38 results about "Solidus" patented technology

The present invention provides a highly fusible Ni-based alloy which has a low solidus temperature and is capable of easily forming, at a low temperature, a coating film that is excellent in terms of corrosion resistance, crack resistance and high toughness. The highly fusible Ni-based alloy contains, in mass%, 0.1% to 7.0% of P, 5.0% or less of B, 5.0% or less of Si, 2.0% or less of C, 30.0% or less of Cr, one or two of Mo and W in the total amount of Mo + W / 2 of 9.0% or less, 10.0% or less of Cu, one or more of Mn, Fe, and Co each in an amount of 10.0% or less, with the balance being made up of Ni and inevitable impurities. The Ni-based alloy has a hard phase that has a P content of 1% or less, and a structure in which P is solid-solved and / or compounds having a precipitation phase size of 10 μm or less and containing P are dispersed in a γ-Ni matrix. In addition, the Ni-based alloy has a solidus temperature of 800°C to 950°C inclusive.

The invention belongs to the technical field of microstructure simulation in the solidification process, and particularly relates to a nickel-based superalloy laser welding solidification structure evolution law prediction method and system.The method comprises the steps that simulation parameters are determined, a macroscopic temperature field is simulated to obtain molten pool temperature field data, a cellular automaton model is constructed, and grids are divided; initializing state variables such as component concentration and solid-phase fraction; coupling temperature field data, solving an optimized solute diffusion and redistribution equation to obtain a concentration field, updating a solid phase fraction according to local supercooling drive, and marking grain growth; counting a solid-phase fraction, and updating a solid-phase position; and judging whether the temperature of the cladding layer is lower than the solidus temperature and the solid fraction reaches a complete solidification threshold value or not, and if yes, outputting weld microstructure and target element concentration data. According to the method, the evolution law of the welding macroscopic temperature field and the structure and solute concentration field can be effectively predicted, experiments are replaced with numerical simulation, the cost is reduced, the technical blank is filled up, and reliable support is provided for precise regulation and control of the nickel-based high-temperature alloy laser welding process.

The application discloses a design method and system of a single-crystal high-temperature alloy solid solution heat treatment system, relates to the cross technical field of numerical simulation and material processing, and comprises the following steps: based on the relationship between element concentration and solidus temperature, determining the solidus temperature distribution of a cast single-crystal high-temperature alloy sample according to the element concentration distribution extracted from the cast single-crystal high-temperature alloy sample; adopting a phase field method to simulate solid solution heat treatment of the cast single-crystal high-temperature alloy sample, so as to obtain the element concentration distribution under the initial melting temperature and heat preservation for one simulation time step, and mark the element concentration distribution after treatment as the element concentration distribution, and determine the segregation coefficient of each element; when the segregation coefficients of all elements are within a preset range, marking all initial melting temperatures and corresponding current simulation times as heat treatment simulation results, and then determining the actual solid solution heat treatment system of the cast single-crystal high-temperature alloy sample. The application has the advantages of short time consumption, high efficiency and low cost.

A fusible link element (10; 15; 25; 35) comprising a metal composite material in which a first fusible metal (11; 21; 31) and a second fusible metal (12; 22; 32) are layered on top of each other, wherein the second fusible metal (12; 22; 32) has a lower melting temperature than the first fusible metal (11; 21; 31), characterized by the fact that the first fusible metal (11; 21; 31) is a Sn-Ag alloy and the Sn-Ag alloy contains at least 20 wt% and at most 30 wt% Ag, and the second fusible metal (12; 22; 32) is a Sn-Bi alloy and the Sn-Bi alloy contains at least 40 wt% and at most 70 wt% Bi, wherein at a common working temperature at least part of a component of the second fusible metal (12; 22; 32) is melted and part of a component of the first fusible metal (11; 21; 31) is melted, and where, at the common working temperature, the difference between a liquidus temperature and a solidus temperature of the first fusible metal (11; 21; 31) and the second fusible metal (12; 22; 32) is reduced by a shift in the equilibrium of Sn between the first fusible metal (11; 21; 31) and the second fusible metal (12; 22; 32) and by a mutual diffusion of Ag and Bi between the first fusible metal (11; 21; 31) and the second fusible metal (12; 22; 32).

