Super-thin steel foil rolls off the production line at Taiyuan Iron and Steel. [Photo by Sun Rongxiang for China Daily]
Steel is the most popular metal used in industries and daily life. However, few people are aware that certain steel varieties can be sold at prices even higher than that of gold.
About five years ago, broadsheet super-thin stainless steel foil with thickness of less than 0.02 millimeters was sold in China at several hundred yuan per gram depending on its actual thickness, while the price of gold was less than 300 yuan ($46).
This is because the Chinese market for such products was dominated by overseas suppliers.
In 2016, to break the monopoly of foreign suppliers, Taiyuan Iron and Steel, a State-owned enterprise based in the Shanxi provincial capital of Taiyuan, began research and development into broadsheet super-thin stainless steel foil.
With a thickness of 0.02 mm, or one-third of the diameter of a human hair, the product can be easily torn apart by hand. As a result, it is called "hand-torn steel" by the company's workers.
"The steel foil sheet is made this thin to meet special requirements in specific industries," said Liao Xi, an engineer responsible for the product's development.
"Generally speaking, the product is meant to take the place of aluminum foil in similar industrial applications, like in the fields of aerospace, electronics, petrochemicals and automobiles.
"Compared with aluminum foil, the super-thin stainless steel foil performs better in resistance to erosion, moisture and heat," Liao said.
According to the engineer, only steel sheet thinner than 0.05 mm can be called steel foil.
"Most of the steel foil products made in China are more than 0.038 mm in thickness. We are among the few companies in the world capable of producing soft stainless steel foil of 0.02 mm," Liao said.
The company's executives said the technological breakthrough was made thanks to the painstaking efforts of researchers, engineers and workers.
"After more than 700 experiments and trials over two years since 2016 when our R&D team began working on the product, we successfully developed the product in 2018," Liao said.
"In the manufacturing process, 24 pressings are required for the 0.02-mm-thick and 600-mm-wide steel sheet," he added.
Wang Tianxiang, general manager of the stainless steel foil division of Taiyuan Iron and Steel, said the company's hand-torn steel is currently sold at less than 10 yuan a gram. The price represents dramatically lower purchasing costs for buyers compared with several years ago.
He revealed that the company is now producing an even thinner steel foil with a diameter of 0.015 mm, which is used in the production of batteries for electric vehicles.
"Based on our increasing competence in innovation, we are confident that we can sustain our development by creating more cutting-edge products," Wang said.
Wang Pei contributed to this story.