METHOD OF TESTING FOR SULPHIDE CRACKING OF METAL OF ELECTRIC WELDED AND SEAMLESS PIPES Russian patent published in 2016 - IPC G01N3/20 

FIELD: measuring equipment.

SUBSTANCE: invention relates to measurement equipment for industry and can be used for testing of longitudinal and transverse specimens of parent metal pipes, samples with welded seams, including repair weld seam, for studying properties of sputtered materials, organic coatings for evaluation of steel to sulphide stress cracking. Tested pipe specimen loading is secured in symmetry on 4-point bend between two inner supports and two external supports. Before loading test specimen is placed in a closed loop holder case between a pair of internal cylindrical supports arranged, for accurate fixation of pair of upper support points of sample, lower part of movable plate, and a pair of outer cylindrical supports arranged, for accurate fixation of pair of lower points of support of sample, in grooves in housing bottom holder. Initial design force loading of tested sample is applied from above via adapter jack at compression dynamometer to moving plate, bent middle sample two internal cylindrical supports arranged in grooves of movable plate symmetrically about centre of sample and external supports. Accurate bringing applied force to rated value of deflection of sample and its alignment between symmetrical inner supports are turned left and right screws to displace moving wedges along tapers to centre of movable bar to transfer force from screws through movable wedges plate and through inner support on test sample. Excluded displacement of movable wedges angularity, for maintaining accuracy of sample loading during tests, for this purpose movable wedges, when rated defined by geometric parameters of pipe specimen deflection, reliably fixed by screws between plate and upper part of housing of holder.

EFFECT: higher accuracy of determining (trap) of origination and development of corrosion cracks in samples of metal seamless and electric welded pipes, including thicker wall.

1 cl, 3 dwg