Fracture Failure Analysis Of A Furnace Tube In Residual Oil Hydrogenation Unit

The residue hydrodesulfurization technology is used for product high quality fuel by Inferior fuel primitively.Then this technology combine with the catalytic cracking process and highly improve light crude’s production.It have a good social benefit.A residue hydrodesulfurization of Shanghai petrochemical which can product 390 million tons productin is the biggest device in China.A pipe of the device’s export for high heat air separation cooler was broken in 2012.9 when the pipe was given a hydrostatic test.The paper have conducted a study on the reason of this accident.All kind of tests and theoretical analysis was put into effect. Specific research contents are as follows:(1) Firstly, we conducted a series of physical and chemical properties test on Pipe material,including chemical component tes、tensile test、hardness test etc.The result of these tests illustrated that the pipe’s property meet the requirements. At the same time,we also conducted the three-point bending fracture toughness test and metallographic analysis for preparation of follow-up studies.(2) Through the macroscopic analysis of the fracture, we found out the start location of the crack and the form of the crack.The pipe was broken from weld support ring where the shape was like the letter of "V".and the crack is brittle.(3) We also did the SEM test on key pars of the fracture to make certain the influence of slag.(4) Finally, we conducted the mechanics analyses on the fractureThrough the experimental analysis and theoretical analysis, we finally found out the reason. The stress concentration and welding residual stress exist in weld support ring where the shape was like the letter of "V" is the reason of brake.