A brazeable casting aluminum alloy with a high solidus line, the aluminum alloy comprising the following components in percentages by mass: Mn: 1.5-2.5%, Zn: 2.2-3.5%, Fe: 0.5-1.0%, Ni: 1.8-2.5%, Ti: 0.05-0.10%, Zr: 0.2-0.5%, Cr: 0.2-0.35%, Si:≤0.2%, and the balance of aluminum and inevitable impurities. The brazeable casting aluminum alloy material with a high solidus line has the advantages of a high solidus line, good castability, low hot cracking tendency, good mechanical properties, etc., can serve as a brazing aluminum alloy material for direct brazing, and meets the use requirements of the market for brazeable casting aluminum alloys.

The application provides a mixed powder for foamed aluminum, a foamed aluminum composite material and a preparation method thereof, the mixed powder comprising a base material, a foaming agent and a brazing agent; the base material comprises aluminum elements, silicon elements and copper elements; the copper elements exist in the form of copper powder; the difference between the solidus temperature of the brazing agent and the hot rolling temperature is-30 DEG C to 30 DEG C, and the mass percentage of the brazing agent is greater than or equal to 0.2wt% based on the mixed powder. For the foamed aluminum alloy system with Cu as a secondary main alloy element, the application can directly foam without diffusion annealing, and uniform and small pores are obtained, so the application prospect is wide.

The invention is directed to a method for improving the wear resistance of a vanadium alloyed powder metallurgy produced cold work tool steel comprising 1-20 %V, 1 – 5 %Mo and ≤ 1 %W by HIPing the steel and subjecting the HIPed steel to a heat treatment at a temperature of at least 5 °C higher than the solidus temperature of the tool steel for a time of at least 30 minutes in order to increase the size of the VC-particles, wherein the cold work tool steel after hardening and tempering does not contain noticeable amounts of other carbides than VC.

This invention relates to a method and product for efficiently solidifying coarse primary carbides in high-carbon alloy steel, belonging to the field of high-carbon alloy steel production. The method includes the following steps: determining the thermodynamic equilibrium temperature A3 corresponding to the nominal composition of the high-carbon alloy steel billet or ingot for complete austenite transformation; calculating the degree of segregation of solute elements and the corresponding solidus temperature T based on the steel composition of the high-carbon alloy steel billet or ingot and the cooling rate under actual solidification conditions. SS During the cooling and solidification process or the heating and solution treatment process of high-carbon alloy steel billets or ingots, A3~T SS Electrical pulse treatment is performed within a temperature range of -200℃, followed by a period of treatment and air cooling to room temperature. The resulting billet or ingot is then heated to 900–1150℃ and held for 1–3 hours, followed by hot deformation and air cooling to room temperature. This invention achieves efficient solution treatment (annealing time ≤3 hours) of primary carbides in high-carbon alloy steel at relatively low temperatures (≤1150℃) through electrical pulse treatment during the cooling process of hot billets / ingots or the solution treatment process of cold billets / ingots.

The invention relates to the technical field of solder, in particular to a solder composition and a preparation method and application thereof, and the solder composition comprises a first alloy and a second alloy; the first alloy comprises the following components in percentage by weight: 65-78% of Sn, 18-30% of In and 2-5% of Ag; and the second alloy comprises the following components in percentage by weight: 94-97% of Sn, 2-7% of Ag and the balance of Cu. The solder composition has double melting behaviors before reflow and has high solidus temperature after reflow, so that the problem of hot cracking caused by mismatching of coefficient of thermal expansion (CTE) among a substrate, a package and a welding spot is solved, and the solder composition is suitable for high-reliability electronic packages including BGA, CSP and flip chip assemblies.

The invention discloses an electric pulse crack propagation inhibition method for fatigue cracks of an aluminum alloy plate. Preparing an electric pulse applying device (2) and a thermal infrared imager (3); performing electric pulse treatment on the fatigue cracks on the aluminum alloy plate component (1) by adopting an electric pulse applying device; performing real-time temperature monitoring on fatigue cracks on the aluminum alloy plate component by adopting an infrared thermal imager; and the temperature data, monitored in real time, of the fatigue crack is used as feedback data, and parameters for performing electric pulse treatment on the fatigue crack are controlled and adjusted according to the feedback data, so that the peak temperature of the crack tip of the fatigue crack is far lower than the solidus temperature of the aluminum alloy plate component. According to the method for inhibiting crack propagation through the electric pulse, the stress state of the crack tip of the fatigue crack on the aluminum alloy plate component is changed through non-high-temperature electric energy input, and the microstructure passivation of the crack tip is induced, so that the macroscopic propagation rate of the crack in the subsequent fatigue load is effectively reduced, and the purpose of prolonging the service life of the aluminum alloy plate component is achieved.

