The Influence of Segregations after Forming on the Heat Treatment Result of Bevel Gears

Abstract

The process‐chain of highly stressed parts incorporates among others casting, forming, and heat treatment. Segregations are always found within these parts. Segregations and its consequences are only understandable by considering the whole process‐chain. In this paper, segregations within the hot rolled bar and after cold forging to bevel gears are analyzed metallographically. Dilatometer specimens are used for analyzing the phase transformation behavior from different segregation structures within the hot rolled bar. The deformation during forming and the influence on the microstructure after heat treatment is discussed. A coupled forming‐heat treatment simulation is presented based on the experimental findings. The deformation of the macro‐segregation is calculated by a forming simulation. A phase transformation model depending on the macro‐segregation is used for calculation of the microstructure after heat treatment. The final microstructure and hardness distribution of formed parts is calculated and discussed in comparison with the experimental results.

Optimizing Mandrel Dimensions for a Fixture Hardening Process of High-Strength Steel Aerospace Parts by Finite Element Simulation

“…Parameters to calculate plastic deformations as described in Equation (6) are given in Table 2: Table 2. Hardening parameters for steel SAE 5120 according to work in [21,22]. Due to confidentiality some of the measured data, e.g., values for Martensite Start temperatures and the fitted k parameter cannot be made available for this publication.…”

“…Parameters to calculate plastic deformations as described in Equation (6) are given in Table 2: Table 2. Hardening parameters for steel SAE 5120 according to work in [21,22].…”

Effect of Design Modification on the Distortion Behavior of a Complex Counter Gear

“…In the last decade, the effect of segregation on distortion behavior has been extensively researched using both experiments and simulation [15][16][17]. Furthermore, in recent times, process chain simulations have gained importance, and work has been carried out on the combination of forging and heat treatment with a focus on segregation [18], as well as forming, heat treatment, and crash [19]. However, most of the research focuses on improving and optimizing processes and process steps, understanding the influence of different effects arising during heat treatment on final properties and distortion, and the effect of different manufacturing processes on the final distortion behavior.…”

“…Figure18. Tilt angle development of web, gear rim, and gear tooth for the geometry type G3 (circle with fill) and comparison with geometry type G5 (circle without fill) during quenching (left), and temperature distribution and contour plot for G3 and G5 after 5 s (right).…”