Explanation

Low carbon or ultra-low-carhon steel with acicular ferrite or acicular ferrite and a small amount of equiaxed ferrite as the structure at room temperature. The acicular iron has a high density dislocation and dislocation configuration inside, and its strength is significantly higher than that of equiaxed iron. Therefore, it has higher strength than equiaxed iron steel at the same carbon content, while at the same strength level, it has lower carbon content than equiaxed iron steel, which can significantly improve the low-temperature conductivity and weldability of steel. It can be obtained by using lower carbon content, adding alloy elements such as Nb, Mo, Mn that inhibit pearlite phase transformation and adopting appropriate controlled cooling process. It is widely used for pipe line steel with high requirements on strength and toughness.

Classification