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 本文提出了一种基于直接冲击电压对电器绕组匝间绝缘的试验方法。用电压波形比较法，把冲击电压经高速切换，交替施加于被测绕阻两端和参考物绕组两端，通过观察电压衰减振荡波形的变化，便可检测被测绕组的匝间是否有异常。     

快速加热过程中Fe-40Ni-Ti合金的晶粒长大行为

利用热模拟技术、金相观察及定量统计,通过分析Fe-40Ni-Ti合金快速升温过程中试样不同部位的晶粒长大规律,模拟研究了焊接过程中奥氏体晶粒的长大行为.结果表明:温度最高的中心线附近晶粒长大显著,5 s内温度达到1350℃时,其尺寸达到了180 μm;而距离中心线4 mm处的热影响区及母材(试样端部)晶粒变化不大,在80 μm左右.金相观察发现TiN颗粒对晶界迁移产生了明显的阻碍作用.     

Effects of minor yttrium addition on hot deformability of lamellar Ti-45Al-SNb alloy

The effects of 0.3%（molar fraction, the same below） yttrium addition on hot deformability of lamellar Ti-45Al-5Nb alloy were investigated by simulated isothermal forging tests. The ingots with the nominal compositions of Ti-45Al-5Nb and Ti-45Al-5Nb-0.3Y were prepared by induction skull melting. Simulated isothermal forging tests were conducted on Gleeble 1500D thermo-simulation machine using a 6 mm in diameter and 10 mm in length compressive specimen at the deformation temperatures of 1 100, 1 150, 1 200 ℃ and strain rates of 1.0, 0.1, 0.01 s^-1. The results show that yttrium addition remarkably improves hot deformability of Ti-45Al-5Nb alloy. An appropriate hot deformation processing parameter of Ti-45Al-5Nb-0.3Y alloy is determined as 1 200 ℃, 0.01 s^-1. The flow stresses are decreased by yttrium addition under the same compressive conditions. The activation energies of deformation Q are calculated as 448.6 and 399.5 kJ/mol for Y-free and Y-containing alloys, respectively. The deformed microstructure observation under 1 200 ℃, 0.01 s^-1 condition indicates that Ti-45Al-5Nb-0.3Y alloy shows more dynamic recrystallization. The improvement of hot deformability of Ti-45Al-5Nb-0.3Y alloy induced by yttrium addition should be attributed to that the smaller the original lamellar colonies, the lower the deformation resistance and activation energy of deformation are, and the more the dynamic recrystallization is.     

微合金元素Nb,Mo在应变诱导析出过程中的相互作用

运用热模拟技术和透射电子显微镜,研究了C-Mo、C-Ti-Mo和C-Nb-Mo三种简单成分钢奥氏体变形后松弛过程中微合金元素Nb、Mo在析出物中的相瓦作用.结果表明:在850℃变形后松弛1000 s.三种钢均保持了奥氏体状态,但C-Ti-Mo和C-Nb-Mo钢有析出发生,能谱分析显示析出颗粒分别是Ti(C,N)和含Mo的Nb(C,N).微合金元素Mo与Nb有较强的相互作用,在Nb(C,N)析出后,Mo可能溶入Nb(C,N)的析出颗粒之中.     

中温变形对圆环链用钢23MnNiCrMo54组织的影响

用Gleeble-1500热模拟试验机对组织为M B AR的圆环链用钢23MnNiCrMo54进行了650℃的中温加工，应变量分别为0．3，0．5，应变速率分别为0．01s^-1，0．1s^-1，1s^-1，并在变形后进行了650℃回火。组织观察表明，各试样在变形后均析出了弥散、细小的颗粒状碳化物。变形Z参数和变形量较大时，回火后的组织为等轴状铁素体及弥散分布的碳化物；反之，除铁素体和弥散分布的碳化物外，还存在部分贝氏体组织。Z参数和变形量越小；贝氏体的数量越多，尺寸愈大。     

Effects of minor yttrium addition on hot deformability of lamellar Ti-45Al-5Nb alloy

The effects of 0.3%(molar fraction,the same below)yttrium addition on hot deformability of lamellar Ti-45Al-5Nb alloywere investigated by simulated isothermal forging tests.The ingots with the nominal compositions of Ti-45Al-5Nb andTi-45Al-5Nb-0.3Y were prepared by induction skull melting.Simulated isothermal forging tests were conducted on Gleeble 1500Dthermo-simulation machine using a 6 mm in diameter and 10 mm in length compressive specimen at the deformation temperatures of1 100,1 150,1 200℃and strain rates of 1.0,0.1,0.01 s-1.The results show that yttrium addition remarkably improves hotdeformability of Ti-45Al-5Nb alloy.An appropriate hot deformation processing parameter of Ti-45Al-5Nb-0.3Y alloy is determinedas 1 200℃,0.01 s-1.The flow stresses are decreased by yttrium addition under the same compressive conditions.The activationenergies of deformation Q are calculated as 448.6 and 399.5 kJ/mol for Y-free and Y-containing alloys,respectively.The deformedmicrostructure observation under 1 200℃,0.01 s-1condition indicates that Ti-45Al-5Nb-0.3Y alloy shows more dynamicrecrystallization.The improvement of hot deformability of Ti-45Al-5Nb-0.3Y alloy induced by yttrium addition should be attributedto that the smaller the original lamellar colonies,the lower the deformation resistance and activation energy of deformation are,andthe more the dynamic recrystallization is.     

低碳Q690qENH高强桥梁钢的动态再结晶行为

对低碳Q690qENH高强桥梁钢进行压缩实验,研究了动态再结晶行为。结果表明,在低碳Q690qENH高强桥梁钢的轧制热变形过程中,其软化以动态回复为主,只在0.1 s^-1和0.2 s^-1低应变速率下才发生明显的动态再结晶.通过计算将应力因子α修正为0.0099 MPa^-1,得到了实验钢的动态再结晶激活能,建立了动态再结晶动力学模型。采用P-M-K法确定了εc/εp约为0.72,且峰值应变与Z/A满足幂函数关系,建立了动态再结晶临界应变模型,其计算值与热变形中的显微组织演变规律一致。研究了温度对动态再结晶过程中界面迁移速率的影响规律。     

热送热装工艺对管线钢性能影响的研究

实验室模拟热送直装生产工艺，研究不同装炉温度对产品组织和性能的影响，以实验室得出的结果为基础，提出了高性能管线钢X70钢的热装和直接装炉加热以及轧制工艺。通过三次现场试验，基本确定在同一轧制条件下，板厚为17．5mm的X70钢可以进行直装或热装轧制，热装或直装钢板性能达到了冷装炉水平。     

低碳钢中微合金元素Nb，Mo在析出过程中的相互作用

运用热模拟技术和TEM分析法，研究了C-Ti．Mo和C-Nb-Mo两种简单成分钢奥氏体变形后弛豫过程中微合金元素Nb，Mo在析出物中的相互作用。结果表明：在850℃变形后弛豫1000s，C-Ti-Mo和C-Nb-Mo钢均保持了奥氏体状态且两种简单成分钢中均有析出发生，能谱分析显示析出颗粒分别是Ti（C，N）和含Mo的Nb（C,N）。微合金元素Mo与Nb有较强的相互作用，在Nb（C,D）析出后，Mo可能溶入Nb（C，N）的析出颗粒之中。