According to relevant standards

there are four main testing methods for diffusive hydrogen:glycerol method

mercury method

gas chromatography method and thermal displacement method. Among them

glycerol method has the characteristics of the most common application

the longest use time

the lowest test cost and the best safety

so it has been applied in the standard for a long time. However

the accuracy of glycerol method is low

especially in the case of ultra-low hydrogen

it is difficult to meet the requirements. The latest national standards are no longer recommended. Based on the discharging method of Tianjin University

a new diffusive hydrogen testing technology by glycerol method was realized through structural optimization and improvement. The results show that the precision of alkaline electrode E5015（Tianjin Bridge） used in electrode arc welding is 24%～28% higher than that of KQ-3 equipment

28% higher than that of CO

2

gas shielded welding and 28.7% higher than that of argon arc welding.