41results about How to "Low content of alloying elements" patented technology

The invention discloses a cooling after rolling method for high-weather fastness hot-rolled H-steel with yield strength up to 550MPa. The high-weather fastness hot-rolled H-steel with the yield strength up to 550MPa comprises the following components in weight percentage: 0.06-0.12 percent of C, 0.30-0.60 percent of Si, 1.25-1.50 percent of Mn, 0.010-0.030 percent of P, 0.001-0.015 percent of S, 0.20-0.35 percent of Cu, 0.20-0.40 percent of Cr, 0.15-0.30 percent of Ni, 0.10-0.12 percent of V, 0.008-0.014 percent of N, 0.003-0.030 percent of Als and the balance of ferrum and residual trace impurities. An H-steel rolling process comprises the following steps of: heating a casting blank in a heating furnace, rolling by a roughing mill, rolling by a universal rolling mill, and performing two-stage rapid cooling after rolling is ended. According to the cooling after rolling method for the high-weather fastness hot-rolled H-steel with the yield strength up to 550MPa, through adopting a two-stage rapid cooling method after hot rolling is performed on the H-steel and by utilizing a refined crystalline strengthening mechanism, a precipitation strengthening mechanism and a phase change strengthening mechanism, an H-steel texture which is provided with single-phase bainite on the surface layer, is of a multiphase structure inside and has fine grains is obtained, thereby, the additive amount of alloying elements is reduced, the production cost is obviously reduced, the welding performance of the steel is improved, and the production efficiency is increased.

The invention discloses a cooling-after-rolling method of high-weather resistance hot-rolling H-shaped steel with yield strength of 500MPa. The high-weather resistance hot-rolling H-shaped steel with yield strength of 500MPa comprises the following components in percentage by mass: 0.06-0.12% of C, 0.30-0.60% of Si, 0.80-1.20% of Mn, 0.010-0.030% of P, 0.001-0.015% of S, 0.20-0.35% of Cu, 0.20-0.40% of Cr, 0.15-0.30% of Ni, 0.040-0.060% of Nb, 0.003-0.030% of Als, and the balance of iron and residual trace impurities. The H-shaped steel rolling technology comprises the steps of: heating with a casting blank heating furnace, rolling with a cogging mill, rolling with a universal mill and two-segment quick cooling after the rolling. In the invention, by adopting a two-segment quick cooling method after the hot rolling of the H-shaped steel and by use of a refined crystalline strengthening, precipitation strengthening and phase change strengthening mechanism, the H-shaped steel organization state with single-phase bainite on the surface layer and complex-phase organization inside and with small grains is obtained, the addition of the alloy elements is obviously reduced, the production cost is lowered, the weather resistance of the H-shaped steel is improved, the welding performance of the steel is enhanced, and the production efficiency is increased.

The invention discloses a method for cooling a low-alloy hot-rolled H-shaped steel with yield strength of 550MPa after rolling, wherein the low-alloy hot-rolled H-shaped steel with the yield strength of 550MPa comprises following components by mass: 0.13-0.18% of C, 0.30-0.50% of Si, 1.40-1.60% of Mn, not more than 0.025% of P, not more than 0.025% of S, 0.10-0.12% of V, 0.010-0.014% of N, 0.003-0.030% of Als, and the balance of iron and residual trace impurities; a rolling process of the H-shaped steel is as follows: heating casting blank in a heating furnace, performing rolling by a cogging mill, performing rolling by a universal rolling mill and quickly cooling the steel in two-stage manner after rolling; the method adopts the two-stage quick cooling method after the H-shaped steel is hot-rolled, so that the high-temperature H-shaped steel is cooled to proper temperature at short time; by using the cooling method after colling, texture state of the H-shaped steel with fine crystal particles and complex phase texture is obtained, adding amount of the alloy elements is drastically reduced, production cost is notably reduced when requirement of high-strength performance is satisfied, and welding performance of the steel and production efficiency are improved.

The invention discloses a wear-resistant lining board and a preparation method thereof. The invention solves the problems of high cost and the like in the wear-resistant lining board in the prior art. The wear-resistant lining board comprises the following component elements in percentage by mass: 0.25%-0.30% of C, 0.70%-0.90% of Mn, 0.30%-0.60% of Si, 0.8%-1.10% of Cr, 0.15%-0.25% of Mo, 0.015%-0.050% of Al, 0.025%-0.050% of Zr, at most 0.50% of Cu, at most 0.020% of Nb, at most 0.020% of Sn and the balance of Fe and inevitable impurity. The invention also provides a preparation method of the wear-resistant lining board, which comprises the following steps: proportioning, casting, casting head cutting and heat treatment. The wear-resistant lining board disclosed by the invention has the advantages of low cost, favorable mechanical properties and long service life.