The effects of sulfate reduced bacterium （SRB） on the corrosion behavior of 10CrMoAl steel in seawater were studied by chemical immersion, potentiodynamic polarization, electrochemical impedance spectroscopy measure...The effects of sulfate reduced bacterium （SRB） on the corrosion behavior of 10CrMoAl steel in seawater were studied by chemical immersion, potentiodynamic polarization, electrochemical impedance spectroscopy measurement, and scanning electron microscope techniques. The results show that the content of element sulfur in the corrosion product of 10CrMoAl steel in seawater with SRB is up to 9. 23 %, which is higher than that of the same in sterile seawater. X-ray diffraction demonstrates that the main corrosion product is FeS. SRB increases the corrosion rate by anodic depolarization of the metabolized sulfide product. SEM observation indicates that the corrosion product is not distributed continuously; in addition, bacilliform sulfate-reduced bacterium accumulates on the local surface of 10CrMoAl steel. Hence, SRB enhances sensitivity to the localized corrosion of 10CrMoAl steel in seawater.展开更多
The 10Ni5CrMoV steel examined was a 16 mm thick plate. Specimens measuring 12 mm×12 mm×120 mm were thermally cycled using DM-100A weld simulator with various parameters. The main results are summarized as fo...The 10Ni5CrMoV steel examined was a 16 mm thick plate. Specimens measuring 12 mm×12 mm×120 mm were thermally cycled using DM-100A weld simulator with various parameters. The main results are summarized as follaws. In the coarse-grained austenitized region（ Tm = 1 300℃ ＋ 1300℃ ） ,the microstructure is in good toughness. At the condition of Tm = 1 300℃ ＋ 850℃ and t8/5=43 s, the toughness decreases heavily because M-A constituent and twin martensite appear at the prior aastenite grain boundaries. When Tm= 1300℃ ＋ 850℃ or 1300℃ ＋ 730℃ and t8/5 = 85 s, local brittle zone is formed because of relatively coarse granular bainite.展开更多
The addition of Cu-10Sn alloy for developing the high strength 465 maraging stainless steel from elemental powders was studied. The sintering parameters investigated include the sintering temperature, the sintering ti...The addition of Cu-10Sn alloy for developing the high strength 465 maraging stainless steel from elemental powders was studied. The sintering parameters investigated include the sintering temperature, the sintering time, and the mass percent of Cu-10Sn. For vacuum sintering, effective sintering occurs at temperature between 1 250 ℃ and 1 300 ℃. The maximum sintered density was achieved at 1 300 ℃ for 60 min with 3% （in mass percent） Cu- 10Sn alloy. More than 3% （in mass percent） Cu-10Sn content and temperature above 1 300 ℃ caused slumping of the samples. A maximum density of 7.4 g/cm^3 was achieved with 3% （in mass percent） Cu-10Sn content at a sintering temperature of 1 300 ＂C for 60 rain. A maximum ultimate tensile strength （UTS） of 517 MPa was achieved with 3% （in mass percent） Cu-10Sn content. With content higher than 2% （in mass percent） Cu-10Sn, a maximum increase in the density was observed. The fracture morphologies of the sintered samples are also reported.展开更多
文摘The effects of sulfate reduced bacterium （SRB） on the corrosion behavior of 10CrMoAl steel in seawater were studied by chemical immersion, potentiodynamic polarization, electrochemical impedance spectroscopy measurement, and scanning electron microscope techniques. The results show that the content of element sulfur in the corrosion product of 10CrMoAl steel in seawater with SRB is up to 9. 23 %, which is higher than that of the same in sterile seawater. X-ray diffraction demonstrates that the main corrosion product is FeS. SRB increases the corrosion rate by anodic depolarization of the metabolized sulfide product. SEM observation indicates that the corrosion product is not distributed continuously; in addition, bacilliform sulfate-reduced bacterium accumulates on the local surface of 10CrMoAl steel. Hence, SRB enhances sensitivity to the localized corrosion of 10CrMoAl steel in seawater.
文摘The 10Ni5CrMoV steel examined was a 16 mm thick plate. Specimens measuring 12 mm×12 mm×120 mm were thermally cycled using DM-100A weld simulator with various parameters. The main results are summarized as follaws. In the coarse-grained austenitized region（ Tm = 1 300℃ ＋ 1300℃ ） ,the microstructure is in good toughness. At the condition of Tm = 1 300℃ ＋ 850℃ and t8/5=43 s, the toughness decreases heavily because M-A constituent and twin martensite appear at the prior aastenite grain boundaries. When Tm= 1300℃ ＋ 850℃ or 1300℃ ＋ 730℃ and t8/5 = 85 s, local brittle zone is formed because of relatively coarse granular bainite.
文摘The addition of Cu-10Sn alloy for developing the high strength 465 maraging stainless steel from elemental powders was studied. The sintering parameters investigated include the sintering temperature, the sintering time, and the mass percent of Cu-10Sn. For vacuum sintering, effective sintering occurs at temperature between 1 250 ℃ and 1 300 ℃. The maximum sintered density was achieved at 1 300 ℃ for 60 min with 3% （in mass percent） Cu- 10Sn alloy. More than 3% （in mass percent） Cu-10Sn content and temperature above 1 300 ℃ caused slumping of the samples. A maximum density of 7.4 g/cm^3 was achieved with 3% （in mass percent） Cu-10Sn content at a sintering temperature of 1 300 ＂C for 60 rain. A maximum ultimate tensile strength （UTS） of 517 MPa was achieved with 3% （in mass percent） Cu-10Sn content. With content higher than 2% （in mass percent） Cu-10Sn, a maximum increase in the density was observed. The fracture morphologies of the sintered samples are also reported.