The invention relates to an aluminum alloy composite material and a preparation method thereof. The preparation method comprises the following steps that a core material and a shell material are mixed and then pressed to obtain a blank; wherein the core material is aluminum alloy particles with hollow core structures inside, the shell material is aluminum alloy powder, and the liquidus Ta of the core material is 30 DEG C or above higher than the liquidus Tm of the shell material; the blank is heated to the temperature T1 of a solid-liquid two-phase region of the shell material under the protective atmosphere, heat preservation is conducted for 20-60 min, and first-stage sintering is completed; then, the temperature is increased to T2, heat preservation is conducted for 10-30 min, and second-stage sintering is completed; wherein T1 = Tm-(0.1-0.5) delta T, and delta T is a temperature difference between a solidus line and a liquidus line of the shell material; t2 = Ta-(0.1-0.3) delta T ', and delta T' is the temperature difference between the solidus and liquidus of the core material.

This application discloses a method for preparing a multilayer composite aluminum alloy for water-cooled plates, comprising: casting a core layer, a first intermediate layer, a second intermediate layer, and a brazing layer respectively; sawing and milling the core layer, the first intermediate layer, the second intermediate layer, and the brazing layer respectively; hot rolling the first intermediate layer, the second intermediate layer, and the brazing layer respectively; performing composite hot rolling, cold rolling, and annealing in the order of brazing layer, first intermediate layer, core layer, and second intermediate layer; brazing the annealed composite material at a temperature of 600-615℃ for a holding time of 6-10 minutes; and artificially aging the material after cooling at an aging temperature of 180-220℃ for a holding time of 60-120 minutes. By optimizing the content and ratio of Mg and Si elements in the core material, the solidus temperature is maximized to ensure that overheating does not occur during brazing.

The application discloses a high-strength cadmium-free low-silver silver brazing filler metal. The silver brazing filler metal is composed of 7.5-8.5% of Ag, 38.5-43.5% of Zn, 14.5-15.5% of Sn, 5.0-5.5% of Ni, 0.0005-0.001% of nano NbBe 12 , 0.0005-0.001% of nano MoBe 12 , and the balance of Cu, wherein the solidus temperature of the silver brazing filler metal is less than or equal to 660 DEG C, and the liquidus temperature is less than or equal to 720 DEG C. When the silver brazing filler metal is used in brazing purple copper-Q235 steel, purple copper-yellow copper, yellow copper-stainless steel with a commercially available FB102 brazing flux, the shear strength of the brazed joint is significantly higher than that of the existing BAg12CuZn(Si) brazing filler metal and BAg5CuZn(Si) brazing filler metal.

The application relates to a pipeline connecting process, a pipeline connecting structure and application thereof. The pipeline connecting process comprises the following steps: taking a copper alloy as cladding material to cladding on the surface of a steel pipe to obtain a copper sleeve, the length of the copper sleeve is less than or equal to the length of a straight section of the steel pipe, and the liquidus temperature of the copper alloy is greater than the solidus temperature. The pipeline connecting process provided by the application has high welding stability, low precision requirement, low defective rate, simple process, low production cost, and the prepared pipeline connecting structure has high stability and simple structure, and is suitable for large-scale production.

This invention discloses a method for preparing a large slag pot trunnion, comprising: (1) heating the steel ingot: heating and holding the steel ingot in sections until the temperature rises to 100-150°C below the solidus temperature of the material, and holding for a certain period of time; (2) forging the trunnion blank: performing a three-upsetting and three-drawing process on the steel ingot, controlling the upsetting reduction rate at 35-50% during upsetting, controlling the height-to-diameter ratio at 2.0-2.5 during the first two drawing processes, then using a triangular knife to press and divide the octagonal blank, and then drawing and rounding each section of the ingot body to the desired length. (3) Heat treatment of trunnion blank: normalizing and tempering are performed on the trunnion blank. When the trunnion blank is taken out of the furnace for normalizing, when it is cooled to the point where the flange starts to turn black, the trunnion is put into water for 3-5 minutes to accelerate the cooling speed of the flange. Then it is taken out of the water and put into the furnace for tempering. (4) Trunnion machining and forming: the heat-treated trunnion blank is machined until the finished size of the trunnion is reached. The trunnion flange prepared by the method of this invention has a fine structure, excellent mechanical properties, and a greatly extended service life.

