The Effect Of Hydrogen Anti-permeation Agent On Hydrogen Damage Behavior Of 10CrSiNiCu Steel In The Simulated Deep Sea Environment

Due to the high specific strength and great welding property,low alloy high strength steel has been widely utilized in ocean structure and shipbuilding industry.For example,many submarines and ships were built by low alloy high strength steel 10CrSiNiCu.However,there are high density dislocations and defects in metallic matrix,which make small hydrogen atoms enter so easily to deteriorate the plasticity.Thus,high strength steel tends to occur hydrogen embrittlement and has high hydrogen-induced damage(HID)susceptibility.As the shallow sea resources are consumed more and more,deep sea resources cause more and more concern.Compared to shallow sea environment,deep sea environment is more severe,and the requirement of corrosion resistance and mechanical property of naval materials is higher,while the use of low alloy high strength steel was restricted because of its high HID susceptibility.However,there is little research on hydrogen-induced damage of metals in deep sea environment,let alone on the compound action of hydrostatic pressure and hydrogen anti-permeation agent on HID.Therefore,it is important to do this.In this paper,under the condition of uniaxial tensile stress or not,the effect of compound action of different hydrostatic pressure and hydrogen anti-permeation agent on HID and its mechanism has been studied by Devnathan-Stachurski double cell hydrogen permeation experiments,tensile test,weight loss experiments,potentiodynamic polarization test,electrochemical impedance spectroscopy test,microscopic surface morphology observation and so on.Besides,the effect of compound action of hydrostatic pressure and different concentration of hydrogen anti-permeation agent on HID has been studied.The results indicate that:With the increasing of hydrostatic pressure,the degree of HID and corrosion of high strength steel 10CrSiNiCu became lower and then rose.As the hydrogen anti-permeation agent is added into corrosive medium,the degree of HID and corrosion was inhibited more.This is because that:(1)Under the hydrostatic pressure,the hydrogen atoms and hydrogen molecules on surface are fixed at active position so that subsequent hydrogen ion is hindered and subsequent reaction is inhibited.But when the hydrostatic pressure reached 90atm,the fixed hydrogen atoms left the surface by the only way enter in the metal.Therefore,it accelerated the degree of HID and corrosion.(2)The hydrogen anti-permeation agent could occupy active position.When hydrostatic pressure existed,hydrogen anti-permeation agent was fixed at active position to inhibit the sequent reaction.Besides,hydrogen anti-permeation agent could accelerate the process of dehydrogenation,which reduced the concentration of Had and the degree of HID.(3)When hydrostatic pressure<80atm,the compound action of hydrostatic pressure and hydrogen anti-permeation agent could enhance the effect of inhibiting HID and corrosion.But after hydrostatic pressure>90atm,hydrostatic pressure played the leading role.Meanwhile,hydrostatic pressure inhibited the process of dehydrogenation.All this made the compound action of hydrostatic pressure and hydrogen anti-permeation agent not inhibit HID.Under the condition of hydrostatic pressure,the added hydrogen anti-permeation agent could inhibit HID effectively.What's more,it existed some concentration that inhibited HID best.It is due to the synthetic effect of covering of hydrogen anti-permeation agent and accelerating the process of dehydrogenation.Under the condition of uniaxial tensile stress,the effect of compound of different hydrostatic pressure and hydrogen anti-permeation agent is the same as the one under no stress condition.But the effect is weaker,and it could not inhibit HID.This is because the uniaxial tensile stress reinforced the adsorption of Had so that enhanced the quantity of permeating hydrogen atoms.What's more,the loss of plasticity existed a upper limit.Because of the uniaxial tensile stress,the loss of plasticity of high strength steel 10CrSiNiCu exceeded the upper limit.Thus,the hydrostatic pressure and hydrogen anti-permeation agent could not work.