Steel for disk blade, production method and disk blade treatment method

Abstract

The invention provides steel for a disk blade, a production method and a disk blade treatment method. The steel includes chemical components of, by weight, 0.25% to 0.35% of C, 0.1% to 0.40% of Si, 1.0% to 1.5% of Mn, not larger than 0.5% of Cr, 0.01% to 0.05% of Al, 0.015% to 0.06% of Ti, 0.001% to 0.006% of B, not larger than 0.0070% N, not larger than 0.020% of P, not larger than 0.015% of S and the balance Fe and impurities, wherein the inequation 4<=(Ti+Al) / N<=20 is satisfied. Continuous casting and rolling is adopted, the cast blank furnace entry temperature is larger than 830 DEG C, the heating temperature ranges from 1100 DEG C to 1200 DEG C, and the temperature is kept for 1 h to 4 h; and the rough rolling and finish rolling temperature ranges from 920 DEG C to 980 DEG C. After finish rolling is finished, the steel is cooled to the temperature ranging from 550 DEG C to 650 DEG C at the cooling speed of 50-100 DEG C / s and then coiled, and the steel is covered with a hood and slowly cooled for over 48 h. The heating temperature of a disk blade blank ranges from 800 DEG C to 1000 DEG C and the temperature is kept for 15 min to 50 min. The pre-quenching temperature is larger than or equal to 830 DEG C, water quenching is performed for 1 min to 10 min, and the water temperature at which the steel is away from water is smaller than or equal to 200 DEG C. The tempering temperature ranges from 200 DEG C to 300 DEG C and the temperature is kept for 2 h to 6 h. The hardness of the disk blade is larger than 55 HRC, the ballistic work is larger than 25 J, abrasive resistance, toughness and plasticity are good, and the service life is longer than that of a 65 Mn steel disk blade.

Description

technical field [0001] The invention belongs to the technical field of metallurgical technology, and in particular relates to a hot-rolled steel strip suitable for rake blades, a production method of the hot-rolled steel strip and a heat treatment method for rake blade blanks. Background technique [0002] At present, agricultural machinery accessories-rake blades are generally made of 65Mn high-quality carbon hot-rolled strip steel after shearing, oil quenching at 850°C-910°C, and tempering at 300°C-400°C. With the enhancement of our country's awareness of environmental protection, the heat treatment process of oil quenching will be gradually replaced by water quenching, and the harrow blade industry is also actively reforming the quenching process. The 65Mn rake is not suitable for water quenching production process due to its high carbon content, high brittleness, and poor plasticity and toughness. [0003] Papers such as "Research on As-Cast Microstructure and Wear Resi...

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Problems solved by technology

However, due to the high carbon content, high brittleness and poor plasticity and toughness of 65Mn rake blades, it is not suitable for water quenching production process.

[0003] Papers such as "Research on As-Cast Microstructure and Wear Resistance of MO-Nb Bainite Steel" and "New Technology of Squeeze Casting of Ductile Iron Rake" and other papers introduce new material rakes directly formed by casting methods, and the casting process is complicated. Low production efficiency

[0004] Patent Publication No. CN85100775A discloses a "new spring steel 28 manganese silicon boron steel for manufacturing automobile leaf springs", which is a steel with high Si content, high production cost, high Si content, and many inclusions in the steel, which affect toughness, plasticity and fatigue performance

[0005] The boron steel in "a boron-containing steel and its preparation method" provided by CN101148737A is a medium-carbon bar boron steel produced by electric furnace smelting and cannot be used to make rake blades

[0006] Patent Publication No. CN102080179A discloses the boron-containing Q345B steel plate in "A Manufacturing Method of Boron-Containing Structural Steel". The formability is not good, and the patent does not mention the performance of the steel plate after heat treatment. According to the analysis, the carbon content of the steel plate is low, and the hardness after heat treatment is not enough, so it is not suitable for making rake blades

[0007] Patent "Carbon steel with excellent formability and its preparation method" (CN101346482A), the hot-rolled plate produced by reheating the steel ingot is mainly bainite, and annealing treatment is required to ensure the toughness and plasticity of the steel plate, the production cost is high, and During smelting, it is required to precisely control the content of B and N before adding Ti element, which makes the smelting operation difficult

And the Mn content of the steel plate produced by this patent is 0.1-1.2%, the Mn content of the medium and low carbon steel is low, and the hardness after heat treatment is insufficient

[0008] The steel types mentioned in the above documents and patents are not suitable for the requirements of the water quenching method to produce rake blades

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