141results about How to "Grain refinement" patented technology

The invention discloses a close isothermal forging method of GH4169 alloy tray-shaped forging in the air, the technological process is that: making GH4169 finegrain roughcast adopting method of upsetting, punching and rolling after heating GH4169 alloy original rod material to 995-1005 DEG C; respectively heating the finegrain roughcast to 995-1005 DEG C and forging die to 950-965 DEG C; diefilling and positioning the finegrain roughcast; while heating finegrain roughcast and forging die to keep the heating warm humidity; forging die and forging press the finegrain roughcast forming under the 55MN to 65MN forging pressure and 0.01s-1 to 0.05s-1 strain rate; obtaining the tray-shaped forging; water-cool processing the tray-shaped forging. Adopting forging method of the invention can realize forming of the GH4169 alloy material tray-shaped forging difficult to deform and obtain the GH4169 alloy tray-shaped forging with weensy crystal grain, high intensity and complicated shape.

The invention proposes an added material manufacturing method under a vibration condition. In an arc wire feeding added material manufacturing or laser powder feeding melting added material manufacturing process, mechanical vibration with a certain frequency is synchronously introduced, so that parts are located in a micro vibrating state; and the mechanical vibration acts on a micro liquid-state molten bath formed in the added material manufacturing process to refine grains, so that the structure becomes more uniform, and such phenomenon as air holes, inclusions and incomplete fusion is reduced or even eliminated. Meanwhile, the vibration acts on metal just condensed, so that the stress generated by vibration and residual stress generated in the added material manufacturing process are superposed to generate local plastic deformation to achieve the purpose of reducing residual stress and deformation of added material manufacturing parts, and the added material manufacturing parts under vibration condition are more excellent in performances.

The invention discloses 1200-MPa-level cold milling steel and a manufacturing method thereof. The steel comprises, by mass, 0.15-4.0% of C, 0.3-2.0% of Si, 1.0-5.0% of Mn, S with the amount equal to or smaller than 0.01 ppm, P with the amount equal to or smaller than 0.01 ppm, H with the amount equal to or smaller than 20 ppm, 0.02-2.0% of Al, 0.01-0.04% of Nb, and the balance Fe and unavoidable impurities. As the Nb element is added to the steel, crystal grain can be effectively refined, the area of crystal boundaries is increased to adsorb hydrogen atoms, and then hydrogen spreading is effectively restrained; in addition, a precipitate Nb (C, N) formed by Nb is a hydrogen trap and can effectively adsorb hydrogen in the steel so that hydrogen can be distributed uniformly in the steel and restrained from spreading or gathering, and the hydrogen induced cracking resistant characteristic of the steel is improved; in addition, the Nb element is a stable retained austenite element and can increase the strength and ductility product of the steel; due to microalloying of Nb, the hydrogen induced cracking resistant characteristic of the steel can be effectively improved; meanwhile, the crystal grain can be refined, and the stability of austenite is improved. The steel has the advantages of being high in hydrogen induced cracking resistance, large in strength and ductility product, and capable of effectively improving the driving safety of an automobile.

The invention provides a preparation method of an Al-Cu-Mg-Ag ultrafine crystal heat-resistant aluminum alloy, comprising the following steps: hot extrusion, solid solution hardening, equal channel angular pressing and ageing treatment, thus finally improving the heat resistance of Al-Cu-Mg-Ag alloy. The specific steps are as follows: homogenizing annealing of the as-cast aluminum alloy, hot extrusion with the extrusion ratio of 8-15, multi-pass equal channel angular heat extruding deformation at the temperature of 350-430 DEG C, solution treatment, hardening in water at a room temperature, and then ageing treatment at the temperature of 150-210 DEG C; or solution treatment of the alloy in a hot extrusion state, hardening in water at the room temperature, multi-pass equal channel angular heat extruding deformation at the room temperature and then ageing treatment. The process method of the invention can improve the heat resistance of the Al-Cu-Mg-Ag alloy and enlarge the application range of the aluminum alloy on the basis of the existing alloy. The preparation method of the invention has simple process and convenient operation, and can effectively refine crystal particles of the Al-Cu-Mg-Ag alloy, improve the density of a precipitated and strengthened phase, enhance the overall strength and the high-temperature heat resistance of the Al-Cu-Mg-Ag alloy, and achieve industrialized production and application.

