57results about How to "Prevent mixed crystals" patented technology

The invention provides X65 pipe line steel and a production method thereof. The X65 pipe line steel comprises the following chemical components in percentage by weight: 0.055 to 0.090 percent of C, 0.15 to 0.35 percent of Si, 1.50 to 1.65 percent of Mn, less than or equal to 0.005 percent of S, less than or equal to 0.020 percent of P, 0.040 to 0.055 percent of Nb, 0.040 to 0.070 percent of V, 0.010 to 0.025 percent of Ti, less than or equal to 0.008 percent of N, 0.005 to 0.060 percent of Als, and the balance Fe and inevitable impurities. After heating and descaling, rough rolling and finishrolling are continuously completed on the same double-rack compact steckel mill, the reinforcing effect of Nb, V and other microalloyed elements added in the steel can be sufficiently played by delaycontrolled rolling in the rolling process, a micro-uniform tissue can be obtained, the occurrence of mixed crystals can be effectively prevented, and the strength and toughness of the X65 pipe line steel can be greatly improved. The produced X65 pipe line steel belongs to the product with high technology content and high additional value, and has remarkable economic benefit.

The invention discloses a high-strength steel wire rod with good low temperature impact toughness and a production method of the high-strength steel wire rod. The high-strength steel wire rod contains the following steel type components by weight percent: 0.30%-0.50% of C, 0.10%-0.40% of Si, 0.70%-1.00% of Mn, less than or equal to 0.020% of P, less than or equal to 0.020% of S, 0.70%-1.20% of Cr, 0.10 %-0.30% of Mo, and the balance of Fe and trace impurities. The high-strength steel wire rod contains small and uniform in crystalline grains, and is low in ductile-brittle transition temperature, and has high material strength and toughness. The high-strength steel wire rod is free of other precious metals, is low in heat treatment cost, and has the characteristics of low production cost and low using cost. The method controls the austenitizing degree and phase change temperature by adjusting the temperatures of heating, finish rolling and spinning, as well as cooling speed, and the low temperature impact toughness of the product is improved by improving the grain size of the product and reducing the ductile-brittle transition temperature. The method does not need to increase equipment or investment, does not increase the production cost, and makes full use of existing equipment and process, so that the method has the characteristics of low cost and low product use cost.

The invention relates to Q345-grade anti-seismic steel and a method for producing the Q345-grade anti-seismic steel by virtue of a steckel mill, belonging to the technical fields of machining and forming of metal materials. The Q345-grade anti-seismic steel comprises the following components: C, Si, Mn, S, P, Nb, V, Ti, N, Als and the balance of Fe and impurities. The method comprises the steps of firstly heating a plate blank, spraying water to remove phosphorous, continuously finishing rough milling and precision milling on a double-stander compact steckel mill, feeding the finely milled steel plate to a reeling machine to be reeled, and naturally air cooling to the room temperature, so as to obtain the Q345-grade anti-seismic steel with high strength and low yield ratio. By adding microalloying elements such as Nb and V into the Q345-grade anti-seismic steel, the strength and the toughness of the Q345-grade anti-seismic steel are effectively improved. According to the Q345-grade anti-seismic steel produced by virtue of the method, the potential of the double-stander compact steckel mill manufactured by Kunming iron and steel Co., Ltd. is adequately explored, the variety of plate strip products is expanded, and the product structure is optimized.

The invention provides an X52 pipeline steel and a production method thereof. The X52 pipeline steel comprises the following chemical components: 0.070-0.090wt% of C, 0.15-0.30wt% of Si, 1.10-1.30wt% of Mn, 0.006wt% or more of S, 0.020wt% or more of P, 0.020-0.040wt% of Nb, 0.010-0.020wt% of Ti, 0.008wt% or more of N, 0.010-0.040wt% of Als, the rest of Fe and unavoidable impurities. After heating and descaling, rough rolling and finish rolling are performed on the same dual-frame compact Steckel mill continuously; through delayed rolling control in rolling process, the enhancement function of microalloy elements such as Nb and V added to the steel are given a full play, thereby obtaining superfine and uniform tissue, effectively preventing the occurrence of mixed crystal, and greatly improving the strength and toughness of the X52 pipeline steel. The X52 pipeline steel produced with the method belongs to high-technology product with high additional value, thus the economical benefit is significant.