866 results about "Hot working" patented technology

The invention relates to the technical field of twinborn model simulation, and discloses a twinborn model simulation method and system for hot working of large forgings. The method comprises the following steps: collecting and preprocessing process parameters, quality data and environment information in a multi-source manner, and obtaining hot working characteristic data; performing correlation analysis to construct a process knowledge graph; calculating the distribution of a temperature field, a stress field and an organization field by using a self-sensing multi-field coupling var value neural network; comparing and analyzing to obtain deviation data and correction parameters; adjusting a network parameter optimization prediction result; and executing multi-objective optimization calculation, and generating a whole-process technological parameter and a control instruction. According to the method, full-process multi-physics field coupling calculation from smelting, casting, forging and pressing to heat treatment can be achieved, model parameters are dynamically adjusted according to real-time production data, the optimal process scheme is generated, and therefore the manufacturing quality and efficiency of large forgings are improved.

The invention relates to the technical field of processing temperature control, and discloses a temperature control method and system for a hot processing process and a storage medium. The method comprises the following steps: collecting hot working whole process temperature data through multiple sensors, calculating a temperature change rate, an extreme point and a uniformity index, and obtaining key characteristic parameters; establishing a quantitative relation matrix of the process parameters and the temperature field by using an orthogonal test; calculating an optimal process parameter combination based on the matrix by using a rolling time domain optimization algorithm to generate a control instruction; and performing execution opportunity and duration prediction and correction on the instruction to form a precise target control instruction. The temperature control precision and stability in the hot working process of the large alloy steel component are improved, so that the product quality is improved, the energy consumption is reduced, and the production period is shortened.

The invention relates to a 1400 MPa-grade nickel-based alloy for a second-generation high-temperature superconducting base band and a preparation method of the 1400 MPa-grade nickel-based alloy, and belongs to the technical field of materials. The nickel-based alloy comprises the following chemical components in percentage by weight: 15.0 to 17.0 percent of Cr, 13.0 to 15.0 percent of Mo, 5.5 to 9.0 percent of W, 5.0 to 7.0 percent of Fe, 0.4 to 0.6 percent of Mn, 0.01 to 0.05 percent of Si, 0.1 to 0.2 percent of V, 0.0 to 2.5 percent of Co, 0.1 to 0.2 percent of Al, 0.001 to 0.01 percent of B and Clt, 0.005%, Plt; 0.005%, Slt; 0.002%, Olt; 0.002%, Nlt; 0.002%, and the balance being nickel. On the basis of the Ni-Cr-Mo alloy, the composition design thought of increasing W and reducing Mo is adopted, the optimized hot working and heat treatment process is matched, and finally the strength of a base body is improved through cold deformation; the content of C is controlled, precipitation of carbides is controlled, and alloy elements are ensured to be completely dissolved into a matrix during homogenization treatment; and a pure smelting process is adopted, so that the oxygen content in the alloy is reduced, the inclusion content is controlled, and high purity is ensured.

The invention belongs to the technical field of gas turbine maintenance, and particularly relates to a solid-state repair method for a hot-end component of a gas turbine, which comprises the following steps: S1, acquiring damage information of the surface of a to-be-repaired matrix; s2, roughening treatment is conducted on a damaged area on the surface of the to-be-repaired base body, and electrochemical activation treatment is conducted on the roughened damaged area; s3, supersonic speed cold spraying treatment is conducted on the treated damaged area, and gradient materials are deposited on the damaged area layer by layer till a compact repairing layer is deposited on the surface of the base body; s4, selective laser remelting treatment is conducted on the compact repairing layer of the damaged area; s5, carrying out laser shock on the dense repair layer subjected to the remelting treatment; and S6, the base body subjected to laser shock treatment is machined till the standard geometric dimension of the base body is recovered. The method can solve the problems of large heat input, matrix damage, insufficient bonding strength and the like in the process of repairing the damaged area of the matrix in the traditional hot working technology.

