KR102323170B1 - Manufacturing method of high-speed tool steel for powder metallurgy - Google Patents

Abstract

The present invention relates to a method for manufacturing high-speed tool steel for powder metallurgy, which enables the production of high-speed tool steel using a powder mixture in order to manufacture high-speed tool steel by powder metallurgy methods. The method for manufacturing high-speed tool steel for powder metallurgy is characterized by: heating a molded material to 1,500℃ and sintering the same for 42-70 hours in a sintering step; molding the sintered material for 40-60 minutes at a high pressure of 1,200 kg/cm^2 to densify the material itself in a hot isostatic treatment step; performing softening heat treatment with workability on the material after the hot isostatic treatment and peeling off an outer skin of the softened material in a softening and peeling treatment step; lapping the processed material to increase a roughness thereof in a lapping step; curing the lapped material by heat treatment at 900-1,100℃ and then heating the same at 500-600℃ in a curing and tempering treatment step; performing final lapping for a surface roughness and burning punched holes after the cruing and tempering treatment in a lapping and burning step; and inspecting the material and dimensions based on specifications of the material in an inspection step.

Description

Manufacturing method of high-speed tool steel for powder metallurgy

The present invention relates to a method of manufacturing high-speed tool steel for powder metallurgy, which enables the production of high-speed tool steel using a powder mixture to manufacture high-speed tool steel (high-speed steel) by powder metallurgy. Carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), chromium (Cr), molybdenum (Mo) while adjusting the particle size of iron (Fe) powder to manufacture high-speed tool steel And vanadium (V) powder is mixed, classified, dried and pulverized to form a powder mixture, and the powder mixture of high-speed tool steel is subjected to molding treatment, sintering treatment, hot isostatic pressure treatment, softening and peeling treatment, processing treatment, lapping treatment, hardening and It relates to a manufacturing method of high-speed tool steel that enables manufacturing of high-speed tool steel through tempering treatment, lapping and burring treatment and inspection steps.

In general, powder metallurgy is manufactured by compacting and sintering metal powder, which is a raw material, and is greatly changed from existing manufacturing methods such as rolling, forging, and casting, so that it is difficult to manufacture tungsten (W) using the existing melting process. ) and high-melting-point metal materials such as molybdenum (Mo), oil-impregnated bearings or multi-tasking materials for filters, cemented carbide and parts such as thermit were made possible through powder metallurgy.

In addition, the powder metallurgy method has advantages in terms of productivity such as improved material yield obtained by non-cutting and high precision that cannot be obtained as a material manufactured by melting, segregation and Since it has various kinds of advantages such as advantages in terms of physical properties such as anisotropy, various kinds of parts manufactured by melting processes are now being manufactured by powder metallurgy.

As prior art related to the conventional method for manufacturing high-speed tool steel, Patent Publication No. 10-0693666 (high-speed steel manufactured by powder metallurgy) and Patent Publication No. 10-0316342 (high-speed tool steel for powder metallurgy) have been proposed.

The former patent is a high-speed steel in wt% 1 to 2.5 C, 1 to 3.5 N, 0.05 to 1.7 Mn, 0.05 to 1.2 Si, 3 to 6 Cr, 2 to 5 Mo, 0.5 to 5 W, 6.2 to 17 (V +2Nb), the remainder having a chemical composition containing iron and standard amounts of unavoidable impurities, and the carbon equivalent Ceq expressed as Ceq = C + (12/14)N and the vanadium equivalent expressed as Veq = V + 2Nb are mutually exclusive In balance, the amounts of the elements expressed in the equivalent weight are within the region A1-B1-C1-D1-A1 in the coordinates of FIG. 1, and points A1 to D1 in the Ceq / Veq coordinates are A1: 4.5/17, B1: 5.5/17 , C1: 2.5/6.2, D1: 1.5/6.2, and in a state in which the steel is hardened and tempered, the high-speed steel is histologically composed of MX-type particles uniformly distributed in the matrix of the steel in 12 to 40% by volume. Including hard phase particles, M in the MX-type hard phase particles is composed of at least one of vanadium and niobium, and X has a structure composed of 30 to 50% by weight of carbon and 50 to 70% by weight of nitrogen.

