WO2024070413A1 - Matériau de barre en acier inoxydable martensitique à coupe libre et son procédé de production - Google Patents

Matériau de barre en acier inoxydable martensitique à coupe libre et son procédé de production Download PDF

Info

Publication number
WO2024070413A1
WO2024070413A1 PCT/JP2023/031185 JP2023031185W WO2024070413A1 WO 2024070413 A1 WO2024070413 A1 WO 2024070413A1 JP 2023031185 W JP2023031185 W JP 2023031185W WO 2024070413 A1 WO2024070413 A1 WO 2024070413A1
Authority
WO
WIPO (PCT)
Prior art keywords
less
cutting
carbide
stainless steel
steel bar
Prior art date
Application number
PCT/JP2023/031185
Other languages
English (en)
Japanese (ja)
Inventor
義洋 岡
光司 高野
雅之 天藤
利治 間曽
Original Assignee
日鉄ステンレス株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日鉄ステンレス株式会社 filed Critical 日鉄ステンレス株式会社
Publication of WO2024070413A1 publication Critical patent/WO2024070413A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur

Definitions

  • the present invention relates to a martensitic free-cutting stainless steel bar material with excellent machinability that suppresses tool wear and built-up edges and is used for materials cut into small parts that require corrosion resistance, and to a method for manufacturing the same.
  • High-hardness, corrosion-resistant martensitic stainless steels with a hardness of 400Hv or more are used in industrial equipment and precision equipment parts because of their wear resistance, fatigue strength, and corrosion resistance.
  • Precision equipment parts which are cut from polished bars made from wire rods, are often used as rotating bodies, so they require particularly precise cutting workability.
  • tool wear during cutting is required to be small at 200 ⁇ m or less, and after cutting, the cutting surface must be smooth enough that minute built-up edge marks can be seen here and there.
  • Tool wear is accelerated by hard precipitates and inclusions present in the workpiece. Built-up edges are deposits that form and grow on the tip of the cutting tool due to adhesion of the base material. They fall off from the tip of the tool during cutting and are pressed onto the cutting surface, degrading the quality of the cutting surface.
  • a martensitic free-cutting stainless steel with improved wear resistance and machinability has been proposed by adding S to high-hardness, high-corrosion-resistant martensitic stainless steel and defining the sulfide composition and size and carbide size (Patent Document 1).
  • Patent Document 1 A martensitic free-cutting stainless steel with improved wear resistance and machinability has been proposed by adding S to high-hardness, high-corrosion-resistant martensitic stainless steel and defining the sulfide composition and size and carbide size (Patent Document 1).
  • Patent Document 1 A martensitic free-cutting stainless steel with improved wear resistance and machinability
  • Patent Document 2 a steel has been proposed in which the average equivalent circle diameter of carbides and the cleanliness of inclusions are specified to improve cold workability and machinability.
  • Patent Document 2 improves machinability and cold workability through low hardness by setting the average equivalent circle diameter of carbides to 0.25 ⁇ m or more and 0.8 ⁇ m or less.
  • coarse carbides with an average equivalent circle diameter of carbides exceeding 0.8 ⁇ m deteriorate machinability by promoting tool wear, and it is said that when the average equivalent circle diameter of carbides is less than 0.25 ⁇ m, the hardness is high and the effect of improving machinability cannot be obtained.
  • the cutting surface properties there is no mention of the cutting surface properties.
  • the inventors have found that the known techniques described in the background art above or combinations of these techniques are unable to achieve excellent tool life by suppressing tool wear during cutting to 200 ⁇ m or less in high-hardness, highly corrosion-resistant martensitic free-cutting stainless steels that have been given excellent machinability, and furthermore are unable to achieve both tool life and excellent smooth surface properties by suppressing built-up cutting edge marks.
  • the problem to be solved by the present invention is to provide a high-hardness, high-corrosion-resistant martensitic free-cutting stainless steel bar material, which is suitable for use in precision parts made of martensitic stainless steel used in severely corrosive environments, has excellent tool life during cutting, and preferably is capable of producing cutting surface properties with excellent flatness during cutting, and a method for producing the same.
