# Influence of Sample Mass and Pouring Temperature on the Effectiveness of Thermal Analysis for Estimating Gray Iron Inoculation Potential

## TL;DR

This study examines how sample mass and pouring temperature affect thermal analysis for controlling gray iron inoculation potential and melt quality.

## Contribution

The study identifies the minimum eutectic temperature as a reliable parameter for inoculation control under varying mass and temperature conditions.

## Key findings

- Minimum eutectic temperature is robust for inoculation control with cup masses between 268–390 g and pouring temperatures between 1235–1369 °C.
- Cups under 268 g and low pouring temperatures are unsuitable for inoculation control but still useful for carbon equivalent control.
- Cooling times under 180 s indicate unsuitable samples, and a bimodal cell surface population was observed in the samples.

## Abstract

Thermal analysis (TA) has been a valuable tool for controlling the carbon equivalent (CE) of cast irons. Additionally, this technique can provide enhanced control over melt quality, allowing for the avoidance of defects such as undesirable graphite morphology and the formation of carbides. To obtain the most valuable information from the TA, it is necessary to minimize the variations in the filling operation of the TA cups. However, the mass and pouring temperature of TA cups can vary in TA’s typical foundry operations. A design of experiments was performed to determine whether specific parameters of cooling curves used for quality control can distinguish the inoculation effect in the melt when the mass and the pouring temperature of TA cups are varied. The minimum temperature of the eutectic arrest proved to be a robust inoculation potential control parameter when variations in the cup’s mass were within a range of 268–390 g and were filled at any pouring temperature between 1235 and 1369 °C. Lighter cups under 268 g and poured at a low temperature are not suitable for controlling inoculation potential by TA; however, they remain helpful in controlling CE. These later cups are related to cooling times of less than 180 s, which can serve as a criterion for discarding unsuitable samples. A bimodal population of cell surfaces was revealed in the samples, with the population of small cells being proportionally more numerous in samples with lower TEmin values.