WO2018109259A1 - Fonte ductile et procédé de fabrication d'un article - Google Patents

Fonte ductile et procédé de fabrication d'un article Download PDF

Info

Publication number
WO2018109259A1
WO2018109259A1 PCT/FI2016/050889 FI2016050889W WO2018109259A1 WO 2018109259 A1 WO2018109259 A1 WO 2018109259A1 FI 2016050889 W FI2016050889 W FI 2016050889W WO 2018109259 A1 WO2018109259 A1 WO 2018109259A1
Authority
WO
WIPO (PCT)
Prior art keywords
ductile iron
percent
article
ductile
iron
Prior art date
Application number
PCT/FI2016/050889
Other languages
English (en)
Inventor
Jarkko Laine
Original Assignee
Wärtsilä Finland Oy
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 Wärtsilä Finland Oy filed Critical Wärtsilä Finland Oy
Priority to EP16823022.5A priority Critical patent/EP3555334A1/fr
Priority to PCT/FI2016/050889 priority patent/WO2018109259A1/fr
Publication of WO2018109259A1 publication Critical patent/WO2018109259A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/08—Making cast-iron alloys
    • 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
    • C21D5/00—Heat treatments of cast-iron
    • 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
    • C21D5/00—Heat treatments of cast-iron
    • C21D5/02—Heat treatments of cast-iron improving the malleability of grey cast-iron
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C37/00—Cast-iron alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C37/00—Cast-iron alloys
    • C22C37/04—Cast-iron alloys containing spheroidal graphite
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C37/00—Cast-iron alloys
    • C22C37/10—Cast-iron alloys containing aluminium or silicon
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite

