the precise tones of the Zeng Hou Yi chime bells to the millennia-old rust-free sword of King Goujian of Yue, and the technological innovation of Qi Wu Huaiwen's "casting steel method." The creative philosophy advocated in the *Kaogongji* (Record of Trades) has been continuously inherited and developed throughout history. Even today, Chinese scientists, building on past achievements, continue the pursuit of the ultimate in "material beauty" with contemporary technology.

Making the Most of Materials:

Ultimate Purity and a Hundred-Meter Rainbow

In the field of high-end metal materials, improving purity is a key technological path. Every ten-thousandth of a percent improvement signifies a leap in performance. my country's independently developed "ultra-pure iron" boasts a purity of 99.9992%, with impurities comprising only eight parts per million.

It is this extreme purity that endows it with outstanding resistance to atmospheric corrosion; samples stored in the laboratory for a year remain "as bright as new." Currently, this material is gradually being applied in the manufacture of core components such as aero-engine main shafts and high-speed train bearings.

China's pursuit of the ultimate in materials is also written on a long and continuous track. From the first 10-meter steel rail at the Hanyang Ironworks to the "384" rail of the Chengdu-Chongqing Railway in the new China, and now to the 100-meter high-speed rails, China's steel rail industry has achieved a leap from its initial "stumbling steps" to a "land-based rainbow." At Ansteel, the modern steel plant can produce a 100-meter rail in just seven minutes, which is then welded into a seamless track thousands of meters long using advanced technology. This smooth, durable, and quiet "Chinese runway" is the most solid foundation for China's high-speed rail to "steadily" achieve world-class speeds.

Breaking Boundaries:

New Materials Drive Industrial Transformation and Future Exploration

Graphene, hailed as a "miracle material," has quietly integrated into daily life and production: from heated clothing to new energy vehicle batteries, its extreme structure breaks the "impossible triangle" of materials, achieving a high degree of unity between thinness, strength, and multifunctionality, demonstrating its all-around application potential.

Carbon fiber has also achieved a leap from "high-end" to "accessible." With breakthroughs in domestic large-scale production technology, it serves not only as the "backbone" of major national projects such as large aircraft and spacecraft, but also as a "lightweight champion" in civilian products such as sports equipment and rail transportation.

In the program, T1100 carbon fiber successfully pulled a 46-ton counterweight, heavier than the C919 domestically produced large passenger aircraft, a truly remarkable feat.

The lunar flag, woven from basalt fiber, landed on the far side of the moon with Chang'e 6 and remained "as vibrant as ever" under extreme temperature differences and strong radiation. Basalt fiber, with its excellent temperature resistance and radiation resistance, also provides a reliable new option for special protective clothing.

Making the most of materials, craftsmanship knows no bounds. On November 2nd, the "Chinese Craftsmanship Records" New Materials Chapter invites you to witness how China's new materials industry is using the rules of the ancients to create a new future.