Hydrogen Damage Of Cold And Hot Rolled Strip Working In Hydrogen Environment

The involvement of hydrogen can degrade the properties of the metal material.When there is an external load,the plasticity of the material is reduced,and under some certain conditions will induce the generation of cracks,causing the material to fail early in service.The research on the hydrogen damage of cold and hot rolled strip working in hydrogen environment,study on the hydrogen resistance and hydrogen damage of materials with different processes,it's an important and practical subject.The main contents of this paper are as follows:(1)The hydrogen diffusion coefficient of cold and hot rolled 65 Mn was measured,it can provide an important basis for the study of hydrogen damage resistance of materials.Since the radius of free hydrogen atom is very small,hydrogen is susceptible to migration and diffusion due to the effects of concentration,temperature and stress gradients in metallic materials,and the difficulty of hydrogen diffusion in different materials is often not the same.Therefore,the measurement of hydrogen diffusion coefficient is the basis of subsequent experimental study.(2)Carried out the electrochemical hydrogen charging and tensile test of cold rolled and hot rolled 65 Mn specimens.Promote Fick 's Law based on the experiment,and the time and current density of electrochemical hydrogen charging were determined through calculation and simulation to ensure that the specimens has different hydrogen content.The tensile strength,yield strength,elongation and section shrinkage of the specimens with different hydrogen concentrations were recorded and measured,therefore The effects of different hydrogen contents on the strength and toughness of metals can be analyzed.Compared the Hydrogen damage resistance of 65 Mn material with cold and hot rolled process can provide guidance for the selection of metal materials in the presence of hydrogen.(3)Observation of the fracture surface of tensile specimens,including macroscopic observation with naked eye and optical microscope and microscopic observation using scanning electron microscope,the macro and micro fractography of tensile specimens were analyzed.Studied the fundamental reason for the loss of the strength and toughness of 65 Mn material under the intervention of hydrogen,and the influence of hydrogen content on the fracture properties of the material.