The Research On Structure And Performance Of Low-temperature And High Strength Steel

The welding technique of 9%Ni steel was still mastered by minority developed countries and the manufacturing technology and market of the matched nickel-based welding material was controlled by minority transnational corporations. Therefore the design and construction of ethylene compressor was always depending on foreign countries witch lead to long-period and high cost, and also be adverse to domestic application of 9%Ni steel. So it is very important to develop the matched welding material for 9%Ni steel and its related welding technique.The property of the welded joint of 9%Ni steel is directly related to the quality and safe reliability of impeller of centrifugal compressor. So we firstly carried out the study on weldability and welding procedure of 9%Ni steel aiming at mastering the weldability and the processing property of post weld heat treatment (PWHT) and then put forward property welding procedure and responsible heat treatment parameter for impeller welding of centrifugal compressor to ensure the safety and permanent operation of centrifugal compressorThe welding procedure qualification and heat treatment experiment was performed in accordance with actual requirement;and the groove type and welding procedure of welding impeller was designed in accordance with the weldabiity and product characteristics. The crack resistance experiment and welding material qualification was performed and the welding contraction value was given according to experiment. The welding performance of welded joint at -150℃was qualified and the welding procedure and procedure of PWHT was put forward. The results of welding material qualification and welding procedure qualification and microscopic test were applied to the production of low-temperature compressor successfully.The required temperature of centrifugal compressor impeller of HUA JIN Ethylene project is -150℃and 9%Ni steel is firstly adopted for SHENYANG BLOWER WORKS (GROUP) CO.,LTD and the low-temperature at -150℃is the record for impeller welding for our company.The successful of the subject fills up the nation blank in this field and provide the world's leading performance and technique storage for impeller welding of 9%Ni steel for our company.