112results about How to "Eliminate casting defects" patented technology

The invention discloses a disk-shaped roller cutter ring with high hardness, good toughness and excellent comprehensive performance. The disk-shaped roller cutter ring comprises the following ingredients of: 0.46-0.56% of C, 0.80-1.20% of Si, 0.20-0.65% of Mn, 5.00-5.80% of Cr, 1.15%-1.55% of Mo, 0.85-1.40% of V and the balance Fe and impurities, wherein the content of P is no more than 0.02%, and the content of S is no more than 0.01%; and the overall hardness of the cutter ring is HRC55-61 (Rockwell Hardness C55-61), or the hardness is of graded distribution, i.e. the hardness of a working edge area is HRC55-61, the hardness of a transition surface area is HRC50-57, and the hardness of a step assembly surface area and an inner ring is HRC44-51. A preparation method of the disk-shaped roller cutter ring comprises the following steps of: smelting the raw materials in an electric furnace; carrying out electroslag remelting; preforging; carrying out die forging; carrying out slow cooling; annealing; carrying out rough machining to obtain a disk-shaped roller cutter ring rough blank; carrying out high-temperature vacuum hardening and two-time high-temperature tempering on the cutter ring rough blank; carrying out low-temperature destressing treatment; carrying out fine finishing to obtain the cutter ring with the overall hardness of HRC55-61, wherein the cutter ring with the overall hardness of HRC55-61 is applicable to the tunneling of a hard rock formation by a shield tunneling machine; or carrying out medium-frequency induction tempering treatment prior to the low-temperature destressing treatment to obtain the cutter ring with graded-distribution hardness, wherein the cutter ring with the graded-distribution hardness is applicable to the tunneling of a rock formation with an upper soft part and a lower hard part.

The present invention relates to surface or locally gradient reinforced antiwear composite manganese steel material and its preparation process. The composite material has matrix of austenite with relatively high toughness; reinforcing layer comprising TiC with relatively high hardness, martensite and metastable austenite; and intermediate transition layer comprising gradient varying TiC, martensite and austenite. The preparation process includes the following steps: designing metastable austenite manganese steel matrix composition with C 0.8-1.3 wt% and Mn 6-13 wt%; setting Ti-Fe alloy powder as composite medium in special parts of the cast mold and casting high temperature manganese steel melt to obtain the surface or local TiC reinforcement plus metastable austenite as-cast structure; and liquid nitrogen deep cooling the surface or local to obtain phase changed gradient martensite layer. The present invention can raise comprehensive mechanical performance of manganese steel.

The invention discloses a preparation method of a low-alloy high-carbon steel with a high-strength and high ductility nano structure, which is characterized in that the steel contains the following chemical components in percent by weight: 0.7-0.9 percent of C, 1.4-1.6 percent of Si, 1.2-1.4 percent of Mn, 1.4-1.6 percent of Al, 0.7-0.9 percent of Cr, 0.7-0.9 percent of W, less than 0.02 percent of P, less than 0.02 percent of S and the balance of Fe. The preparation method comprises the following steps: melting the chemical components according to the weight percent, pouring to form a steel ingot and slowly cooling to the room temperature; heating the steel ingot to 1,160-1,180 DEG C, cogging, and hot rolling to form a plate blank with the thickness being less than 25 mm, wherein the finally rolling temperature is 990-1,010 DEG C; rapidly putting the plate blank into a salt bath with the temperature of 220-260 DEG C after the rolling, and keeping the constant temperature for 4-24h, and then cooling in the air to the room temperature to obtain the low-alloy high-carbon steel with a high-strength and high ductility nano structure, wherein a microstructure comprises bainitic lath ferrites with the thickness of 60-90 nm and residual austenite and has the tensile strength of 2,000-2,300MPa, the yield strength of 1,500-1,900MPa under the condition of 0.2 percent of strain, the total elongation percentage of 6.7-7.8 percent and the uniform elongation percentage of 3.8-5.6 percent; and the Charpy measured by the ASTM:E23-02 standard, i.e. room-temperature impact work of a U-shaped notch specimen, is 7-22J. The invention has simple preparation process, direct constant temperature process in the salt bath after the hot rolling, short period of thermal treatment, low cost and easy application in production.

