Steel U7A

  • U16 steel (EI336)
  • U9A steel
  • U9 steel
  • U8GA steel
  • U8G steel
  • U8A steel
  • U8 steel
  • U7A steel
  • U7 steel
  • U12A steel
  • U12 steel
  • U11A steel (U11)
  • U10A steel
  • U10 steel
  • Steel AU10E (ASU10E)
  • A85 steel
  • Steel A75 (U7AB)

    • Designation

    Name The value
    Designation GOST Cyrillic У7А
    Designation GOST Latin U7A
    Transliteration U7A
    By chemical elements 7

    Description

    Steel U7A is used: for the manufacture of tools for working wood (axes, kolunov, chisels, bits); pneumatic tools small size (chisels, swages, dies); forging dies; needle wire; machinist’s tools (hammers, sledge hammers, drifts, screwdrivers, compound pliers, nippers, oblique cutting pliers, etc.); cold-rolled heat-treated ribbon with a thickness of 0.05 to 1.30 mm and rolled heat-treated strip thickness 0.15−2.00 mm for the manufacture of spring details and springs, with the exception of the crown; measuring tapes.

    Standards

    Name Code Standards
    Sheets and strips В23 GOST 103-2006
    Bars and shapes В22 GOST 1133-71, GOST 2590-2006, GOST 2591-2006, GOST 2879-2006
    Bars and shapes В32 GOST 1435-99, GOST 5210-95, GOST 7417-75, GOST 8559-75, GOST 8560-78, GOST 14955-77, TU 14-1-1910-76, TU 14-1-505-73, TU 14-11-245-88, TU 14-1-1271-75
    Tape В34 GOST 2283-79, GOST 10234-77, GOST 21996-76, GOST 21997-76, TU 3-939-81, TU 14-1-2993-80
    Sheets and strips В33 GOST 4405-75
    Steel wire medium and high carbon В72 GOST 5468-88, GOST 9389-75

    Chemical composition

    Standard C S P Mn Cr Si Ni Fe Cu
    GOST 1435-99 0.65-0.74 ≤0.018 ≤0.025 0.17-0.28 ≤0.2 0.17-0.33 ≤0.25 Rest ≤0.25
    Fe is the basis.
    According to GOST 1435-99, the mass fraction of chromium, nickel and copper is indicated for 1 group of metal products. The mass fraction of sulfur in steel obtained by the electroslag remelting method should not exceed 0.013%. In the metal products of the 2nd group, the mass fraction of Cr ≤ 0.12%, Ni ≤ 0.12%, Cu ≤0.20% and their total mass fraction ≤ 0.40%. In the metal products of the third group, the mass fraction of Cr ≤ 0.20-0.40%, Ni ≤ 0.25%, Cu ≤0.25%. In metal products of the 1 st and 3 rd groups, made of steel obtained by scrap-process, the mass fractions of nickel, copper and chromium are increased by 0.05% of each element as compared to those in the table. In a metal designed for the manufacture of cold-rolled strip, an increase in the mass fraction of nickel, copper and chromium is not allowed.
    According to TU 14-1-505-73, by agreement of the parties for special purpose hardware, steel should be supplied with reduced content limits of elements without treatment with synthetic slag and purging with argon.
    For the tape according to TU 14-1-2993-80 produced in accordance with GOST 2283, the deviation in chromium content is allowed up to +0,020%.

