T91 steel pipe is a steel pipe, T91 steel in the United States as a tree Ridge National Laboratory and the US Combustion Engineering Metallurgical Materials Laboratory cooperation in the development of the new martensitic steel. It is based on reducing the carbon content of steel 121MoV strictly limit the content of sulfur, phosphorus, and add a small amount of vanadium, niobium alloying elements. According ASTM213 / A213M-85C, the chemical composition of T91 steel in Table 1. T91 steel and the corresponding number of German steel X10CrMoVNNb91 t91, Japanese steel for HCM95, France was TUZ10CDVNb0901. Table 1 T91 steel chemical composition% T91 steel alloy containing trace nitrogen imports t91, the role of nitrogen in two aspects. On the one hand from the solid solution strengthening effect t91 pipe, at room temperature, the solubility of nitrogen in the steel is very small, after T91 steel weld heat-affected zone in the welding heat and weld heat treatment process, has appeared in the solution and precipitation process VN: Welding austenite during heating of the heat-affected zone has formed due to VN of dissolved nitrogen content increases, the degree of supersaturation at room temperature after which the tissue to improve, there is a small VN precipitates in the subsequent post-weld heat treatment, which increases tissue stability, improve the enduring strength of the value of the heat affected zone. On the other hand, T91 steel also contains a small amount of A1, with the formation of nitrogen can A1N, A1N in a lot more than 1 100 ℃ was dissolved in the matrix, again precipitated at lower temperatures, can play a better dispersion strengthening effect. t91 alloy tube 51X3.5, PengShuiXian t91, Katherine source of steel provided by source Pipe Co., Ltd. Liaocheng trillion. Liaocheng Katherine source Pipe Co., Ltd. (www.lczygg.com) strong, credible, Liaocheng in Shandong steel industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving Katherine source of innovative ideas will lead pipe and you work into the brilliant, for a better future!