The invention discloses an abrasion-resistant alloy cast iron material with high hardness for a chute lining plate, and a preparation method thereof. The abrasion-resistant alloy cast iron material comprises the following chemical components in percentage by weight: 2.6-3.0% of C, 0.3-1.0% of Si, 0.5-1.0% of Mn, 21-23% of Cr, 0.8-1.2% of Mo, 0.8-1.2% of Cu, 0.6-0.9% of W, 0.1-0.2% of V, 0.06-0.12% of Ti, 0.001-0.003% of B, 0.04-0.08% of RE, 0.04-0.08% of Y, 0.04-0.08% of Al, less than or equal to 0.06% of S, less than or equal to 0.06% of P and the balance of Fe. According to the abrasion-resistant alloy cast iron material provided by the invention, the hardness of the abrasion-resistant alloy cast iron material is improved by controlling the content of chromium element and the proportion of Cr/C. Noble metal elements such as Mo, W, V, Ti and Cu are added into the cast iron, and through complex use of the noble metal elements, the stability of austenite is enhanced, grains are refined, and the high temperature stability and red hardness of carbides are improved, so that the hardness of the cast iron material provided by the invention is further improved, and the abrasive resistance is correspondingly improved. The average hardness of the alloy cast iron material provided by the invention can reach over HRC63, and the impact toughness aK of the alloy cast iron material can reach 5J/cm<2>.

The invention relates to a combined type water-cooled casting mould integrating directional casting blank solidification and selective area cooling. By the adoption of the combined type water-cooled casting mould, from-bottom-to-top forced cooling and directional solidification of a casting blank are achieved, the situation that columnar crystals grow in the direction perpendicular to the wall of the mould and the situation that because the columnar crystals which grow in a non-directional manner are overdeveloped, the columnar crystals grow in the direction perpendicular to a base plate are avoided, the problems of central shrinkage porosity and V-shaped segregation are eliminated, a large-piece-weight cast-forged blank with grain being refined, grain size being uniform in ultrasonic testing and a solidification structure being compact, uniform and free of lacks is obtained, and the ultrasonic flow detection yield is improved; the upper half portion of a casting mould body is of a hollow heat-preservation structure; a cooling water channel and a base plate water cooler on the lower half portion of the casting mould body can conduct segmented selective cooling on different areas of the casting mould; establishment of a one-dimensional temperature field and the achievement of high cooling intensity are both considered; most of sensible heat and most of latent heat of the cast blank are conducted from the base plate, and therefore directional solidification is achieved; and a hot feeding riser is adopted, a molten glass layer, a heat generating agent layer and a covering layer which are arranged in the hot feeding riser enable a shrinkage cavity area to be mainly concentrated on the hot feeding riser, the solid height in the hot feeding riser is increased, and the ratios of a top crop and a back-end crop of the cast blank are reduced.

The present invention relates to a preparation method of soft magnetic Fe-Ni50 system alloy powder. Said method includes the following steps: smelting Fe-Ni50 system alloy, spraying to obtain powder by adopting water atomization process, processing said powder, making heat treatment, passivation treatment, adding insulating agent, lubricating agent and demoulding agent into the alloy powder, mould-pressing and forming, heat treatment and coating surface.

The invention discloses a heat treatment method for improving mechanical property of a normalized steel plate, which belongs to the medium and thick steel plate manufacturing technical field. A rolled microalloying steel plate containing niobium is placed into a quenching furnace for conventional normalizing treatment, and is taken out of the furnace after 3 to 40 minutes of heat insulation, the quenching furnace is adopted to perform weak water-cooling treatment to the steel plate, the ratio of water supply and drain at a water outlet of a quenching machine is controlled to between 1 and 1.8, the roll speed is maintained to between 10 and 40m/min, and the measured surface temperature of the steel plate after the weak water-cooling treatment is between 600 and 800 DEG C. The method greatly improves the comprehensive performance of the steel plate compared with the conventional normalizing treatment: the yield strength is improved by between 50 and 80MPa, the tensile strength is improved by between 20 and 30MPa, the low-temperature toughness and the strain aging performance of the steel plate are both improved, the uniformity of the performance in the thickness direction of the steel plate is improved, and the plate shape and the surface quality of the steel plate are good.

