From the ‘accidental discovery’ of corrosion-resistant steel plates in 1913 to today's advanced materials underpinning aerospace and hydrogen energy, stainless steel technological innovation has undergone a century of iterative development. Continuous breakthroughs across three key domains—smelting processes, composition design, and forming techniques—have progressively resolved the industry's inherent trade-offs between corrosion resistance and cost, as well as strength and toughness. This evolution has established stainless steel as a core driver of manufacturing advancement.Early Exploration: Laying the Corrosion-Resistance Foundation and Launching IndustrialisationAt the dawn of the 20th century, stainless steel technology existed in a phase of ‘serendipitous discovery.’ In 1913, British scientist Brearley, while researching gun barrel materials, unexpectedly observed that alloy steel containing 12.8% chromium exhibited remarkable resistance to rusting in acidic environments. This discovery marked the dawn of stainless steel technology. Subsequently, German engineer Maurer further optimised the composition by increasing chromium content to 18% and adding 8% nickel, developing the first austenitic stainless steel grade—18-8 stainless steel. This significantly enhanced corrosion resistance and workability, achieving industrial production by 1920 and rapidly finding applications in kitchenware, chemical pipelines, and other scenarios. The core technology of this era was ‘chromium-nickel synergy,’ which formed a dense oxide film to resist corrosion, laying the foundation for subsequent innovations. However, constrained by smelting techniques, products suffered from low purity, high costs, and limited applications.Mid-Period Development: Process Innovation Reduces Costs, Diversifies ApplicationsFrom the 1950s to the 1980s, stainless steel technology entered a phase of ‘proactive optimisation,’ with breakthroughs in smelting and forming processes becoming pivotal. The widespread adoption of electric arc furnace technology, replacing traditional open-hearth furnaces, propelled crude stainless steel production from under one million tonnes in 1950 to 15 million tonnes by 1980, reducing costs by over 40%. The adoption of continuous cold-rolling processes elevated stainless steel strip precision from millimetre to micrometre levels, meeting the mass-production demands of sectors like home appliances and automotive. In terms of composition design, enterprises developed diverse grades tailored to specific applications: ferritic stainless steel 430 reduced costs by lowering nickel content, becoming dominant in decoration and home appliances; martensitic stainless steel 410 penetrated the cutlery and mechanical components market through its heat-treatable hardening properties; The development of dual-phase stainless steel 2205 pioneered the combination of ‘high strength + high corrosion resistance’. Its application in Norway's North Sea oil field pipelines in 1970 resolved stress corrosion cracking issues in traditional austenitic steels, ushering in a new era for extreme environment applications.Contemporary Breakthroughs: Dual-Drive of High-End and Green DevelopmentEntering the 21st century, stainless steel technological innovation has centred on ‘high-end substitution’ and ‘green low-carbon’ development, overcoming multiple critical bottleneck technologies. In compositional innovation, high-nitrogen stainless steel employs ‘nitrogen substitution for nickel,’ reducing nickel content from 8% to below 3% and cutting costs by 30%. The atmospheric-pressure-melted high-nitrogen steel developed by North Heavy Industries Group maintains stable nitrogen levels above 0.85%, with corrosion resistance surpassing 316L, and has been deployed in deep-sea equipment. Nano-crystalline technology enhances the high-temperature oxidation resistance of 304 stainless steel by 50% through microstructural regulation. Nano-crystalline plates developed by the Chinese Academy of Sciences' Institute of Metal Research are now utilised in aero-engine components. In process innovation, hydrogen-based smelting technology is progressively replacing traditional coke. TISCO's hydrogen-based vertical furnace project reduces carbon emissions per tonne of steel by 60%. Additive manufacturing has overcome forming limitations, with laser-printed 316L stainless steel components achieving 99.8% density, meeting customised demands for medical implants and aerospace precision parts.Today, stainless steel innovation has evolved from ‘single-property optimisation’ to ‘multi-functional integration’. Future breakthroughs in hydrogen embrittlement resistance and lightweighting technologies will open broader applications in hydrogen storage/transport and new energy vehicles, providing enduring ‘steel’ support for high-end manufacturing.