Effects of cooling rate and annealing treatment on sensitization of austenitic-ferritic duplex stainless steel

Duplex stainless steel has higher corrosion resistance and better mechanical properties than conventional type 300 series stainless steel. The corrosion behavior of duplex stainless steel is strongly dependent on the ratio, shape, size and distribution of austenite and ferrite phase in the microstructure. The relationship between the microstructure and the corrosion behavior of the duplex stainless steel was studied. For this purpose, the duplex stainless steel samples were solution heal treated at 1150°C followed by either cooling at various rates (water quenching, air coooling, furnace colling with door opened and door closed) to 820°C and then water quenching to room temperature, or quenching to room temperature and annealing heat treatment at 840°C for various lengths of time. A double loop electrochemical polentiodynamic reactivation (EPR) test was carried out to examine the effect of various cooling procedures or annealing treatment on the sensitization of duplex stainless steel. The grain size, shape, and distribution of the two phases were examined under microscope. From the test results, the relationships were discussed among heat treatment, electrochemical properties and microstructure.     

具有接头系统的冲击凿入效率研究

本文运用波动力学对具有接头系统的冲击凿入效率进行了理论分析,给出了具有接头的冲击凿入系统传递函数Ｈ＿（ＪＰ）（Ｓ）＝Ｈ＿ｊ（Ｓ）·Ｈ＿ｐ（Ｓ）［此外Ｈ＿Ｊ（ｓ）为接头传递函数,Ｈ＿Ｐ（Ｓ）为凿入传递函数］,实际计算了刚性和等截面活塞两种具有接头凿入系统的能量传递效率,并分析了凿入系统各参数对能量传量传递效率的影响。     

Radiative Ignition of Pyrotechnics: Effect of Wavelength on Ignition Threshold

Using a broadband Xenon lamp and a high power laser diode, the ignition of several pyrotechnic compositions was evaluated using ultraviolet(UV), visible and infrared(IR) radiation. At irradiance levels of 4.9 W/cm² none of the compositions were ignited using UV radiation but SR112, B/Fe₂O₃ and gunpowder showed reactions to visible radiation at irradiance levels as low as 8.1 W/cm². Most of the compositions were ignited with IR radiation but Mg/NaNO₃ and SR 112 could not be ignited at irradiance levels of up to 300 W/cm². It is proposed that the difference in the response of the compositions was not directly related to the radiation absorption characteristics of the compositions; but was dependant on many physical, chemical and optical characteristics of the pyrotechnic powders. Increasing the irradiance reduces the time to ignition for most compositions.