Investigation of the Precipitation and Solid Solution Behavior of TiN Inclusions in SWRH92A High‐Carbon Tire Cord Steel

Abstract

TiN, a typical nonmetallic titanium inclusion, is regarded harmful for the quality of hypereutectoid tire cord steel. At present, the effective methods of controlling the TiN inclusions in the high‐carbon tire cord steel are still uncertain. Herein, the precipitation and solid solution behavior of the TiN inclusions in SWRH92A tire cord steel are studied. The main characteristics, e.g., size distribution and morphology, of the TiN inclusions precipitated under different steel remelting conditions (e.g., Ti and N concentrations and cooling rate) are analyzed. The results indicate that the average TiN inclusion size is proportional to the Ti and N concentration product, and Ti shows larger effect on the TiN inclusion size than N. For the samples with heat treatment, the number percentage and average size of larger TiN inclusions decrease compared with reference sample. As heating temperature increases from 1150 to 1250 °C, the total TiN inclusion number decreases, and the number percentage and average size of larger TiN inclusions decrease. After heating, the sample with a higher cooling rate has a higher number percentage of finer inclusions and the average size of larger inclusions is smaller, indicating that increasing cooling rate is helpful to refining the TiN inclusions.