WO2018056884A1 - Acier à outils pour travail à chaud - Google Patents

Acier à outils pour travail à chaud Download PDF

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Publication number
WO2018056884A1
WO2018056884A1 PCT/SE2017/050906 SE2017050906W WO2018056884A1 WO 2018056884 A1 WO2018056884 A1 WO 2018056884A1 SE 2017050906 W SE2017050906 W SE 2017050906W WO 2018056884 A1 WO2018056884 A1 WO 2018056884A1
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WO
WIPO (PCT)
Prior art keywords
steel
work tool
hot
μιη
fulfilling
Prior art date
Application number
PCT/SE2017/050906
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English (en)
Inventor
Sebastian Ejnermark
Original Assignee
Uddeholms Ab
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 Uddeholms Ab filed Critical Uddeholms Ab
Publication of WO2018056884A1 publication Critical patent/WO2018056884A1/fr

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Classifications

    • 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
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron

Definitions

  • the invention relates to a hot work tool steel.
  • Vanadium alloyed matrix tool steels have been on market for decades and attained a considerable interest because of the fact, that they combine a high wear resistance with an excellent dimensional stability and because they also have a good toughness. These steels have a wide range of applications such as die casting and forging.
  • the steels are generally produced by conventional metallurgy followed by Electro Slag Remelting (ESR).
  • Uddeholm DIEVAR is a high performance chromium-molybdenum-vanadium steel, containing balanced carbon and vanadium contents as described in WO 99/50468 Al.
  • Tempering resistance is the ability of a hot-work tool steel to keep its hardness at an elevated temperature for prolonged time.
  • vanadium alloyed tool steels produced by ESR have better properties than conventionally produced tool steels with respect to heat checking, gross cracking, hot wear and plastic deformation, there is a need for further improvements in order to reduce the risk for hot work tool failure, such as heat checking and gross cracking in high pressure die casting. In addition, it would be beneficial to further improve the hot strength and temper resistance of hot work tool steel.
  • the object of the present invention is to provide a hot work tool steel having an improved property profile leading to an increased life of the tool.
  • Another object of the present invention is to provide a steel having an improved tempering resistance in combination with a high toughness and a good hardenability allowing large sections to be produced with good properties. It is also desirable to improve the heat checking, while still maintaining a good hot wear resistance and a good resistance to gross cracking.
  • Still another object is provide a steel composition, which in powder form is suitable for Additive Manufacturing (AM), in particular for making or repairing injection moulding tools and dies.
  • AM Additive Manufacturing
  • the amount of carbon should be controlled such that the amount of primary carbides of the type M 2 3C 6 , M 7 C 3 and M 6 C in the steel is limited, preferably the steel is free from such primary carbides. Silicon (0.1 - 0.3 %)
  • Silicon is used for deoxidation. Si is present in the steel in a dissolved form. Si is a strong ferrite former and increases the carbon activity and therefore the risk for the formation of undesired carbides, which negatively affect the impact strength. Silicon is also prone to interfacial segregation, which may result in decreased toughness and thermal fatigue resistance. Si is therefore limited to 0.3 %.
  • the upper limit may 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23 and 0.22%.
  • the lower limit may be 0.12, 0.14, 0.16, 0.18 and 0.20%. Preferred ranges are 0.10 - 0.25 % and 0.15 - 0.24%.
  • Manganese contributes to improving the hardenability of the steel and together with sulphur manganese contributes to improving the machinability by forming manganese sulphides.
  • Manganese shall therefore be present in a minimum content of 0.1 %, preferably at least 0.2, 0.3, 0.35, 0.4, 0.45 or 0.5 %. At higher sulphur contents manganese prevents red brittleness in the steel. Mn may also cause undesirable micro-segregation resulting in a banded structure.
  • the steel shall contain maximum 0.8 %, preferably maximum 0.7, 0.6, 0.55 or 0.5 %.
  • Chromium is to be present in a content of at least 1.6 % in order to provide a good
  • the lower limit may be 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, or 2.6 %.
  • the upper limit may be 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7 or 3.8%.
  • Mo is known to have a very favourable effect on the hardenability. Molybdenum is essential for attaining a good secondary hardening response. The minimum content is 2.0 %, and may be set to 2.1, 2.2 or 2.3 %. Molybdenum is a strong carbide forming element and also a strong ferrite former. The maximum content of molybdenum is therefore 3.0 %. Mo may be limited to 2.9, 2.8, 2.7, 2.6, 2.5 or 2.4 %.
  • Tungsten is an essential element in the present invention.
  • W contributes to the secondary hardening and does not react with nitrogen to form nitrides if the steel is subjected to nitrogen gas atomizing.
  • Tungsten may form carbides of the type M 2 C during the secondary hardening. It is believed that the large radius of the tungsten atom make its diffusion slow and therefore positively contributes to the improved tempering resistance.
  • Nickel 0.6 -1.7 %)
  • Nickel shall be present in an amount of 0.6 -1.7 % in order to give the steel a good
  • Ni in combination with Mo reduces the amount of retained austenite in the claimed type of steel.
  • the upper limit may therefore be set to 1.6, 1.5, 1.5, 1.4 or 1.3 %.
  • the lower limit may be set to 0.7, 0.8, 0.9, 1.0 or 1.1 %.
  • Vanadium (0.1 - 0.4 %)
