Finite Element Diagnosis and Material-Based Redesign of Dosing Pump Plungers: A Case Study of Premature Failure with Galling Damage

The premature failure (service life ≈ 4 months) of AISI 321 steel plungers due to galling in critical dosing pumps at a thermoelectric power plant significantly compromises system reliability. This study identifies the root cause of this recurring failure and develops a robust engineering solution. Finite element analysis (FEA) was employed to diagnose the original component and numerically validate a redesign using 17-4 PH H900 steel. Additionally, economic viability was assessed through a Life-Cycle Cost (LCC) analysis. The FEA revealed a severe stress concentration where the original design operated at 97.3% of its yield strength, with a critical safety factor of 1.03. This finding suggested that the structural deficiency may have indirectly contributed to the observed galling damage by compromising the contact conditions in the guiding elements. This coupling is proposed as a mechanistic hypothesis, not as an experimentally validated tribological mechanism. The redesigned plunger achieved a safety factor of 5.74, representing a 457% increase in the structural safety margin. Furthermore, the LCC analysis demonstrated the economic superiority of locally manufacturing the improved component rather than importing the original spare part. Ultimately, the proposed solution eliminates the failure’s root cause, proving to be structurally robust and economically viable. The methodology presented offers a transferable framework for diagnosing and redesigning critical industrial components.