Effect of Diffusion Hydrogen Distribution in the Fusion Zone on Welding Crack for HQ130 High Strength Steel

摘要

The distribution of diffusion hydrogen in the welding zone of HQ130 high strength steel is calculated by using finite element method (FEM). The finite element program of diffusion hydrogen in the welding zone is worked out. In the program, the effects of welding heat input (E), temperature and surface-escaping coefficient of hydrogen etc., are taken into account. Crack morphology in the fusion zone and effect of diffusion hydrogen on crack is analyzed. Crack originated in the partially-melted zone at about 20-60 μm from the melting interface line and propagated parallel to the fusion zone or turned into the weld metal. Hydrogen accumulates seriously nearby the fusion zone, particularly at the root fusion zone. This is one of the important reasons why cracks are produced in this zone. The test results and analysis indicate that welding heat input should be controlled to about E = 1.28 kJ/mm to prevent crack producing and propagating for HQ130 steel.