The corrosion resistance and mechanical properties were tested and compared for the newly synthesized as-cast,as-solution Ni-Cr-Mo-Cu corrosion resistant alloys and 1Cr18Ni9Ti austenitic stainless steel. Their valence...The corrosion resistance and mechanical properties were tested and compared for the newly synthesized as-cast,as-solution Ni-Cr-Mo-Cu corrosion resistant alloys and 1Cr18Ni9Ti austenitic stainless steel. Their valence electron structural units were constructed,and the relative parameters were calculated by means of the Empirical Electron theory of Solids and Molecules(EET). The results show that,during alloy elements Cr,Mo and Cu entering Ni-matrix,the bonding strength nA and bonding energy EA of the strongest bond of the alloy are greatly increased,causing the stronger solid solution strengthening effects(about 30% increase in σb). Also,as reinforcement of the main bond network and the improvement of stability of the alloy system due to the solution of these alloying elements in γ-Ni,the ionization of metal atoms in corrosion solution and the flow of electrons from anode to cathode would all be impeded during electro-chemical corrosion processes,which leads to the excellent corrosion resistant ability of the present Ni-Cr-Mo-Cu alloy(about 2-3 orders of magnitude as high as 1Cr18Ni9Ti austenitic stainless steel) in several highly aggressive solutions.展开更多
The use of high-temperature materials is especially important in power station construction, heating systems engineering, furnace industry, chemical and petrochemical industry, waste incineration plants, coal gasifica...The use of high-temperature materials is especially important in power station construction, heating systems engineering, furnace industry, chemical and petrochemical industry, waste incineration plants, coal gasification plants and for flying gas turbines in civil and military aircrafts and helicopters. Particularly in recent years, the development of new processes and the drive to improve the economics of existing processes have increased the requirements significantly so that it is necessary to change from well-proven materials to new alloys. Hitherto, heat resistant ferritic steels sufficed in conventional power station constructions for temperatures up to 550℃ newly developed ferritic/martensitic steels provide sufficient strength up to about 600 - 620℃. In new processes, e.g. fluidized-bed combustion of coal, process temperatures up to 900℃ occur. However, this is not the upper limit, since in combustion engines, e.g. gas turbines. Material temperatures up to 1100℃ are reached locally. Similar development trends can also be identified in the petrochemical industry and in the heat treatment and furnace engineering. The advance to ever higher material temperatures now not only has the consequence of having to use materials with enhanced high-strength properties, considerable attention now also has to be given to their chemical stability in corrosive media. Therefore not only examples of the use of high-temperature alloys for practical applications will be given but also be contributed to some general rules for material selection with regard to their high-temperature strength and corrosion resistance.展开更多
In this study, a roll-bonded UNS N088225 alloy clad pipeline steel was investigated and developed in Baosteel. Based on the requirements of a number of potential projects, we performed a series of strict evaluations i...In this study, a roll-bonded UNS N088225 alloy clad pipeline steel was investigated and developed in Baosteel. Based on the requirements of a number of potential projects, we performed a series of strict evaluations including mechanical and corrosion tests. The results show the mechanical properties and corrosion resistance of this clad steel to be excellent and to meet the requirements of all the design parameters.展开更多
