Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering st...Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering steel.The rust layers formed on weathering steel were characterized by scanning electron microscopy,X-ray diffraction,electron probe microanalysis,X-ray photoelectron spectroscopy,and electrochemical measurements.The results of periodic immersion corrosion test for 72 h showed that the mass loss rates of Cu-P-Cr-0.14Ni steel and Cu-P-Cr-0.04Ni steel were 1.57 and 1.61 g/(m^(2)h),respectively.According to the electrochemical experiment,the corrosion potentials of the two tested steels at the initial stage of corrosion were-0.6852 and-0.7037 V,respectively.With the corrosion time reaching 72 h,the corrosion potential difference between the two tested steels was gradually reduced.In the initial stage,NiO was formed in the rust layer and can dramatically promote the crystallization of corrosion products to improve the stability of the rust layer.After periodic immersion corrosion test for 72 h,Ni element had no obvious effect.At this time,it was mainly the enrichment of Cu and Cr elements in the form of CuO and Cr_(2)O_(3)in the rust layer that could further protect the matrix.展开更多
The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti content.The yield strength and elongation of the ...The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti content.The yield strength and elongation of the steel were 640 MPa and 25.5%,respectively.The microstructure was ferrite and pearlite,and the average grain size was 5.4μm.The precipitates were mainly TiC with the size below 20 nm,and the average diameter was 18.2 nm.The yield strength of the newly proposed weathering steel with Ti content of 0.018%higher than that of the traditional steel reached up to 709 MPa,and the elongation was 23.5%.The ferrite grain was refined to 3.8μm,the fraction of TiC under 10 nm was obviously increased,and the average diameter of particles was 9.8 nm.The increase in Ti also promoted the recrystallization process,thus leading to the reduction in dislocation density.The yield strength of the newly proposed weathering steel was increased to higher than 700 MPa by adjusting the Ti content mainly resulting from three aspects:grain refinement,precipitation and dislocation strengthening.The contributed values were 45,64 and–40 MPa,respectively.展开更多
基金The authors appreciate the financial support from Maanshan Iron&Steel Co,Ltd.and Student Research Training Program of University of Science and Technology Beijing.
文摘Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering steel.The rust layers formed on weathering steel were characterized by scanning electron microscopy,X-ray diffraction,electron probe microanalysis,X-ray photoelectron spectroscopy,and electrochemical measurements.The results of periodic immersion corrosion test for 72 h showed that the mass loss rates of Cu-P-Cr-0.14Ni steel and Cu-P-Cr-0.04Ni steel were 1.57 and 1.61 g/(m^(2)h),respectively.According to the electrochemical experiment,the corrosion potentials of the two tested steels at the initial stage of corrosion were-0.6852 and-0.7037 V,respectively.With the corrosion time reaching 72 h,the corrosion potential difference between the two tested steels was gradually reduced.In the initial stage,NiO was formed in the rust layer and can dramatically promote the crystallization of corrosion products to improve the stability of the rust layer.After periodic immersion corrosion test for 72 h,Ni element had no obvious effect.At this time,it was mainly the enrichment of Cu and Cr elements in the form of CuO and Cr_(2)O_(3)in the rust layer that could further protect the matrix.
基金support from Maanshan Iron&Steel Co.,Ltd.and student research training project of University of Science and Technology Beijing.
文摘The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti content.The yield strength and elongation of the steel were 640 MPa and 25.5%,respectively.The microstructure was ferrite and pearlite,and the average grain size was 5.4μm.The precipitates were mainly TiC with the size below 20 nm,and the average diameter was 18.2 nm.The yield strength of the newly proposed weathering steel with Ti content of 0.018%higher than that of the traditional steel reached up to 709 MPa,and the elongation was 23.5%.The ferrite grain was refined to 3.8μm,the fraction of TiC under 10 nm was obviously increased,and the average diameter of particles was 9.8 nm.The increase in Ti also promoted the recrystallization process,thus leading to the reduction in dislocation density.The yield strength of the newly proposed weathering steel was increased to higher than 700 MPa by adjusting the Ti content mainly resulting from three aspects:grain refinement,precipitation and dislocation strengthening.The contributed values were 45,64 and–40 MPa,respectively.