The invention relates to a free forging method for preparing an AAA nondestructive inspection grade large-specification TC4 alloy bar, and belongs to the technical field of titanium alloy hot working. According to the method, as-cast grains are fully crushed and refined through high-temperature and large-deformation forging in the cogging stage; high-low-high heating forging at the lower phase transformation point and the upper phase transformation point is used for promoting the high-temperature dynamic recrystallization process so as to homogenize crystal grains; the corner deformation dead zone is fully reduced through multi-heating-number diagonal drawing-out forging, and a U-shaped anvil is adopted in the forming stage to reduce metal flowing in all directions in the rolling stage. According to the free forging method for the large-specification TC4 alloy bar, the structure uniformity of the TC4 alloy bar can be improved, and the AAA-level nondestructive testing requirement is met.

The invention belongs to the technical field of aluminum alloy heat treatment, and particularly relates to a high-strength Al-Mg alloy and a preparation method thereof. According to the Al-Mg alloy, nucleation particles are provided for an AlMn second phase in an aluminum matrix through Mn and Zn alloying, and the activation energy of the AlMn second phase is reduced. According to the preparation method, the prepared alloy is mainly subjected to multi-stage homogenization treatment, and in multi-stage homogenization, the low temperature is used for second-phase pre-nucleation, the middle temperature is used for second-phase nucleation and precipitation, and the high temperature is used for coarse crystal phase redissolution. The alloy ingot is subjected to multi-stage homogenization heat treatment by adopting the method, the second phase precipitation number density of the alloy ingot can be remarkably improved, and the distribution uniformity of the alloy ingot can be improved, so that the strength of the alloy is improved, a large number of subcrystal structures are reserved in the alloy in the subsequent hot working process, and recrystallization and abnormal growth are effectively inhibited; and an optimal deformation structure is provided for obtaining a high-performance aluminum alloy product.

The invention relates to the technical field of metal material hot working, and discloses a hot-rolled coiled plate production process which comprises the following steps: preparing a reaction type protective agent, the high-temperature-resistant coating is prepared from the following raw materials in parts by weight: 20 to 40 parts of tetraethoxysilane, 5 to 15 parts of triethyl phosphate, 1 to 5 parts of triethyl borate, 0.5 to 2.0 parts of cerous nitrate (III) hexahydrate, 0.1 to 1.0 part of lithium acetate and 0.01 to 0.05 part of vanadyl acetylacetonate (IV). Coating the surface of a hot-rolled plate blank with the protective agent; the coated plate blank is heated in a heating furnace, so that the protective agent forms a molten-state protective layer in situ; carrying out hot rolling on the plate blank with the molten protective layer; and cooling and coiling the hot-rolled steel strip. In the whole heating and hot rolling process, the molten protective layer isolates the contact between the steel and the oxidizing atmosphere, so that the generation of oxide scales is fundamentally inhibited, the production process is simplified, and the metal yield is increased.

The invention belongs to the technical field of titanium alloy hot working stress analysis, and discloses a method and system for predicting high-temperature flow stress and plastic damage behavior of a titanium alloy, and the method comprises the following steps: obtaining true stress-true strain data of the titanium alloy through a high-temperature tensile experiment; establishing a unified constitutive model for predicting the high-temperature flow stress and the plastic damage behavior of the titanium alloy; and determining material parameters of the unified constitutive model for predicting the high-temperature flow stress and the plastic damage evolution behavior of the titanium alloy by utilizing a numerical difference principle and combining true stress-true strain data of the titanium alloy, and predicting the high-temperature flow stress and the plastic damage behavior of the titanium alloy under the conditions of constant temperature and constant strain rate. According to the method, through a titanium alloy high-temperature tensile experiment, a mathematical model for predicting the titanium alloy high-temperature flow stress and the plastic damage behavior is provided based on a dislocation density theory and a damage evolution mechanism, and the influence of plastic damage on the titanium alloy thermal deformation behavior is considered; and rapid and accurate prediction of the high-temperature flow stress and the plastic damage behavior of the titanium alloy under the high-temperature deformation condition is realized.

