test
Vybavení
Creep laboratories
31 creep machines of own construction allowing:
  1. constant tensile load tests
    • max. load 8000 N
    • max. elongation (50 mm gauge length of specimens) 0.60 (0.47 true)
  2. constant tensile stress tests
    (Hostinský and Čadek, J. Test. Eval. 4, 1976, p. 26)
    • max. initial load 8000 N
    • max. elongation 0.42 (0.35 true)
    • specimen gauge lengths 25, 35 and 50 mm
  3. constant compressive stress tests
    ( Dobeš et al., J. Test. Eval. 14, 1986, p. 271)
    • max. load 8000 N
    • max. elongation 0.32 (0.28 true)
    • specimen gauge lengths 10, 12, 15 mm
  4. constant tensile stress (or load) with a possibility of rapid cooling under stress at a predetermined time of creep exposure - see a) or b) - 1 machine
  5. combined creep and fatigue tests - 2 machines
    • max. load 8000 N
    • frequency 25 Hz
    • load amplitude 500 A
  6. small punch creep test (ceramic ball is penetrated through a thin disk under a given force, central deflection of the disc is measured)
In all tests - possibility of protective atmosphere: purified dry argon, hydrogen, nitrogen
Testing temperatures:
R.T., 150 - 1000 °C, constant within:
  • 1 deg for 150 - 600 °C
  • 2 deg for 650 - 1000 °C
Temperature gradient along the whole 50 mm gauge length - lower than 2 deg
Elongation detection:
  • continuous analog and digital recording
  • range of creep rates: 10-10 to 10-2 s-1
  • registration of data - PROGRAM CRTES1
Creep curves processing:
  • fitting by standard constitutive equations; statistical treatment.
Possibility of recording of creep tests with varying applied stress:
  • computer treated creep dip tests, tests with slow applied stress cycling
Laboratory of Viscous Creep
The laboratory is equipped with two special creep machines for low stress/low strain rate creep tests using helicoid spring specimen technique and one special creep machine for low stress / low strain rates torsion tests of brittle materials (ceramics, intermetallics). Optical measurement of strain eliminates any influence on the stress state and provides high strain sensitivity.
Helicoid spring machines
  • Temp. range: 150°C to 1000°C
  • Stress range: 0.2MPa to approx. 100MPa
  • Strain sensitivity: better than 10-6
  • Strain rate range: 10-9 to 10-13 s-1
  • Protective atmosphere: purified argon or hydrogen, air
Two methods have been developed to produce the helicoid spring specimens from metallic materials
  1. (right) Wire drawing, wounding on the threaded bolt and annealing. The method is suitable for pure metals and mild model alloys.
  2. (left) Machining from tube. The method is suitable for structural materials. The microstructure of the original tube is maintained
Torsion machine
  • Temp. range: 300°C to 1200°C
  • Stress range: 2MPa to approx. 100MPa
  • Strain sensitivity: better than 10-6
  • Strain rate range: 10-9 to 10-13 s-1
  • Atmosphere: air
Poslední změna
26. 08. 2009