The latter registered patent is for powder metallurgy high-speed tool steel manufactured by powder manufacturing, canning, high temperature isostatic forming, hot working and heat treatment, C 1.5-2.5wt%, Cr 3-5wt%, W 5-7wt% , Mo 3-6wt%, Co 4-6wt%, V 4-6wt%, Nb 1-2wt%, Si 1wt% or less, Mn 0.6wt% or less The remainder consists of Fe and other unavoidable impurities, and W + 2Mo is 13 -19wt%, Nb + V is 6-8wt%, and the Nb/V ratio is 0.2-0.4.

In the former patent, the powder is pressed to form a compacted body through hot isostatic sintering (HIP) in order to provide high-speed steel for cold working tools having very high resistance to adhesion wear, and then the steel is annealed, rolled and extruded. A mixture of tungsten (W), vanadium (V) and niobium (Nb) in a powder mixture with a high content of nitrogen (N) in the form of a body formed through compaction of alloyed metal powder. wherein the carbon in the mixture is present in a sufficient amount in the steel substrate such that the carbon forms vanadium and niobium carbonitrides with nitrogen and with vanadium and niobium and to provide martensite of the desired hardness obtained after hardening and tempering. it must exist

The latter patent contains niobium and vanadium at the same time, controls the amount of niobium and vanadium to a minimum compared to conventional materials, and appropriately harmonizes the ratio of niobium and vanadium, so that the carbide is refined and the powder has excellent high-temperature hardness and high-temperature stability. In order to provide metallurgical high-speed tool steel, a high content of tungsten, cobalt (Co) and niobium powder is mixed in the powder mixture to produce a round powder by gas injection, and canning, high temperature isostatic forming, hot working (hot forging) , rolling) and heat treatment.

Therefore, the present invention was created for the purpose of solving the above-mentioned problems of the prior art, and while adjusting the particle size of the iron powder, carbon, silicon, manganese, phosphorus, sulfur, chromium, molybdenum and vanadium powder composed of a predetermined weight ratio to the iron powder. Mixing for a certain period of time, classifying, drying and pulverizing to form a powder mixture, forming the powder mixture of the high-speed tool steel, forming treatment step, sintering treatment step, hot isostatic treatment step, softening and peeling treatment step, processing step, lapping treatment step, hardening and a method for manufacturing high-speed tool steel for powder metallurgy capable of manufacturing high-speed tool steel through the tempering treatment step, the lapping and burring treatment step, and the inspection step.

In the present invention, the material formed in the sintering treatment step is heated to 1,500° C. and sintered for 42-70 hours, and the material sintered in the hot isostatic pressure treatment step is molded for 40-60 minutes at 1,200 kg/cm 2 high pressure for densification of the material itself. In the softening and peeling treatment step, after hot isostatic pressure treatment, softening heat treatment with workability, peeling the outer skin of the softened material, and lapping to increase the roughness of the processed material in the lapping step, and lapping in the hardening and tempering treatment step After hardening with heat treatment of 900-1,100℃, heating to 500-600℃, after curing and tempering in the lapping and burning processing step, finally lapping the surface roughness and burning the perforated ball, according to the specifications of the material in the inspection step It is characterized in that it is made by inspecting the dimensions and materials.

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Therefore, in the present invention, a powder mixture consisting of carbon, silicon, manganese, phosphorus, sulfur, chromium, molybdenum and vanadium powder composed of a predetermined weight % and iron powder with the remainder being molded, sintered, hot isostatically treated, softened and peeled High-speed tool steel is manufactured through processing, lapping, hardening and tempering, lapping and burring, and inspection steps, so it has excellent abrasion resistance and low friction coefficient. Because it can be machined before heat treatment, it has excellent machinability and can reduce processing costs. it will work

1 is a flowchart showing the overall process steps of the present invention;

Hereinafter, the configuration and operation of the subject matter of the present invention will be described in detail in connection with the accompanying drawings.

1 is a flowchart showing the entire process of the present invention; The manufacturing method of the high-speed tool steel through the processing step, the lapping step, the hardening and tempering treatment step, the lapping and burring treatment step, and the inspection step is shown.

