High strength and toughness steel rail for crane and manufacturing method thereof

Abstract

The invention belongs to the technical field of steel rails, and particularly relates to a high strength and toughness steel rail for a crane and a manufacturing method thereof. The steel rail comprises the following components of, in percentage by weight, 0.15%-0.30% of C, 1.20%-1.70% of Si, 1.50%-2.50% of Mn, less than or equal to 0.025% of P, less than or equal to 0.015% of S, 0.30%-0.80% of Cr, 0.30%-0.70% of Mo, 0%-0.08% of Nb, 0%-0.020% of Ti, 0.20%-0.60% of Ni, the balance Fe, and unavoidable impurities; and the manufacturing method of the steel rail comprises the following steps that the soaking temperature of a continuous casting billet is 1280-1340 DEG C, the heat preservation time is 1-1.5 hours, two-stage rolling is carried out, straightening and heat-preserving are carried out, and then cooling is carried out. According to the manufacturing method, the production method is adopted, C-Si-Mn-Cr-Mo-Ni are utilized, microalloying elements such as Nb and Ti are added compositely, and the rolling interval time and the temperature of each steel rolling process are controlled, so that a refined austenite grain is obtained, and air cooling is carried out, so that the crane steel rail with a lath bainite structure with good strength and toughness is obtained.

Description

technical field [0001] The invention belongs to the technical field of steel rails, in particular to a high-strength and toughness steel rail for cranes and a manufacturing method thereof. Background technique [0002] Crane rails are mainly used for enterprise cranes or trucks to transport heavy-duty materials. In my country, crane rails generally use pearlite materials such as U71Mn or U75V. The tensile strength of crane rails made of U71Mn and U75V is only 880MPa and 980MPa, and compared with the 43-75kg / m rail type, the section of crane rails increases, and the compression ratio decreases when rolling rails with continuous casting slabs of the same specification. The density of steel is significantly reduced, and its performance is even worse. The load of crane rails is far greater than that of railway transportation lines. Phenomena such as rail crushing and fracture are common in use. There are two main process routes to improve the strength of rails: one is to develo...

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Problems solved by technology

[0005] Compared with pearlitic steel rails, bainitic steel rails obtain higher strength through alloying and have good ductility and plasticity. Body rail and production process", the composition design in this method is to obtain bainite rail with better strength and toughness through C-Si-Mn-Cr-Mo and Nb, V, Ti microalloying, but it is not used in crane rail type 201310327055.9 discloses "a steel for bainite rail and its manufacturing method". In this method, in addition to elements such as Mn, Mo, Nb, and V, the element content of Cr is 1.3% to 2.0%, and the content of Al is 0.05%- 1.0%, although more alloying elements are added, but there is no provision for the control process, so the improvement of the strength of the bainite rail is limited, the tensile strength is only above 1250MPa, and the yield strength is only above 850MPa

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