226results about How to "Reduce composition segregation" patented technology

The invention discloses a plastic mold steel which comprises the following chemical components in percentage by weight: 0.25-0.29% of C, 1.30-1.50% of Mn, 0.40-0.60% of Si, 1.20-1.50% of Cr, 0.40-0.50% of Mo, 0.02-0.05% of Nb, less than or equal to 0.15% of Ni, less than or equal to 0.15% of Cu, less than or equal to 0.020% of P, less than or equal to 0.015% of S, less than or equal to 0.012% of N and the balance of iron and inevitable impurities. In the manufacture method of the plastic mold steel, a quenching and tempering heat treatment process is not used, and direct air cooling after forging is carried out, thus prehardened plastic mold steel with thickness above 600 mm and uniform hardness from core to surface is manufactured. According to the plastic mold steel disclosed by the invention, the limit that the existing non-quenched and tempered mold steel has thickness smaller than 400 mm is overcome, and the requirements of mold industries on low-cost high-quality large-sized prehardened plastic mold steel are reached.

The invention discloses an economical non-quenched and non-tempered micro-alloyed plastic die steel plate and a making method thereof. The economical non-quenched and non-tempered micro-alloyed plastic die steel plate comprises 0.32-0.40wt% of C, 0.20-0.50wt% of Si, 1.00-1.50wt% of Mn, 1.20-1.70wt% of Cr, 0.20wt% or less of Mo, 0.0025wt% or less of B, 0.03wt% or less of Ti, 0.03wt% or less of Nb, and the balance Fe. The making method comprises the following steps: carrying out converter smelting, LF+RH refining and continuous slab casting; heating the obtained slab at 1200-1230DEG C, carrying out precision rolling at 900-950DEG C, and carrying out finishing rolling at 870-920DEG C; carrying out controlled cooling after the steel plate rolling; and tempering the steel plate obtained after the controlled rolling and controlled cooling at 550-600DEG C to obtain the finished pre-hardened plastic die steel plate having a bainite structure. The yield strength, the normal temperature impact toughness and the cross section hardness of the steel plate are above 800MPa, above 20J and 310-350HB respectively. The making method is suitable for the production of pre-hardened plastic die steel plates with the specification of below 120mm from 320mm continuous casting blanks.

The invention discloses a low-energy-consumption electromagnetic stirring method for continuous casting. The hot top composite novel low-energy-consumption electromagnetic stirring technique is used. A hot top is arranged in a crystallizer, a steady magnetic field with no energy consumption and low energy consumption is exerted on the periphery simultaneously, an electrode bar is inserted in a tundish, a roller electrode is arranged at the solidifying tail end of a continuous casting billet, and therefore alternating current can be exerted on all non-solidification metal melts between the crystallizer and the solidifying tail end. The alternating current and an additional steady magnetic field are acted with each other so as to enable all the non-solidification metal melts in the whole continuous casting billet in a continuous casting process to generate electromagnetic stirring force for driving the continuous casting melts to rotate clockwise and counterclockwise, thereby stirring non-solidification structures, smashing dendrites of solidification front edges of the melts, refining the solidification structures, reducing segregation and cracks. The invention further provides a metal continuous casting device which can be applied to a continuous casting process of various molten metals prone in segregation and draw an alloy continuous casting billet with refined solidification structure, small segregation and no crack.

A copper chromium zirconium alloy comprises, by weight, 0.7% to 2.0% of chromium, 0.05% to 0.3% of zirconium, 0.01% to 0.08% of magnesium, 0.01% to 0.1% of yttrium and the balance copper. The invention further provides a preparing method of the copper chromium zirconium alloy. The preparing method sequentially comprises the following steps that firstly, the copper, the chromium, the zirconium, the magnesium and the yttrium are prepared according to the proportion and are subject to vacuum purified smelting and flow dividing type casting, and a casting blank is prepared; secondly, the casting blank is subject to homogenization treatment and hot extrusion, and a sheared billet is prepared; thirdly, the sheared billet is subject to solid-solution treatment; fourthly, the sheared billet obtained after the solid-solution treatment is subject to cold deformation machining; and fifthly, a material obtained after cold deformation machining is subject to aging treatment, and the needed copper chromium zirconium alloy is obtained. The copper chromium zirconium alloy has the good comprehensive performance, the room temperature tensile strength of the copper chromium zirconium alloy is larger than 520 MPa, the room temperature elongation of the copper chromium zirconium alloy is larger than or equal to 22%, the room temperature electric conductivity of the copper chromium zirconium alloy is larger than or equal to 90%IACS, and the 350 DEG C high-temperature tensile strength of the copper chromium zirconium alloy is larger than 390 MPa.