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79.01-82.50wt% of iron powder is added to control the particle size while carbon (C) 1.75-1.98wt%, silicon (Si) 0.10-0.80wt%, manganese (Mn) 1.00-1.20wt%, phosphorus (P) 0.01 -0.03wt%, sulfur (S) 0.01-0.03wt%, chromium (Cr) 5.15-5.45wt%, molybdenum (Mo) 1.25-1.50wt% and vanadium (V) 8.00-10.00wt% powder are added for a certain time Mixing raw material input, milling and mixing treatment step, classification, drying and pulverization treatment step, molding treatment step, sintering treatment step, hot isostatic treatment step, softening and peeling treatment step, processing treatment step, lapping treatment step, hardening and tempering treatment In the manufacturing method of high-speed tool steel for powder metallurgy through the step, the lapping and burning processing step and the inspection step,

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The material formed in the sintering treatment step is heated to 1,500° C. and sintered for 42-70 hours, and the material sintered in the hot isostatic pressure treatment step is molded for 40-60 minutes at 1,200 kg/cm 2 high pressure for densification of the material itself. In the softening and peeling treatment step, after hot isostatic pressure treatment, softening heat treatment with workability, peeling the outer skin of the softened material, and lapping treatment to increase the roughness of the material processed in the lapping treatment step, and lapping treatment in the hardening and tempering treatment step After curing the material by heat treatment at 900-1,100℃, heating it to 500-600℃, after curing and tempering in the lapping and burning processing step, finally wrapping the surface roughness, burning the perforated ball, and in the inspection step It is made by inspecting the dimensions and materials according to the standard.

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As described above, the present invention has excellent wear resistance of high-speed tool steel manufactured by powder metallurgy, and low friction coefficient enables cost reduction and product weight reduction when the product of the same volume is applied. In order to provide a powder mixture of high-speed tool steel that not only reduces processing costs, has excellent dimensional stability due to low dimensional deformation before and after heat treatment, and does not have any internal air bubbles by heat treatment, and a method for manufacturing the same, A powder mixture in which the composed carbon, silicon, manganese, phosphorus, sulfur, chromium, molybdenum and vanadium powders are mixed for a certain period of time is formed, and the powder mixture is subjected to a molding treatment step, a sintering treatment step, a hot isostatic treatment step, a softening and peeling treatment step, An object of the present invention is to provide a method of manufacturing high-speed tool steel for powder metallurgy, which can be manufactured through a processing step, a lapping treatment step, a hardening and tempering treatment step, a lapping and burring treatment step, and an inspection step.

The present invention is a method for manufacturing high-speed tool steel using a powder mixture for manufacturing high-speed tool steel. The powder mixture of high-speed tool steel is iron powder with a predetermined weight% of carbon, silicon, manganese, phosphorus, sulfur, chromium, molybdenum and vanadium powder. It is made by mixing for a certain time, classifying, drying and pulverizing, and as shown in FIG. 1 , the method for manufacturing high-speed tool steel of the present invention includes raw material input, milling and mixing treatment steps, classification, drying and pulverization treatment steps, molding treatment steps , sintering treatment step, hot isostatic treatment step, softening and peeling treatment step, processing step, lapping treatment step, hardening and tempering treatment step, lapping and burring treatment step and inspection step.

The powder mixture for producing the high-speed tool steel for powder metallurgy is carbon (C) 1.75-1.98 wt%, silicon (Si) 0.10-0.80 wt%, manganese (Mn) 1.00-1.20 wt%, phosphorus (P) 0.01-0.03 wt%, sulfur (S) 0.01-0.03 wt%, chromium (Cr) 5.15-5.45 wt%, molybdenum (Mo) 1.25-1.50 wt% and vanadium (V) 8.00-10.00 wt% iron (Fe) powder 79.01- It is composed of 82.50 wt%.

The powder mixture is made by mixing carbon, silicon, manganese, phosphorus, sulfur, chromium, molybdenum and vanadium powders for a certain period of time while adjusting the particle size of the iron powder, followed by classification, drying and pulverization.

In the manufacturing method for manufacturing high-speed tool steel for powder metallurgy, the raw material input, milling and mixing treatment steps are performed by quantitatively inputting iron powder and adjusting the particle size through milling, and then carbon, silicon, manganese, phosphorus, sulfur, chromium, molybdenum. and mixing the vanadium powder in a predetermined weight ratio for a predetermined time.

The weight ratio of each powder in the raw material input, milling and mixing treatment step is iron powder 79.01-82.50wt%, carbon powder 1.75-1.98wt%, silicon powder 0.10-0.80wt%, manganese powder 1.00-1.20wt%, phosphorus powder 0.01 -0.03wt%, sulfur powder 0.01-0.03wt%, chromium powder 5.15-5.45wt%, molybdenum powder 1.25-1.50wt% and vanadium powder 8.00-10.00wt% are preferably mixed.

