The effect of aging on the mechanical properties and microstructures of a new ZG12Cr9 MolColNiVNbNB ferritic heat resistant steel was investigated in this work to satisfy the high steam parameters of the ultra-supercr...The effect of aging on the mechanical properties and microstructures of a new ZG12Cr9 MolColNiVNbNB ferritic heat resistant steel was investigated in this work to satisfy the high steam parameters of the ultra-supercritical power plant.The results show that the main precipitates during aging are Fe（Cr,Mo）23C6,V（Nb）C,and（Fe2Mo） Laves in the steel.The amounts of the precipitated phases increase during aging,and correspondingly,the morphologies of phases are similar to be round.Fe（Cr,Mo）23C6 appears along boundaries and grows with increasing temperature.In addition,it is revealed that the martensitic laths are coarsened and eventually happen to be polygonization.The hardness and strength decrease gradually,whereas the plasticity of the steel increases.What＇s more,the hardness of this steel after creep is similar to that of other 9%-12%Cr ferritic steels.Thus,ZG12Cr9 MolColNiVNbNB can be used in the project.展开更多
Microstructure and high-temperature dry sliding wear at 600 ~C in ambient air of austenitic heat-resistant steel ZG40Cr25Ni20 with different contents （mass percent） of AI （0 to 7.10~） have been investigated. The r...Microstructure and high-temperature dry sliding wear at 600 ~C in ambient air of austenitic heat-resistant steel ZG40Cr25Ni20 with different contents （mass percent） of AI （0 to 7.10~） have been investigated. The results show that microstructures of 4.68% and 7.10% A1 addition content consist of the matrix and reinforcement of inter- metallic compound y＇ and carbide, while microstructures of ZG40Cr25Ni20 without A1 and with A1 of 1.68% are ab- sent of y＇. Higher wear resistance than the original ZG40Cr25Ni20 alloy is achieved in alloys with higher content of A1 under the same high-temperature wear test condition. The wear rates of Fe-25Cr-20Ni-7.10A1 and Fe-25Cr-20Ni- 4.68A1 are only 20.83% and 45.83% of that of Fe-25Cr-20Ni, respectively. Heat-resistant steels with higher con- tents of AI （4.72% and 7.10%） have higher hardness than those with lower contents of AI （1.68% and 0）. Wear mechanisms of ZG40Cr25Ni20 are considered as severe plough plastic deformation and slight adhesive. However, wear mechanisms of Fe-25Cr-20Ni 4.68A1 are light micro-cutting and oxidation-wear, while that of Fe-25Cr-20Ni- 7. 10A1 are severe adhesive transfer and oxidation-wear_展开更多
By using scanning electron microscopy, energy-dispersive spectrometry, X-ray diffraction, strength and hardness measurements, the microstructure, precipitation, mechanical properties, and corrosion resis- tance have b...By using scanning electron microscopy, energy-dispersive spectrometry, X-ray diffraction, strength and hardness measurements, the microstructure, precipitation, mechanical properties, and corrosion resis- tance have been investigated for two super ferritic stainless steels, 26Cr-3.SMo-2Ni and 29Cr-3.5Mo- 2Ni, with the aim to consider the effect of Cr content. The results showed that with the addition of Cr content, the recrystallization temperature was increased; the precipitation of Laves and Sigma （o） phases was promoted and the mechanical properties of super ferritic stainless steel were modified. Further- more, the pitting corrosion resistance and corrosion resistance to H2SO4 of the two super ferritic stainless steels were improved. In addition, suitable annealing processing is a key factor to maintain integrated performance by optimizing microstructure and removing detrimental precipitation phases.展开更多
基金supported by the Science and Technology Program of Sichuan Province,China(No.2013GZX0146)
文摘The effect of aging on the mechanical properties and microstructures of a new ZG12Cr9 MolColNiVNbNB ferritic heat resistant steel was investigated in this work to satisfy the high steam parameters of the ultra-supercritical power plant.The results show that the main precipitates during aging are Fe（Cr,Mo）23C6,V（Nb）C,and（Fe2Mo） Laves in the steel.The amounts of the precipitated phases increase during aging,and correspondingly,the morphologies of phases are similar to be round.Fe（Cr,Mo）23C6 appears along boundaries and grows with increasing temperature.In addition,it is revealed that the martensitic laths are coarsened and eventually happen to be polygonization.The hardness and strength decrease gradually,whereas the plasticity of the steel increases.What＇s more,the hardness of this steel after creep is similar to that of other 9%-12%Cr ferritic steels.Thus,ZG12Cr9 MolColNiVNbNB can be used in the project.
文摘Microstructure and high-temperature dry sliding wear at 600 ~C in ambient air of austenitic heat-resistant steel ZG40Cr25Ni20 with different contents （mass percent） of AI （0 to 7.10~） have been investigated. The results show that microstructures of 4.68% and 7.10% A1 addition content consist of the matrix and reinforcement of inter- metallic compound y＇ and carbide, while microstructures of ZG40Cr25Ni20 without A1 and with A1 of 1.68% are ab- sent of y＇. Higher wear resistance than the original ZG40Cr25Ni20 alloy is achieved in alloys with higher content of A1 under the same high-temperature wear test condition. The wear rates of Fe-25Cr-20Ni-7.10A1 and Fe-25Cr-20Ni- 4.68A1 are only 20.83% and 45.83% of that of Fe-25Cr-20Ni, respectively. Heat-resistant steels with higher con- tents of AI （4.72% and 7.10%） have higher hardness than those with lower contents of AI （1.68% and 0）. Wear mechanisms of ZG40Cr25Ni20 are considered as severe plough plastic deformation and slight adhesive. However, wear mechanisms of Fe-25Cr-20Ni 4.68A1 are light micro-cutting and oxidation-wear, while that of Fe-25Cr-20Ni- 7. 10A1 are severe adhesive transfer and oxidation-wear_
文摘By using scanning electron microscopy, energy-dispersive spectrometry, X-ray diffraction, strength and hardness measurements, the microstructure, precipitation, mechanical properties, and corrosion resis- tance have been investigated for two super ferritic stainless steels, 26Cr-3.SMo-2Ni and 29Cr-3.5Mo- 2Ni, with the aim to consider the effect of Cr content. The results showed that with the addition of Cr content, the recrystallization temperature was increased; the precipitation of Laves and Sigma （o） phases was promoted and the mechanical properties of super ferritic stainless steel were modified. Further- more, the pitting corrosion resistance and corrosion resistance to H2SO4 of the two super ferritic stainless steels were improved. In addition, suitable annealing processing is a key factor to maintain integrated performance by optimizing microstructure and removing detrimental precipitation phases.
