太阳能光热发电系统GH3625合金加热管开裂原因探讨

Discussion about the cracking reason for GH3625 alloy heating tube used for solar thermal generation system

GH3625高温合金管(规格φ4.5 mm×0.75 mm)制作的太阳能加热管在进行样机研制和装机运行试验过程中多次发生局部爆裂。对失效管件样品进行了理化检验分析,发现造成管件开裂的主要原因是管件在钎焊过程中工艺设计不当造成管件晶粒粗大,在功能试验过程中,长时间在600～800℃运行时,晶界析出网状金属间化合物,降低了管材塑性,当管中气体压力达到极限值时,发生开裂。

Solar heating tube made by GH3625 alloy tube(specification:φ 4.5 mm × 0.75 mm)frequently partially cracked in the process of prototype manufacture and working test. The failure tube samples were analyzed by physical and chemical test. And it was found that the main reason for the cracking of the pipe fittings was the large grain size in tube parts caused by the improper process design during the brazing process. In the process of functional testing,the intermetallic compound was precipitated at the grain boundary when it was operating for a long time at 600-800 ℃,which reduced the ductility of the pipe. And when the gas pressure in the tube reached the limit value,the cracking occurred.