Definitions

  • the present invention relates to a ductile iron in accordance with claim 1 .
  • the invention also concerns a method of manufacturing an article of a ductile iron as defined in the other independent claim.
  • a cylinder head of a piston engine serves several purposes: it defines one end of a combustion chamber, provides space for intake and exhaust ducts and cooling medium ducts and accommodates intake and exhaust valves and fuel injectors.
  • the shape of a cylinder head is often very complex and cylinder heads need to withstand high temperatures and significant forces. To ensure sufficient strength and other properties of cylinder heads and at the same time allow easy manufacturability and reasonable price, high requirements are set for the selection of a cylinder head material.
  • cast irons are typically used. While satisfactory properties can be achieved with different known cast irons, usually some properties are optimized at the cost of other desired properties.
  • An object of the present invention is to provide an improved ductile iron, which can be used, for instance, as a cylinder head material.
  • the characterizing features of the ductile iron according to the invention are given in claim 1 .
  • Another object of the invention is to provide an improved method of manufacturing an article of a ductile iron. The characterizing features of the method are given in the other independent claim.
  • the ductile iron according to the invention comprises, by weight, 3.6-4.3 percent of carbon, at most 1 .75 percent of silicon and at least 92 percent of iron, the microstructure of the ductile iron comprising, by volume, at most 60 percent of pearlite and at least 40 percent of ferrite.
  • the ductile iron according to the invention has good thermal conductivity and suitable other physical properties for use as a material of cylinder heads of pis- ton engines.
  • the low Si-content of the ductile iron significantly increases the thermal conductivity of the ferrite.
  • the thermal conductivity of the ferrite dictates the thermal conductivity of the material. The desired properties are thus achieved by the specific combination of the low Si-content and the microstructure where at least 40 percent of the iron is ferritic.
  • the ductile iron comprises, by volume, at most 45 percent of pearlite and at least 55 percent of ferrite.
  • the ductile iron comprises at most 0.8 percent of manganese. According to an embodiment of the invention, the ductile iron comprises at least 1 .0 percent of silicon.
  • the ductile iron can additionally comprise copper and/or tin. With copper or tin, the amount of pearlite can be controlled.
  • the amount of copper can be in the range of 0.005-0.5 percent by weight.
  • the amount of tin can be in the range of 0.001 -0.1 percent by weight, preferably at most 0.07 percent.
  • the ductile iron consists of Fe, C, Si, Mn and inevitable impurities.
  • the ductile iron can additionally comprise Cu and/or Sn.
  • the method of manufacturing an article of a ductile iron defined above com- prises the steps of casting the article, austenitizing the article at a temperature of 900-920 °C for 2-4 hours, and converting the microstructure of the article to a ferritic-pearlitic matrix by keeping the article at a temperature of 675- 700 °C for 1 -4 hours.
  • a cylinder head according to the invention is made of a ductile iron defined above. Description of embodiments of the invention
  • the present invention concerns a ductile iron.
  • the ductile iron according to the invention can be used, for instance, as a cylinder head material in piston engines, especially in large internal combustion engines, such as main or auxilia- ry engines of ships or power plant engines.
  • ductile iron refers to a group of materials, where the common defining characteristic is graphite, which is at least partly in the form of nodules, i.e. small spherical particles.
  • ductile iron at least the following names can be used: ductile cast iron, nodular cast iron, spheroidal graphite iron, spheroidal graphite cast iron, spheroidal iron and SG iron.
  • graphite In grey iron, graphite is in the form of flakes. The sharp flakes of grey iron create stress concentration points within the metal matrix, which makes grey iron brittle. The rounded graphite nodules of ductile iron prevent formation of cracks and improve thus ductility of the material. In practice, not all the graphite in a ductile iron is in the form of nodules, but part of the graphite can appear in other forms. The proportion, size and distribution of nodules are significant factors affecting the properties of ductile irons. Nodularity of a ductile iron can be estimated, for instance, using visual inspection, image analysis, or ultrasonic testing. Nodularity is expressed as a percentage. The carbon contents of ductile irons range from 2 percent to over 4 percent.
  • ductile irons typically comprise silicon (Si), manganese (Mn), phosphorus (P) and sulfur (S). Copper (Cu) and tin (Sn) can be used for increasing tensile and yield strength. Nickel (Ni), copper and chromium (Cr) can be used for providing corrosion resistance.
  • Ductile irons are available with different microstructures, which provide different properties. The microstructure can be, for instance, ferritic, pearlitic, mar- tensitic or austenitic.
  • Ferrite provides in general high ductility and toughness, but lower strength and hardness.
  • Pearlite provides high strength but decreased ductility.
  • properties between ferritic and pearlitic ductile irons can be achieved.
  • good machinability and low production costs can be combined to a material with strength and ductility suitable for many purposes.
  • the microstructure of the ductile iron according to the invention is a ferritic- pearlitic matrix.
  • the ductile iron comprises, by volume, 0-60 % of pearlite, preferably 0-45 %, the balance being ferrite.
  • the desired microstructure can be achieved directly with suitable alloying, via heat treatment, or by a combina- tion of alloying and heat treatment.
  • the carbon content is 3.6-4.3 %.
  • the ductile iron according to the invention comprises at least 92 w-% of iron.
  • the ductile iron according to the invention comprises at most 1 .75 % of silicon. By keeping the Si-content at 1 .75 % or below, the thermal conductivity of the ferrite can be significantly increased. In a ferritic-pearlitic microstructure, the thermal conductivity of the ferrite controls the thermal conductivity of the material.
  • the proportion of pearlite in the microstructure can be increased.
  • the amount of copper can be in the range of 0.005-0.5 percent by weight.
  • the amount of tin can be in the range of 0.001 -0.1 percent by weight, preferably at most 0.07 percent.
  • the ductile iron according to an embodiment of the invention comprises, by weight, 3.6 ⁇ 1.3 percent of carbon, at most 1 .75 percent of silicon, at most 0.8 percent of manganese, at most 0.5 percent of copper and at most 0.1 percent of tin.
  • the balance is iron and unavoidable impurities.
  • the ductile iron comprises at least 1 .0 percent of silicon.
  • Table 2 shows the chemical composition of a ductile iron in accordance with one example. With a pearlite content of 45 %, the thermal conductivity of the material was 45 W/mK at a temperature of 300 K. Standard EN 1563:2012 concerning spheroidal graphite cast irons requires thermal conductivity of 35.2 W/mK. An increase of nearly 28 percent was thus achieved. Table 2
  • an article is manufactured by casting the article, austenitizing the article at a temperature of 900-920 °C for 2-4 hours, and exposing the article to a temperature of 675-700 °C for 1 to 4 hours. At the latter heat treatment, the microstructure of the article is converted from austenite to ferrite and pearlite.
  • the desired microstructure can also be achieved without heat treatment by cooling the article in the mold.
  • Desired physical properties of the ductile iron include tensile strength of at least 350 MPa and thermal conductivity of at least 38 W/(m- K).
  • a suitable tensile strength range for the material is 350-600 MPa.
  • a suitable thermal conductivity range is 38-60 W/(m- K).