This invention discloses a high-strength magnesium alloy composite structural component and its preparation method. The component is composed of a wrought magnesium alloy insert and a semi-solid injected magnesium alloy matrix, forming a diffusion-metallurgical bonding interface between them. The preparation method includes: cleaning and micro-roughening pretreatment of the wrought magnesium alloy insert; preheating the insert to 250°C to 50°C below the solidus temperature under a non-oxidizing atmosphere; preparing a semi-solid slurry with a solid fraction of 30%~90% from the magnesium alloy raw material, and injecting it into the mold cavity of the pre-placed insert under a protective atmosphere; after pressure solidification, opening the mold, removing the component, and performing post-processing. This invention utilizes the mechanical crushing effect of the semi-solid slurry on the pre-oxidized layer on the insert surface to achieve a strong metallurgical bond, significantly reducing shrinkage cavities, residual stress, and deformation, while retaining the high strength and high toughness of the wrought magnesium alloy, making it suitable for lightweight thick-walled structural components.

The application discloses a semi-solid thixotropic die casting forming method of a narrow solid-liquid two-phase zone alloy, and comprises the following steps: step one: the narrow solid-liquid two-phase zone alloy is added into a heating device and heated to a superheating temperature, and after complete melting, the alloy is cooled for a certain time to obtain an alloy blank with a cast structure; step two: the alloy blank is added into an extrusion device to complete cold extrusion, and an alloy blank containing high-density dislocations and lattice distortion structures is obtained; step three: the alloy blank is heated for the first time, the heating temperature is set between a recrystallization temperature and a solidus temperature of the alloy, and isothermal heat treatment is carried out to obtain fine and uniform recrystallized grains; step four: the alloy blank is heated for the second time, the temperature is set above the solidus temperature of the narrow solid-liquid two-phase zone alloy, and isothermal heat treatment is carried out to obtain a semi-solid blank; and step five: the semi-solid blank is subjected to die casting forming. The application has the advantages that excellent castings with physical properties are formed.

The present application belongs to the technical field of metal additive manufacturing, and provides a method for regulating mechanical properties of additive manufacturing GH5188 high-temperature alloy by powder surface treatment. The method comprises the following steps: alloy ingot smelting of GH5188 alloy is carried out without adding La-containing alloy and with addition of excessive C element. The base alloy powder is prepared by taking the alloy ingot as raw material. The La2O3 powder and the base alloy powder are introduced into a high-temperature zone by using a high-frequency thermal plasma treatment device, and the temperature is controlled to be between the solidus and the liquidus of the base alloy, so that the surface layer is micro-melted to form a liquid phase. The liquid phase captures the La2O3 powder and rapidly solidifies to obtain an integrated powder with La2O3 powder particles uniformly coated on the surface. Finally, the integrated powder is used as raw material for additive manufacturing. The present application reduces the anisotropy of the additive manufacturing GH5188 high-temperature alloy without changing the standard composition of the material, and the comprehensive mechanical properties are obviously improved.

The present application relates to the field of fuel assembly, especially to a method for welding integral control rod assembly star frame. The method is as follows: TIG fixed point welding is performed on the insertion position of integral handle body branch wing and connecting rod, all welding points are formed by one-time molding without adding wire, each connecting rod has only one TIG welding point, the welding point is located on the outer side of the upper end of the connecting rod and the branch wing contact part, and an integral star frame is obtained; the welding seam of the integral star frame is coated with brazing filler metal, after completing all coating operations, the center cylinder surface of the integral star frame and the conical head of the 24 connecting rods are coated with stop flux, and then dried; the integral star frame is brazed; the brazing condition is that the vacuum degree is below 0.1 Pa, the temperature starts to rise, and the rising speed is controlled to be 15-20 ℃ / min; when the temperature is heated to 50-100 ℃ lower than the solidus temperature of the brazing filler metal, the temperature is kept for 8-15 min; then the temperature is raised to 950-1030 ℃ at a speed of 8-12 ℃ / min, the temperature is kept for 40-60 min at this temperature; finally, the pressure is filled and fast cooled, and the cooling speed is greater than 11 ℃ / min, and the temperature is cooled to 400 ℃; finally, the furnace is cooled to below 120 ℃, and then the furnace is discharged. The present application ensures the positioning accuracy, controls the welding thermal deformation and the brazing seam quality, and meets the use requirements.