  • the inventors conducted various studies on S-containing martensitic free-cutting stainless steel that can achieve a high hardness of 400 Hv or more by quenching. As a result, they discovered that controlling the average circle equivalent diameter and number density of Cr carbides can provide excellent tool life during precision cutting, and more preferably, controlling the average circle equivalent diameter and number density of sulfides can suppress built-up cutting edge marks and provide surface properties with excellent smoothness.
  • the present invention has been made based on the above findings, and the gist of the present invention is as follows.
  • [1] Having a chemical composition consisting of, in mass%, C: 0.10 to 0.60%, Si: 0.1 to 2.0%, Mn: 0.1 to 3.0%, S: 0.15 to 0.40%, P: 0.10% or less, Cr: 11.0 to 16.0%, the balance Fe and impurities;
  • a martensitic free-cutting stainless steel bar material characterized in that the average Cr carbide equivalent circle diameter is 0.80 ⁇ m or less and the Cr carbide number density is 0.10 particles/ ⁇ m2 or more.
  • the chemical components of the steel are, in mass %, substituted for a portion of the Fe, and include B: 0.01% or less, N: 0.15% or less, Al: 0.008% or less, O: 0.015% or less, Ni: 1.5% or less, Cu: 1.5% or less, Co: 1.5% or less, Mo: 2.5% or less, W: 2.5% or less, Bi: 0.2% or less, Sn: 0.3% or less, Sb: 0.3% or less, Ag: 0.3% or less, T
  • the martensitic free-cutting stainless steel bar according to [1] or [2], characterized in that it contains one or more selected from the group consisting of e: 0.1% or less, V: 0.8% or less, Nb: 0.3% or less, Ti: 0.3% or less, Ta: 0.3% or less, Mg: 0.01% or less, Ca: 0.01% or less, Hf: 0.01% or less, and REM: 0.05% or less.
  • [4] A method for producing martensitic free-cutting stainless steel bar material according to [1] or [2], characterized in that the finish rolling temperature of the hot working is 800 to 1150°C, and after the hot working, batch annealing is performed in which the material is held at 700 to 900°C for 60 to 300 minutes and cooled to 600°C at a rate of 20 to 200°C/h, or strand annealing is performed at 700 to 850°C and held for 30 to 1000 seconds in addition to the batch annealing.
  • the present invention provides a martensitic free-cutting stainless steel bar material that provides a good cutting tool life and excellent flat cutting surface properties with reduced built-up cutting edge marks, and is suitable for precision parts with high hardness and excellent corrosion resistance, as well as a method for manufacturing the same.
  • the present invention is intended for parts having a hardness of 400 Hv or more, which is generally effective for wear resistance, and is based on high-hardness martensitic free-cutting stainless steel that exhibits at least 400 Hv in a quenched state.
  • C is contained at 0.10% or more to ensure that the hardness of the base material after quenching is 400Hv or more.
  • the C content exceeds 0.60%, the average Cr carbide circle equivalent diameter exceeds 0.8 ⁇ m, and the cutting tool life is deteriorated. Therefore, the C content is limited to 0.60% or less.
  • the preferred range is 0.20-0.50%.
  • Si is contained at 0.1% or more to suppress the formation of coarse inclusions that deoxidize and reduce the life of cutting tools.
  • the Si content exceeds 2.0%, the tool hardens and the life of the cutting tool decreases, and it also promotes adhesion of the base material to the tool, promoting the formation of built-up cutting edge marks. For this reason, the Si content is limited to 2.0% or less. The preferred range is 0.2 to 1.0%.
  • Mn is contained at 0.1% or more to suppress the formation of coarse inclusions that deoxidize and reduce the life of cutting tools, and to form sulfides to ensure good cutting surface properties.
  • the Mn content exceeds 3.0%, the material will harden, reducing the life of the cutting tool, and the average sulfide circle equivalent diameter will exceed 5 ⁇ m, degrading the cutting surface properties.
  • the Mn content is limited to 3.0% or less. The preferred range is 0.2 to 2.0%.
  • S forms sulfides to ensure good cutting tool life and cutting surface properties, so it is contained at 0.15% or more.
  • the S content exceeds 0.40%, the material will harden, deteriorating cutting tool life, and the average sulfide circle equivalent diameter will exceed 5 ⁇ m, deteriorating cutting surface properties. For this reason, the S content is limited to 0.40% or less. The preferred range is 0.17 to 0.35%.
  • the P is mixed in as an unavoidable impurity from the raw materials, but if it is contained in excess of 0.10%, not only does it deteriorate corrosion resistance due to grain boundary segregation, but it also significantly reduces manufacturability. For this reason, the P content is limited to 0.10% or less. Preferably, it is 0.05% or less.
  • Cr is a basic element for achieving the corrosion resistance function of stainless steel, and is contained at 11.0% or more. However, if the Cr content exceeds 16.0%, it becomes impossible to ensure a hardness of 400 Hv or more after quenching. Therefore, the Cr content is limited to 16.0% or less. The preferred range is 11.5 to 15.0%.
