33results about How to "Fully refined grains" patented technology

The invention discloses a method for producing an iron-zinc alloy coated steel plate with the yield strength being equal to or higher than 220 MPa. The method comprises the steps that molten iron desulphurization, smelting through a converter and continuous casting are conducted, so that a billet is formed; hot rolling is conducted; rolling is conducted; cold rolling is conducted till the billet reaches the required thickness; continuous hot galvanizing is conducted; rapid cooling is conducted; aerial fog is used for cooling after zinc and iron are alloyed; finishing is conducted; oiling treatment is conducted; and sampling, performance testing and subsequence procedure treatment are conducted. According to the method for producing the iron-zinc alloy coated steel plate with the yield strength being equal to or higher than 220 MPa, on the premise that the yield strength ranges from 220 MPa to 260 MPa, the tensile strength ranges from 300 MPa to 380 MPa, and the elongation is equal to or higher than 43%, grains on the surface of a zinc-iron alloy coating are fine and are even in size distribution, the area ratio of holes in the surface of the coating is equal to or smaller than 5%, no microcrack exists on the surface, and the phenomena of pulverization and falling of the coating are unlikely to occur during stamping forming, namely the 90-degree V bending test grade reaches the level 2.

The invention discloses low-temperature X80HD (High Density) large-deformation pipeline steel with great wall thickness and a production method thereof, belonging to the technical field of medium-thickness plate production and longitudinal submerged arc welded tube production. A steel plate comprises the following chemical components in percentage by mass: not less than 0.04% and not greater than 0.09% of C, not greater than 0.35% of Si, not less than 1.5% and not greater than 1.85% of Mn, not greater than 0.012% of P, not greater than 0.004% of S, not less than 0.02% and not greater than 0.05% of Nb, not less than 0.008% and not greater than 0.025% of Ti, not less than 0.10% and not greater than 0.50% of Ni, not less than 0.10% and not greater than 0.45% of Cr, not less than 0.10% and not greater than 0.30% of Cu, not less than 0.10% and not greater than 0.35% of Mo, not less than 0.020% and not greater than 0.070% of Alt, not greater than 0.0005% of B, not greater than 0.0050% of Ca, and the balance of Fe and inevitable impurities. A preparation method of the steel plate comprises the processes such as converter smelting, external refining, continuous casting, heating, controlled rolling, relaxation phase change control and quick cooling; a texture of the rolled steel plate is ferrite, bainite and a little M / A (Martensite / Austenite), wherein ferrite content is 60%-85%, and bainite and M / A content is 15%-40%. The obtained X80HD large-deformation pipeline steel has high strength and toughness, a high work-hardening index, high uniform ductility, a low yield ratio and good deformation resistance.

The invention discloses a thick-specification acid-corrosion-resisting X65 pipeline steel plate and a manufacturing method thereof. The yield strength of the steel plate is level 450MPa, a low-carbon and low-alloy composition design concept is adopted, the molten steel purity is improved through refining, the balled impurity form is processed through calcium, and production is performed through a controlled rolling and controlled cooling technology, so that the steel plate has the excellent HIC (hydrogen induced cracking) and SSCC (sulfide stress corrosion cracking) acid-corrosion resistance, and meanwhile, the steel plate is a product with excellent comprehensive properties such as the high strength, the high anti-crack toughness, the good weldability and the like.

The invention discloses a high-toughness non-tempering steel wire rod and a preparation method thereof. The preparation method comprises processes of heating, rolling and cooling. The steel wire rod comprises the following chemical components in percentages by weight: 0.22-0.31% of C, 1.20-1.55% of Mn, 0.25-0.70% of Si, less than or equal to 0.015% of P, less than or equal to 0.015% of S, 0.10-0.40% of Cr, 0.05-0.20% of V, 0.010-0.050% of Ti, 0.010-0.025% of N, 0.010-0.050% of Al, less than or equal to 0.25% of Cu, less than or equal to 0.20% of Ni, less than or equal to 0.10% of Mo, and the balance of Fe and inevitable impurity elements. The microstructure of the steel wire rod obtained by the method consists of ferrite and pearlite, the grain size is greater than level 7, the tensile strength is 750-850 MPa, reduction of area is greater than or equal to 40%, and impact toughness AkV is greater than or equal to 110J; strength and impact toughness are relatively high, and requirements of downstream customers on production of parts of automotive steering systems can be met; and meanwhile, quenching and tempering are omitted, and production and manufacturing costs are reduced.

The invention belongs to a heat-controlling-cooling process in the field of steel rolling, and is a heat-controlling-cooling process for ultra-low carbon fiber steel. The hot section is kept warm for a certain period of time; the rolling start temperature is controlled at 1070±20°C, and the rolling temperature is controlled after the pre-finishing rolling is completed, that is, the temperature is lowered to 910°C by water cooling, and the rolling is carried out in the finishing mill. After the finish rolling mill, the temperature of the wire rod is controlled at 850±10°C, and after the final rolling, the temperature of the wire rod is reduced to 880±10°C through a temperature control process, and finally enters spinning and forming; the final cover temperature is guaranteed to be ≤400°C, and the final coil is collected . The invention can improve the drawing performance of the product, ensure that the product has high ductility and drawing performance, and at the same time make the product have higher tensile strength.

The invention discloses a Mo-Nb-Ti-Mg steel smelting method for improving welding performance. The smelting method comprises the specific flowing processes of converter steelmaking, LF refining and continuous casting working procedures. Mo-Nb-Ti-Mg microalloyed steel chemically comprises, in percentage by mass, 0.06-0.08% of C, 1.25-1.60% of Mn, 0.010% or smaller of S, 0.025% or smaller of P, 0.20-0.40% of Si, 0.010-0.030% of Als, 0.060-0.080% of Mo, 0.010-0.020% of Ti, 0.002-0.005% of Mg, 0.020-0.035% of Nb and the balance of Fe and other unavoidable impurities. According to the Mo-Nb-Ti-Mg steel smelting method, Al final deoxidization is adopted for carrying out Mo-Nb-Ti-Mg microalloying, steel obdurability is obviously improved, control is simple, the production cost is low, and industrial mass production of steel for large heat input welding can be achieved.

The invention discloses a microalloying method capable of improving performance of steel for large heat input welding. The specific flow process of the production method comprises a converter steelmaking process, an LF refining process and a continuous casting process; according to the kind and the adding sequence of a deoxidizing agent in the LF refining process, Mo, Mn, Si, Nb, Al, Ca, Mg and Ti are included; the Al is adopted for final deoxidation, Mo-Nb-Mg-Ti alloying is carried out, the dispersive action of the MgO on Al2O3 and Ti2O3 serves as the foundation, dispersed, rich and small refractory oxides are formed to serve as cores, and generation of acicular ferrite in austenitic crystalline grains is promoted; on the other hand, a certain amount of Mo and Nb improve toughness of the steel while the grains are refined, and forming of pro-eutectoid ferrite of the grain boundary is restrained; in addition, part of small inclusion particles and carbon nitrogen carry out pinning on the austenite grain boundary, through several-aspect joint action, heat affected zone grains are fully refined, and the toughness of the steel is obviously improved; and the method is simple in control and low in production cost, and the steel for large heat input welding can be subject to large-scale production in an industrialization manner.