高温脆性(国外英文资料).docVIP

低温脆性(国外英文资料) Low temperature brittleness Low temperature brittleness and selection of low alloy structural steel Low temperature brittleness refers to the phenomenon that the material is made brittle and the shock value is reduced by the temperature below a certain temperature. This kind of phenomenon occurs frequently in the commonly used medium and low strength structural steel. Many mines in our country northeast import large machinery, in winter there is caused by low temperature brittleness of girder, frame, such as fracture phenomenon, in addition, the Japanese car frame also has appeared in the northeast winter low temperature brittle fracture problem. In Albert canal, Belgium in 1935, about 50 welding bridge is built on the bridge in the next few years continuously brittle fracture accident: 38 years march Hasseld bridge Albert river total length of 74.5 meters brittle fracture occurred when the temperature - 20 ℃, the entire bridge is broken into three sections of fall in the river; Then there were a series of ruptures, and by 1950 there were six crunchy breaks at low temperatures. During world war ii, the United States welded ships had a large number of ruptures in use, of which 238 were completely discarded and 19 sank. Significantly, most of the crunch occurred when the temperature was low. At the time, there was no requirement for ships to use steel in the low temperature brittleness and notch sensitivity. People dont realize the importance of this problem. These are the issues we need to pay attention to in designing and manufacturing high-altitude cars. The causes of low temperature brittleness: Metal materials are different in different temperature, stress state, loading speed and environment. Steel used in the engineering practice, the brittle fracture of the micro crack formation mechanism is a very complicated problem, at present a lot of literatures published research results in this respect, the main thought: The second phase of steel (inclusio