Study Of P92 Steel Weld-joint Properties Techology

With the rapid development of our national economy, the electric power supply becomes the important factor of the guarantee of our economic and social stabilization. The situation that our country has more coal and less oil (uranium) determines the generation of electric power by thermal power occupies an equivalent gravity in the electric power supply of our country. Increasing the parameters (steam temperature and pressure) of the station boiler can not only increase the efficiency of electric generating set, but can also largely decrease the exhalation of pollutant. At the present time, according to the situation our country develops the supercritical electric generating set vigorously, its steam temperature reach 600~630 degree CenGTAWrade and its pressure reach 20~23MPa.The increasing of the generating set's parameters brings forward a much strict requirement to the materials which have to endure the high temperature and high pressure. The principles of the requirement to the rolled steel's performance include the following aspects: meeting the need of the parts'operating temperature;possessing the high endurance strength, creep strength under the operating emperature, and prior choosing the materials which have high creep strength when other conditions are same or close; having the stable metallurgical structure, non-cold-shortness and long-period aging shortness; contradicting the steam oxidation, the fume corrosion and the stress corrosion; being prone to cold and hot working; ensuring the original performance of the welding procedure of the dissimilar steel. The P92 steel with the well performance of high temperature is the material which is used in the main steam conduit of the supercritical generating set. Studying the reasonable and feasible welding procedure is very essential to ensure the property of the welding joint under the condition of high temperature and high pressure.Start with the reaserch of P92 steel performance, large amount of tests and vast reaserch were executed on the weld technic test, design of the weld scheme and the validatory test of the joint, which were based on the lucubrate of P92 steel weldabilities and the factor affecting the joint performance. Lots of means, such as micrographic and SEM and so on, were used to prove the joint of room mechanics performance, high temperature mechanics performance, micrograph structure etc. The results prove that the welding joint coincides the related requirement of the code of welding procedure qualification(DL/T868-2004), and the technologic scheme is feasible.