The biodegradable magnesium alloy blood vessel rack consists of magnesium in 60-95 wt% and other metals, including RE, for the rest. Metal magnesium as the basic material has excellent tissue compatibility and blood compatibility, and the added other metal, including RE, elements raise and improve the comprehensive performance, especially mechanical strength, plasticity, degradability and biocompatibility. The magnesium alloy blood vessel rack has tensile strength of 200-300 MPa, elastic module of 10-50 GPa, elongation at break of 2-10%and degrading half life of 6-18 weeks. Most of the degraded metal ions are drained through renal tubules while small part being utilized by human body.

The invention discloses a method for preparing a high-purity oxygen-free copper rod by a upper leading method. The method comprises the following steps: (S1) electrolytic copper is molten to obtain molten copper; molten salt is added, and consists of 60-65% of sodium borate, 10-15% of sodium fluosilicate, 10-15% of cryolite, 5-10% of calcium fluoride, 1-5% of titanium dioxide and 5-10% of sodium chloride; and high-purity nitrogen is introduced in the molten copper; (S2) a deoxidizer consisting of a Cu-Re alloy and lithium oxide is added in the molten copper for stirring to reach uniform distribution; (S3) the molten copper is leaded to an insulation furnace; and a layer of flake graphite covers the surface of the molten copper; and (S4) a hollow crystallizer extends in the molten copper; a solid is condensed in the hollow crystallizer; and the upper end of the solid is pulled by a stretching mechanism to prepare the high-purity oxygen-free copper rod. The method for preparing the high-purity oxygen-free copper rod by the upper leading method is simple, high in impurity removing and oxygen removing efficiency and lower in pollution, and can obtain the high-purity oxygen-free copper rod with an oxygen content of not higher than 20 PPM.

The invention discloses a heatproof magnesium alloy, which belongs to the magnesium alloy field. The magnesium alloy is composed of Mg, Zn, Zr, rare earth, Nb, Al and M, and comprises the following components by weight: 0.2-9% of Zn, 0.1-2% of Zr, 0.0002-16% of rare earth, 0.0002-4% of Nb, 0.001-1.49% of Al, 0.001-2% of M and the balance of Mg. The M element is at least one selected in Ti, Sr, Ca, C and B. The rare earth and an Nb element are added in the magnesium alloy, and a structure of a beta phase is changed; the combined action of Zr and the M element can strongly refine the crystal grain, and Zr and M are reacted with certain impurity element (such as Si) in an alloy liquid and deposited, and the alloy liquid is purified. The combined effect of the elements enhances the high temperature resistance performance of the magnesium alloy, the heatproof magnesium alloy has excellent mechanical property and machinery processability, and good fluidity and die casting performance, and is suitable for casting the heatproof magnesium alloy and die casting of the heatproof magnesium alloy.

The invention discloses a sintered neodymium-iron-boron magnet without heavy rare earth and a preparation method of the sintered neodymium-iron-boron magnet. The constituent of sintered neodymium-iron-boron magnet is Re<Alpha>Fe<100-Alpha-Beta-Gamma>B<Beta>M<Gamma>, wherein Re is a light rare earth element and comprises an element selected from one or more than one of La, Ce, Pr, Nd, Sm and Eu; M is an addition element and comprises an element selected from one or more than one of Ti, V, Cr, Ni, Zn, Ga, Ge, Al, Zr, Nb, Co, Cu, Ag, Sn, W, Mo, Pb, Bi, Mg and Pd; Fe comprises Fe and an inevitable impurity; Alpha, Beta and Gamma are respectively atomic percentage of each element; and Alpha is more than or equal to 12 and less than or equal to 17, Beta is more than 5 and less than or equal to 6.5, and Gamma is more than or equal to 0.1 and less than or equal to 5. The sintered neodymium-iron-boron magnet has the advantages that low-melted light rare earth micro-powder is used for achieving a grain refinement effect on liquid-state coated nano metal powder moved and uniformly distributed in a grain boundary during high-temperature sintering, and moreover, the light rare earth micro-powder can simultaneously play in improving magnetic performance of a product.