The invention discloses a novel cross-series difference light high-strength corrosion-resistant aluminum alloy and a preparation method thereof. Alloy components break through an existing aluminum alloy component system and comprise the following alloy elements in percentage by weight: 2-3.5 wt% of Mg, 1-2 wt% of Cu, 0.3-0.8 wt% of Li, 0-0.5 wt% of Si, at least two microalloy elements of Zr, Hf, Ti, V, Nb, Y, Sc or Er with the Mg / Cu weight ratio of 1.5-2 and the total content not exceeding 1 wt%, and the balance of Al and inevitable impurities. The preparation method of the alloy comprises the following steps: (1) casting the aluminum alloy; (2) homogenizing heat treatment; (3) carrying out thermal deformation to obtain a hot working material; (4) optionally obtaining a cold working material through cold deformation; and (5) the machined material is subjected to solid solution and aging treatment, and a finished product material is obtained. The aluminum alloy material shows excellent comprehensive service performance, including low specific gravity (2.64-2.67 g / cm < 3 >, lower than that of pure aluminum), high strength (peak aging tensile strength 430-460 MPa), excellent plasticity / toughness (peak aging elongation gt; the product of strength and elongation is gt; the stress corrosion resistance (the stress corrosion sensitivity coefficient is smaller than or equal to 5%) is achieved, and wide engineering application prospects are achieved.

The invention discloses a wide and thick plate hot working burner period intermittent control method considering input saturation. The method comprises the steps that burner heat supply controllable areas are divided according to burner distribution positions in the length direction of a wide and thick plate; on the basis of the operation time sequence of the wide and thick plate in the furnace, a burner heat supply controllable area distribution parameter model is established according to the temperature sensor distribution position and temperature information. And designing a burner period intermittent control method considering input saturation. And on the basis of a Lyapunov functional and a linear matrix inequality theory, calculating and designing sufficient conditions for finite time stability of a burner heat supply controllable area distribution parameter system under the control method. Through the steps, the temperature control performance of the heating furnace can be improved, sufficient combustion of fuel in the furnace is achieved, and it is ensured that wide and thick plates are heated evenly and the target temperature reaches the standard.

The invention discloses a lightweight ultrahigh-strength high-modulus weldable aluminum-lithium alloy material and a preparation method thereof. The aluminum-lithium alloy comprises 3.20 wt%-3.49 wt% of Cu, 1.45 wt%-1.75 wt% of Li, 0.35 wt%-0.50 wt% of Mg, 0.20 wt%-0.40 wt% of Ag, 0.11 wt%-0.17 wt% of Sc, at least one of Zr, Mn, Ti, Hf and V with the total content not larger than 0.60 wt%, the balance Al and inevitable impurities, each impurity element is smaller than or equal to 0.15 wt%, and the sum of the impurity elements is smaller than or equal to 0.40 wt%. The preparation method of the alloy deformation processing material comprises the following steps: (1) manufacturing an aluminum-lithium alloy ingot blank; (2) homogenizing heat treatment; (3) thermally processing the ingot blank into a required processing material or a pre-processing material; (4) optionally reheating the pre-processing material, and processing the pre-processing material into a required processing material through cold deformation; (5) carrying out solid solution heat treatment on the processing material; (6) the machined material subjected to solution heat treatment is rapidly cooled to the room temperature; and (7) aging treatment is conducted on the machined material. The aluminum-lithium alloy material shows excellent comprehensive performance of low density, high strength, high modulus, weldability and the like.

The invention relates to a preparation process optimization method of a zirconium alloy material with high fretting wear resistance, which comprises the following steps: setting a chemical component optimization range of a zirconium alloy, including specific proportions of tin, iron, niobium, chromium and oxygen elements; establishing a computer simulation model, and predicting the wear volume, tribological stability and microstructure evolution of the material under the fretting wear condition; then, a complete optimization scheme is output based on the model optimization homogenization treatment temperature interval, the hot working deformation range, the cold working cumulative deformation degree and the annealing system; and finally, a preparation process sequence including smelting, homogenization treatment, hot working deformation, cold working deformation and final heat treatment is implemented, the zirconium alloy material with the equiaxed grain structure is prepared, and the wear resistance of the zirconium alloy material is verified through an experimental fretting wear performance test. Compared with the prior art, the method has the advantages that through systematic component design and process parameter simulation optimization, the material performance is remarkably improved, and the application reliability is enhanced.