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)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)

Abstract

L'invention concerne une fonte ductile comprenant, exprimé en poids, 3,6 à 4,3 % de carbone, maximum 1,75 % de silicium et minimum 92 % de fer, la microstructure de la fonte ductile comprenant, exprimé en volume, maximum 60 % de perlite et minimum 40 % de ferrite.
PCT/FI2016/050889 2016-12-16 2016-12-16 Fonte ductile et procédé de fabrication d'un article WO2018109259A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP16823022.5A EP3555334A1 (fr) 2016-12-16 2016-12-16 Fonte ductile et procédé de fabrication d'un article
PCT/FI2016/050889 WO2018109259A1 (fr) 2016-12-16 2016-12-16 Fonte ductile et procédé de fabrication d'un article

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/FI2016/050889 WO2018109259A1 (fr) 2016-12-16 2016-12-16 Fonte ductile et procédé de fabrication d'un article

Publications (1)

Publication Number Publication Date
WO2018109259A1 true WO2018109259A1 (fr) 2018-06-21

Family

ID=57755328

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI2016/050889 WO2018109259A1 (fr) 2016-12-16 2016-12-16 Fonte ductile et procédé de fabrication d'un article

Country Status (2)

Country Link
EP (1) EP3555334A1 (fr)
WO (1) WO2018109259A1 (fr)

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4236944A (en) * 1977-10-24 1980-12-02 Sandvik Aktiebolag Cast iron especially suited for ingot molds
US4990194A (en) * 1988-09-09 1991-02-05 Hitachi Metals, Ltd. Thin high-strength article of spheroidal graphite cast iron and method of producing same
JPH06322470A (ja) * 1993-05-10 1994-11-22 Hitachi Powdered Metals Co Ltd 粉末冶金用鋳鉄粉及び耐摩耗性鉄系焼結合金
US5858127A (en) * 1996-08-02 1999-01-12 Gunite Corporation Metal alloys and brake drums made from such alloys
JP2000256776A (ja) * 1999-03-12 2000-09-19 Kawasaki Heavy Ind Ltd 車両用ブレーキディスク材
JP2000273569A (ja) * 1999-03-18 2000-10-03 Isuzu Motors Ltd シリンダーヘッド用ｃｖ黒鉛鋳鉄材
WO2001038593A1 (fr) * 1999-11-23 2001-05-31 Sintercast Ab Nouvel alliage de fonte et procede de fabrication
US20030051776A1 (en) * 2001-03-13 2003-03-20 Aisin Seiki Kabushiki Kaisha Nodular graphite cast iron with high strength and high toughness
US20080145645A1 (en) * 2006-12-15 2008-06-19 The Dexter Company As-cast carbidic ductile iron
WO2015114210A1 (fr) * 2014-01-28 2015-08-06 Wärtsilä Finland Oy Fonte a graphite sphéroïde pour culasses et son procédé de fabrication