    Mechanical properties

    Section, mm t отпуска, °C sT|s0,2, MPa σU, MPa d5, % d4 d y, % KCU, kJ/m2 HB, MPa HV, MPa
    Tape flatted average strength of 0.1-4.0 mm according to GOST 10234-77 in the state of delivery (indicated delivery)
    - - - 780-1270 - - - - - - -
    - - - 780-930 - - - - - - -
    - - - 930-1080 - - - - - - -
    - - - 1080-1230 - - - - - - -
    - - - ≤780 - - ≥10 - - - -
    - - - ≤570 - - - - - - -
    Tape cold-rolled heat-treated (0,05-1,30 mm) for spring parts and springs according to GOST 21996-76 and flattened strip (0,15-2,00 mm) according to GOST 21997-76 (listed group strength tape)
    - - - 1270-1570 - - - - - - 375-485
    - - - 1580-1860 - - - - - - 486-600
    - - - ≥1860 - - - - - - ≥600
    Quenching in fine-grained structure with cooling in water + Vacation
    - 300 ≥1370 ≥1590 - - - ≥8 ≥310 - -
    A sample with a diameter of 5 mm and a length of 25 mm deformed and annealed. A strain rate of 10 mm/min strain Rate 0,007 1/C
    - - - ≥105 ≥64 - - ≥90 - - -
    Quenching in fine-grained structure with cooling in water + Vacation
    - 400 ≥1180 ≥1270 - - - ≥11 ≥440 - -
    A sample with a diameter of 5 mm and a length of 25 mm deformed and annealed. A strain rate of 10 mm/min strain Rate 0,007 1/C
    - - - ≥94 ≥65 - - ≥100 - - -
    Quenching in fine-grained structure with cooling in water + Vacation
    - 500 ≥970 ≥1090 - - - ≥13 ≥730 - -
    A sample with a diameter of 5 mm and a length of 25 mm deformed and annealed. A strain rate of 10 mm/min strain Rate 0,007 1/C
    - - - ≥63 ≥60 - - ≥100 - - -
    Quenching in fine-grained structure with cooling in water + Vacation
    - 600 ≥830 ≥980 - - - ≥17 ≥930 - -
    A sample with a diameter of 5 mm and a length of 25 mm deformed and annealed. A strain rate of 10 mm/min strain Rate 0,007 1/C
    - - - ≥36 ≥62 - - ≥100 - - -
    - - - ≥22 ≥65 - - ≥100 - - -
    - - - ≥17 ≥92 - - ≥100 - - -
    Rolled steel. Quenching in oil from 860 °C to + Vacation at 450 °C
    - - ≥1760 ≥1860 ≥10 - - ≥32 ≥240 - -
    Cold-rolled steel strip of 0.1-4.0 mm according to GOST 2283-79 on delivery
    - - - 740-1180 - - - - - - -
    - - - ≤640 - ≥15 - - - - -
    Rolled steel. Annealing
    - - - - ≥26 - - ≥71 - - -
    Cold-rolled steel strip of 0.1-4.0 mm according to GOST 2283-79 on delivery
    - - - ≤740 - ≥10 - - - - -
    Rolled steel. Annealing
    - - - - ≥65 - - ≥99 - - -
    Cold-rolled steel strip of 0.1-4.0 mm according to GOST 2283-79 on delivery
    - - - ≤640 - ≥10 - - - - -
    Rolled steel. Annealing
    - - - - ≥58 - - ≥98 - - -
    Cold-rolled steel strip sagatovna (specified strength class)
    0.1-4 - - 750-900 - - - - - - -
    Rolled steel. Annealing
    - - - - ≥59 - - ≥92 - - -
    Cold-rolled steel strip sagatovna (specified strength class)
    0.1-4 - - 900-1050 - - - - - - -
    Rolled steel. Annealing
    - - - - ≥38 - - ≥71 - - -
    Cold-rolled steel strip sagatovna (specified strength class)
    0.1-4 - - 1050-1200 - - - - - - -
    Rolled steel. Annealing
    - - - - ≥45 - - ≥88 - - -
    Rolled steel. Annealing or normalizing
    - - - ≤690 ≥16 - - ≥30 - ≤200 -
    - - - ≤660 ≥13 - - ≥22 - ≤200 -
    - - - ≤640 ≥18 - - ≥20 - ≤200 -
    - - - ≤620 ≥22 - - ≥26 - ≤180 -
    - - - ≤460 ≥27 - - ≥34 - ≤155 -
    - - - ≤330 ≥33 - - ≥45 - ≤135 -
    - - - ≤205 ≥38 - - ≥60 - ≤110 -

    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
    d5 Elongation after rupture
    d4 Elongation after rupture
    d Elongation after rupture
    y The relative narrowing
    KCU Toughness
    HB Brinell hardness number
    HV The Vickers hardness

    Physical characteristics

    Temperature r, kg/m3 l, W/(m · °C) R, Mr. · m С, J/(kg · °C)
    0 7830 46 130 -
    100 - 46 - -
    300 - 41 - 580
    600 - 33 - 970
    900 - 29 - 706
    400 - - - 664
    500 - - - 819
    700 - - - 710
    1100 - - - 685

    A description of the physical symbols

    Name Description
    Е The normal elasticity modulus
    G Modulus of elasticity shear torsion
    r Density
    l Coefficient of thermal conductivity
    R UD. the resistivity
    a The coefficient of linear expansion
    С Specific heat

    Technological properties

    Name The value
    Weldability Does not apply to welded structures.
    Склонность к отпускной хрупкости Tend not.
    The temperature of forging Start - 1180 °C, the end - of 800 °C. the cooling of the workpiece cross-section up to 100 mm in the air, 101-300 mm in the pit.
    Flock-sensitive sensitivity not sensitive.
    Machinability In the annealed condition with HB 187 and blower SB=620 MPa Kn TV.SPL.=1,2 Kn b.St.=1,1.
    Microstructure The microstructure of the untreated strips with thickness up to 2.2 mm on the other 14-1-2993-80 must meet: lamellar pearlite is not more than 6 points; tsementita mesh - no more than 3 points.
    Particularities of production of goods Rod on the other 14-1-505-73 comes Beloretsky metallurgical plant.
    Sanding behaviour Good.