Algorithm Scheme to Simulate the Distortions during Gas Quenching in a Single-Piece Flow Technology

Jacek Sawicki,Victoria Buzalski,Krzysztof Krupanek,Wojciech Stachurski

doi:10.3390/coatings10070694

Jacek Sawicki, Victoria Buzalski + Show 2 more

Open Access

https://doi.org/10.3390/coatings10070694

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Abstract

Low-pressure carburizing followed by high-pressure quenching in single-piece flow technology has shown good results in avoiding distortions. For better control of specimen quality in these processes, developing numerical simulations can be beneficial. However, there is no commercial software able to simulate distortion formation during gas quenching that considers the complex fluid flow field and heat transfer coefficient as a function of space and time. For this reason, this paper proposes an algorithm scheme that aims for more refined results. Based on the physical phenomena involved, a numerical scheme was divided into five modules: diffusion module, fluid module, thermal module, phase transformation module, and mechanical module. In order to validate the simulation, the results were compared with the experimental data. The outcomes showed that the average difference between the numerical and experimental data for distortions was 1.7% for the outer diameter and 12% for the inner diameter of the steel element. Numerical simulation also showed the differences between deformations in the inner and outer diameters as they appear in the experimental data. Therefore, a numerical model capable of simulating distortions in the steel elements during high-pressure gas quenching after low-pressure carburizing using a single-piece flow technology was obtained, whereupon the complex fluid flow and variation of the heat transfer coefficient was considered.

Highlights

Avoiding distortions is cost-effective for the quality control of chemically treated steel elements.As an example, gears with large distortions can produce more noise and have shorter durability [1,2].the correction of distortions is one of the most expensive processes [3,4,5]
In the perspective of constructing a new device that gives optimized outcomes in minimizing distortions, this study developed a simulation around Vacuum UniCase Master (UMC® ) Furnace design by SECO/WARWICK (Świebodzin, Poland) that uses low-pressure carburizing (LPC), followed by high-pressure gas quenching (HPGQ) in a 4D chamber (4D Quench® ), all conducted using the single-piece flow method
This paper proposes an algorithm scheme that provides accurate simulation results of distortions formed during the quenching process

Summary

Introduction

The correction of distortions is one of the most expensive processes [3,4,5]. For this reason, despite being inevitable [6,7], methods to avoid them as much as possible must be developed and studied. In the perspective of constructing a new device that gives optimized outcomes in minimizing distortions, this study developed a simulation around Vacuum UniCase Master (UMC® ) Furnace design by SECO/WARWICK (Świebodzin, Poland) that uses low-pressure carburizing (LPC), followed by high-pressure gas quenching (HPGQ) in a 4D chamber (4D Quench® ), all conducted using the single-piece flow method. The single-piece flow model takes every single element through the exact same position and process conditions as the others, avoiding variations in the physical and Coatings 2020, 10, 694; doi:10.3390/coatings10070694 www.mdpi.com/journal/coatings

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