Failure of tubes in a heat exchanger was studied through analysis of Optical microscope, water analysis, X-ray diffraction pattern, and Scanning Electron Microscope. The damage tube displays a large unsmooth corrosion area with decreased hardness. Moreover, two different corrosion layers were found on the waterside of the pipe surface. The tube failed due to dissolved oxygen in feed water. Some recommendations of delaying corrosion was also put forward.

We are studying the Leak-before-break (LBB) test, which is an important test for the safety performance verification of CNG-II bottles, and it is a necessary link for new product identification. We ruptured during the LBB test of a CNG-II gas cylinder. Through the chemical composition analysis, metallographic observation, mechanical performance test, scanning electron microscope and other tests of the failed gas cylinder, we found that the cylinder failure was due to the curved part. There are oxide slag inclusions. Under the fatigue test under the action of alternating load, slag inclusions are used as the fatigue source, which accelerates the crack growth and eventually causes the cylinder to fail.

Our regular inspection during the use of cylinders is an important means to ensure the safe use of cylinders, and reasonable periodic inspection efficiency is a necessary means to ensure the normal circulation of cylinders and maintain the stability of the cylinder industry. As a bottleneck in the testing process of the hydrostatic test, the efficiency of periodic inspection of gas cylinders has been affected for a long time. In order to solve the above problems, this thesis mainly researches and solves the bottleneck problems that affect the efficiency of hydraulic pressure tests, in order to achieve rapid detection of the hydraulic pressure tests of cylinders, and develops a kind of gas cylinders to dial, rotate, flip, water, hoist, weigh It can accurately and accurately locate the water jacket, pour water, purge, and dry the cylinder logistics conveying device, and realize the fast and accurate cylinder hydraulic pressure test, eliminating the bottleneck problem in the detection process and achieving the effect of rapid cylinder detection.

In view of the current necessity of the road transportation safety of the dangerous goods, the lack of effective emergency blocking technology is the Current issues that need to be focused on. This paper designs a kind of emergency blocking equipment for the leakage of dangerous goods transport vehicle tanks. By introducing a strong magnet and blocking with a rubber layer, the leakage on the surface of the ferromagnetic equipment can be quickly blocked. A simulated test of the designed 1.5 MPa leak stopper was carried out on a vechicle gas cylinder. The test results showed that there was no pressure drop in the gas cylinder during the holding time of 1.5MPa, and the leak plugging effect was better, which can be widely used in maintenance work. In addition, the continuous test found that the leakage limit pressure at the shoulder and bottom of the gas cylinder is lower than that at the cylinder body, and it should be focused on in the subsequent promotion process.