A Novel Approach for Evaluating the Contraction of Hypo-Peritectic Steels during Initial Solidification by Surface...

Area of Science:

• Materials Science
• Metallurgy
• Solidification Science

Background:

• Contraction during the initial solidification of peritectic steels significantly impacts surface defect formation in continuously cast slabs.
• Understanding the contraction behavior is crucial for controlling casting processes and improving product quality.

Purpose of the Study:

• To investigate the contraction behavior during the initial solidification of peritectic and non-peritectic steels.
• To correlate solidification processes with surface roughness.
• To evaluate the effectiveness of surface roughness as a metric for peritectic transformation contraction.

Main Methods:

• Utilized Confocal Scanning Laser Microscopy (CSLM) to observe solidification processes.
• Examined commercial hypo-peritectic and several non-peritectic steels.
• Calculated surface roughness (Ra(δ→γ)) to quantify contraction due to delta-Fe (δ) to austenite (γ) transformation.

Main Results:

• Observed massive δ-γ transformation in hypo-peritectic steel, leading to surface wrinkles and increased roughness.
• Demonstrated a direct relationship between δ-γ transformation and increased surface roughness.
• Validated surface roughness as a viable method for estimating contraction levels.

Conclusions:

• The δ-γ transformation is a primary cause of surface contraction and defects in hypo-peritectic steels.
• Surface roughness measurements provide a reliable and accessible method for estimating the extent of peritectic transformation contraction.
• This finding aids in predicting and mitigating surface defects in continuous casting.