  • the average Cr carbide circle equivalent diameter is limited to 0.80 ⁇ m or less, and the Cr carbide number density is limited to 0.10 pieces/ ⁇ m2 or more.
  • the average Cr carbide circle equivalent diameter is 0.70 ⁇ m or less, and the Cr carbide number density is 0.20 pieces/ ⁇ m2 or more.
  • Sulfides are effective in forming starting points for cutting chips during cutting, suppressing the generation of built-up edges and obtaining good surface properties.
  • the stainless steel of the present invention is composed of chemical components consisting of Fe and impurities other than the elements mentioned above. Furthermore, in addition to the above-mentioned composition, the following elements may be selectively contained in place of a portion of Fe.
  • B may be included as necessary, since, when included together with N, it forms fine BN, suppresses adhesion of the base material to the tool surface, and prevents built-up edge marks on the cutting surface.
  • the B content exceeds 0.01%, coarse borides are generated, shortening the cutting tool life and promoting the generation of built-up edges. For this reason, the B content is limited to 0.01% or less. To ensure the above effects, it is preferable to limit the B content to 0.002% or more and 0.007% or less.
  • N not only forms fine BN to prevent cutting edge marks on the cutting surface, but also increases the hardness of the base material after quenching, so it may be included as necessary. However, if the N content exceeds 0.15%, coarse nitrides are formed, reducing the cutting tool life. For this reason, the N content is set to 0.15% or less. To ensure the above effect, it is preferable to set the N content to 0.03% or more and 0.10% or less.
  • Al may be included for deoxidation, but if it is included in excess of 0.008%, coarse inclusions will form and the cutting tool life will be reduced. Therefore, the Al content is limited to 0.008% or less. Preferably, it is 0.006% or less.
  • O is mixed in as an unavoidable impurity, but if it is contained in excess of 0.015%, coarse inclusions form, reducing the life of the cutting tool. Therefore, the O content is limited to 0.015% or less. Preferably, it is 0.012% or less.
  • Ni, Cu and Co may be included as necessary to improve the corrosion resistance and toughness of the product. However, if each of them is included at more than 1.5%, it will deteriorate the cutting tool life. Therefore, the content of each element is limited to 1.5% or less. To ensure the above effects, it is preferable to limit the content of each element to 0.01% or more and 1.0% or less.
  • Mo and W may be included as necessary to improve the corrosion resistance of the product. However, if each is included at more than 2.5%, the effect saturates and the cutting tool life is deteriorated. Therefore, the content of each element is limited to 2.5% or less. To ensure the above effects, it is preferable to limit the content of each element to 0.01% or more and 2.0% or less.
  • Bi acts as a self-lubricant during cutting, suppressing the formation of built-up edges and improving the cutting surface properties, so it may be included as necessary. However, if it is included in an amount exceeding 0.2%, hot manufacturability is significantly deteriorated, making it impossible to manufacture. Therefore, the Bi content is limited to 0.2% or less. To ensure the above effects, it is preferable to limit the Bi content to 0.005% or more and 0.10% or less.
  • Sn, Sb and Ag act as self-lubricants during cutting, suppressing the formation of built-up edges and improving the cutting surface properties, so they may be included as necessary.
  • the content of each element is limited to 0.3% or less. To ensure the above effects, it is preferable to limit the content of each element to 0.005% or more and 0.20% or less.
  • Te may be included as necessary, as it produces spherical sulfides, inhibits the stacking and growth of the cutting edge, and improves the cutting surface properties. However, if it is included in an amount exceeding 0.1%, hot manufacturability is significantly deteriorated, making it impossible to manufacture. Therefore, the Te content is limited to 0.1% or less. To reliably obtain the above effects, it is preferable to limit the Te content to 0.005% or more and 0.05% or less.
  • V may be included as necessary to improve the corrosion resistance of the product. However, if it is included in excess of 0.8%, coarse carbonitrides are formed, which reduces the life of the cutting tool. For this reason, the V content is limited to 0.8% or less. To ensure the above effects, it is preferable to limit the V content to 0.05% or more and 0.5% or less.
  • Nb, Ti and Ta may be included as necessary to improve the corrosion resistance of the product.