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4236944A (en) * 1977-10-24 1980-12-02 Sandvik Aktiebolag Cast iron especially suited for ingot molds
US4990194A (en) * 1988-09-09 1991-02-05 Hitachi Metals, Ltd. Thin high-strength article of spheroidal graphite cast iron and method of producing same
JPH06322470A (ja) * 1993-05-10 1994-11-22 Hitachi Powdered Metals Co Ltd 粉末冶金用鋳鉄粉及び耐摩耗性鉄系焼結合金
US5858127A (en) * 1996-08-02 1999-01-12 Gunite Corporation Metal alloys and brake drums made from such alloys
JP2000256776A (ja) * 1999-03-12 2000-09-19 Kawasaki Heavy Ind Ltd 車両用ブレーキディスク材
JP2000273569A (ja) * 1999-03-18 2000-10-03 Isuzu Motors Ltd シリンダーヘッド用ｃｖ黒鉛鋳鉄材
WO2001038593A1 (fr) * 1999-11-23 2001-05-31 Sintercast Ab Nouvel alliage de fonte et procede de fabrication
US20030051776A1 (en) * 2001-03-13 2003-03-20 Aisin Seiki Kabushiki Kaisha Nodular graphite cast iron with high strength and high toughness
US20080145645A1 (en) * 2006-12-15 2008-06-19 The Dexter Company As-cast carbidic ductile iron
WO2015114210A1 (fr) * 2014-01-28 2015-08-06 Wärtsilä Finland Oy Fonte a graphite sphéroïde pour culasses et son procédé de fabrication

Also Published As

Publication number Publication date
EP3555334A1 (fr) 2019-10-23

Similar Documents

Publication Publication Date Title
US8333923B2 (en) High strength gray cast iron
JPH0210222B2 (fr)
CN105531387B (zh) 内燃机用高导热性活塞环
CN101880833A (zh) 一种采用稀土微合金化的不锈轴承钢及其制备方法
CN104357736A (zh) 一种钒钛蠕墨铸铁
CN102268586B (zh) 耐腐蚀合金铸铁及其制备方法
CA2018636C (fr) Trempe de l'acier ferritique-perlitique par precipitation
Roučka et al. Properties of type SiMo ductile irons at high temperatures
JPH0718368A (ja) 優れた耐食性と耐摩耗性を有する鋳鉄及び該鋳鉄で形成されたシリンダライナ
CN106319362A (zh) 具有抗酸性腐蚀性能x52无缝管线钢管及其制造方法
WO2018109259A1 (fr) Fonte ductile et procédé de fabrication d'un article
EP3099834B1 (fr) Fonte a graphite sphéroïdal pour culasses et son procédé de fabrication
CN107287497A (zh) 高珠光体高韧性球墨铸铁及其表面处理工艺
Li et al. Influence of V content on microstructure and mechanical properties of gray cast iron for super-large cylinder liner
Byun et al. Correlation of microstructure and microfracture mechanism of five work rolls
CN108866453A (zh) 一种马氏体耐热钢及其制备方法
EP0746635A4 (fr) Fonte grise en alliage presentant une resistance elevee a la fatigue thermique et une bonne aptitude a l'usinage
KR20090049638A (ko) 가공성 및 내구성이 우수한 베이나이트 비조질강 및 이를이용한 크랭크샤프트 제조 방법
KR101598663B1 (ko) 실린더 라이너
CN101481770A (zh) 一种冷激合金铸铁
Silman et al. Graphitized cast irons
Vaško et al. Fatigue behaviour of NiCr-type of austenitic nodular cast iron
Tiedje Specification and selection of ductile irons
Jiang et al. Influence of Cr element on impact fracture process of ductile Ni-resistant alloyed iron at low temperature
Gao et al. Effects of alloy compositions on mechanical properties of as-cast banite iron materials for cylinder liners

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: 16823022

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2016823022

Country of ref document: EP

Effective date: 20190716