Abstract: Pinhole and micro-shrinkage are the ordinary defects founded in the aluminum and magnesium alloy castings, the existence of hydrogen is the main reason for these defaults. So the measurement of hydrogen in aluminum and magnesium alloy melt is an important means to test the degassing effect and to ensure the quality of the melt, and it is significant to improve the casting’s quality. With the increasing application of aluminum and magnesium alloy, the development of quantitative and rapid measurement of hydrogen in aluminum and magnesium alloy melt gets more attractive to the metallurgists and foundrymen. The principles, instruments and features of several popular measurement techniques, such as inert gas circulation method, electrochemical method, pressure evaluation method based on Sieviet’s law and the method based on acoustic emission, are analyzed and evaluate respectly. It is indicated that those measurement techniques taking high testing speed and low testing cost as main characteristics have a great prospect.

Key words: Aluminum and magnesium alloy melt, Hydrogen content, Quantitative measurement