  • each of these elements is included in an amount exceeding 0.3%, coarse carbonitrides are formed, which reduces the cutting tool life. Therefore, the content of each element is limited to 0.3% or less. To ensure the above effects, it is preferable to limit the content of each element to 0.01% or more and 0.2% or less.
  • Mg, Ca and Hf have the effect of improving hot workability and may be included as necessary.
  • the content of each element is limited to 0.01% or less. To ensure the above effects, it is preferable to limit the content of each element to 0.001% or more and 0.005% or less.
  • REM has the effect of improving hot workability, so it may be included as necessary. However, if the REM content exceeds 0.05%, the effect saturates and coarse oxides are generated, deteriorating the cutting tool life. Therefore, the REM content is limited to 0.05% or less. To reliably obtain the above effect, it is preferable to keep the REM content between 0.001% and 0.005%.
  • REM rare earth elements refers to two elements, scandium (Sc) and yttrium (Y), and 15 elements (lanthanoids) from lanthanum (La) to lutetium (Lu). They may be included alone or as a mixture.
  • Representative impurities contained in the stainless steel of the present invention include Zn, Pb, Ge, Se, etc., and these are usually mixed in at about 0.1% as impurities during the steel manufacturing process.
  • the impurity oxygen exists in steel mainly as inclusions, and the oxygen content of stainless steel produced by conventional refining is between 0.001 and 0.015%.
  • Representative elements for the selective inclusion are specified in (3) above, but elements not listed in this specification may also be included within a range that does not impair the effects of the present invention.
  • finishing rolling temperature for hot working is less than 800°C, the rolling load will be high, which will reduce manufacturability.
  • the finishing rolling temperature exceeds 1150°C, the Cr carbides will become coarse and the above-mentioned average Cr carbide circle equivalent diameter condition will no longer be met. Therefore, the finishing rolling temperature for hot working is specified as 800 to 1150°C.
  • the annealing temperature is lower than 700°C and the batch annealing holding time is shorter than 60 minutes, the annealing will be insufficient and manufacturability will decrease.
  • the batch annealing temperature is higher than 900°C, the batch annealing holding time is longer than 300 minutes, and the cooling rate to 600°C after the end of holding is slower than 20°C/h, the Cr carbides will coarsen and will no longer satisfy the above-mentioned circle equivalent diameter.
  • the cooling rate is faster than 200°C/h, the material will harden due to martensite transformation, making it more likely to cause delayed fracture, etc. There is no need to particularly limit the cooling rate below 600°C.
  • the batch annealing conditions are the same as those for batch annealing alone.
  • strand annealing temperature is lower than 700°C and the strand annealing holding time is shorter than 30 seconds, annealing will be insufficient and manufacturability will decrease.
  • the strand annealing temperature is higher than 850°C and the strand annealing holding time is longer than 1000 seconds, not only will the Cr carbides become coarse and no longer satisfy the above-mentioned circle equivalent diameter, but they will also exceed the Ac1 point and undergo martensite transformation upon cooling, hardening them and making them more susceptible to delayed fracture, etc.
  • the hot working finishing rolling temperature is limited to 800-1150°C
  • batch annealing conditions are 700-900°C held for 60-300 minutes with a cooling rate to 600°C of 20-200°C/h
  • strand annealing conditions are 700-850°C held for 30-1000 seconds.
  • the finish rolling temperature is preferably less than 1000°C, and more preferably less than 900°C.
  • the finish rolling temperature is 850°C or more and less than 900°C
  • the batch annealing conditions are 750 to 850°C, held for 90 to 200 minutes, and a cooling rate of 30 to 100°C/h to 600°C after holding
  • the strand annealing conditions are 750 to 825°C, held for 40 to 800 seconds.
  • Strand annealing is an annealing method in which wire rod or steel wire coil wound in a ring shape is unrolled into a straight line and heat-treated for a short time in a single straight line (in an atmosphere of nitrogen, Ar, ammonia decomposition gas, etc.), and then air-cooled or indirectly water-cooled. This makes it possible to achieve a significantly faster cooling rate than batch annealing of the entire ring-shaped coil.
  • the area reduction rate of cold working such as cold wire drawing becomes higher than about 70%, defects such as cracks may occur due to work hardening. To prevent this, cold working such as cold wire drawing and annealing may be repeated multiple times. In this case, the annealing performed between cold working steps must be performed under the annealing conditions described in the above "Cr carbide control method" in order to control Cr carbides.
