Steel 20L

  • 08L steel
  • 15L steel
  • Steel 20L
  • Steel 25L
  • 30L steel
  • Steel 35L
  • 40L steel
  • 45L steel
  • 50L steel

    • Designation

    Name The value
    Designation GOST Cyrillic 20Л
    Designation GOST Latin 20L
    Transliteration 20L
    By chemical elements 20

    Description

    20L steel is used: for the manufacture of valves, fittings casting parts, General machinery, manufactured by investment casting; parts carnality structures and other details, operating at temperatures from -40 to 450 °C; casting parts, steam, gas, hydraulic turbines and compressors operating at temperatures from -40 to +350 °C; casting the 2nd and 3rd parts of valves and actuators to it (buildings of the connections to weld and cast and welded structures were) with the working environment temperature from -30 to +450 °C without restriction of the nominal working pressure; cast centers wheelsets of locomotives and motor cars of electric and diesel trains of the Railways of 1520 mm in climatic design UHL; casting equipment parts (valves) for nuclear power stations, heat supply stations, heat and power plants, experimental and research nuclear reactors and installations; tsentrobezhnolityh pipes used as components in equipment for metallurgical, engineering, glass, ceramic, mining and processing petrochemical industry and is intended for the manufacture of blanks and parts used in the composition of the products of aviation and the nuclear industry.

    Note

    Steel pearlitic class.
    Allowed to apply casting parts of pipe fittings of steel grade 20L to the operating temperature minus 40 °C subject to thermal treatment in the hardening regime plus vacation or normalizing plus a vacation with the testing of impact toughness KCU-40≥200 kJ/m2 (2,0 kgf·m/cm2).

    Standards

    Name Code Standards
    Bandages. Wheels. Axis В41 GOST 4491-86
    Steel castings В82 GOST 977-88, OST 108.961.04-80, OST 26-07-402-83, OST 24.920.01-80, OST 3-4365-79, OST 5Р.9285-95, TU 26-02-19-75, TU 108.11.352-87, TU 4112-091-00220302-2006, ST ЦКБА 014-2004, TU 5.961-11151-92
    Hard alloys, ceramic-metal products and metal powder В56 OST 107.750001.001-91
    Classification, nomenclature and General rules В20 OST 84-218-85
    Welding and cutting metals. Soldering, riveting В05 RTM 108.020.122-78
    Steel pipes and fittings to them В62 TU 1333-003-76886532-2014

    Chemical composition

    Standard C S P Mn Cr Si Ni Fe Cu
    GOST 4491-86 0.17-0.25 ≤0.025 ≤0.03 0.6-0.9 ≤0.5 0.2-0.52 ≤0.5 Rest ≤0.4
    TU 5.961-11151-92 0.17-0.25 ≤0.025 ≤0.025 0.45-0.9 - 0.2-0.52 - Rest -
    TU 1333-003-76886532-2014 0.17-0.25 ≤0.04 ≤0.04 0.45-0.9 - 0.2-0.52 - Rest -
    ST ЦКБА 014-2004 0.17-0.25 ≤0.04 ≤0.04 0.45-0.9 ≤0.45 0.2-0.52 ≤0.4 Rest ≤0.4
    Fe is the basis.
    According to GOST 977-88 the mass fraction of S and P content is indicated for 1 group of castings from the main steel. The content of sulfur and phosphorus in the castings of groups 2 and 3, in sour and basic open-hearth steel - see Table 4a in GOST 977-88.
    According to TU 5.961-11151-92 for castings of grades 1 and 2 the mass fraction of cobalt in steel should not exceed 0.20%, and for castings in the direct irradiation zone - 0.15%.

