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The mechanical behaviors of dissimilar metal weld SA508-52M-316L in several environments were investigated by using tensile tests with smooth specimens, focusing on the behavior of SA508-52M weld part during slow strain rates testing (SSRT) at 290°C in nitrogen gas and in simulated primary water at different electrode potentials. The mechanical properties at room temperature of main materials were obtained first. When tested at 290°C, the weld exhibited characteristics of dynamic strain ageing (DSA), which was more significant when strain rate was decreased from 1x10-6(1/s) to 3.1 x10-7(1/s). When tested in the water at the potentials from-720 to +200mV(SHE) , SA508-52M specimens showed the mechanical behaviors almost the same as that in nitrogen gas, with ductile failure happened in the 52M bulk weld metal. When the potential was raised to +300 and +400mV(SHE), brittle failure of stress corrosion cracking (SCC) took place around the interface, causing the significant drop of elongation and reduction in area.

In analyzing the factors of traffic accident, the most important reasons are the influence of people, vehicles, roads, and the environment for traffic accident. Learning how to handle traffic accident normatively and identify the traffic accident correctly, is the important lesson need to be solved urgently. however, the current safety performance technical expertise work for accidental vehicles lack of according with relevant laws and regulations, scientific, adaptable, and workable identification norms. To solve this problem stated previously, this paper studies the technical identification standard of accident vehicles, which mainly introduces the effect, basis, selection of identification items of accidental vehicles safety performance technical identification, the content and demand of the identification process.

With the rapid development of the automobile industry and transport, the increasing traffic accidents have become the serious problems for the traffic management. The important issue that we how to deal with the traffic accidents scientifically and make an accurate identification about the traffic accidents is badly in need of solving. Based on the current situation and research methods of traffic accidents at home and abroad, this paper illustrates the research on accident vehicle safety performance technology identification from one of factors causing traffic accidents-vehicles, which makes the identification for the accident vehicles about the operation process. The selection and process of identification items and information record will be strictly controlled to make the work quality and efficiency improve greatly.