Method for detecting phase change temperatures of molten metal

A method of detecting phase change temperatures of a sample of molten iron or molten cast iron, the method comprising the steps of:

• providing a detection device including a temperature sensor and a sample cup with a cavity configured to receive a sample of molten iron or molten cast iron;
• arranging a blob in the cavity, the blob comprising a carbide stabilizer and magnesium hydroxide as a hydrogen releasing material;
• depositing a sample of molten iron or molten cast iron into the cavity, the blob reacting with the molten iron or molten cast iron sample upon contact therewith, such that hydrogen is released from the magnesium hydroxide into the molten iron or molten cast iron sample;
• and
• allowing the molten iron or molten cast iron sample to solidify while simultaneously measuring phase change temperatures of the solidifying sample.