How to Improve Fatigue Life and Residual Stress in Compressor Reeds through Shot Peening

Abstract

Numerous industrial areas involve the utilization of shot peening as a well-known surface enhancement method for increasing the fatigue life and residual stress of cyclically loaded crucial parts. This study examines the effects of shot peening on compressor reeds that can lengthen their life cycle with an accelerated rate of residual stress thereby improving reliability and performance of entire compressor system. The paper explains the principles behind shot peening, its influence on materials, and some specific advantages that it gives to thin reed compressors. Materials selection, parameters for shot peening and testing methods are described as experimental methods. Results from residual stress analysis show how much more efficient shot peening makes compressor reeds tough and reliable. Moreover, this paper provides insight into practical aspects, difficulties faced in practice and directions for further research when applying shot peeing to compressor’s reed components.

Introduction

I. INTRODUCTION

Compressor reeds are vital components in reciprocating compressors, responsible for sealing gas passages and managing fluid flow within the system. These reeds experience substantial cyclic loading during operation, which can lead to fatigue failure over time. Improving the fatigue life and residual stress of compressor reeds is crucial for enhancing the reliability and longevity of compressor systems. Shot peening, a surface treatment technique, has proven to be a promising method to achieve these goals.

II. PRINCIPLES OF SHOT PEENING

Shot peening is a cold working process where the surface of a material is bombarded with small spherical media, typically composed of steel, ceramic, or glass, at high velocities. This process causes plastic deformation on the surface, generating compressive residual stresses while enhancing surface hardness and resistance to fatigue crack initiation and propagation.

III. EFFECTS OF SHOT PEENING ON MATERIAL PROPERTIES

Shot peening brings about several beneficial changes in material properties, including:

1. Generation of compressive residual stresses.
2. Work hardening and improvement in surface hardness.
3. Reduction of surface roughness and microcracks.
4. Enhancement of fatigue strength and resistance to corrosion.

IV. APPLICATION OF SHOT PEENING TO COMPRESSOR REEDS

For compressor reeds, shot peening offers numerous advantages:

VI. RESULTS AND DISCUSSION

The analysis of residual stress indicates that shot peening significantly enhances the performance of compressor reeds. Shot peened reeds show a marked improvement in fatigue life and exhibit higher levels of compressive residual stress when compared to untreated reeds. This section explores the mechanisms behind these improvements and their implications for the reliability of compressor systems.

VII. LIFE PREDICTION

The Paris equation describes the stage II crack growth behavior during fatigue in metallic materials and is used to evaluate crack propagation life. In this equation, 'da/dN' represents the crack growth rate, while 'ΔK' is the range of stress intensity factor (ΔK = Kmax - Kmin). The constants 'C' and 'n' are the Paris constants. With the introduction of the concept of crack closure by Elber, the Paris law was modified to use 'ΔKeff' instead of 'ΔK'. This modification accounts for the higher crack opening levels in peened components, resulting in a lower 'ΔKeff'. Here, 'Kop' is the crack opening stress intensity factor after shot peening, leading to a reduced crack growth rate in peened components (da/dN)p. The modified Paris law is expressed as (da/dN)p = C(ΔKeff)^n.

VIII. PRACTICAL CONSIDERATIONS AND CHALLENGES

Implementing shot peening for compressor reeds involves several practical considerations such as the availability of appropriate equipment, maintaining process control, and meeting surface finish requirements. Challenges like peening-induced surface roughness and potential material degradation must be addressed through process optimization and stringent quality control measures.

Conclusion

In conclusion, shot peening is an effective method for enhancing the fatigue life and residual stress of compressor reeds, thereby boosting the reliability and performance of compressor systems. Future research could focus on developing new shot peening techniques, optimizing process parameters for specific compressor applications, and exploring the combined effects of shot peening with other surface treatment methods.

References

[1] \"Impact\", Fall 1989, Metal Improvement Company, Bloomfield, Connecticut. [2] “John S. Eckersley, ushing shot peening to multiply the life of compressor components” [3] https://istsurface.com/resources/abrasive-blasting-equipment/shot-peening/ [4] https://img.antpedia.com/standard/pdf/T06/1612/SAE%20J2441-2000_317.pdf [5] \"SAE J2441, Issued 2000-08, Surface Vehicle standard. [6] \"SAE AMS2430, Issued 1948-09, AEROSPACE MATERIAL SPCIFICATION [7] SHOT PEENING A N D ITS I M P A C T O N FATIGUE LIFE OF ENGINEERING COMPONENTS R . K . Pandey M. N. Deshmukh, Department of Applied Mechanics, Indian Institute of Technology, Delhi, India [8] ARAI -Automotive Research Association of Indi, Research Institute of the automotive industry with Ministry of Heavy Industries, Govt. of India This research paper provides valuable insights into the application of shot peening for enhancing the performance of compressor reeds, contributing to the advancement of surface engineering technologies in the field of compressor systems.

Copyright

Copyright © 2024 Anand Kalamkar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.