One aspect of the present disclosure is an aluminum alloy sheet for a can lid including a silicon (Si) content of 0.20 mass % or more and 0.47 mass % or less; an iron (Fe) content of 0.30 mass % or more and 0.70 mass % or less; a copper (Cu) content of 0.11 mass % or more and 0.40 mass % or less; a manganese (Mn) content of 0.70 mass % or more and 1.20 mass % or less; a magnesium (Mg) content of 1.1 mass % or more and 3.7 mass % or less; and a balance consisting of or including aluminum (Al) and inevitable impurities. The aluminum alloy sheet has a solidus temperature higher than a solid solutionizing temperature of Mg2Si.

The invention discloses a high-heat-conductivity solderable die-casting aluminum alloy and a preparation method and application thereof.The aluminum alloy comprises, by mass, 1.5%-3.5% of Ni, 0.5%-1.5% of Fe, 0.05%-0.5% of Co, smaller than 0.1% of Si, smaller than 0.1% of Mg, smaller than 0.02% of Ti and the balance Al and inevitable impurities, and the die-casting aluminum alloy successfully achieves the high solidus temperature (gt; 635 DEG C), high thermal conductivity (as-cast gt; the flux is 190 W / (m.K), and the flux is gt after brazing; the high-pressure die-casting aluminum alloy has the advantages of high mechanical property, high mechanical property in a casting state and a brazing state and excellent high-pressure die-casting manufacturability, is suitable for high-efficiency die-casting and brazing connection forming of a heat management system of a new energy automobile and the like which require a complex structure, and has a wide application prospect.

The invention discloses a high-temperature alloy blade surface defect in-situ alloying brazing repair method, and belongs to the technical field of high-temperature alloy blade surface defect repair. The repair material consists of Ni (62 to 75 at.%)-Cr (15 to 18 at.%)-Si (10 to 20 at.%) alloy powder and high-temperature alloy base metal powder, wherein the base metal powder accounts for 5 to 30 vol.%. And under the vacuum condition, heating is conducted till the temperature is higher than the repairing temperature of the liquidus of the Ni-Cr-Si alloy and lower than the solidus of the base metal powder, defect gaps are filled with the liquid Ni-Cr-Si alloy, isothermal diffusion occurs between the liquid Ni-Cr-Si alloy and the solid high-temperature alloy powder, and in-situ alloying brazing repairing is achieved. The method has the advantages that (1) the required repairing temperature is low, and the influence on the structure property of the high-temperature alloy base material is small; compared with traditional brazing, components of a repairing area are similar to components of base metal, the heat-resisting temperature is high, and the high-temperature mechanical property is good, compared with TLP, the components of the repairing area are more uniform, the process belongs to a large-area and short-distance rapid diffusion mechanism, the needed time is short, and brazing repairing of large-size cracks and corrosion pits can be achieved.

The casting method includes a pouring step of pouring molten steel and non-ferrous metal into a mold in which a chill is embedded, and a first cooling step of cooling the poured molten metal so as to lower the temperature of the molten metal to the solidus temperature of the molten metal, thereby causing the molten metal to become a solidified body, the volume of the molten metal poured into the mold in the pouring step being 105% or more and 108% or less of the volume of the solidified body, the chill being embedded in the mold in such a manner that the molten metal solidifies from the lower portion to the upper portion in the first cooling step.

The invention provides an aluminum alloy brazing method. The aluminum alloy brazing method comprises the following steps that a workpiece to be welded is placed in a brazing furnace; vacuumizing is performed until the vacuum degree is 0.5-1 Pa; the temperature is increased to be smaller than or equal to a brazing filler metal solidus within the time t1, and heat preservation is conducted for the time T2; the temperature is increased to the brazing temperature larger than or equal to the liquidus of the brazing filler metal and smaller than the solidus of the base metal of the aluminum alloy workpiece within the time length t3, heat preservation is conducted for the time length T4, and brazing is conducted; wherein the ratio range of T2 / t1 is 0.5-2; the ratio range of T4 / t3 is 4-15; and t1 / t3 ranges from 6 to 28. Good aluminum alloy welding quality can be achieved in a low-vacuum environment achieved by only using a secondary pump to vacuumize.

