Ultra-high strength strapping raw sheet and manufacturing method thereof

Abstract

The invention provides an ultra-high strength strapping raw sheet and a manufacturing method thereof. The raw sheet comprises the following chemical components by weight percent: 0.15-0.60% of C, 0.25-1.80% of Si, 1.0-3.5% of Mn, the balance of Fe and inevitable impurities, wherein one or more of 0.05-1.00% of Cr, 0.05-0.50% of Ni, 0.01-0.50% of Mo, 0.002-0.010% of B, 0.01-0.10% of Ti, 0.01-0.10% of V, and 0.01-0.10% of Nb also can be added to the steel. The manufacturing method of the raw sheet mainly adopts the processes of smelting, casting, hot rolling, pickling and cold rolling; the hot rolling finishing temperature is 850-950 DEG C; the hot-rolling coiling temperature is 550-750 DEG C; and the cold rolling reduction ratio is 50-70%. The tensile strength of the raw sheet disclosed by the invention after the process of isothermal quenching, or quenching and tempering can achieve over 1250 MPa; the extensibility can be up to over 12%; the requirements of wool and cotton packaging on the high strength and high tenacity are met; the section size of the strapping steel is reduced; consumption of steel products is reduced; and the ultra-high strength strapping raw sheet has a broad popularization and application prospect.

Description

technical field [0001] The invention belongs to the field of strapping steel, and in particular relates to an ultra-high-strength strapping original plate and a manufacturing method thereof. Background technique [0002] In the field of strapping steel, in order to improve the efficiency of steel use, ensure packaging quality, and meet the requirements of various industries, high-strength strapping steel and its manufacturing technology have been continuously developed. Higher requirements for toughness. CN95103707.2 adopts aluminum-killed steel with a carbon content of 0.20%-0.25%, a manganese content of 0.30%-0.60%, and a ratio of boron to free nitrogen of 1.07-1.43. The coiling temperature is 600 ° C, and the cold rolling reduction is about 80 %, the tensile strength of the manufactured strap steel is 880-1090MPa, and the elongation is not more than 4%. The strap needs to be galvanized; CN02109635. 1.5%, aluminum content ≥ 0.015%, niobium content ≥ 0.012% of the chilled...

AI Technical Summary

Problems solved by technology

[0003] To sum up, there are currently four main production processes for high-strength strapping steel: one is the process of annealing after strengthening by cold rolling, making full use of the work hardening of cold rolling. The strapping steel manufactured by this process has low toughness and performance is affected. The influence of raw materials is greater; the second is the bainite strengthening process using lead bath isothermal quenching, but the equipment is complicated, especially the use of lead bath treatment will cause serious environmental pollution, and some countries have restricted its use; the third is the use of two-phase zone The martensitic strengthening process of quenching can use water as the quenching medium without environmental pollution; the fourth is the process of hot rolling bar into flat material

However, the above-mentioned technology cannot produce ultra-high-strength strapping steel and its original plate with a tensile strength of 1250MPa and an elongation of 12%.