Grain boundary segregation of phosphorus, manganese, and carbon in boiler shell weld material
Grain boundary segregation of phosphorus, manganese, and carbon in boiler shell weld material
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锅炉壳体焊缝材料中磷、锰、碳的晶界偏析
DOI：
10.1179/026708301101509584
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发表时间：
2001
影响因子：
1.8
通讯作者：
J. Cowan
中科院分区：
文献类型：
--
作者：
P. Maier;R. G. Faulkner;P. Spellward;J. Cowan
采用埋弧焊材料研究了锰和碳对磷偏析和晶间脆化的影响。在两种不同的锅炉壳体焊接材料中，这些元素在时效过程中的平衡晶界偏聚行为进行了研究，这两种不同的锅炉壳体焊接材料在使用过程中的锰浓度和操作温度主要不同。在锅炉运行期间，这些材料经历了300 ℃以上的温度，在该温度下发生热致偏析和脆化。一个新的共离析模型已与现有的网站竞争模型进行了比较。显微组织显示出细晶和粗晶区。研究了锰和碳对磷晶界偏聚的影响。描述了在长达50年的整个使用寿命期间，作为温度函数的热致晶界偏析。为了评估给定元素的游离基质浓度，使用平衡热力学软件来考虑在合金基质内形成沉淀物的趋势。预测结果揭示了晶界浓度与温度的关系，并表明锰和碳通过位竞争减少了磷的偏聚。最终偏析包括非平衡偏析和平衡偏析，它们发生在焊后淬火、焊后热处理和使用过程中。已通过光学显微镜和透射电子显微镜的显微组织进行了研究，以显示碳化物形成在晶界和MnS的晶间沉淀。对晶界进行了初步分析，并将结果与理论偏聚预测进行了比较。
Submerged arc weld materials have been employed in a study of the effects of manganese and carbon on phosphorus segregation and intergranular embrittlement. The equilibrium grain boundary segregation behaviour of these elements during aging has been studied in two different boiler shell weld materials, which differ mainly in the manganese concentration and operating temperature during service. The materials have seen temperatures above 300C during operation of the boiler in service, at which temperature thermally induced segregation and embrittlement occurs. A new co-segregation model has been compared with the existing site competition model. The microstructure shows fine and coarse grained regions. The effects of manganese and carbon on the grain boundary segregation of phosphorus have been examined. Thermally induced grain boundary segregation during full service life up to 50 years as a function of temperature is described. To evaluate the free matrix concentration of a given element, equilibrium thermodynamic software was used to allow for the tendency to form precipitates within the alloy matrix. The predicted results reveal the dependence of the grain boundary concentration on temperature and show that manganese and carbon decrease the phosphorus segregation by site competition. The final segregation consists of non-equilibrium and equilibrium segregation, which occur during quenching after welding, post-weld heat treatment, and service. The microstructure has been investigated by optical microscopy and transmission electron microscopy to show carbide formation at the grain boundaries and intergranular precipitation of MnS. Preliminary analysis of the grain boundary has been made and the results compared with theoretical segregation predictions.