In the classification, drying and pulverization treatment step, the mixed raw material of the material that has been subjected to the raw material input, milling and mixing treatment steps is separated from the ball, the nucleic acid is dried, and then pulverized in a pulverizer and sent to a post-process.

The molding processing step is a step of molding the classified, dried and pulverized materials to meet the required specifications.

In the sintering treatment step, the molded material is heated to a high temperature of 1,500° C. and sintered for 42-70 hours.

The hot isostatic treatment step is a step of densifying the material itself by molding the sintered material at a high pressure of 1,200 kg/cm 2 for 40-60 minutes.

The softening and peeling treatment step is a step of performing softening heat treatment with a material having workability after sintering, and performing peeling operations on the outer skin of the softened material by lathe and milling.

The processing step is a step of processing through lathe, milling, and polishing operations according to the specifications of the material after softening and peeling treatment.

The lapping step is a step of improving the roughness by applying a wrap to the surface of the processed material and hitting the abrasive to precisely finish the surface of the material.

In the hardening and tempering treatment step, when the lapped material is hardened through heat treatment at 900-1,200°C, and then heated to 500-600°C to remove thermal stress to make the material uniform, alloy carbides are finely precipitated instead of cementite. to perform tempering to harden.

In the lapping and burning process step, in order to finally improve the surface roughness of the material, a lap is applied to the surface of the material and an abrasive is applied to precisely finish the surface of the material to improve the surface roughness, and the perforated ball of the material is burned with a press punch. This is the step to get the job done.

The inspection step is to determine whether or not the material is manufactured with dimensions and materials that meet specifications such as density, Rockwell hardness, modulus of elasticity, tensile strength, and tensile strength of the material, and then shipped.

The density (g/cm2) of the high-speed tool steel prepared as described above was 7.43, the annealing of the Rockwell 'C' hardness (HRC) was 25-28, the hardening was 53-59, the modulus of elasticity (Gpa) was 219, the tensile strength ( kg/㎟) is 603-618, and tensile strength (kg/㎟) can maintain the range of 93-109, so it has excellent wear resistance of high-speed tool steel and low friction coefficient to reduce cost and reduce product weight when applying the same volume product. It can be machined before heat treatment, so it has excellent machinability and can reduce processing costs. It was possible to provide a method for manufacturing high-speed tool steel.

The present invention is not limited to the specific preferred embodiments described above, and various modifications can be made by anyone skilled in the art without departing from the gist of the present invention as claimed in the claims. and such modifications are intended to be within the scope of the claims.

Claims (3)

delete 79.01-82.50wt% of iron powder is added to adjust the particle size while carbon (C) 1.75-1.98wt%, silicon (Si) 0.10-0.80wt%, manganese (Mn) 1.00-1.20wt%, phosphorus (P) 0.01 -0.03wt%, sulfur (S) 0.01-0.03wt%, chromium (Cr) 5.15-5.45wt%, molybdenum (Mo) 1.25-1.50wt% and vanadium (V) 8.00-10.00wt% powder are added for a certain time Mixing raw material input, milling and mixing treatment step, classification, drying and pulverization treatment step, molding treatment step, sintering treatment step, hot isostatic treatment step, softening and peeling treatment step, processing treatment step, lapping treatment step, hardening and tempering treatment In the manufacturing method of high-speed tool steel for powder metallurgy through the step, the lapping and burning processing step and the inspection step,
The material formed in the sintering treatment step is heated to 1,500° C. and sintered for 42-70 hours, and the material sintered in the hot isostatic pressure treatment step is molded for 40-60 minutes at 1,200 kg/cm 2 high pressure for densification of the material itself, and In the softening and peeling treatment step, after hot isostatic pressure treatment, softening heat treatment with workability, peeling the outer skin of the softened material, and lapping treatment to increase the roughness of the material processed in the lapping treatment step, and lapping treatment in the hardening and tempering treatment step After curing the material by heat treatment at 900-1,100°C, heating it to 500-600°C, after curing and tempering treatment in the lapping and burning treatment step, finally wrapping the surface roughness and burning the perforated ball, and the material in the inspection step A method of manufacturing high-speed tool steel for powder metallurgy, characterized in that it is made by inspecting dimensions and materials according to the standard of delete

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