Comprehensive investigations and simulation study on fractured tenon of
compressors X20Cr13 blade used in ironmaking plant
Abstract
The fracture of compressor blade’s tenon is a concrete problem in the
operation of ironmaking plant. A systematic research on the fracture
failure of the tenon of X20Cr13 blade has been carried out in this
paper. Systematic research consists of two parts: comprehensive analysis
and simulation analysis. Comprehensive analysis includes macroscopic
analysis, metallographic structure analysis, SEM characterization, EDS
characterization, mechanical property analysis, chemical composition
analysis, hardness analysis and assembly structure analysis. The
simulation analysis includes heat treatment simulation analysis, static
stress software simulation analysis and resonance damage calculation
analysis. The comprehensive analysis shows that the performance,
chemical composition and hardness of blade are not the cause of failure.
The cracks of blade tenon have the obvious fatigue crack
characteristics. The fretting wear can produce the failure source which
leads to the occurrence and development of cracks. A large number of
M23C6 carbides with large particle size appeared in the metallographic
structure and distributed unevenly and intensively along the grain
boundary. These carbides not only damage the continuity of matrix
structure but also create conditions for the initiation and propagation
of fatigue cracks. Improper assembly of blades can also lead to
excessive local stress. The simulation analysis further confirmed that
the stress at the root of blade tenon is too large and the possibility
of failure caused by resonance is eliminated. Improper heat treatment is
also one of the causes of fracture. Based on the research conclusion,
this paper also puts forward some constructive suggestions for this
engineering problem.