MANUFACTURING METHOD OF COLD-ROLLED STAINLESS PIPES WITH RATIO OF WALL THICKNESS S TO OUTER DIAMETRE D OF 0,5 TO 0,008 Russian patent published in 2010 - IPC C21D9/08 C21D11/00 G01N29/04 

FIELD: metallurgy.

SUBSTANCE: multiple cold deformation of pipes is performed with intermediate heat treatment and ultrasonic examination of wall thickness, metal grain value and available discontinuities, which is performed during the first cycle prior to cold deformation and after heat treatment; at that, available pipe is obtained with irregular grain size of 1-2. For the first time, all the above quality parametres are checked out simultaneously throughout the length and surface of examined pipes. Owing to prompt checkout of three main quality parametres, such as deformation (wall thickness), heat treatment and the increase of metal grain value, which corresponds to them, there is also the possibility of determining triadic diagram for any stainless steel grades and pipe size.

EFFECT: improving quality of pipes owing to possible control of discontinuities, grain value and deviations of wall thickness from nominal value.

3 dwg