  • Vanadium forms evenly distributed primary precipitated carbides and carbonitrides of the type V(N,C) in the matrix of the steel.
  • This hard phase may also be denoted MX, wherein M is mainly V but Cr and Mo may be present and X is one or more of C, N and B. Vanadium shall therefore be present in an amount of 0.1 - 0.4 %.
  • the upper limit may be set to 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31 or 0.30 %.
  • the lower limit may be 0.15, 0.16, 0.17, 0.18, 0.19 or 0.20 %.
  • Aluminium is used for deoxidation in combination with Si and Mn.
  • the lower limit is set to 0.001, 0.003, 0.005 or 0.007% in order to ensure a good deoxidation.
  • the upper limit is restricted to 0.06% for avoiding precipitation of undesired phases such as AIN.
  • the upper limit may be 0.05, 0.04, 0.03, 0.02 or 0.015%.
  • Nitrogen is an optional element. N may be restricted to 0.01 - 0.12 % in order to obtain the desired type and amount of hard phases, in particular V(C,N).
  • vanadium rich carbonitrides V(C,N) will form. These will partly be dissolved during the austenitizing step and then precipitated during the tempering step as particles of nanometer size.
  • the thermal stability of vanadium carbonitrides is considered to be better than that of vanadium carbides, hence the tempering resistance of the tool steel may be improved and the resistance against grain growth at high austenitizing temperatures is enhanced.
  • the lower limit may be 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019 or 0.02%.
  • the upper limit may be 0.11, 0.10, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04 or 0.03 %. Copper (0.02 - 2.0%)
  • Cu is an optional element, which may contribute to increase the hardness and the corrosion resistance of the steel. If used, the preferred range is 0.02 - 1%. However, it is not possible to extract copper from the steel once it has been added. This drastically makes the scrap handling more difficult. For this reason, copper is normally not deliberately added.
  • Co is an optional element. Co causes the solidus temperature to increase and therefore provides an opportunity to raise the hardening temperature, which may be 15 - 30 °C higher than without Co. During austenitization it is therefore possible to dissolve larger fraction of carbides and thereby enhance the hardenability. Co also increases the M s temperature.
  • the maximum amount is 8 % and, if added, an effective amount may be 2 - 6 %, in particular 4 to 5 %. However, for practical reasons, such as scrap handling, deliberate addition of Co is generally not made.
  • the maximum impurity content may then be set to 1 %, 0.5%, 0.3 %, 0.2% or 01%.
  • Niobium is similar to vanadium in that it forms carbonitrides of the type M(N,C). However, Nb results in a more angular shape of the M(N,C) and may reduce the hardenability at high contents. The maximum amount is therefore 0.1 %, preferably 0.05 %. Nb precipitates are more stable than V precipitates and may therefore be used for grain refinement, since the fine dispersion of NbC plays the role of pinning the grain boundaries leading to grain refinement and improved toughness and improved resistance to softening at high temperatures. For this reason Nb may be present in an amount of ⁇ 0.1 %, preferably in an amount of 0.01 - 0.05 %.
  • These elements are carbide formers and may be present in the alloy in the claimed ranges for altering the composition of the hard phases. However, normally none of these elements are added.
  • B may be used in order to further increase the hardness of the steel.
  • the amount is limited to 0.01%, preferably ⁇ 0.005%.
  • a preferred range for the addition of B is 0.001 - 0.004 %.
  • P, S and O are the main impurities, which generally have a negative effect on the mechanical properties of the steel.
  • P may therefore be limited to 0.03%, preferably to 0.01%.
  • S may be limited to 0.0015, 0.0010, 0.0008, 0.0005 or even 0.0001%.
  • O may be limited to 0.0015, 0.0012, 0.0010, 0.0008, 0.0006 or 0.0005 %.
  • S may optionally be used in the range of 0.005 - 0.5 %, in particular 0.05 - 0.3 % for improving the machinability of the steel.
  • the tool steel having the claimed chemical composition can be produced by conventional metallurgy including melting in an Electric Arc Furnace (EAF) and further refining in a ladle, optionally followed by a vacuum treatment before casting.
  • EAF Electric Arc Furnace
  • the ingots may also be subjected to Electro Slag Remelting (ESR) in order to further improve the cleanliness and the
  • microstructural homogeneity of the ingots is gas atomizing followed by hot isostatic pressing (HIP).
  • HIP hot isostatic pressing
  • the steel thus produced can be used as HIPed or be subjected to further working such as forging and rolling.
  • Austenitizing may be performed at an austenitizing temperature (T A ) in the range of 1000- 1070 °C, preferably 1030 - 1050 °C.
  • T A austenitizing temperature
  • a typical T A is 1040 °C with a holding time of 30 minutes followed by rapid quenching.
  • the tempering temperature is chosen according to the hardness requirement and is performed at least twice at 600 - 650 °C for 2 hours (2x2h) followed by cooling in air.
  • the alloys had the following compositions (in wt. %): Steel 1 Steel 2 Uddeholm Dievar
  • the tempering resistance of the alloys was examined at a temperature of °C. Although the inventive steels had a lower initial hardness at the beginning of the test it is apparent from Fig. 1 that the inventive steels had a significant better tempering resistance than the comparative steel Uddeholm Dievar .
  • the tool steel of the present invention is useful in dies requiring a good hardenability and a good tempering resistance.
  • Atomized powder of the alloy can be used to produce HIPed products having superior structural uniformity.
  • Powder of the alloy can be used for producing or repairing dies, in particular by additive manufacturing methods.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

