Steel for hot-rolled ultra-thin laser welding saw blade substrate and production method

Abstract

The invention discloses steel for hot-rolling an ultra-thin laser welding saw blade base. The steel comprises the following components in percentage by weight: 0.26-0.34% of C, 0.25-0.37% of Si, 0.40-0.60% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, less than or equal to 0.006% of N, 0.80-1.10% of Cr, 0.15-0.25% of Mo and 0.005-0.045% of Ti. Production comprises the following steps: smelting and continuously casting to prepare a blank, heating a cast blank, rolling, performing laminar cooling, coiling, slowly cooling a steel roll in a warehouse or insulating hood to be the room temperature, and finely settling. The tension strength of a steel plate is 600-900MPa, the ductility A is 15-28%, the hardness is 160-260HB, the tensile strength fluctuation between the head part and the middle part of the steel roll is smaller than 150MPa, the thickness of a single side decarburized layer is less than or equal to 1.1% of the thickness of the steel plate, the hardness fluctuation after quenching is less than 2HRC, the thickness reduction of an edge part is less than or equal to 100mu m, the unflatness is less than or equal to 12mm / m, the thickness of a product is 1.0-3.0mm, the effect of replacing cold rolling by hot rolling can be partially achieved, and the cost is lowered.

Description

technical field [0001] The invention relates to a hot-rolled strip steel and a production method, in particular to a hot-rolled ultra-thin laser welding saw blade substrate steel and a production method. Background technique [0002] The steel used for the laser welding saw blade substrate needs to have good welding performance, hardenability, good toughness and appropriate strength. At present, the steel used for laser welding saw blade base is often produced by hot rolling process, which is mainly divided into conventional process and thin slab continuous casting and rolling process, and the product thickness is above 3.0mm. [0003] In recent years, with the increasing demand for "replacing cold with heat", the demand for hot-rolled thin-gauge saw blade base steel is increasing, especially for products with a thickness of 2.5mm and below. However, for the conventional process, it is very difficult to produce such thin-gauge products. There are problems such as serious de...

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Problems solved by technology

Its disadvantages: In the alloy composition, there is no addition of alloying element Ti combined with the residual O and N in the steel. These free O and N will segregate at the grain boundary, resulting in a decrease in material toughness and fatigue performance. Due to the laser welding of the saw blade matrix Working at 100~300°C for a long time, so under this composition, the fatigue performance of the product is low and the service life is short. In addition, due to the segregation of N in the continuous casting process, edge cracks are prone to occur, and the final rolling temperature and coil If the temperature is too low, the shape of the material will be poor, such as unevenness, high strength, and reduced toughness. Especially for thin-gauge saw blades, the temperature is too low to cause unevenness of the material, which is difficult to eliminate through flattening, which will affect the normal use of the product.

Its disadvantages: its products also exist, because there is no addition of alloying elements Ti, etc., it is easy to cause slab cracks and reduce fatigue performance in the slab continuous casting process

In addition, the B added in the steel is also easy to cause quality problems such as cracks at the edge of the slab, but it is mainly for thicker steel plates, and the coiling temperature can not be controlled, so there is no problem such as poor plate shape, but this process cannot be used for Production of thin gauge steel

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