Photo taken on Jan. 10, 2017 shows ballpoint pen tips made of homemade stainless steel at Taiyuan Iron and Steel (Group), or TISCO, in Taiyuan, north China's Shanxi Province. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

A staff member of Taiyuan Iron and Steel (Group), or TISCO, examines stainless steel wire for ballpoint pen tips making in Taiyuan, north China's Shanxi Province, Jan. 10, 2017. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

A staff member of Taiyuan Iron and Steel (Group), or TISCO, examines 0.02-mm-thick ultra-thin stainless steel strip in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

A worker of Taiyuan Iron and Steel (Group), or TISCO, operates processing equipment for ultra-thin stainless steel strip in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

Workers of Taiyuan Iron and Steel (Group), or TISCO, walk past a stereoscopic warehouse for ultra-thin stainless steel strip in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

A worker of Taiyuan Iron and Steel (Group), or TISCO, operates a stereoscopic warehouse in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

Workers of Taiyuan Iron and Steel (Group), or TISCO, operate steel rolling equipment in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

A worker of Taiyuan Iron and Steel (Group), or TISCO, tears up a piece of 0.02-mm-thick ultra-thin stainless steel strip in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

A worker of Taiyuan Iron and Steel (Group), or TISCO, operates mobile device for ultra-thin stainless steel strip in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

A worker is seen on the production line of steel components for pen tips at Taiyuan Iron and Steel (Group), or TISCO, in Taiyuan, north China's Shanxi Province, Jan. 10, 2017. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

Photo taken on May 24, 2019 shows ultra-thin stainless steel strips made by Taiyuan Iron and Steel (Group), or TISCO, in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)

A worker of Taiyuan Iron and Steel (Group), or TISCO, packs ultra-thin stainless steel strip products in Taiyuan, north China's Shanxi Province, May 24, 2019. As a leading stainless steel maker, TISCO boasted research and development of high-tech stainless steel products by large efforts on innovation. So far TISCO possesses over 2,700 authorized patents, including 772 patents for invention. (Xinhua/Cao Yang)