  • the above area reduction rate of cold working such as cold wire drawing is the sum of the area reduction rates of each cold working performed multiple times.
  • martensitic stainless steel refers to steel that hardens due to martensitic transformation during quenching.
  • bar-shaped steel material includes “steel bar,” “wire rod,” “wire rod,” “steel wire,” “deformed wire,” and “deformed steel bar.”
  • Example 1 In order to investigate the effect of the components, steels having the chemical compositions shown in Tables 1 to 3 were melted at 1600 ° C in a 45 kg vacuum melting furnace and then cast into a mold. After that, the steels were heated to 1200 ° C and then hot rolled at a finish rolling temperature of 880 ° C to obtain wire rods having a diameter of ⁇ 5.5 mm, and cooled to room temperature. Then, batch annealing was performed under the conditions of an annealing temperature of 850 ° C, a holding time of 180 minutes, and a cooling rate of 50 ° C / h to 600 ° C after holding.
  • the wire rods obtained in this manner were evaluated using the following evaluation methods for the average Cr carbide circle equivalent diameter, Cr carbide number density (number per unit area), average sulfide circle equivalent diameter, sulfide number density, tool life after peripheral cutting, and surface properties.
  • the results are shown in Tables 4 to 6.
  • Tables 4 and 5 show the evaluation results of the examples of the present invention, and Table 6 shows the evaluation results of the comparative example.
  • Hardened hardness was evaluated by quenching from 1,050°C with air cooling, with a value of 400 Hv or more considered good. Corrosion resistance was evaluated by conducting an acetic acid salt spray test for 48 hours, with a value of good if there was no trace of rust. If either the hardened hardness or corrosion resistance did not meet the good standard, the notes stated “poor hardened hardness” or “poor corrosion resistance,” and no other evaluation was performed. Furthermore, if the product could not be manufactured for any reason, it was noted “unmanufacturable,” and no quality evaluation was performed.
  • the specimen was embedded in resin so that the longitudinal section of the wire rod was the test surface, and the test surface was mirror-polished and then etched with aqua regia. An area of 100 ⁇ m2 was observed in five fields of view with a SEM. Among the inclusions in the field of view, inclusions in which a large amount of Cr and C was detected by EDX analysis were identified as Cr carbides.
  • the average Cr carbide circle equivalent diameter was calculated by calculating the circle equivalent diameter for each of 100 or more Cr carbides and averaging the circle equivalent diameters.
  • the Cr carbide number density was calculated by measuring the total number of Cr carbides in the five fields of view and converting it into the number of Cr carbides per 1 ⁇ m2.
  • the sample was embedded in resin so that the longitudinal section of the wire rod was the test surface, and the test surface was mirror-polished, and then five fields of view with an area of 3 mm2 were observed with a SEM. Among the inclusions in the field of view, inclusions in which a large amount of S was detected by EDX analysis were identified as sulfides.
  • the average sulfide circle equivalent diameter was calculated by calculating the circle equivalent diameter of 100 or more sulfides and averaging the circle equivalent diameters.
  • the sulfide number density was calculated by measuring the total number of sulfides in the five fields of view and converting it into the number of sulfides per 1 ⁇ m2.
  • Cutting tool life The outer circumference of the wire rod was cut in the circumferential direction for 1 hour under the following precision cutting conditions: Tool used: Carbide P type, cutting edge R 0.03 mm, cutting speed: 20 m/min, feed rate: 0.01 mm/rev, depth of cut: 0.1 mm, cutting oil (mineral oil): present.
  • Tool used Carbide P type, cutting edge R 0.03 mm, cutting speed: 20 m/min, feed rate: 0.01 mm/rev, depth of cut: 0.1 mm, cutting oil (mineral oil): present.
  • the tool after cutting was observed under an optical microscope at 200x magnification. If the boundary wear width of the tool after cutting was 100 ⁇ m or less, it was evaluated as "S”, if it was more than 100 ⁇ m and less than 200 ⁇ m, it was evaluated as "G”, and if it was more than 200 ⁇ m, it was evaluated as "X”.
  • Cutting surface properties carbide P type, cutting edge R 0.03 mm, cutting speed: 20 m/min, feed rate: 0.
  • the outer circumference of the wire rod was cut in the circumferential direction for 1 hour under the precision cutting conditions of 0.01 mm/rev, depth of cut: 0.1 mm, and cutting oil (mineral oil): present.
