AUSTENITIC STAINLESS STEELS

EVALUATION OF THE FATIGUE STATE OF EQUIPMENT FROM AUSTENITIC STAINLESS STEELS

In stainless austenitic metastable steels at production stage and during the operation life, occur technological and operational phase transformations, resulting in accumulation of ferritic phase. Heating and deformation in production and heating pressure loads and other parameters in operating lead to ferritization, and fatigue type degradation, accumulation of damage at micro level. Most effective monitoring of such two-parameter degradation can be carried out using a non-destructive method to measure the magnetic characteristic, the coercive force.

Applications:

● Nuclear power plants,

● Oil & gas industry,

● Chemical,

● Food industry.

Equipment:

● Magnetic structurescope (coercimeter) MC-04H-2

 

 

 

Steel grade: 

● 12X18H10T (chemical composition: C – 0.98; Mn – 1.33; Si – 0.66;
Cr – 18.2; Ni – 10.6; Ti – 0.66; Mo ≤ 0.1; S – 0.003; P – 0.40)

● 08X18H9 (C – 0.036; Mn – 1.73; Si – 0.42; Cr – 18.2; Ni – 8.2; Ti ≤ 0.1;
Mo ≤ 0.20; S – 0.003; P – 0.028)

Tension test specimens: strip-shaped
Form of samples
for cyclic hydraulic
internal pressure tests:

● pipe segments diameters 73 and 42 mm wall thicknesses of 3 and 1 mm

● spherical hollow cylinders diameter 130 mm and wall thickness 3 mm

Cyclic tests mode: low-cycle fatigue mode
Limit of load: fatigue
Coercive force variation: from 0 to 45 A/cm