L'invention concerne un acier à outils pour travail à chaud. L'acier comprend les composants principaux suivants en % en poids: C 0,26-0,38, Si 0,1-0,3, Mn 0,1-0,8, Cr 1,4-3,9, Mo 2,0-3,0, W 0,8-1,5, Ni 0,6-1,7, V 0,1-0,4, des éléments facultatifs de complément, du fer et des impuretés.
PCT/SE2017/050906 2016-09-26 2017-09-14 Acier à outils pour travail à chaud WO2018056884A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1651268A SE1651268A1 (en) 2016-09-26 2016-09-26 Hot work tool steel
SE1651268-3 2016-09-26

Publications (1)

Publication Number Publication Date
WO2018056884A1 true WO2018056884A1 (fr) 2018-03-29

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SE (1) SE1651268A1 (fr)
TW (1) TW201814067A (fr)
WO (1) WO2018056884A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110344053A (zh) * 2019-08-06 2019-10-18 贵州大学 一种高强贝氏体钢激光修复用合金粉末及其制备方法
CN111954725A (zh) * 2018-05-14 2020-11-17 日立金属株式会社 增材层制造的热作模具、其制造方法以及用于增材层制造热作模具的金属粉末

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA3133822A1 (fr) 2019-03-22 2020-10-01 Dmc Global Inc. Article gaine dote d'une couche de gaine ayant une epaisseur variable

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03134135A (ja) * 1989-10-18 1991-06-07 Hitachi Metals Ltd 熱間加工用工具鋼
JPH07179988A (ja) * 1993-12-24 1995-07-18 Aichi Steel Works Ltd 高温強度の優れた熱間工具鋼
WO2003083154A1 (fr) * 2002-04-03 2003-10-09 Industeel (France) Bloc en acier pour la fabrication de moules pour le moulage par injection de matieres plastiques ou pour la fabrication d'outils pour le travail des metaux
EP1696045A1 (fr) * 2003-12-19 2006-08-30 Daido Steel Co., Ltd. Acier a outils pour travail a chaud et element de moule excellent en termes de resistance a la fusion

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03134135A (ja) * 1989-10-18 1991-06-07 Hitachi Metals Ltd 熱間加工用工具鋼
JPH07179988A (ja) * 1993-12-24 1995-07-18 Aichi Steel Works Ltd 高温強度の優れた熱間工具鋼
WO2003083154A1 (fr) * 2002-04-03 2003-10-09 Industeel (France) Bloc en acier pour la fabrication de moules pour le moulage par injection de matieres plastiques ou pour la fabrication d'outils pour le travail des metaux
EP1696045A1 (fr) * 2003-12-19 2006-08-30 Daido Steel Co., Ltd. Acier a outils pour travail a chaud et element de moule excellent en termes de resistance a la fusion

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111954725A (zh) * 2018-05-14 2020-11-17 日立金属株式会社 增材层制造的热作模具、其制造方法以及用于增材层制造热作模具的金属粉末
CN110344053A (zh) * 2019-08-06 2019-10-18 贵州大学 一种高强贝氏体钢激光修复用合金粉末及其制备方法
CN110344053B (zh) * 2019-08-06 2021-05-25 贵州大学 一种高强贝氏体钢激光修复用合金粉末及其制备方法

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Publication number Publication date
SE540108C2 (en) 2018-03-27
SE1651268A1 (en) 2018-03-27
TW201814067A (zh) 2018-04-16

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