The invention discloses a steel ring billet casting technique based on casting and rolling combined forming. The steel ring billet casting technique based on casting and rolling combined forming comprises the steps that firstly, a casting mold is manufactured by means of water glass sand, the casting mold is dried and sprayed with painting, casting raw materials of a steel ring are smelted and are poured into the casting mold, and normalizing, tempering and quenching-tempering heat treatment are conducted on a steel ring billet formed through pouring; secondly, the steel ring billet is cooled to the room temperature, and polishing and machining are conducted on the cooled steel ring billet; finally, the steel ring billet which can be directly used for casting and rolling combined forming is obtained. According to the steel ring billet cast according to the technique, the defects, such as shrinkage cavities, shrinkage porosity and segregation, appearing in the steel ring billet casting process can be reduced, grains are refined to the maximum extent, and the high-quality steel ring billet capable of meeting the requirement for the ring rolling performance is manufactured; due to the fact that the processes of the casting and rolling combined forming technique are simplified, the quality and performance of the ring rolling technique and a ring workpiece are guaranteed.

The invention discloses a low-lithium high-plasticity high-strength Mg-Li alloy prepared from the following components in percentage by mass: 4-7% of Li, 2-6% of Al, 0.5-3% of Zn, 0.2-1% of Mn, 0.1-1% of RE, 0-0.05% of Ti+B, less than 0.3% of impurities and the balance of Mg. The invention also discloses a preparation method of an Mg-Li alloy plate. The preparation method comprises the following steps: proportioning, smelting, casting, homogenizing, extruding, rolling and annealing. The Mg-Li alloy related to the invention is relatively low in Li content and relatively high in strength and corrosion resistance; meanwhile, due to the addition of Li, a close-packed hexagonal crystal structure of Mg is changed, the alloy has relatively high plasticity and can be subjected to cold-rolling deformation; and the adopted extrusion rolling process is simple in operation, the finished product rate is relatively high, and the obtained plate has favorable overall performances.

The invention relates to a roll-bonding process for semisolid copper-lead bearing alloys/steel bimetals. The weight content percentage of the lead in the copper-lead bearing alloy is 10.0 to 30.0%. In order to refine the crystalline grain of the lead and improve the mechanical property of the alloy, sulfur, tin, nickel, manganese, rare earth and other the third alloy elements can be added in the copper-lead alloy. The process comprises four steps: pretreatment of steel plates, preparation of semisolid sizing agent, roll bounding and water cooling. The detailed process comprises the following steps: performing mechanical agitation to the melted copper-lead bearing alloys at 930 to 1050 DEG C to obtain the semisolid sizing agent; pouring the semisolid sizing agent on the pretreated steel plates; synchronously feeding the semisolid copper-lead bearing alloys and solid steel plates in to a mill for rolling; spraying water for cooling to obtain the bimetallic composite plate. The invention effectively overcomes the defect of lead segregation in the production of the copper-lead bearing alloys in the prior art, therefore, metallographic structure with fine lead particle and even distribution is obtained. According to mechanical test results, the interfacial shear strength of the copper-lead bearing alloys/steel bimetallic slabs prepared using the process is more than 60Mpa, increased by about 10Mpa.

The invention relates to a forging process for eliminating anisotropism of a large-sized AQ80M magnesium alloy bearing member and belongs to the technical field of magnesium alloy material machining. The process specifically includes the steps that an ingot blank is prepared; extrusion blooming is performed with the low extrusion ratio, specifically, extrusion is performed on an extruding machine with the extrusion ratio being 3-4 and the extrusion speed being 0.3-2.8 mm/s; cooperating with intermediate annealing, multiple passes of direction-changing heading are performed on a hydraulic press so that the blank can be forged into a large-sized magnesium alloy bearing member; and the magnesium alloy bearing member is subjected to aging treatment. By means of the forging process, preparation of magnesium alloy bearing members with the size being larger than 470*390*170 mm<3> can be achieved; after aging treatment is finished, the yield strength difference among the length direction, the width direction and the height direction is smaller than or equal to 10 MPa at both the room temperature and the temperature of 150 DEG C; and the problem of anisotropism of large-sized magnesium alloy parts is solved.

