METHOD FOR SECURING TUBE IN OPENING OF TUBE PLATE OF HEAT EXCHANGE APPARATUS (VARIANTS) Russian patent published in 1998 - IPC

FIELD: plastic metal working, particularly, manufacture of ship power plants. SUBSTANCE: method comprises steps of placing heat treated tube made of martensite steel with retained austenite in opening of tube plate of heat exchange apparatus; expanding tube in oil at temperature 225-230 C for 1-6 h. In variant tube is made of material usually used for manufacturing tubes of ship heat exchangers and only sleeve is made of martensite steel with retained austenite. Sleeve is placed in opening of tube wall and tube is inserted into it. Then expansion process is realized at heating sleeve and end portion of tube in oil at temperature 225-230 C for 1-6 h. EFFECT: enhanced reliability of tube mounting. 2 cl, 1 tbl