【摘要】 <正> 前言本文基于试验及理论分析,提出多年以来被各国(包括我国)锅炉强度标准所不用的外置式单面角焊平端盖反而比内置式单面角焊平端盖的受力条件明显优越,加之工艺也较简单,因而建议允许在一定的压力范围内采用。更多还原

【Abstract】 The external flat head with fillet weld is a type of the flat heads that wasnot adopted in the code of every country.According to the experimental dataof burst tests of four types of flat heads and theoretical analysis,its strength isnot lower than that of other three non-external flat heads.From experimentaldata we have seen the burst pressure of external head is ten times more than theallowable pressure of present code of our country.And its scatter of experime-ntal data is smaller than that of non-external flat heads.That means its stru-ctural strength is higher and the relevant vessel is much more reliable.Fromtheoretical analysis of this structure,because of the increase in diameter of theplate of the external flat head by the amount of the overhung part of the head,the stiffness of the plate is larger than that of the other types.In addition,the plates are joined to the ends of shell,and the stiffness of the end of theshell is smallest,so the stress in the welded seam is greatly reduced.The peakof the stress is located in the region of welded seam and the adjacent parent ma-terial(the result of the burst tests clearly verifies that the fracture is takenplace in that region).Because of this,its strength is elevated and its fabricationis simplified and convenient.Based on this,authors suggest that the external flat head with fillet weldshall be allowed to use in certain range of pressure.更多还原