The invention belongs to the field of aluminum alloy powder material preparation, and relates to rare-earth modified high strength aluminum alloy powder special for additive manufacturing. The rare-earth modified high strength aluminum alloy powder special for additive manufacturing comprises, by mass, 3.8%-5.2% of Mg, 0.2%-0.5% of Zn, 0.2%-0.5% of Ti, 0.04%-0.2% of Zr, 0.06%-0.2 of RE, and the balance Al. RE is a rare earth element combination and comprises Sc and rare earth M, and M is one or more, by any mass ratio, of Ce, La, Nd, and Yb; and the range of the mass ratio of Sc to rare earthM is 6:(4-9). By adding the rare earth elements into an aluminum alloy substrate and the optimum ratio of other elements in aluminum alloy, the combination property of additively-manufactured aluminumalloy workpieces can be enhanced effectively, compared with congeneric aluminum alloy products which are not added with the rare earth elements, the increment of yield strength of the rare-earth modified high strength aluminum alloy additively-manufactured workpieces is up to 80-178 Mpa, and meanwhile a powder bed which is uniformly laid during the manufacturing process is achieved.

The invention discloses a manufacturing process for a bolt with high strength of more than phi 30. The manufacturing process comprises the following steps of: forging; performing heat treatment and after treatment, wherein the heating forging temperature is between 1,100 and 1,300 DEG C, and the heating forging time is between 2 and 5 minutes; directly feeding workpieces into a mesh belt furnace quickly after forging for high temperature tempering, wherein the mesh belt furnace comprises a preheating area, a first heating area, a second heating area and a heat preservation area; preheating the workpieces through the preheating area after the workpieces are fed into the mesh belt furnace, and heating the workpieces through the first heating area and the second heating area; preserving the heat through the heat preservation area; cooling the workpieces which are subjected to the high temperature tempering; and trimming the cooled workpieces. By the manufacturing process, the workpieces are directly fed into the mesh belt furnace for high temperature tempering after being heated and forged, the excess heat of the forged workpieces is fully used, and time and energy are saved. The workpieces have a tempered sorbite structure after the high temperature tempering, grains are refined, and the phenomena that the grains are coarse and a martensite structure and a raw material structure are blended are prevented.

The invention discloses an E-level extra-thick high-intensity steel plate produced by using continuous casting billet and a production method thereof. The steel plate includes the following chemical components by weight percent: 0.16-0.19% of C, 0.15-0.55% of Si, 1.45-1.58% of Mn, less than or equal to 0.018% of P, less than or equal to 0.015% of S, 0.020-0.025% of Nb, 0.020-0.050% of Alt, and the balance of Fe and unavoidable impurities; carbon equivalent CEV is 0.40-0.46%. According to the production method, optimized components, an advanced smelting technology, an optimized continuous casting process (low super-heat degree for casting, low casting speed and reasonable light pressure), and an improved heating and rolling process (heating by stages) are adopted to smelt high-quality continuous casting billet; continuous casting billet is directly used as blank instead of steel ingots, and deficiencies of the prior art are overcome; compared with the steel plate produced by using steel ingots, the E-level extra-thick high-intensity steel plate produced by using continuous casting billet has the advantages that the production process is simplified, the production cost is reduced, and the production period is shortened; compared with the steel plate produced by composite billet, the E-level extra-thick high-intensity steel plate produced by using continuous casting billet has the advantages that the plate billet composition process is eliminated; the method of using continuous casting billet to produce the high-intensity steel plate enables the thickness of the steel plate to be enlarged to 240 mm and the compression ratio to decrease to 1.38 for the first time.

The invention relates to a process for manufacturing a solid high manganese steel frog, in particular to a technique for casting the solid high manganese steel frog which has long service life and is subjected to grain refining. The technique is suitable for manufacturing various types and specifications of solid high manganese steel frogs with a weight of less than 2 tons. The technique comprises: 1) adopting a heat-insulated riser as a riser; 2) discharging molten steel at a high temperature, and performing argon gas blowing, feeding and refining in a refining ladle after discharging; 3) performing microalloying in the refining ladle, and adding molybdenum, niobium, vanadium and titanium; 4) filling argon gas into a die cavity before casting, and performing casting under the protection of the argon gas; and 5) adopting a hot shake-out process, thermally cutting the riser, and thermally sending the cut riser into a heat treatment kiln for homogenizing. The process reduces oxidation of molten metals through nitrogen protection, purifies the molten metals due to refining in the refining ladle, and solves the problems of large crystal grains, hole shrinkage, microcracks, short service life and the like of the solid high manganese steel frog due to grain microalloying and thinning and dispersed distribution of inclusion.