The present application relates to the technical field of superalloys, and particularly relates to an 800°C-resistant high-strength and high-toughness nickel-based wrought superalloy and a preparation method therefor, and a turbine disc. The nickel-based wrought superalloy comprises: 10-12% of Cr, 14-16% of Co, 2.5-3.5% of W, 3.75-5% of Mo, 3.5-4.5% of Al, 2.5-3.1% of Ti, 3-3.8% of Nb, 0.01-0.08% of C, 0.005-0.05% of B, 0.01-1% of V, 0.025-0.075% of Zr, 0.005-0.3% of Si, 0.02-0.05% of Re, 0.001-0.08% of Sc, 0.001-0.08% of La, 0.001-0.05% of Ce, 0.001-0.05% of Nd, 0.001-0.15% of Mg, and the balance of Ni. In the present application, by rationally designing the components of the nickel-based superalloy in cooperation, and by coarsening a γ' phase by means of process regulation and control, the alloy achieves good hot working performance for engineering, and a turbine disc satisfying requirements can also be obtained by means of a heat treatment.

The invention discloses a casting shrinkage-proof device for hot-working casting, and belongs to the technical field of hot-working casting, by arranging a heating mechanism and a knocking mechanism, through vibration and disturbance generated by knocking, the static state of 21800 austenitic stainless steel metal liquid in a casting mold can be broken, and the shrinkage-proof performance of the casting is improved. According to the technical scheme, small bubbles originally attached to the interior or the wall face of liquid are disturbed and start to float upwards, meanwhile, vibration can improve the liquidity of the metal liquid, crank knocking is started in the process that the metal liquid is injected into a casting mold, knocking is still continuously kept after the metal liquid is injected, knocking power is from pushing of steam, and therefore the effect of improving the fluidity of the metal liquid is achieved. No other external force is needed in the process, and the knocking frequency is gradually reduced until the knocking frequency is completely stopped along with cooling of metal, weakening of power generated by steam and reduction of the casting mold temperature, so that the purpose of preventing the stability of metal liquid during condensation from being damaged by excessive knocking is achieved.

The invention discloses a preparation method of an ultra-large-diameter copper-nickel alloy seamless tube, which comprises the following steps of: obtaining a cold-rolled raw material which is uniform in internal structure and free from pores by using forging and cross piercing methods, and then performing cold rolling to eliminate an as-cast state, performing hot working on the structure to fully refine crystal grains and drawing the raw material which meets the equipment requirements in diameter and wall thickness; the large-diameter seamless pipe with the diameter of 508 mm is prepared, and the produced large-diameter seamless pipe is excellent in mechanical performance, uniform in grain size and internal structure and high in practicability and economic benefits.

The invention discloses a multi-scale simulation method for a thermal compression deformation behavior of TC4 titanium alloy, and belongs to the field of metal material processing simulation. Comprising the following steps: 1, carrying out thermal compression experiments at different temperatures to obtain a deformed sample; 2, analyzing the grain orientation, orientation difference angle and texture evolution of the sample by using an electron back scattering diffraction technology; 3, constructing a crystal plasticity finite element model, and simulating a polycrystalline deformation process; 4, constructing a molecular dynamics model, and simulating phase change and dislocation evolution in thermal compression and cooling processes; and 5, based on a multi-scale simulation result, hot working parameters are optimized, dynamic recrystallization and a beta-to-alpha phase change path are regulated and controlled, and grain refinement and performance homogenization are achieved. The invention discloses a correlation mechanism of the microstructure and the mechanical property in TC4 titanium alloy thermal compression deformation, and provides a theoretical basis for optimization of a thermal processing technology of a high-performance titanium alloy component in the aerospace field.

The invention belongs to the technical field of high-temperature alloy heat treatment, and discloses a method for improving the hot working performance of a nickel-based high-temperature alloy for a molten salt reactor by combining pre-deformation and homogenization. The method comprises the steps that raw materials of the nickel-based superalloy for the molten salt reactor to be improved are sequentially subjected to vacuum induction melting, pouring and electroslag remelting refining treatment, and an electroslag remelting refined alloy cast ingot is obtained; the electroslag remelting refined alloy cast ingot is sequentially subjected to heating, heat preservation and pre-deformation treatment and is air-cooled to the room temperature, and a pre-deformed cast ingot is obtained; and the pre-deformed cast ingot is subjected to homogenization treatment and air cooling to the room temperature, and the method is completed. The method is a novel heat treatment process combining pre-deformation and high-temperature homogenization, the hot working performance of the alloy is optimized, the high-temperature alloy uniform in structure and excellent in mechanical property is obtained, and application in the field of high-temperature molten salt energy systems is met.

