Quantification of ridging in ferritic stainless steel sheets by electron backscattered diffraction R-value maps

Area of Science:

• Materials Science
• Metallurgy
• Surface Engineering

Background:

• Ferritic stainless steel (FSS) is prone to surface defects like ridging during deep drawing processes.
• The formation of ridging is linked to the heterogeneous distribution of grain orientations within the material.

Purpose of the Study:

• To investigate the relationship between grain orientation distribution and ridging formation in FSS sheets.
• To introduce and utilize a novel electron backscattered diffraction R(α)-value map for analyzing ridging.
• To understand the influence of tensile directions on ridging severity.

Main Methods:

• Development and application of a new electron backscattered diffraction (EBSD) R(α)-value map.
• Analysis of grain orientation distributions in FSS sheets.
• Correlation of R(α)-value map features with observed ridging defects.

Main Results:

• The study successfully introduced an R(α)-value map for assessing grain orientation in FSS.
• A direct correlation was found between large grain colonies visualized in R(α)-value maps and the occurrence of severe ridging.
• The dependence of tensile directions on ridging formation was elucidated through the R(α)-value map analysis.

Conclusions:

• Large grain colonies are a critical factor contributing to severe ridging defects in FSS.
• The R(α)-value map is an effective tool for predicting and understanding ridging formation in deep-drawn FSS.
• Controlling grain colony size and distribution is essential for mitigating ridging in FSS manufacturing.