油浆蒸汽发生器管板减应力槽的设计

Design of stress reducing grooves of slurry steam generator tube sheet

油浆蒸汽发生器在使用过程中管板处经常出现开裂的情况。试验表明,管板受到温差交变应力,即交变的热载荷作用而产生疲劳破坏。同时又存在拉应力的作用,并且设备长期承受介质腐蚀和应力腐蚀,导致管板开裂。经理论和实验验证,焊接接头在管板的减应力槽上的位置产生了一个应力低谷,开槽管板焊接热影响区的低应力区范围较不开槽的有所扩大,能够有效预防径向裂纹的萌生和扩展,因此大大延长了设备使用寿命,满足装置的正常运行。以油浆蒸汽发生器的管板结构为例,在符合GB/T 151—2014《热交换器》要求的情况下进行减应力槽的设计。分别设计了换热管直径为25 mm和32 mm的管板减应力槽,满足了实际生产和设备运行需要。

Slurry steam generator tube sheet often crack during the working process.The test results show that the tube sheet occurred fatigue failure due to alternating temperature stress,which is also called alternating thermal load.At the same time,there is the effect of tensile stress,and the equipment has been subjectedto medium corrosion and stress corrosion for a long time,which cause the tube sheet crack.Through theoretical and experimental verification,the position of the welded joint on the stress relief groove of the tube sheet created a stress trough.The range of the low stress zone in the heat affected zone of grooved tube sheet welding is larger than that in the non-grooved one,which can effectively prevent the initiation and propagation of radial cracks.Therefore,the service life of the equipment is greatly extended to meet the normal operation of the device.Taking the tube sheet structure of the oil slurry steam generator as an example,the design of the stress relief groove in accordance with the requirements of GB/T 151—2014.And the stress relief groove of tube sheet with 25 mm and 32 mm heat transfer tube diameters are designed respectively,which meet the needs of actual production and equipment operation.