The invention discloses a method for optimizing an iron-nickel-based high-temperature alloy grain boundary carbide for an ultra-supercritical unit pipeline and application, and belongs to the technical field of alloy materials. The grain boundary carbide optimization method comprises the steps that high-temperature solution treatment is conducted, specifically, an iron-nickel-based high-temperature alloy pipe is placed in the temperature range of 140-200 DEG C below the solidus temperature to be subjected to heat preservation treatment, and then water cooling is conducted to the room temperature; the iron-nickel-based high-temperature alloy pipe is placed in the temperature range of 225-315 DEG C below the solidus temperature to be subjected to heat preservation treatment, then water cooling is conducted to the room temperature, and the iron-nickel-based high-temperature alloy pipe with the MC type carbide separated out from the grain boundary is obtained. The MC-type carbide is separated out at the grain boundary of the iron-nickel-based high-temperature alloy pipe, and the carbide is discontinuously separated out in a necklace-shaped form, so that the grain boundary strength is enhanced, the continuous film-forming separation of the brittle M23C6-type carbide on the grain boundary in the later period is inhibited, and the alloy strength and the thermal stability of the grain boundary organization structure are improved.

The invention discloses a cadmium-free low-silver silver solder. The cadmium-free low-silver silver solder is prepared from the following components in percentage by mass: 3.5% to 4.0% of Ag, 39.0% to 44.0% of Zn, 5.0% to 6.0% of Sn, 0.5% to 1.0% of In, 0.5% to 1.0% of Ga, 0.5% to 1.0% of Ni, 0.1% to 0.3% of Te, 0.001% to 0.002% of P, 0.01% to 0.02% of Li, 0.1% to 0.4% of Cr and the balance of Cu. The solidus temperature of the cadmium-free low-silver silver brazing filler metal is smaller than or equal to 695 DEG C, the liquidus temperature of the cadmium-free low-silver silver brazing filler metal is smaller than or equal to 795 DEG C, when the cadmium-free low-silver silver brazing filler metal is matched with commercially available FB102 brazing flux for brazing red copper-brass, red copper-stainless steel and brass-Q235 steel, the shear strength of a brazed joint is better than that of existing BAg20CuZn (Si) brazing filler metal, and the brazing requirements of various structures of materials such as the red copper-brass, the red copper-stainless steel and the brass-Q235 steel can be met.

The application discloses a kind of cadmium-free low silver brazing filler metal.The brazing filler metal is made of 6.0-8.0% Ag, 39.0-43.0% Zn, 13.0-14.5% Sn, 0.05-0.1% In, 0.05-0.1% Ga, 2.5-3.5% Ni, 0.005-0.01% Be, 0.0001-0.0005% nanometer cadmium telluride and the balance of Cu by mass percentage ratio.The solidus temperature of the brazing filler metal is less than or equal to 680 DEG C, and the liquidus temperature is less than or equal to 745 DEG C.When brazing red copper-Q235 steel, red copper-brass, brass-stainless steel with commercially available FB102 flux, the shear strength of the brazed joint is better than that of the existing BAg12CuZn(Si) brazing filler metal and BAg5CuZn(Si) brazing filler metal.

A method is for manufacturing a part including a support provided with at least one hollow filled with an aesthetic element forming a decoration on a face of the part intended to be visible. The method includes providing the support provided with the at least one hollow and providing a preform intended to form the aesthetic element of the part, and inlaying by pressing the preform into the at least one hollow of the support. The preform is made of a crystalline aluminium alloy. The inlaying is carried out at a temperature between the solidus temperature and the liquidus temperature of the crystalline aluminium alloy.

To provide a method for producing an aluminum alloy material by which the aluminum alloy material having excellent brazability can easily be produced.SOLUTION: The method for producing an aluminum alloy material includes a selection step of selecting only an aluminum alloy scrap material having a Mg content of 0.10% by mass or less as a casting raw material A, a casting step of casting an ingot using the casting raw material A and the casting raw material B for addition, and a molding step of molding the ingot to mold an aluminum alloy material having a predetermined composition and a solidus temperature of 600 °C or higher. When a recycle ratio representing a mass ratio of the casting raw material A to the total mass of the ingot is represented by R (%) and a Si content in the casting raw material A is represented by [Si] A in mass%, the recycle ratio R is determined between the selection step and the casting step so that a value calculated by Formula (1): [Si] A * R / 100 is 0.50 or more and 1.10 or less. The casting raw material A contains predetermined amounts of Si and Zn.SELECTED DRAWING: None

The present invention relates to a method of improving the resistance to chipping of a PM cold work tool steel, wherein the steel comprises: 1.2 - 3.5 C; 0.1 - 2.2 Si; 0.1 - 1.0 Mn; 2 - 20 Cr; ≤ 5 Mo; ≤1 W; 1 - 20 V, balance Fe, optional components and impurities. The steel is subjected to conventional gas atomizing and HIP followed by a super-solidus treatment of the HIPed container, which results in an improved compressive yield strength and an improved resistance to chipping. The invention also relates to a steel produced by said method.