Research On The High-temperature Oxidation And Corrosion Behavior Of Hot-corrosion-resistant Martensitic Steel

With the development of ultra-supercritical thermal power units at home and abroad,the steam pressure and temperature of the boiler are rising,which puts forward more demanding performance requirements for Heat-resistant material used in boiler,especially the anti high temperatureoxidationresistanceandantihotcorrosionresistanceofmaterials,ZG1Cr10NiAlMoVNbN steel is a new type of heat resistant steel for boiler,the study on anti high temperature oxidation resistance and anti hot corrosion resistance has an important guiding significance for designing and developing heat-resistant steel used in boiler.In this paper,the microstructures and mechanical properties at room temperature of three kinds of ZG1Cr10NiAlMoVNbN steels with different aluminum content were studied,Results show that with the increase of Aluminum content in the test steel,the delta-ferrite began to form in the organization,which agrees well with the Thermo-Calc software simulation results,however the formation of delta ferrite in steel has a great influence on the mechanical properties at room temperature,especially theimpact toughness,when the aluminum content of test steel increases to 3.67%,the matrix structure is delta-ferrite,A typical river pattern is shown in the fracture surface of the impact sample,belonging to cleavage fracture mechanism.The static discontinuous weighing method is used for 600?/300 h,650?/300h,800?/300h air oxidation tests.Results show that the addition of aluminum in test steels plays a role in improving its anti high temperature oxidation resistance,and with increasing aluminum content,the antioxidation resistance of test steel gets reinforced.EDS analysis results show that a certain amount of Al oxides generates in Test steel oxide layer.At 600?/300h,650?/300h air oxidation conditions,three kinds of ZG1Cr10Ni Al MoVNbN steels with different aluminum content show excellent antioxidation resistance,belonging to the complete antioxidation level,which is better than the contrast materials such as T91?304?HR3C;and at 800?/300h air oxidation conditions,due to cracking and spalling of the oxide layer,the antioxidant properties of ZG1Cr10NiAlMoVNbN steel get weakened,with the loss of Beneficial antioxidant elements.Meanwhile,600?/300h,650?/300h hot corrosion tests were also carried out,the hot corrosion environment consists of 75%Na₂SO₄+25%NaCl?both mass fraction?salt deposition and air.Results show that the anti hot corrosion resistance of test steel is improved at this hot corrosion conditions,with the increase of aluminum content,and is better than that of contrast material.The adhesion between corrosion layer of the high-Cr alloy steel such as HR3C?304 and substrate is poor,the cracking and spalling of corrosion layer is very serious,showing higher Cr content in the material can't improve its anti hot corrosion resistance at this conditions.