Precipitates in W Alloyed 9Cr Weld Metal for Heat Resistant Steel.
Precipitates in W Alloyed 9Cr Weld Metal for Heat Resistant Steel.
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耐热钢用 W 合金 9Cr 焊缝金属中的析出物。
DOI：
10.2207/qjjws.16.512
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
M. Fuji
中科院分区：
文献类型：
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作者：
H. Morimoto;Tanaka Takashi;S. Ohkita;M. Fuji
通过对9CrW合金焊缝金属经焊后热处理和持久试验后残留物的分析，研究了焊缝金属在焊后热处理和持久试验过程中的析出行为。将分析结果与Thermo-CALC的预测结果进行了比较，并用Thermo-CALC预测了M23C6和MX型碳氮化物在PWHT平衡态的析出。除M23C6和MX型碳氮化物外，Thermo-CALC还预测Laves相将在蠕变断裂试验平衡状态下析出。X-射线衍射分析表明，焊缝金属在PWHT过程中析出M23C6和MX型碳氮化物，与Thermo-CALC结果一致。经X-射线衍射分析，焊缝金属中存在M23C6和MX型碳氮化物，在873K下的蠕变断裂时间小于100h。在873K蠕变断裂试验中，Laves相的析出时间超过100-1000h。X射线衍射分析表明，在873K/1126.7 h蠕变断裂试验后的焊缝金属中存在Laves相。在873K下进行蠕变断裂试验后，从焊缝金属中提取的残留物中W的含量随着时间超过100-1000h而显著增加。萃取渣中W含量的增加可能是由于Laves相的析出所致。焊缝金属经873K蠕变断裂后的残渣中W和Mo的含量在10000小时左右达到恒定值，这些值与Thermo-CALC的预测值很好地吻合。在873K和923K蠕变断裂试验中，焊缝金属残留物中W含量随时间的变化规律与Jhonson-Mehel-Avrami型方程的计算结果吻合较好。
Precipitation behaviors in W alloyed 9Cr weld metal during PWHT (Post Weld Heat Treatment) and creep rupture test have been studied by analyzing extracted residues from the weld metals after PWHT and creep rupture test. The results of analysis were compared with the prediction by THERMO-CALC.M23C6 and MX type carbo-nitrides were predicted to precipitate at PWHT temperatures in equilibrium states by THERMO-CALC. In addition to M23C6 and MX type carbo-nitrides, Laves phase was predicted to precipitate at creep rupture test temperatures in equilibrium states by THERMO-CALC. X-ray diffraction analysis showed that M23C6 and MX type carbo-nitrides precipitates in the weld metal during PWHT in accordance with the results from THERMO-CALC. Less than 100 hours in creep rupture test at 873 K, M23C6 and MX type carbo-nitrides were detected in weld metals by X-Ray diffraction analysis. Laves phase precipitates more than 100-1000 hours during creep rupture test at 873 K. Presence of Laves phase in the weld metal after creep rupture test at 873 K/1126.7 hours was revealed by X-ray diffraction analysis. Content of W in extracted residues from weld metals after creep rupture test at 873 K increased substantially with time more than 100-1000 hours. This increase in W content in extracted residue is probably due to the precipitation of Laves phase. Contents of W and Mo in extracted residues from weld metals after creep rupture test at 873 K reach constant values at roughly more than 10000 hours, and these values are in good agreement with those predicted by THERMO-CALC. Time dependence of W content in extracted residue from weld metals of creep rupture test at 873K and 923K are in good agreement with the calculated results based on Jhonson-Mehel-Avrami type equation.