The invention relates to the technical field of parameter optimization, and discloses a titanium alloy die forging process parameter optimization method and system.The method comprises the steps that thermophysical parameters and mechanical property parameters of a titanium alloy blank are collected; constructing a hot working diagram based on the thermophysical parameters and the mechanical property parameters; identifying a stability region of the hot working diagram, and calibrating an instability parameter domain; performing quantitative decoupling on the critical characteristics of the instability parameter domain to obtain a cracking critical strain rate interval and a grain coarsening critical temperature interval; determining a quality index based on the cracking critical strain rate interval and the grain coarsening critical temperature interval; associating the quality indexes with equipment control parameters of the titanium alloy forgings to obtain a parameter-quality relation table; performing quality-oriented screening on the parameter-quality relation table, and outputting an optimized process parameter group meeting the comprehensive quality requirement of the titanium alloy forge piece; according to the method, the accuracy and efficiency of titanium alloy die forging process parameter optimization can be improved.

The invention belongs to the field of metal material processing, and particularly relates to a high-strength high-temperature nickel alloy welding material and a preparation method thereof.The high-strength high-temperature nickel alloy welding material comprises, by weight, 0.02%-0.05% of C, 0.10%-0.20% of Si, 18.0%-22.0% of Cr, 7.0%-9.0% of Fe, 4.0%-6.0% of Co, 2.0%-4.0% of W, 3.0%-6.0% of Mo, 0.005%-0.010% of B, 0.5%-2.5% of the total amount of Al and Ti, 0.05%-0.08% of Zr, 2.0%-2.5% of Nb, 0.30%-0.40% of RE, smaller than 0.005% of S, smaller than 0.005% of P, 1.5%-4.0% of modified boron nitride mixed powder and the balance Ni, the high-strength and high-temperature nickel alloy welding material is obtained through hot working, heat treatment, surface treatment and coating preparation, and the problem that in the prior art, deposited metal formed after welding of the high-strength and high-temperature nickel alloy welding material is poor in high-temperature mechanical property in a high-temperature environment can be effectively solved.

The invention discloses a novel high-strength plastic magnesium alloy and a preparation and processing method thereof. The magnesium alloy is prepared from, by mass, 3%-10% of Gd, 1%-5% of Y, 0.3%-5.0% of Sn, 0.3%-1.5% of Sb, 0.3%-1.0% of Ge, 0.3%-1.0% of Ca, 0.3%-1.2% of Sr, 0.3%-1.0% of Zr and the balance pure magnesium. The preparation and processing method of the alloy comprises the following steps: (1) preparing raw materials according to target alloy components, and smelting to obtain a magnesium alloy melt; (2) pouring the magnesium alloy melt to form a cast ingot; (3) heating the cast ingot for deformation cogging; (4) carrying out homogenizing heat treatment on the blank; (5) carrying out hot working on the homogenized alloy, and then carrying out artificial aging under the combined action of pulse current and direct current; and (6) the aged material is placed in liquid nitrogen to be kept, and then the deformation residual stress of the material is reduced in a cold water pouring and freezing mode. The defect of the magnesium alloy in the aspect of plastic deformation capacity can be effectively overcome, the controllability of the magnesium alloy structure can be achieved, and the application range of the magnesium alloy is further expanded.

The invention provides austenitic steel for manufacturing a furnace roller and a process of the austenitic steel, and belongs to the technical field of austenitic steel, the austenitic steel for manufacturing the furnace roller comprises the chemical components of carbon, silicon, manganese, chromium, nickel, molybdenum, niobium, titanium, aluminum, phosphorus, sulfur and the like according to a specific proportion, and the austenitic steel is manufactured through the processes of smelting, casting, hot working, solution treatment, cold working, aging treatment and the like after raw materials are mixed through a stirring mechanism. The stirring mechanism comprises a stirring barrel, a rotating disc and a shaft which are rotationally connected, various stirring blades, a motor and related transmission parts, accurate temperature, time, deformation and the like are controlled in each step in the process, the austenitic steel has good high-temperature performance and comprehensive mechanical performance, the service life of a furnace roller can be prolonged, the manufacturing process meets the high-performance requirement, the cost can be reduced, and the production cost is reduced. The problems that an existing furnace roller material is insufficient in high-temperature strength, prone to deformation and abrasion, limited in manufacturing process and the like are solved, and the material is suitable for manufacturing furnace rollers of equipment such as industrial furnaces and has important practical application value.