The invention relates to a substrate triggered single crystal high temperature alloy directional solidification technology. The technology comprises the following steps: (1) preparing a single crystalsubstrate material matched with the crystallographic characteristics of a single crystal high temperature alloy; (2) preparing a single crystal substrate chilling plate from the obtained single crystal substrate material; and (3) applying the obtained single crystal substrate chilling plate to directional solidification equipment, and carrying out high temperature alloy smelting and directional solidification preparation to obtain a single crystal high temperature alloy product. Compared with a crystal selection method and a seed crystal + crystal selection method, on the basis of accuratelycontrolling the orientation of the single crystal high-temperature alloy, the overall height of a casting is reduced by eliminating a spiral crystal selector, and the purposes of enhancing axial heatdissipation, improving the temperature gradient of a pasty region and eliminating freckles and mixed crystals near an edge plate are achieved. By means of successful implementation of the technology,the blade preparation quality and the preparation success rate are greatly improved, and the preparation cost of a single crystal high temperature alloy blade is reduced.

The invention discloses a diffusion welding method for tin bronze and steel welded structures. The diffusion welding method is characterized by comprising steps of 1, machining a plurality of components according to drawings, carrying out oil and rust removal treatment on welded surfaces of the multiple components and then assembling the components to obtain welded assemblies; 2, placing the welded assemblies between lower support plates in furnaces of vacuum diffusion welding equipment and separating the welded assemblies from the support plates by graphite paper; 3, allowing the internal vacuum degree of the vacuum diffusion welding equipment to range from 1.0*10<-3> to 1.0*10<-4> Pa under the control and carrying out heating and pressurizing treatment on the welded assemblies; 4, cooling the welded assemblies and fetching weldments. The components comprise steel matrixes, tin bronze plates and closed end covers. The diffusion welding method has the advantages that loss of tin bronze compositions QSn10-2-3 can be prevented, and the material stability can be guaranteed; casting defects of tin bronze QSn10-2-3 can be eliminated to a certain extent, and copper matrixes can be guaranteed against cracking after heat treatment is carried out on the weldments.

The invention relates to a swaging integrated forming process for a large-diameter AQ80M magnesium alloy cake material, and belongs to the technical field of processing of a magnesium alloy material. The process comprises the following specific steps: preparing an AQ80M magnesium alloy ingot blank by semi-continuous casting; heating an extrusion die and an extrusion barrel; carrying out extrusion pre-deformation at low extrusion ratio; straightening and cutting the blank; carrying out multi-directional forging forming; and carrying out aging treatment. By the swaging integrated forming process for the large-diameter AQ80M magnesium alloy cake material, the large-diameter magnesium alloy cake material of which the diameter is phi 690 mm to phi 700 mm, the thickness is 100-110 mm, the tensile strength is greater than or equal to 330 MPa, the yield strength is greater than or equal to 190 MPa and the ductility is greater than or equal to 6% at room temperature, and the tensile strength is greater than or equal to 200 MPa, the yield strength is greater than or equal to 160 MPa and the ductility is greater than or equal to 30% at the temperature of 150 DEG C. The prepared large-size magnesium alloy cake material completely meets requirements of a large magnesium alloy part.