    Mechanical properties

    Section, mm sT|s0,2, MPa σU, MPa d y, % KCU, kJ/m2 HB, MPa
    Casting parts of gas turbines. Normalization at 880-900 °C or Normalizing at 880-900 °C, air cooling + vacation at 630-650 °C, air cooling
    100 ≥216 ≥412 ≥22 ≥35 ≥491 116-144
    Normalization at 870-890 °C With air cooling up to 250-300 °C + vacation at 630-650 °C, air cooling (named place of clippings sample)
    100 210-245 440-490 30-34 44-64 - 131-143
    Castings with wall thickness up to 100 mm in the delivery state on the other 5.961-11151-92. Normalization at 880-900 °C + Vacation at 630-650 °C. the Critical temperature of brittleness of TKO ≤ 55 °C.
    - ≥216 ≥412 ≥22 ≥35 ≥490 116-144
    Normalization at 870-890 °C With air cooling up to 250-300 °C + vacation at 630-650 °C, air cooling (named place of clippings sample)
    200 210-265 430-485 19-37 28-64 - 131
    Castings for shipbuilding. When normalizing 890-920 °C + vacation at 630-670 °C, air cooling
    - ≥220 ≥420 ≥22 ≥35 ≥500 116-144
    Castings with wall thickness up to 100 mm in the delivery state on the other 5.961-11151-92. Normalization at 880-900 °C + Vacation at 630-650 °C. the Critical temperature of brittleness of TKO ≤ 55 °C.
    - ≥170 ≥370 - ≥35 - -
    Centers cast of railcar wheel pairs according to the GOST 4491-86. Normalization at 940-960 °C (exposure for 2.5-3.0 h), accelerated cooling to 300-400 °C at a speed of at least 0.4 °C·s-1 + Vacation at 640-660 °C, exposure for 2.5-3.0 h (KCU+20°/KCU-60°)
    ≥245 ≥440 ≥22 ≥32 ≥490/245 -
    Normalization at 870-890 °C With air cooling up to 250-300 °C + vacation at 630-650 °C, air cooling (named place of clippings sample)
    10 215-225 450-495 27-37 45-63 - 131
    Castings with wall thickness up to 100 mm in the delivery state on the other 5.961-11151-92. Normalization at 880-900 °C + Vacation at 630-650 °C. the Critical temperature of brittleness of TKO ≤ 55 °C.
    - ≥160 ≥370 - ≥33 - -
    Normalization at 870-890 °C With air cooling up to 250-300 °C + vacation at 630-650 °C, air cooling (named place of clippings sample)
    100 200-245 420-485 31-33 44-64 - 131-134
    Castings with wall thickness up to 100 mm in the delivery state on the other 5.961-11151-92. Normalization at 880-900 °C + Vacation at 630-650 °C. the Critical temperature of brittleness of TKO ≤ 55 °C.
    - ≥140 ≥360 - ≥32 - -
    Normalization at 870-890 °C With air cooling up to 250-300 °C + vacation at 630-650 °C, air cooling (named place of clippings sample)
    200 210-255 430-470 14-34 24-61 - 121-143
    30 200-265 425-480 31-37 48-63 - 134-143
    50 200-275 460-480 31-33 48-57 - 124-143

    Description mechanical marks

    Name Description
    sT|s0,2 Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%
    σU Limit short-term strength
    d Elongation after rupture
    y The relative narrowing
    KCU Toughness
    HB Brinell hardness number

    Physical characteristics

    Temperature Е, HPa G, HPa r, kg/m3 l, W/(m · °C) R, Mr. · m a, 10-6 1/°C С, J/(kg · °C)
    20 201 78 7850 54 170 - -
    100 196 76 - 53 220 122 487
    200 188 73 - 51 294 127 500
    300 183 71 - 48 385 131 517
    400 173 67 - 43 490 135 533
    500 165 63 - 39 604 139 559
    600 152 58 - 35 761 144 588
    700 132 50 - 32 932 149 638
    800 120 45 - 27 1101 126 706
    900 - - - 27 1139 126 706
    1100 - - - - - 124 706

    A description of the physical symbols

    Name Description
    Е The normal elasticity modulus
    r Density
    l Coefficient of thermal conductivity
    С Specific heat

    Technological properties

    Name The value
    Weldability Welded without any restrictions. Welding methods: SMAW, ADS under gas protection electroslag welding. After repair of defects by welding is applied leave in 619-660 °C.
    Склонность к отпускной хрупкости Tend not.
    Flock-sensitive sensitivity not sensitive.
    Surfacing Surfacing of sealing surfaces of valves in accordance with OST 26-07-2028-81 is made by manual arc welding electrodes type e-20X13 with plaster SSSI-13НЖ, NII-48, NII-48Ж-1 or SV wire-12H13 or SV-20X13. Surface preparation for overlay welding is performed by machining. Surfacing is performed with preliminary and accompanying heating to 400-450 °C is not less than 3 layers with thickness not less than 4 mm, excluding allowance for machining. Heat treatment after welding is produced by tempering at 550-600 °C (delay of 2-5 h) hardness HB=301-350, at 600-650 °C (delay of 2-5 h) hardness HB=240 to 300, at 400-450 °C (delay of 2-5 h) hardness HB=351-400. The temperature of the furnace when loading the details for the home should be no more than 300 °C.
    Welding defects Welding defects of castings after cutting is usually carried out without prior and concomitant heating. By semiautomatic welding in carbon dioxide environment used welding wire SV-08G2S diameter of 2 mm at a current of 380-420 A. Welding defects by manual welding is done with electrodes Э42А type (GOST 9467) brand SSSI-13/45. When welding the hard contour of the casting or of the sample volume more than 2000 cm3 is recommended before applying the first roller to pre-heating at 120-150 °C. When welding is sample size more than 5000 cm3 it is necessary to produce preliminary and accompanying heating to 150-180 °C.