If Stell-A Steel Sheet to Play A Leading Role in the 21st Century

摘要

If steel, short for "Interstitial atom Free steel", is steel sheet having exceptional press formability. No one knows who authored this already internationally well-known name, But the beginning of IF steel can be traced back to the autumn of 1960 at a research and development center of a certain Japanese steelmaker, when a researcher working on steel sheet received a useful hint from a co-worker engaged in improving the properties of heavy plate and succeeded in developing this unique steel. At the research center in question, the researcher working on heavy plate was struggling to improve its strength and toughness for use in shipbuilding and for tanks. He manufactured various types of plate by way of trial and error, by varying the content of carbon and adding varied amounts of titanium. One day, while analyzing his experimental plates, he murmnured that plate with a titanium content somewhat greater than the carbon content leads to a reduction in the steel's yield strength that made the plate useless. This was because it is of the utmost importance to secure a yield strength for steel plate exceeding a predeter-mined level. This murmur, however, furnished a useful hint to the person working on steel sheet, who happened to overhear it.