The Improvement Mechanical Properties of Pressure Tube by Induction Hardening Process

Abstract

The aim of this study was to explore the impact of induction hardening on the microstructure and mechanical properties of AISI 4130 steel improvement strength of pressure tube application. The primary objective is to enhance the strength of the tube ends, which are susceptible to failure due to excessive loads during service. However, due to the shape limitations of the pressure tube, traditional electric furnace hardening methods cannot be used to increase its strength. Therefore, there is a need to study induction hardening methods that can apply localized heat treatment. The investigation commenced use of finite element analysis to predict the result of the process. In experiments the samples were heated with a 15 kHz medium frequency induction hardening process, followed by water quenching. Subsequently, the samples underwent metallographic preparation, microstructural analysis, hardness testing and tensile testing. The findings revealed that the microstructure of Hardening Zone, HZ exhibited lath martensite and retained austenite in their microstructures. The average as-rolled was mechanical properties measured at 284.65 HV for hardness and ultimate and yield strength 749.39 MPa, 685.17 MPa respectively for tensile properties. In contrast, Hardening Zone, HZ containing lath martensite, experienced an approximately two-fold increase in mechanical properties compared to the as-rolled state. The finite element analysis results are closely align with experimental findings. Conclusion, induction hardening proved to be an effective heat treatment method for enhancing the mechanical properties of the AISI 4130 steel, as evidenced by the observed changes in microstructure and mechanical properties. The above method can be applied to improve the mechanical properties of pressure tube to application more responsive to usage. Furthermore, it confirms the usefulness of finite element methods in the design process.