The invention discloses high-carbon microalloy round steel for a fracture splitting connecting rod of an automotive engine and a production method thereof. The steel comprises the following chemical components in percentage by weight: 0.60 to 0.80 percent of C, 0.17 to 0.37 percent of Si, 0.30 to 0.90 percent of Mn, 0.020 to 0.60 percent of P, 0.050 to 0.080 percent of S, 0.015 to 0.0300 percent of N, one or several of microally elements V, Nb, Ti and B, and the balance of Fe and inevitable impurities. The production method of the high-carbon microalloy round steel comprises: (1) steel tapping by high catching carbon; (2) vacuum degassing (VD) vacuum treatment; (3) treatment in ladle furnace (LF); (4) execution of a continuous casting process; and (5) heating and rolling of continuously cast blank, and execution of a segmental cooling process of high-temperature quick cooling and low-temperature slow cooling. The high-carbon microalloy round steel provided by the invention has the characteristics of high cleanness, small composition segregation, low crack sensitivity, uniform and fine texture and high surface quality, and the provided production method has the characteristics of low production cost, energy conservation, simple process route, high maneuverability and simplicity of control.

The invention discloses a hot top casting process for a phi 784-mm 7xxx-series superhard aluminum alloy round bar. The aluminum alloy round bar is composed of, by mass, 0.25% of Si, 0.4% of Fe, 1.55-1.65% of Cu, 0.25% of Mn, 2.55-2.65% of Mg, 0.19-0.25% of Cr, 5.6-5.7% of Zn, 0.15% of Ti, 0.03% of Zr and the balance Al. The manufacturing process comprises the steps of a, material preparation; b, smelting; c, stirring; d, refining; e, slagging-off; f, heat preservation and standing; g, online thinning; h, online degassing; i, filtration; j, casting; k, homogenizing. Through the process, the defects, such as cracks, component segregation, bright grains, thick grains and loose pores, which often appear when a direct condensation casting technology is adopted for large-diameter superhard aluminum alloy are overcome, and by the adoption of hot top casting, the defects of surface segregation tumors, thick coarse-grain layers and the like are overcome.

The invention discloses non-quenched and tempered steel for automobile parts and a production process thereof. The non-quenched and tempered steel comprises less than or equal to 0.20% of Ni, 0.010-0.025% of Ti, 0.012-0.025% of Nb and 0.013-0.019% of N. The process comprises converter smelting, LF refining, RH vacuum treatment, continuous casting and rolling. According to the non-quenched and tempered steel, through reasonable design of components, trace elements such as Ni, Nb, Ti and N are added to refine grains and improve the strength and toughness of the material; refining is carried outthrough a narrow component control technology, soft reduction is used in the continuous casting process, reasonable parameters are adopted to reduce the low-power defects of a casting blank, and the density of the material can be improved; and the structure is uniform through a high-temperature diffusion process in the rolling process, the grains are refined through a controlled cooling and controlled rolling technology, the strength is improved, and finally the comprehensive performance of the material is greatly improved.

The invention relates to a silicon nitride material and a preparation method of a heat insulating disc cover prepared from the same. The silicon nitride material consists of the following raw materials in percentage by weight: 65-87.5 percent of silicon nitride, 5-15 percent of nano-silicon nitride, 8-15 percent of a sintering aid and 0.5-5 percent of tungsten carbide; and the preparation method of the heat insulating disc cover prepared from the silicon nitride material comprises the following steps of: weighing the silicon nitride, nano-silicon nitride, sintering aid and tungsten carbide according to the percentage by weight, performing ball milling and mixing uniformly; drying a mixed material to obtain a substrate; performing press molding to obtain a cylindrical biscuit; processing to a proper size on a lathe; putting the processed biscuit into a sintering furnace, and charging nitrogen gas for sintering; stopping heating, cooling, opening a furnace door under the normal pressure, and cooling naturally to obtain a blank; and performing end face processing on the blank on a grinding machine to obtain a finished product.