The invention discloses a novel welding technique for hammering and forging a high-temperature welding line. The novel welding technique for hammering and forging the high-temperature welding line relates to a working table, a stand column, a track cross beam, a servo trolley, elastic cushion blocks, a control cabinet and a pneumatic source. The novel welding technique for hammering and forging the high-temperature welding line is characterized in that an electric welding gun, a gas gun, an heat insulation cover plate and at least one pneumatic impact hammer are installed on the servo trolley and can move in a servo mode on the track cross beam under the control of the control cabinet, and a welding part is fixed on the working table through the elastic cushion blocks. According to the novel welding technique for hammering and forging the high-temperature welding line, the surface of the welding line which is just welded is heated through the gas gun during welding, a weld microstructure in the high-temperature state is hammered and forged contentiously through the at least one pneumatic impact hammer, and finally normalizing treatment is automatically carried out on the hammered and forged weld microstructure after heat insulation is carried out on the hammered and forged weld microstructure in the servo moving process of the heat insulation cover plate. The novel welding technique for hammering and forging the high-temperature welding line has the advantages that the structural compactness of the welding area of a component can be improved, welding stress deformation is reduced, residual stress is relieved, and high-carbon steel and alloy steel can be widely applied to the welding field.

The invention discloses cold heading steel with refined crystalline grains and a production process thereof. The cold heading steel comprises, by weight, 0.32-0.38% of C, 0.10-0.35% of Si, 0.60-0.90% of Mn, 0-0.20% of Cr, 0-0.030% of P, 0-0.035% of S, 0-0.20% of Ni, 0.010-0.040% of Al, 0.050-0.080% of Ti, 0-0.30% of Cu and the balance Fe and inevitable impurities. The production process of the cold heading steel comprises smelting, continuous casting and rolling. According to the cold heading steel with the refined crystalline grains and the production process thereof, the elements of the Al and the Ti are added, so that the material crystalline grains are refined, and the structure is more uniform; meanwhile, reasonable timing for using the Al and adding the Ti is chosen, then molten steel deoxidizing is strengthened, and finally the cold heading property of the cold heading steel is greatly improved by improving the purity of molten steel and the grain size of the material.

The invention relates to an electroplating method, in particular to an Al-Ni alloy electroplating method in a low-temperature salt melting system. The Al-Ni alloy electroplating method in the low-temperature salt melting system is characterized in that in a pre- electrolyzing process, both a negative pole and a positive pole adopt aluminium sheets with the purity of 99 percent; and in an electroplating process, a mild steel sheet with the thickness of 1mm is taken as the negative pole, a pure aluminium material with the purity of more than 99 percent is taken as the positive pole, and an NiCl2+RClX+AlCl3+NaCl+KCl mixture is added into an electrolysis bath and is heated and melted into an electrolyte for electroplating. The invention has the advantages that aluminium and nickel chlorides are adopted as raw materials, and an additive is added, so that aluminium ions and nickel ions are electrolyzed and deposit together on negative-pole materials to generate a uniform and dense Al-Ni alloy plating; and through the adoption of the Al-Ni alloy electroplating method provided by the invention, low heat energy is required for producing the plating, the oxidation loss of the alloy metal is small, and the production cost is low.

The invention provides a method for preparing a high-strength aluminum alloy through selective laser melting. The method for preparing the high-strength aluminum alloy through selective laser meltingcomprises the following steps: a high-strength spherical aluminum alloy powder and functional composite particles are provided, the functional composite particles are the mixture of a hard phase and alloy elements, and mixing treatment is carried out on the high-strength spherical aluminum alloy powder and the functional composite particles to obtain a mixed powder body; and under the condition ofinert atmosphere, selective laser melting equipment is adopted for carrying out selective laser melting forming under the conditions that the laser power is 190-220W, the laser beam diameter is 70[mu]m, the scanning speed is 115-155mm/s, the scanning distance is 40-80[mu]m, the powder layer thickness is 70[mu]m, and the powder preheating temperature is 150-250 DEG C, natural cooling is carried out, and then a high-strength aluminum alloy workpiece is prepared.

The invention discloses a method for refining a grain structure of a GH4169 alloy forging by adopting a two-stage stepped strain rate process. The method comprises the following steps: (1) pretreating a solid-solution-state alloy forging, wherein the forging is heated to 900-940 DEG C, and quenching is performed after 20-25 hours' heat preservation; (2) heating the pretreated forging to reach deformation temperature of 970-1,010 DCG C, performing heat preservation till the temperature of the heated forging becomes uniform, and then performing deformation treatment on a blank by adopting the two-stage stepped strain rate process, wherein the first-stage strain rate is 0.01-0.1 s<-1>, the deformation is 20-35%, the second-stage strain rate is 0.005-0.001 s<-1>, and the total deformation in the two stages is 50-70%; and (3) performing quenching. By adoption of the method disclosed by the invention, the purpose of refining the grain structure of a GH4169 alloy under the premise of relatively small deformation can be fulfilled, and a new technique is provided for improvement in the forging quality.