  • the surface of the wire rod after cutting was observed under an optical microscope at 100x magnification. The surface was rated as "X" when clear built-up edge marks were observed, "G” when minute built-up edge marks were scattered, and "S” when no clear marks were observed.
  • Inventive Examples 1 to 57 in Tables 4 and 5 have an average Cr carbide circle equivalent diameter of 0.80 ⁇ m or less, a Cr carbide number density of 0.10 pieces/ ⁇ m2 or more, an average sulfide circle equivalent diameter of 5.0 ⁇ m or less, and a sulfide number density of 0.010 pieces/ ⁇ m2 or more, and all of them exhibit excellent cutting tool life and cutting surface properties.
  • Comparative Examples 1 to 33 in Table 6 are outside the composition range of the present invention and are unable to satisfy both excellent cutting tool life and cutting surface properties. Even when the average sulfide circle equivalent diameter and sulfide number density were within the preferred range, the cutting surface properties deteriorated in accordance with the deterioration of cutting tool life.
  • Example 2 In order to evaluate the influence of the manufacturing process, steel having the chemical composition shown in Steel C in Table 1 was melted at 1600°C in a 45 kg vacuum melting furnace and cast into a mold. The manufacturing conditions are shown in Table 7. As hot working, the steel was heated to 1200°C, and then hot rolled at a finish rolling temperature of 760 to 1170°C to obtain a wire rod having a diameter of ⁇ 5.5 to 40.0 mm, and cooled to room temperature. Thereafter, batch annealing was performed alone, or in addition to batch annealing, strand annealing was performed.
  • the annealing temperature was 650 to 950°C, the holding time was 40 to 360 minutes, and the cooling rate to 600°C after holding was in the range of 10 to 250°C/h.
  • the annealing temperature was 680 to 870°C, and the holding time was in the range of 20 to 1200 seconds.
  • cold wire drawing was performed at a reduction in area of 19.0 to 99.4%, and then straightening and centerless grinding were performed to finish the wire into a polished bar (wire rod) of ⁇ 3.0 mm, which was used as a cutting material.
  • Example 58 of the present invention a wire rod of ⁇ 5.5 was used, and cold wire drawing was not performed, but it was finished into a polished bar (wire rod) of ⁇ 3.0 mm by centerless grinding, which was used as a cutting material. Thereafter, the average Cr carbide circle equivalent diameter, Cr carbide number density, average sulfide circle equivalent diameter, sulfide number density, tool life after peripheral cutting, and surface properties were evaluated using the same evaluation method as in Example 1. The results are shown in Table 7.
  • Inventive Examples 58 and 59 in Table 7 have an average Cr carbide circle equivalent diameter of 0.80 ⁇ m or less and a Cr carbide number density of 0.10 pieces/ ⁇ m2 or more, and show excellent cutting tool life. Note that in Inventive Example 58, cold wire drawing was not performed, and in Inventive Example 59, the wire drawing area reduction rate of the cold wire drawing was outside the lower limit of the preferred range of the present invention, and as a result, the average sulfide circle equivalent diameter and sulfide number density were outside the preferred range, and it was not possible to satisfy excellent cutting surface properties.
  • Examples 60 to 67 of the present invention have an average Cr carbide circle equivalent diameter of 0.80 ⁇ m or less, a Cr carbide number density of 0.10 pieces/ ⁇ m2 or more, an average sulfide circle equivalent diameter of 5.0 ⁇ m or less, and a sulfide number density of 0.010 pieces/ ⁇ m2 or more, and all of them have excellent cutting tool life and excellent cutting surface properties.
  • Comparative Examples 34 to 45 in Table 7 the manufacturing conditions were outside the preferred conditions of the present invention, and either manufacturing was impossible, or even if manufacturing was possible, the average Cr carbide circle equivalent diameter and Cr carbide number density were outside the range of the present invention. As a result, it was not possible to satisfy both excellent cutting tool life and cutting surface properties. Furthermore, in Comparative Example 46, the wire drawing area reduction rate was outside the upper limit of the preferred range of the present invention, and manufacturing was impossible.
  • the present invention can provide a martensitic free-cutting stainless steel that has excellent tool life during precision cutting and, more preferably, excellent cutting surface properties, and can significantly improve the durability of high-hardness parts used in environments that are highly corrosive and require fatigue strength and abrasion resistance, making it extremely useful in industry.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

