# Effect of Rare Earth Element Ce on Nanoscale (Ti, Nb) C Precipitates and Mechanical Properties of High-Strength Low-Alloy Weathering Steel

## TL;DR

Adding cerium to weathering steel changes nanoscale precipitates and mechanical properties, affecting strength and deformation behavior.

## Contribution

The study reveals how Ce modifies nanoscale precipitates and inclusion behavior in weathering steel, impacting mechanical performance.

## Key findings

- Ce addition promotes coarsening of nanoscale precipitates, reducing their strengthening effect.
- Ce refines inclusion size and modifies inclusion types, aiding steel purification.
- A high-strength weathering steel with 635 MPa yield strength was fabricated using Ce-modified precipitates.

## Abstract

This study investigates the influence of rare earth element Ce addition on the nanoscale precipitation, microstructure, and mechanical properties of Ti-containing secondary phases in high-strength low-alloy weathering steel. Mechanical property testing and microstructural characterization were performed on experimental samples subjected to rolling-aging treatment. The results demonstrate that the addition of Ce promotes coarsening of nanoscale precipitates, thereby diminishing their precipitation strengthening effect. At a 0.11% Ce content, an increase in inclusions was observed, leading to crack formation during hot deformation. However, Ce addition also refines inclusion size and modifies inclusion types, contributing to steel purification. Through austenite recrystallization zone rolling combined with an isothermal process, a high-strength ferritic weathering steel with nanoscale precipitates was fabricated, exhibiting a yield strength of 635 MPa, tensile strength of 750 MPa, and elongation of 21.2%. Precipitation strengthening plays a critical role in enhancing the room-temperature strength of ferritic steel.