The invention belongs to high-temperature alloy turbine blade repair and remanufacturing technology, and in particular discloses a high-temperature alloy turbine blade repair material and a repair process using the repair material. The micro-arc spark deposition repair material comprises the following ingredients based on weight percent: 45-60% of Ni, 0-25% of Co, 10-25% of Cr, 5-7% of Al, 2-8% of Ta, 0-6% of Re, 0-2% of Hf, 0-1% of Y and 0-0.1% of C, and the total weight is 100%. The repair process comprises the following steps of: fabricating a round bar with 2-6mm of diameter and 20mm of length using the above repair material, carrying out surfacing on the to-be-repaired area using the micro-arc spark deposition process, wherein the surfacing process parameters are as follows: power is 100W-1500W and the frequency is 100-500HZ, and the processing process is carried out under argon protection or in a vacuum glove box; placing the repair part into a vacuum furnace for thermal treatment after the processing is finished, wherein the thermal treatment process is as follows: solution treatment is carried out at 1150-1230 DEG C for 1-6 hours, and the aging is 4-20 hours at 800-900 DEG C. The novel repair material and the repair process using the repair material are provided for defect repair on the surface of the turbine blade so that the repair of high gamma' high-temperature alloy blade using the high gamma' high-temperature alloy repair material is possible and a novel solution plan is provided for the near/equal strength repair of the high-temperature alloy blade.

The invention discloses a twisted steel for a 785 MPa-level high-strength prestressed structure and a preparation method of the twisted steel. The twisted steel comprises following constituents in percentage by weight: 0.50-0.55% of C, 0.80-1.10% of Si, 1.00-1.30% of Mn, 0.060-0.12% of V, 0.60-0.95% of Cr, 0.0015-0.0040% of B, 0.010-0.025% of S, 0.010-0.025% of P, and the balance of Fe and unavoidable impurities. The preparation method comprises steps of billet preparation, rolling and after treatment. In the preparation process, when vanadium is utilized to conduct microalloying and reinforcement, the alloying element B is appropriately added to improve the steel hardenability, and the addition of the microalloying reinforcing elements is lowered. As the controlled rolling technology is combined and the cooling technology is applied, the grain refinement of steel structure is obvious, the net-like ferritic structure at the core of the steel is lowered, the steel strength is increased, the hardness gradient change is slow, and the stability of the precision rolled twisted steel is improved. The processed steel is stable in technologic and mechanical performances, and good in prestress relaxation performance.

The invention discloses a method for adjusting and regulating a long-periodic structure phase of magnesium alloy. The method comprises the steps of: firstly preparing Mg-Ni (or Zn)-Y alloy containing LPSO, and then adjusting and regulating form and distribution of a long-periodic structure by applying ultrasonic vibration and pressure in sequence in an alloy solidification process. The alloy preparing and processing comprises the following steps: melting the alloy under protection of mixed gas of N2 and SF6, after temperature reaches 720-730 DEG C, placing a melt in a container in a holding furnace, cooling to a temperature more than a liquidus temperature of the alloy by more than 10-50 DEG C, then performing ultrasonic vibration processing on the melt, lasting for 1-5min, after the vibration is finished, pouring into a preheated die of 200-300 DEG C for extruding to solidify under pressure, wherein an extruding pressure is 50-500 MPa, and pressure holding time is 1-3min. The LPSO phase in the alloy prepared by such method is obviously refined and uniformly distributed, and performances of the alloy are greatly improved.

The invention provides a method for manufacturing civil aluminum alloy wiring, belonging to the technical field of wire and cable design and manufacture. The manufacture method comprises the following steps: adding aluminum ingots, aluminum-iron master alloy, aluminum-boron master alloy and aluminum-rare earth master alloy into a shaft furnace; casting into a cast strip after smelting; rolling into an aluminum alloy rod through a rolling mill; preparing an aluminum alloy filament by the aluminum alloy through cold drawing; annealing, and performing extruded insulation on the aluminum alloy wire, wherein the insulation material is silane-crosslinked polyethylene; adding low halogen or halogen-free flame retardant during insulation; and performing warm water crosslinking or steam crosslinking treatment on the aluminum alloy wiring after the extruded insulation is completed. The aluminum alloy wiring has excellent conductivity, tensile property and bending performance; and the wire has better flame retardant performance and longer service life.

The invention relates to a production process of a hot galvanizing alloy and a master alloy thereof, which has the technical proposal that, the components and the weight ratio of a zinc-aluminum binary master alloy are that 16-24 percent is aluminum and the rest is zinc. A method for producing the hot galvanizing alloy by the zinc-aluminum binary master alloy comprises the steps: mixing the zinc and the aluminum by the weight ratio, adding the mixture to a master alloy smelting furnace with the melting temperature of 560-680 DEG C to be molten, uniformly stirring, ingoting to a zinc-aluminum binary master alloy pig, adding the solid zinc required by hot galvanizing alloy production to a hot galvanizing alloy smelting furnace to be molten into zinc liquid, adding the zinc-aluminum binary master alloy required by the produced hot galvanizing alloy to the zinc liquid, and stirring for 20-40min at the melting temperature of 480-520 DEG C to prepare the hot galvanizing alloy. The invention which is applicable to the hot galvanizing alloy production by a cored induction furnace has the advantages of reducing the temperature of the melting alloy, shortening the melting and stirring time, prolonging the service life of the cored induction furnace and ensuring uniform hot galvanizing alloying components.