L'invention concerne un matériau de barre en acier inoxydable martensitique à coupe libre caractérisé en ce qu'il possède des composants chimiques comprenant 0,10 à 0,60 % de C, 0,1 à 2,0 % de Si, 0,1 à 3,0 % de Mn, 0,15 à 0,40 % de S, 0,10 % ou moins de P, et 11,0 à 16,0 % de Cr, le reste étant du Fe et des impuretés, et en ce qu'il a ainsi un diamètre de cercle équivalent de carbure de Cr moyen de 0,80 µm ou moins, et une densité du nombre de carbure de Cr égale ou supérieure à 0,10/μm2. De préférence, le diamètre de cercle équivalent de sulfure moyen est de 5,0 µm ou moins, et la densité du nombre de sulfure est égale ou supérieure à 0,010/μm2. Ceci permet d'obtenir une durée de vie d'outil exceptionnelle pendant la coupe de précision et une qualité de surface coupée ayant une planéité exceptionnelle obtenue par découpe.
PCT/JP2023/031185 2022-09-26 2023-08-29 Matériau de barre en acier inoxydable martensitique à coupe libre et son procédé de production WO2024070413A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022-152958 2022-09-26
JP2022152958 2022-09-26

Publications (1)

Publication Number Publication Date
WO2024070413A1 true WO2024070413A1 (fr) 2024-04-04

