Cast iron ЧНМ1,2

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  • ChTB1.8 cast iron
  • ChNM1.2 cast iron
  • ChM1.8 cast iron
  • SCI cast iron
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  • Cr30 cast iron
  • Cr25 cast iron
  • Cr24 cast iron
  • Cr20CrNi2 cast iron
  • Cr20KhN cast iron
  • Cr20 cast iron
  • Cr18 cast iron
  • Cr15 cast iron
  • Cr10 cast iron
  • Cast iron SCh03Ts01B
  • NKHT pig iron (NKHT)

    • Designation

    Name The value
    Designation GOST Cyrillic ЧНМ1,2
    Designation GOST Latin ChHM1,2
    Transliteration ChNM12
    By chemical elements ZrНMo1,2

    Description

    Cast iron ЧНМ1,2 applies: for the production of castings for aircraft.

    Note

    Modified heat-resistant grey iron.

    Standards

    Name Code Standards
    Castings with special properties (iron and steel) В83 OST 1 90077-72

    Chemical composition

    Standard C S P Mn Cr Si Ni Fe Mo
    OST 1 90077-72 3-3.5 ≤0.1 ≤0.3 0.6-0.9 ≤0.4 1.7-2.4 1.5-2.2 Rest 0.8-1.5
    Fe is the basis.
    According to OST 1 90077-72, with the following mechanical properties and microstructure satisfactory, the following deviations in chemical composition are acceptable: for carbon ± 0.10%, for chromium, silicon, molybdenum, nickel and copper + 0.2% for each.

    Mechanical properties

    σU, MPa HB, MPa
    Castings on OST 1 90077-72
    ≥275 240-320

    Description mechanical marks

    Name Description
    σU Limit short-term strength
    HB Brinell hardness number

    Technological properties

    Name The value
    Macrostructure and pollution The appearance of the fracture of castings on OST 1 90077-72 should be dense, fine-grained, light-gray, with no signs of chill. Surface of castings shall be cleaned of sand and metal penetration. Sprues, heaving, bays, growths and veining must be cut or polished by abrasive material in the tolerances on the drawing. Nikitina, crack and end-to-end sinks are not allowed.
    Microstructure According to OST 1 90077-72 microstructure of castings after aging should consist of pearlite and acicular sorbitol, graphite, small plate and scatter and separate inclusions of complex phosphide-carbide eutectic.
    Features of heat treatment According to OST 1 90077-72 castings of modified cast iron are subjected to natural or artificial aging consisting of heat treatment at a temperature of 550-600°C for 3,0-4,0 hours (depending on wall thickness of casting).