The invention relates to the field of aluminum base composite material processing, in particular to an extrusion process for a vehicle body in-situ nanoparticles enhancing aluminum base composite material. The vehicle body in-situ nanoparticles enhancing aluminum base composite material synthesized in situ under the outer field control is used as a research object, the casting defects such as holes and loosening are eliminated by adopting the hot extrusion plasticity, so that the texture is refined and dense, the extruded grains are uniform and small, and the mechanical properties are obviously improved; meanwhile, under the action of the extrusion pressure, the agglomeration particles are dispersed and dispersed in a matrix, the bonding force with the matrix is higher, a lot of dislocation is generated, a high-density dislocation mesh is formed, and dislocation enhancement is produced accordingly. The T4P+ artificial aging heat treatment of the follow-up extrusion material can eliminate the thermal residual stress caused by the different thermal expansion coefficients of nanoparticles and matrix in the process of the hot extrusion, the plasticity of the vehicle body extrusion material is further improved, and the vehicle body in-situ nanoparticles enhancing aluminum base composite material extrusion material which can replace the steel plate is obtained.

The invention relates to a high-wear-resisting land leveler blade and a production method. The elementary composition of the high-wear-resisting land leveler blade includes, by weight, 0.25-0.27% of C (carbon), 0.4-0.6% of AL (aluminum), 0.8-1% of Mn (manganese), 1.5-2% of W (wolfram), 0.5-0.7% of Si-B-C-N (silicon-boron-carbon-nitrogen) nano amorphous particles, no more than 0.0032% of B (boron), no more than 0.015% of P (phosphorus), no more than 0.015% of S (sulfur) and the balance being Fe (iron). The production method includes performing electric steelmaking, molten iron desulphurization and dephosphorization, performing converter top-bottom combined blowing and vacuum degassing processing, pressing in the Si-B-C-N nano amorphous particles by the pour-over process, casting a blade plate blank, cooling the blade plate blank to 1250-1270 DEG C to preserve heat for 1-2 hours, cooling the blade plate blank to 960-980 DEG C to be quenched with oil, tempering at 300 DEG C and then cooling sharply, and finally obtaining the land leveler blade. The blade has good match of strength, toughness and hardness, abrasive resistance of the blade is increased by more than twice as compared with that of a 65Mn blade, the production method is convenient, cost is low and production efficiency is high.

The invention aims to provide a preparation method of a novel magnesium alloy thick plate. The alloy comprises, by mass, 3.5-5.0% of Al, 2.0-3.5% of Zn, 0.1-0.8% of Mn, 0.01-0.80% of RE, 0.001-0.090%of Ca, less than or equal to 0.005% of Fe, less than or equal to 0.05% of Si, less than or equal to 0.005% of Cu, less than or equal to 0.005% of Ni and the balance Mg, and the total content of impurities does not exceed 0.1%, wherein the sum of the Al content and the Zn content satisfies the condition that Al+Zn is greater than or equal to 6% and less than or equal to 8%. Aiming at a novel Mg-Al-Zn alloy system, a forming process for preparing the large-size magnesium alloy thick plate with low anisotropy and high strength is developed to satisfy urgent demands of such fields as aerospace, weaponry and automobiles on the magnesium alloy thick plate with low cost and high performance.

The invention relates to the technical field of centrifugal roller casting, in particular to a centrifugal roller die casting device and a casting process thereof. The centrifugal roller die casting device comprise a first metal cold mold, a second metal cold mold, a base, a pouring funnel pipe and a pouring pipe, wherein the first metal cold mold is coaxially connected to the upper end of the second metal cold mold; the second metal cold mold is coaxially connected to the upper end of a circular cavity; the pouring funnel pipe is coaxially connected to the upper end of the pouring pipe; the pouring pipe is coaxially connected to the upper end of a square cavity; a main sand core is coaxially connected inside the first metal cold mold and the second metal cold mold; the upper end of the main sand core is connected with an upper sand core; second cavities are formed between the main sand core, the upper sand core, the inner wall of the first metal cold mold and the inner wall of the second metal cold mold; refractory pipeline bricks are arranged in the base, the pouring funnel pipe and the pouring pipe; a first cavity is formed in the refractory pipeline bricks; and the first cavitycommunicates with the second cavity. According to the centrifugal roller die casting device and the casting process thereof, the method is simple, and the operation is simple, convenient, safe and reliable, so that the quality is conveniently controlled, and the manufacturing cost is reduced; and the internal casting defects of a centrifugal roller die can be eliminated, so that the tissue compactness is improved.