The invention provides copper alloy with excellent tensile strength and a copper alloy pipe prepared from the copper alloy. The copper alloy comprises 0.15 to 0.95 mass percent of Sn, 0.01 to 0.060 mass percent of P, 0.001 to 0.01 mass percent of B and the balance of copper and other impurities, wherein the impurity content is less than 0.06 mass percent. The longitudinal tensile strength sigmab of the annealed copper alloy pipe is more than or equal to 250 N/mm<2>, the radial average grain is less than or equal to 0.035 millimeter, and a yield ratio of the yield (limit) strength sigma 0.2 of a longitudinal tensile test to sigma b is less than or equal to 0.27. Compared with the copper alloy pipe made of phosphorus deoxidized copper, the tensile strength is improved, grains are refined, the yield strength is not changed obviously, and the corrosion resistance and heat resistance are excellent.

The invention discloses a preparation method of a hot melt adhesive for a multilayer oil tank. The preparation method comprises the following steps: 1) mixing polyethylene, polypropylene, a monomer, an initiator and a polyolefin nucleating agent in a high-speed mixer, thus obtaining a pre-mixed resin after even mixing; 2) fusing, extruding and granulating the evenly-mixed pre-mixed resin by using a double-screw extruder, thereby obtaining a polyolefin grafting material; and 3) mixing the polyolefin grafting material and the polyethylene in the high-speed mixer; fusing and extruding the evenly-mixed material in the double-screw extruder, thereby obtaining the hot melt adhesive for the multilayer oil tank. The prepared hot melt adhesive has the advantages of being rapid in bonding speed as well as strong and more stable in bonding force, and has the small bonding force attenuation after being soaked in fuel oil for a long time. In addition, the bonding force of the hot melt adhesive is slightly affected by the environment and is stable at high and low temperature environments.

The invention provides pipe line steel for high linear energy welding and a manufacturing method thereof. The pipe line steel for the high linear energy welding comprises the following components in percentage by weight: 0.05 to 0.08 percent of carbon, 0.15 to 0.35 percent of silicon, 1.5 to 1.8 percent of manganese, 0.004 to 0.006 percent of nitrogen, 0.012 to 0.016 percent of titanium, 0.02 to 0.04 percent of aluminum, 0.05 to 0.08 percent of rare earth elements, 0.03 to 0.07 percent of niobium, 0.2 to 0.4 percent of nickel, 0.2 to 0.5 percent of copper, not more than 0.010 percent of phosphorus, not more than 0.005 percent of sulfur, not more than 0.002 percent of oxygen and the balance of Fe and other inevitable impurity elements, wherein the weight ratio of the titanium to the nitrogen is controlled to be between 2 and 4, the weight ratio of the aluminum to the nitrogen is controlled to be between 3 and 10, and the yield strength Rt 0.2 of the pipe line steel for the high linear energy welding is more than 570 MPa. The pipe line steel has a typical needle-like ferritic structure, high comprehensive mechanical properties, high linear energy welding performance and low cost.

The invention relates to steel for an oil casing pipe. The steel comprises the following chemical components by weight percent: 0.25-0.35% of C, 0.1-0.6% of Si, 0.8-1.5% of Mn, not more than 0.015% of P, not more than 0.003% of S, 1-1.5% of Cr, 1-1.5% of Mo, 0.05-0.12% of V, 0.02-0.04% of Nb, 0.01-0.04% of Ti, 0.01-0.08% of Al, 0.0005-0.005% of Ca and the balance of Fe and inevitable impurities. A steel pipe which is obtained through smelting, continuously casting, perforating and hot-rolling by using the components is insulated for 30-60 minutes at an austenitizing temperature of 880-930 DEG C, is cooled with air to 830-850 DEG C after discharged and undergoes water quenching, undergoes high-temperature tempering at 580-620 DEG C and is insulated for 40-80 minutes to obtain the oil casing pipe. The steel grade of the obtained oil casing pipe can be above 160ksi and the impact energy is above 70J. The obtained oil casing pipe has high strength and toughness.

