Grade-90 chain steel

The invention relates to grade-90 chain steel. The grade-90 chain steel is prepared from the following chemical components by weight percent: 0.20 to 0.24 percent of C, 0.15 to 0.35 percent of Si, 0.90 to 1.30 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.020 percent of S, less than or equal to 0.20 percent of Cu, 0.40 to 0.55 percent of Ni, 0.45 to 0.65 percentof Cr, less than or equal to 0.10 percent of Mo, 0.025 to 0.050 percent of Alt, and the balance of Fe and unavoidable impurities. Compared with the brand number corresponding to the national standardand European standard, the grade-90 chain steel disclosed by the invention ahs the following advantages: (1) the contents of C and Mn are increased, the cost is slightly increased, and the strength and hardness of the material are greatly improved; (2) the content of Ni is reduced, no Mo element is added, and the cost is greatly reduced; and (3) by reasonably optimizing the alloy elements, on thepremise of ensuring the qua