30Cr2MoV转子钢高温下的低周疲劳特性实验研究

该文采用总应变控制对30Cr2MoV钢在高温450℃、500℃和550℃下的低周疲劳特性进行了实验研究.采用Manson-Coffin公式对实验结果进行了分析,得到了该材料的高温低周疲劳特性参数、循环应力(应变曲线和具有95%置信度的50%~90%的不同存活率下的应变(寿命曲线,并将实验结果和文献进行了比较,分析了存在差异的原因,对于汽轮机的疲劳设计、延寿和寿命管理具有很大的实用价值.

30Cr2MoV转子钢蠕变过程中的碳化物变化

利用光学显微镜、透射电子显微镜及 X射线衍射仪分析了 30 Cr2 Mo V转子钢蠕变过程中碳化物的变化。研究结果表明 ,材料在蠕变过程中 ,固溶体基体中合金元素含量降低 ,碳化物中合金元素含量增加 ,并且碳化物不断聚集长大 ;晶内和晶界均发生碳化物的析出和结构转变 ,长时间蠕变后 ,30 Cr2 Mo V转子钢的碳化物以 M2 3 C6和 M6C型等碳化物为主。

30Cr2MoV转子钢的常温低周疲劳的实验研究

在试验的基础上研究了 30 Cr2 Mo V钢在常温下的循环应力应变特性。得到了该材料的低周疲劳特性参数、循环应力 -应变曲线和具有 95 %置信度的不同存活率下的应变 -寿命曲线。图 9表 3参

25Cr2MoV钢锅炉螺栓紧固件的热处理工艺

针对锅炉制造业中使用的 2 5Cr2MoV钢螺检紧固件在生产中因强度和硬度不合格而影响产品质量问题 ,探讨了淬火温度和回火温度对 2 5Cr2MoV钢力学性能的影响 ,并借助于SEM、TEM和OM对不同淬火和回火后钢的组织进行了分析。结果表明 ,采用 96 0℃× 30min油冷 +6 6 0℃× 6h空冷的热处理工艺 ,不仅钢的力学性能达到标准 。

Improving cleanliness of 30Cr2Ni4MoV low-pressure rotor steel by CaO-SiO_(2)-MgO-Al_(2)O_(3) slag refining

The optimal composition of a CaO-SiO_(2)-Al_(2)O_(3)-MgO slag in the ladle furnace refining process was investigated to precisely control the contents of[0]and[Si]and improve the cleanliness of 30Cr2Ni4MoV steel.The iso-[O]lines and iso-[Si] lines of the equilibrium between the CaO-SiO_(2)-Al_(2)O_(3)-MgO refining slag and 30Cr2Ni4MoV steel at 1873 K were calculated by the thermodynamic software FactSage 7.3,and the activities of SiO_(2),Al_(2)O_(3)and CaO in the refining slag were discussed to achieve the optimal composition range of the refining slag.Finally,combined with high-temperature"slag-steel"equilibrium experiments,the effects of different refining slags on the oxygen contents,chemical composi-tions,quantities and sizes of inclusions in steels were studied,and then the thermody namic formation mechanism of MgAl_(2)O_(4) inclusions in 30Cr2Ni4MoV steel was discussed.The results showed that the contents of dissolved[O]nd[Si]in steel can be controlled below 10 × 10^(-6)and 0.05%.respectively;when the slag basicity is above 7.the CaO/Al_(2)O_(3)ratio is above I.and the mass fraction of SiO_(2)in the slag docs not cxcced 7%.The chemical composition of the slag has a great influence on the removal and composition of inclusions.The assessed stability phase diagrams of MgO.Al_(2)O_(3)and MgOAl_(2)O_(3) inclusion formation in the Fe-Al-Mg-O system calculated by FactSage 7.3 show good agreement with the experimental results.

Constitutive Modeling for Elevated Temperature Flow Behavior of30Cr2Ni4MoV Ultra-super-critical Rotor Steel

In order to perform numerical simulation of forging and determine the hot deformation processing parameters for 30Cr2Ni4MoV steel, the compressive deformation behaviors of 30Cr2Ni4MoV steel were investigated at the temperatures from 970 to 1270 ℃ and strain rates from 0. 001 to 0.1 s-1 on a Gleeble-3500 thermo-mechanical simulator. The flow stress constitutive equations of the work hardening-dynamical recovery period and dynamical recrystallization period were established for 30Cr2Ni4MoV steel. The stress-strain curves of 30Cr2Ni4MoV steel predicted by the proposed model well agreed with experimental results, which confirmed that the proposed equations can be used to determine the hot deformation processing parameters for 30Cr2Ni4MoV steel.