The effect of aging temperature on erosion corrosion （E-C） behavior of 17-4PH stainless steels in dilute sulphuric acid slurry containing solid particles was studied by using self-made rotating E-C apparatus. The ef...The effect of aging temperature on erosion corrosion （E-C） behavior of 17-4PH stainless steels in dilute sulphuric acid slurry containing solid particles was studied by using self-made rotating E-C apparatus. The effect of impact velocity on EC behavior of 17 4PH steels at different aging temperatures was analyzed. Surface micrographs of the specimens after E C test were observed by using scanning electron microscope （SEM）. The results showed that under the condition of the same solution heat treatment, when aging temperature ranged from 400 ℃ to 610℃, the hardness reached the highest value near the temperature 460℃. The characteristics of E-C for 17-4PH stainless steels at different aging temperatures were as follows： pure erosion （wear） was dominant, corrosion was subordinate and at the same time corrosion promoted erosion. The effect of aging temperature on E-C rate of 17-4PH steels was not significant at low impact velocity, but it was found that E-C resistance of 17-4PH steels aged near 460℃ was the most excellent due to the best precipitation strengthening effect of fine and dispersed e-Cu phase. With a prerequisite of appropriate corrosion resistance, the precipitation hardening could significantly improve the E-C resistance of the materials.展开更多
The relationship between the microstructure transformation of type 17-4 PH stainless steel and the aging hardening behavior was investigated. The results showed that, when 17-4 PH stainless steel aging at 595℃, the b...The relationship between the microstructure transformation of type 17-4 PH stainless steel and the aging hardening behavior was investigated. The results showed that, when 17-4 PH stainless steel aging at 595℃, the bulk hardness of samples attains its peak value （42.5 HRC） for about 20 min, and then decreases at all time. TEM revealed the microstructure corresponding with peak hardness is that the fine spheroid-shape copper with the fcc crystal structure and the fiber-shape secondary carbide M23C6 precipitated from the lath martensite matrix. Both precipitations of copper and M23C6 are the reasons for strengthening of the alloy at this temperature. With the extension of holding time at this temperature, the copper and secondary carbide grow and lose the coherent relationship with the matrix, so the bulk hardness of samples decreases.展开更多
The aim of this investigation is to reveal the influence of rare earths(RE) addition on mechanical properties of plasma nitrocarburized 17-4PH steel.The nitrocarburized layers were characterized by optical microscope,...The aim of this investigation is to reveal the influence of rare earths(RE) addition on mechanical properties of plasma nitrocarburized 17-4PH steel.The nitrocarburized layers were characterized by optical microscope,scanning electron microscope equipped with energy dispersive X-ray analyzer,X-ray diffractometer,microhardness tester and pin-on-disc tribometer.The results showed that RE atoms could diffuse into the surface layer of 17-4PH steel plasma nitrocarburized at 500 °C for 4 h and did not change the ...展开更多
文摘The effect of aging temperature on erosion corrosion （E-C） behavior of 17-4PH stainless steels in dilute sulphuric acid slurry containing solid particles was studied by using self-made rotating E-C apparatus. The effect of impact velocity on EC behavior of 17 4PH steels at different aging temperatures was analyzed. Surface micrographs of the specimens after E C test were observed by using scanning electron microscope （SEM）. The results showed that under the condition of the same solution heat treatment, when aging temperature ranged from 400 ℃ to 610℃, the hardness reached the highest value near the temperature 460℃. The characteristics of E-C for 17-4PH stainless steels at different aging temperatures were as follows： pure erosion （wear） was dominant, corrosion was subordinate and at the same time corrosion promoted erosion. The effect of aging temperature on E-C rate of 17-4PH steels was not significant at low impact velocity, but it was found that E-C resistance of 17-4PH steels aged near 460℃ was the most excellent due to the best precipitation strengthening effect of fine and dispersed e-Cu phase. With a prerequisite of appropriate corrosion resistance, the precipitation hardening could significantly improve the E-C resistance of the materials.
基金This work was financially supported by the Key Nuclear Fuel and Nuclear Materials Laboratory of China(No.51481080104ZS8501).
文摘The relationship between the microstructure transformation of type 17-4 PH stainless steel and the aging hardening behavior was investigated. The results showed that, when 17-4 PH stainless steel aging at 595℃, the bulk hardness of samples attains its peak value （42.5 HRC） for about 20 min, and then decreases at all time. TEM revealed the microstructure corresponding with peak hardness is that the fine spheroid-shape copper with the fcc crystal structure and the fiber-shape secondary carbide M23C6 precipitated from the lath martensite matrix. Both precipitations of copper and M23C6 are the reasons for strengthening of the alloy at this temperature. With the extension of holding time at this temperature, the copper and secondary carbide grow and lose the coherent relationship with the matrix, so the bulk hardness of samples decreases.
基金supported by the National Natural Science Foundation of China (50871035)the Ph.D. Programs Foundation of Ministry of Education of China (20060213017)
文摘The aim of this investigation is to reveal the influence of rare earths(RE) addition on mechanical properties of plasma nitrocarburized 17-4PH steel.The nitrocarburized layers were characterized by optical microscope,scanning electron microscope equipped with energy dispersive X-ray analyzer,X-ray diffractometer,microhardness tester and pin-on-disc tribometer.The results showed that RE atoms could diffuse into the surface layer of 17-4PH steel plasma nitrocarburized at 500 °C for 4 h and did not change the ...