Family

ID=90477114

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/031185 WO2024070413A1 (fr) 2022-09-26 2023-08-29 Matériau de barre en acier inoxydable martensitique à coupe libre et son procédé de production

Country Status (1)

Country Link
WO (1) WO2024070413A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004197198A (ja) * 2002-12-20 2004-07-15 Shin-Hokoku Steel Corp 快削性耐食鋼
JP2015137381A (ja) * 2014-01-21 2015-07-30 山陽特殊製鋼株式会社 優れた被削性、硬さ、耐摩耗性および耐食性を有するステンレス鋼
CN106591730A (zh) * 2016-11-25 2017-04-26 邢台钢铁有限责任公司 低碳马氏体易切削不锈钢及其生产方法
WO2019240209A1 (fr) * 2018-06-13 2019-12-19 日鉄ステンレス株式会社 Acier inoxydable martensitique s de décolletage

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004197198A (ja) * 2002-12-20 2004-07-15 Shin-Hokoku Steel Corp 快削性耐食鋼
JP2015137381A (ja) * 2014-01-21 2015-07-30 山陽特殊製鋼株式会社 優れた被削性、硬さ、耐摩耗性および耐食性を有するステンレス鋼
CN106591730A (zh) * 2016-11-25 2017-04-26 邢台钢铁有限责任公司 低碳马氏体易切削不锈钢及其生产方法
WO2019240209A1 (fr) * 2018-06-13 2019-12-19 日鉄ステンレス株式会社 Acier inoxydable martensitique s de décolletage

Similar Documents

Publication Publication Date Title
JP6880245B1 (ja) 高炭素冷延鋼板およびその製造方法並びに高炭素鋼製機械部品
JP6881613B2 (ja) 浸炭軸受鋼部品、および浸炭軸受鋼部品用棒鋼
JP2007009321A (ja) プラスチック成形金型用鋼
JP2001294972A (ja) 軸受用鋼材
JP4964063B2 (ja) 冷間鍛造性および結晶粒粗大化防止特性に優れた肌焼鋼およびそれから得られる機械部品
JP6207408B2 (ja) 優れた被削性、硬さ、耐摩耗性および耐食性を有するステンレス鋼
WO2017090738A1 (fr) Acier, constituant d'acier cémenté, et procédé de production de constituant d'acier cémenté
WO2019240209A1 (fr) Acier inoxydable martensitique s de décolletage
WO2017090731A1 (fr) Acier, constituant d'acier cémenté, et procédé de production de constituant d'acier cémenté
JP4451808B2 (ja) 疲労特性と耐結晶粒粗大化特性に優れた肌焼用圧延棒鋼およびその製法
WO2021124511A1 (fr) Acier martensitique à haute dureté et à haute résistance à la corrosion ayant une excellente aptitude au façonnage à froid et son procédé de production
JP4264329B2 (ja) 被削性に優れる鋼
JP5370073B2 (ja) 機械構造用合金鋼鋼材
JP6301145B2 (ja) スリーブ・ドッグギヤ
JP7199231B2 (ja) フェライト系ｓ快削ステンレス鋼
JP6658981B1 (ja) 浸炭部品及びその製造方法
JP5459197B2 (ja) 機械構造用合金鋼鋼材
JP2009287111A (ja) 機械構造用鋼
WO2022153790A1 (fr) Matériau en acier inoxydable à base de martensite et son procédé de production
WO2024070413A1 (fr) Matériau de barre en acier inoxydable martensitique à coupe libre et son procédé de production
CN112955571B (zh) 软氮化用钢及软氮化部件以及它们的制造方法
JPH11264049A (ja) 高炭素鋼帯およびその製造方法
JPH05171373A (ja) 粉末高速度工具鋼
JPWO2019142946A1 (ja) 軸受鋼部品、および軸受鋼部品用棒鋼
JP4213948B2 (ja) 被削性に優れる鋼

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23871654

Country of ref document: EP

Kind code of ref document: A1