The invention belongs to the field of hot working forming of metal materials, and particularly relates to a forming method of an asymmetric Y-shaped titanium alloy forge piece blank for aviation. By designing a special forming moulding bed and utilizing an eccentric pressing method, two asymmetric Y-shaped support arms with different lengths are forged, the main deformation process is realized by virtue of the moulding bed, the controllability of the production process is high, the dimensional precision is easy to guarantee, the process completion quality is high, the blank finish forging temperature can be effectively guaranteed, the material structure uniformity is improved, and meanwhile, the production cost is reduced. The streamline of the produced forge piece blank is distributed along the profile of the forge piece, the mechanical properties of the final forge piece in all directions are guaranteed, the forge piece waste rate is reduced, and the material utilization rate and the production efficiency are improved.

The invention discloses a high-efficiency and low-cost TC4 titanium alloy fine-grain rod preparation method, which comprises the following steps of: accurately controlling the structure evolution in the hot working process of a rod material in a manner of replacing forging with rolling and combining forging and rolling, and carrying out cast ingot cogging forging for three heating numbers and low-temperature low-speed large-deformation rolling forming for four heating numbers, so as to obtain the high-efficiency and low-cost TC4 titanium alloy fine-grain rod. And finally, the TC4 titanium alloy fine-grain rod which is uniform and fine in structure and excellent in performance is obtained. The TC4 titanium alloy fine-grain bar prepared by the method reaches a leading level in the aspect of transverse and longitudinal structure uniformity and refinement. According to the preparation method, the difficulty in formulation of a forging and rolling combined process and the difficulty in structure regulation and control are broken through, the heating number of the preparation process is reduced from about 20 of a traditional radial forging process to 4 of rolling, and the preparation method of the TC4 titanium alloy fine-grain bar is efficient and low in cost.

The invention discloses a high-Al and Ti difficult-to-deform high-temperature alloy hot working method, which avoids the melting risk of low-melting-point intermetallic compounds through high-temperature diffusion on one hand, and can realize effective and uniform diffusion of chemical elements on the other hand; on the other hand, through gradual heating number cooling forging, a high-temperature small-deformation forging process is carried out in an as-cast structure interval, and a low-temperature large-deformation process is adopted after the as-cast structure is crushed, so that an ideal uniform and fine recrystallized grain structure is finally realized, and the problems of high possibility of cracking, non-uniform forging structure, coarse grains and the like in a high-temperature alloy forging process are solved; and the high-quality requirement for use of downstream aero-engine components is met.

The invention discloses a preparation method of a titanium alloy cast ingot containing a copper element, and relates to the technical field of smelting. And selecting a titanium-copper intermediate alloy and / or a titanium-copper-aluminum intermediate alloy according to the raw material proportioning value of the copper-containing titanium alloy cast ingot. And uniformly mixing the sponge titanium and the intermediate alloy to prepare the consumable electrode. And the consumable electrode is prepared into a copper-containing titanium alloy cast ingot through vacuum consumable arc melting. On one hand, a titanium-copper intermediate alloy and / or a titanium-copper-aluminum intermediate alloy is selected as an adding mode of a copper element. And on the other hand, inert gas is introduced into the water-cooled copper crucible for vacuum consumable arc melting, so that the reduction of a molten pool is promoted. Under the combined action of the two aspects, the uniformity of the Cu element in the cast ingot is improved, the problem that the titanium alloy cast ingot has the beta spot defect in the hot working process due to copper element segregation is solved, and the application range of the titanium alloy material in the petrochemical industry, the aviation industry, the nuclear power generation industry, the hydrogen storage industry and the military industry is widened.

