| 摘要 |
Provided is a high-toughness, abrasion-resistant, highly-workable steel, the properties of which are not easily influenced by manufacturing conditions. Also provided is a method for manufacturing said steel. The steel is characterized by containing, by mass, 0.15-0.25% carbon, 0.1-1.0% silicon, 0.4-1.3% manganese, at most 0.015% phosphorus, at most 0.005% sulfur, 0.2-0.9% chromium, 0.005-0.03% niobium, 0.005-0.03% titanium, 0.0003-0.004% boron, 0.005-0.08% aluminum, and at most 0.005% nitrogen, with the remainder comprising iron and unavoidable impurities. The provided steel is further characterized by fulfilling relations (1) and (2) and having a Brinell surface hardness between HBW 400 and 500, and may also contain one or more of the following elements: copper, nickel, molybdenum, and vanadium. (1) 0.5 ≤ DI/t ≤ 15.0 (2) Ms ≤ 430 In these relations, is the thickness of a steel sheet (mm), is the hardenability index, and is the martensite start temperature. |
