Creep Test & Creep Rupture Test

Creep Test and Creep Data Analysis

JFE-TEC will perform commissioned "Creep characteristic" test. Deformation of metallic materials will stop even under loading at room temperature if it is below the breaking force. However, the deformation will not stop at high temperature above a certain temperature even under a constant force, and it will continue to be deformed with elapsed time until rupture. This is so-called creep deformation and creep rupture of materials.

Since life of equipment used under high temperature is often determined by the creep rupture of materials, creep characteristics are incorporated in the safety standards used in various fields including thermal power generation.

Outline of Creep Test

• Creep test :
  Creep elongation is measured with elapsed time, and creep curve is determined accordingly.
• Creep rupture test :
  Creep rupture time, break elongation and reduction of area at break are determined. Stress vs rupture time curve is determined and creep rupture characteristics are evaluated.
• Internal-pressure creep test :
  Creep characteristics are evaluated under pressurized conditions to internal surface of a steel pipe.

Creep Test Equipment

Name	Outline of specification
Single creep test machine	Test temp. : max. 1050℃, load: max. 3 tons, 180 units Test temp. : max. 800℃, load: max. 5 tons, 5 units
Spring-type multi creep test machine	Test temp. : max. 750℃ Load: max. 0.8 tons, 6 units (× 6 pull rods/unit × 8 pieces/pull rod)
Lever-type multi creep test machine	Test temp. : max. 900℃ Load: max. 1.5 tons, 12 units (× 6 pull rods/unit × 3 pieces/pull rod)
Direct loading-type creep test machine	Test temp. : max. 1000℃, load: up to 100 kg, 2 units
Internal pressure creep test machine	Test temp. : 300℃ to 800℃ Test pressure: max. 1,500 atm Pipe size: up to 60 mmφ, 6 units

Measurement Example of Creep Curve

Sample:Low alloy steel (JIS STBA25: 5Cr-0.5Mo steel)

Test stress :120MPa

Test temp :550℃

Test machine :Single creep test machine