The invention relates to a design method for machining allowance of an asymmetric bearing ring, and the machining efficiency of batch production is improved by confirming the allowance of the ring before heat treatment of the asymmetric bearing ring. Comprising the following steps: S1, determining a test allowance based on an allowance standard and a heat treatment expansion and shrinkage amount of a bearing ring of the same size section, and determining a test processing technology according to the test allowance; s2, selecting a certain amount of test bearing rings for test processing, and recording the allowance and ellipse at the maximum wall thickness and minimum wall thickness positions of the inner and outer surfaces before and after heat treatment of the test bearing rings; s3, analyzing and calculating the average expansion and contraction amount and the maximum ellipse at different wall thicknesses of the test piece; and S4, on the premise that it is guaranteed that the machining allowance can be compatible with the position with the minimum expansion and contraction amount, and the machining amount after heat treatment is reduced, the formal allowance of the inner surface and the outer surface of the bearing ring under the heat treatment expansion trend and the heat treatment contraction trend is designed. By means of the method, the overall material utilization rate is effectively increased, the ferrule machining allowance is reduced, the hot working efficiency is improved, and the production cost is reduced.

The invention belongs to the technical field of high-temperature alloy hot working, and particularly relates to a method for improving forging cracking of a GH4079 alloy and application of the method. According to the method, the structure evolution control in the forging process is realized by regulating and controlling parameters such as temperature and deformation in the hot working process, so that the hot working cracking tendency is reduced; through specific heating, heat preservation, forging deformation and cooling modes, the problem of cracking of the GH4079 alloy in the hot working process is remarkably solved. According to the method for improving the forging cracking of the GH4079 alloy, the alloy performance can meet the standard requirement, the defects that due to the fact that a large number of strengthening elements are added, the hot working performance is sharply reduced, and the forging cracking tendency is serious are overcome, the problems that the yield of the GH4079 alloy is low and the production cost is high are solved, and application of the GH4079 alloy is promoted.

The invention discloses a sulfur-containing free-cutting titanium alloy without heavy metal and a preparation method thereof, and belongs to the field of nonferrous metal materials. The free-cutting titanium alloy material comprises the following components in percentage by mass: S: 0.2-0.4%; 0.3 to 0.45 percent of O; b: 0.003% to 0.006%; c is less than or equal to 0.03%; less than or equal to 0.03% of N, and the balance titanium and unavoidable impurities. The invention further discloses a preparation method of the raw material sponge titanium of the free-cutting titanium alloy material and a method for preparing the free-cutting titanium alloy material. Through unique component design and a preparation process, addition of heavy metal for fixing S in the free-cutting titanium alloy is avoided, so that the titanium alloy is better in biocompatibility, titanium-sulfur compounds in the titanium alloy are uniformly distributed, the chip breaking property and the tool nose lubricating condition are improved, and the service life of the free-cutting titanium alloy is prolonged. The problems of distribution uniformity of the element S and the element B and cracking of the hot working surface of the titanium alloy material containing the element S are solved, the production period is shortened, the cost is reduced, and the cutting performance of the titanium alloy is remarkably improved.

The invention relates to a multi-pass pressure sintering-based high-quality preparation method of a low-cost multi-reinforcement-containing aluminum-based composite material, in particular to a multi-pass pressure sintering-based high-quality preparation method of a low-cost multi-reinforcement-containing aluminum-based composite material. The method aims at solving the problems that in the powder metallurgy preparation process of the aluminum-based composite material, the density is low, the mechanical property is poor, and interfaces between reinforcement bodies with different properties and a base body are not matched. The method comprises the following steps: 1, weighing a reinforcement material and an aluminum-containing material; 2, uniformly mixing the powder through a mechanical ball milling method or a V-shaped mixer; 3, the mixed powder is put into a mold; 4, performing cold pressing to prepare a prefabricated body; 5, multi-pass hot pressed sintering; and 6, demolding. The aluminum-based composite material is prepared at low equipment cost, and is high in density, excellent in mechanical property and good in hot working property. The aluminum-based composite material can be applied in various scenes through the matching of different types of reinforcements with different volume fractions and the aluminum-containing material.

Provided is an efficient preparation method of a bimetallic seamless composite pipe, and belongs to the technical field of steel pipe manufacture. The efficient preparation method of the bimetallic seamless composite pipe includes following steps: sheathing a base pipe blank on a cladding pipe blank to obtain a composite pipe blank, and carrying out a stress relief annealing treatment on the composite pipe blank, where the base pipe blank and the cladding pipe blank are made of different materials; heating the composite pipe blank after the stress relief annealing treatment to a hot working window temperature, and sheathing on a core rod of an extrusion cylinder after an insulation treatment, and then extruding along an axial direction of the extrusion cylinder to obtain a bimetallic seamless composite pipe.