At the same time , low - temperature superheater keeps on running under the high temperature for long time , microstructure appears globular carbide configuration , and bearing capacity of materials at high temperature declines 同時,低溫過熱器長期高溫運行,組織已出現珠光體球化現象,管材高溫承載能力降低。
During the laser sintering , due to the large liquid phase viscosity and surface tension , the balling effect occurred when the molten did not wet the solid metal particle and the underlying substrate 實驗發現,在液相粘度較高、表面張力大,熔體材料不浸潤固相顆粒和基板等因素的影響下,燒結過程中出現了球化現象。
The simulation results suggest that , at the end of the scanning line , the dissymmetric temperature field and the great temperature gradient result in the balling phenomenon and great thermal stress , which could lead to the destruction of the sintering samples in this region . because of the coupling effect between scanning lines , the balling phenomenon is increased as the increase of the scanning lines , thus the over short scanning lines should be avoided in the sintering process . different scanning strategies have significant influence on the sintering 模擬結果表明,掃描端點溫度場的不對稱及較大的溫度梯度造成了端點球化現象,并在端點處產生較大的熱應力,使燒結成形試樣易在此處破壞;激光掃描線間的耦合作用使端點球化現象隨掃描線的增加而逐漸顯著,燒結時應避免過短的掃描線;不同掃描策略對燒結成形有很大影響,交替掃描會影響燒結試樣的質量,實際制造時應采用單向掃描策略。