按照ASTM G28—2002(Reapproved 2015)《Standard Test Method for Detecting Susceptibility to Intergranular Corrosion in Wrought,Nickel-rich,Chromium-bearing Alloys》中方法A对供货态和表面处理后SB-444 N06625镍基合金材料进...按照ASTM G28—2002(Reapproved 2015)《Standard Test Method for Detecting Susceptibility to Intergranular Corrosion in Wrought,Nickel-rich,Chromium-bearing Alloys》中方法A对供货态和表面处理后SB-444 N06625镍基合金材料进行腐蚀试验,对腐蚀试验后的材料进行取样和金相检测及对比分析。研究结果表明,供货状态材料表面的保护油脂会在热处理时燃烧并分解为碳及碳化物,造成试样渗碳现象,C元素含量的增多直接导致Cr元素与C元素在镍基合金材料近表面生成Cr23C6并析出,最终造成合金材料耐腐蚀性的下降。而对合金表面先进行脱脂处理,然后进行同样的热处理,试样的腐蚀性能只有轻微下降,可以满足使用要求。展开更多
基金Project (SKL05011) supported by the Foundation of State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, China
文摘The corrosion resistance and mechanical properties were tested and compared for the newly synthesized as-cast,as-solution Ni-Cr-Mo-Cu corrosion resistant alloys and 1Cr18Ni9Ti austenitic stainless steel. Their valence electron structural units were constructed,and the relative parameters were calculated by means of the Empirical Electron theory of Solids and Molecules(EET). The results show that,during alloy elements Cr,Mo and Cu entering Ni-matrix,the bonding strength nA and bonding energy EA of the strongest bond of the alloy are greatly increased,causing the stronger solid solution strengthening effects(about 30% increase in σb). Also,as reinforcement of the main bond network and the improvement of stability of the alloy system due to the solution of these alloying elements in γ-Ni,the ionization of metal atoms in corrosion solution and the flow of electrons from anode to cathode would all be impeded during electro-chemical corrosion processes,which leads to the excellent corrosion resistant ability of the present Ni-Cr-Mo-Cu alloy(about 2-3 orders of magnitude as high as 1Cr18Ni9Ti austenitic stainless steel) in several highly aggressive solutions.
文摘The use of high-temperature materials is especially important in power station construction, heating systems engineering, furnace industry, chemical and petrochemical industry, waste incineration plants, coal gasification plants and for flying gas turbines in civil and military aircrafts and helicopters. Particularly in recent years, the development of new processes and the drive to improve the economics of existing processes have increased the requirements significantly so that it is necessary to change from well-proven materials to new alloys. Hitherto, heat resistant ferritic steels sufficed in conventional power station constructions for temperatures up to 550℃ newly developed ferritic/martensitic steels provide sufficient strength up to about 600 - 620℃. In new processes, e.g. fluidized-bed combustion of coal, process temperatures up to 900℃ occur. However, this is not the upper limit, since in combustion engines, e.g. gas turbines. Material temperatures up to 1100℃ are reached locally. Similar development trends can also be identified in the petrochemical industry and in the heat treatment and furnace engineering. The advance to ever higher material temperatures now not only has the consequence of having to use materials with enhanced high-strength properties, considerable attention now also has to be given to their chemical stability in corrosive media. Therefore not only examples of the use of high-temperature alloys for practical applications will be given but also be contributed to some general rules for material selection with regard to their high-temperature strength and corrosion resistance.
基金partially sponsored by Shanghai Pujiang Program(No.16PJ1430200)
文摘In this study, a roll-bonded UNS N088225 alloy clad pipeline steel was investigated and developed in Baosteel. Based on the requirements of a number of potential projects, we performed a series of strict evaluations including mechanical and corrosion tests. The results show the mechanical properties and corrosion resistance of this clad steel to be excellent and to meet the requirements of all the design parameters.
文摘按照ASTM G28—2002(Reapproved 2015)《Standard Test Method for Detecting Susceptibility to Intergranular Corrosion in Wrought,Nickel-rich,Chromium-bearing Alloys》中方法A对供货态和表面处理后SB-444 N06625镍基合金材料进行腐蚀试验,对腐蚀试验后的材料进行取样和金相检测及对比分析。研究结果表明,供货状态材料表面的保护油脂会在热处理时燃烧并分解为碳及碳化物,造成试样渗碳现象,C元素含量的增多直接导致Cr元素与C元素在镍基合金材料近表面生成Cr23C6并析出,最终造成合金材料耐腐蚀性的下降。而对合金表面先进行脱脂处理,然后进行同样的热处理,试样的腐蚀性能只有轻微下降,可以满足使用要求。