The invention belongs to the field of machining of alloy materials and discloses an aluminum alloy pressure-cast door plank. The aluminum alloy pressure-cast door plank is prepared from the following raw materials in percentage by weight: 4.1%-4.3% of magnesium, 1.8%-2.1% of manganese, 0.8%-0.9% of zinc, 0.6%-0.7% of copper, 0.3%-0.4% of nickel, 0.1%-0.2% of white graphite, 0.04-0.05% of cerium, 0.04%-0.05% of yttrium, 0.02%-0.03% of samarium, 0.01%-0.02% of silicon dioxide and the balance of aluminum. The aluminum alloy pressure-cast door plank is high in mechanical strength, can resist corrosion and is unlikely to be oxidized and change color; the preparation method is simple, feasible and suitable for large-scale production.

The invention discloses a magnesium-zinc-manganese-tin-yttrium alloy and a preparation method of the same. The mass percentage content of each component of the magnesium-zinc-manganese-tin-yttrium alloy is as follows: Zn: 2-8%, Mn: 0.1-3%, Sn: 1-6%, Y: 0.1-4%, the inevitable impurities of not more than 0.15%, and the balance of magnesium. The preparation method comprises the following steps of: firstly, adding the selected raw materials in a vacuum induction furnace, smelting and cooling with water, then, machining the smelted alloy to a proper size in a rolling mill, annealing the machined alloy, and finally extruding the annealed alloy into bars. The alloy provided by the invention contains very little rare earth yttrium, during smelting and hot working, crystalline grains can be refined, and sequentially, the comprehensive mechanical property of the alloy is improved; with the yttrium, the hot machining temperature of the alloy can be raised, the resistance to deformation in hot machining is reduced, and the machining efficiency is improved. The magnesium alloy provided by the invention needs simple preparation technology, and has low requirement on production equipment.

The invention discloses a process method for preparing magnesium alloy through electro-slag remelting, which comprises the following steps of: mixing raw materials for preparing the magnesium alloy, and smelting at the temperature of between 800 and 900DEG C under the protection of SF6 and CO2- gases in a crucible to prepare a consumable electrode bar; filling in an electroslag furnace for electroslag smelting, wherein the working voltage is 25-40V, the working current is 0.8-5kA, an arc strike block is a pure aluminum block, arc strike slag is CaF2, the protective gases are SF6 and CO2- gases, the electroslag material kept at the temperature of between 700 and 850DEG C for 6 to 8 hours is added in the smelting process, the adding amount of the electroslag material is 3 to 4 percent of the mass of the consumable electrode bar, and the electroslag material comprises the following components in percentage by mass: 5 to 15 percent of CaO, 5 to 20 percent of Al2O3, 10 to 30 percent of MgOand the balance of CaF2; and performing annealing treatment on a magnesium alloy ingot which is quickly consolidated by a water cooled crystallizer at the temperature of between 500 and 525DEG C for 3 to 5 hours, and machining to obtain the finished product.

The invention discloses a formula for high strength-toughness traction bar bracket steel casting. The high strength-toughness traction bar bracket steel casting comprises the following chemical constituents in percentage by weight (wt%): 0.3 to 0.45 percent of C, smaller than 1.0 percent of Si, smaller than or equal to 1.0 percent of Mn, 0.03 percent of P, 0.03 percent of S, 0.04 to 0.08 percent of Nb, and the balance of Fe. By properly reducing the carbon content in the material, improving the toughness of a steel casting core part and adding trace amount of alloy element niobium, the effects of grain refinement, precipitation strengthening and the improvement of material mechanical property are played. The invention further discloses a production process of the high strength-toughness traction bar bracket steel casting. The production process comprises the following steps: firstly, molten steel smelting, secondly, casting moulding, and thirdly, heat treatment. The production process of the high strength-toughness traction bar bracket steel casting improves the surface and inherent quality of work pieces by optimizing the casting process.

The magnesium alloy contains Zn 5.0-8.5 wt%, Zr 0.6-0.8 wt% and Y 0.7-2.0 wt% except Mg and inevitable impurity. The present invention has high strength like traditional magnesium alloy and greatly raised plasticity. It may be used in industrial production to produce sheet, rod, pipe, section and forged products via plastic metal forming, and may have structure and performance controlled via heat treatment.