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.

The invention relates to steel for a ball screw bearing. Alloy components of the steel comprise, by mass, 0.45-0.60% of C, 0.15-0.40% of Si, 0.50-0.80% of Mn, 0.15-0.40% of Cr, 0.002-0.006% of B, 0.02-0.07% of V, less than or equal to 0.015% of S, less than or equal to 0.025% of P, less than or equal to 0.10% of Mo, less than or equal to 0.08% of Al, less than or equal to 0.0010% of Ca, less thanor equal to 0.0010% of O, less than or equal to 0.04% of As, less than or equal to 0.03% of Sn, less than or equal to 0.005% of Sb, less than or equal to 0.002% of Pb, and the balance Fe and inevitable impurities. A preparation process of a bar product comprises the steps of molten steel smelting, continuous casting, cogging-down, hot rolling, tempering, stress relief annealing and the like. The final properties meet the conditions that the surface hardness of the bar reaches 220-260 HBW, the metallographic structure of the bar is a uniform sorbite structure, the austenitic grain size of the bar is higher than or equal to the seven-level, the yield strength of the bar is 600-800 MPa, the tensile strength of the bar is 800-900 MPa, and the percentage elongation of the bar is greater than orequal to 15%.

The invention provides a zinc alloy for a die. The zinc alloy for the die comprises the following components in percentage by mass: 5 percent to 22 percent of aluminium, 0.01 percent to 0.03 percent of magnesium, 1 percent to 10 percent of copper, 0.05 percent to 0.5 percent of rare earth, 0.01 percent to 0.05 percent of boron, 0.05 percent to 0.1 percent of zirconium, 0.03 percent to 0.1 percent of bismuth and the balance of zinc. According to the zinc alloy for the die, which is provided by the invention, not only can the hardness and the wear resistance be further improved, but also the phenomena of composition segregation and bottom shrinkage are obviously reduced; and on the premise of ensuring the tensile strength basically constant, the size stability and the die making accuracy of the zinc alloy are obviously improved.

The invention relates to a preparation device and method of an aluminum alloy ingot with the ultra-large dimension, and belongs to the field metal material processing. The device mainly comprises a melt processor, a lifting mechanism, a hot top, a crystallizer, a water tank and a dummy ingot; the hot top is installed above the crystallizer, the dummy ingot is arranged below the crystallizer, the crystallizer is fixedly installed on the water tank, the metal processor is connected with the lifting mechanism, the lifting mechanism is fixed to the water tank, and in the casting process, the melt processor is placed on the hot top and/or inside the crystallizer through the lifting mechanism. Accordingly, electromagnetic field applying and forced cooling are conducted on alloy melt on the hot top and inside the crystallizer in the continuous casting process from the interior, heat exchange and mass transfer of the core of the alloy melt are accelerated, the uniformity of a temperature field and a component field of the melt is improved, and fine grain homogeneous casting of the aluminum alloy ingot with the ultra-large dimension is achieved. According to the preparation device and method of the aluminum alloy ingot with the ultra-large dimension, the implementation effect is significant, the production efficiency is high, and the preparation device and method are likely to be combined with large-scale industrial production and have a wide industrial application prospect in the manufacturing fields of aerospace, rail transit, ships and the like.

The invention provides magnesium-lithium alloy with a reinforced LPSO (long-period stacking ordered) structure and a preparation method thereof, which belong to the technical field of high-strength alloy and preparation thereof. The magnesium-lithium alloy with the reinforced LPSO structure is prepared from the following components: Li, Gd, Y, Zn, Zr, Mg and inevitable impurity elements. Accordingto the preparation method of the magnesium-lithium alloy with the reinforced LPSO structure, Gd, Y and Zn elements are added at the same time, so that the Gd, Y and Zn elements are solidly dissolvedin a magnesium-lithium alloy substrate, and homogenization, plastic deformation and aging heat treatment are performed, so that authigene occurs in an alpha-Mg phase and a beta-Li phase so as to obtain the laminar LPSO structure, and the effect of reinforcing the beta-Li phase is achieved, thereby reinforcing the alloy. By adopting the preparation method, the two-phase magnesium-lithium alloy which has the advantages of low density and high strength and can satisfy the requirement of plastic deformation at room temperature is obtained, the elongation of the two-phase magnesium-lithium alloy isgreater than or equal to 20%, and especially, the requirements of light materials with high strength and high plasticity are satisfied.