Introduction of the above technology will make it possible to eliminate the production of ferrite cores and improve pipe quality by enabling the removal of internal flash -- e.g., by inserting a nozzle to blast the weld with oxygen, or by inserting a flash cutter where the ferrite core was located.
DEVELOPMENT OF FLAW DETECTION AT THE FACTORY Yu. A. Mednikov, I. I. Sergeev, V. T. Biryukov, and V. K. Bronnikov
The problem of guaranteeing that the quality of tubular products meets current high standards and specifications cannot be solved without the wide use of nondestructive inspection methods (NIM) to check the parameters of the material at different stages of the production process. Our plant has used NIM to verify tube quality since 1963. Such methods are presently used to check about 85% of the total output of the plant, as well as a significant percentage of the important parts and components of the production equipment. The inspections are effected by more than 50 NI units and stations set up in plant shops. Whereas most of the NIM in use initially at the plant involved manual or selective inspection, current methods entail the use of automated or mechanized complexes to achieve 100% flow-line inspection of tubing at different stages of production. Here, much of the work on selecting and refining the NIM and obtaining the requisite machines and automatic equipment has been accomplished either independently by the plant or through collaboration with specialized organizations. Seamless hot-rolled 70-560-mm-diameter tubes are produced on the TPA 140 and TPA 8-16". The TPA 140 is presently equipped only with nondestructive processing inspection equipment -an IShP-187 photoimpact meter to check the diameter of the hot-rolled tubes, installed beyond the reeling machine, and ITG-5688 thickness gauges installed after the sizing mill. The measurement range of the thickness gauges, designed to check plate up to 12 mm thick, has been expanded to 18 mm without loss of accuracy (1%). The tube is inspected simultaneously by two gauges over 90 ~ of its perimeter through two walls. The signal panel gives the average thickness or individual thickness of tubes. The data is used for real-time correction of tube-rolling regimes. The TPA 8-16" has both processing and delivery nondestructive inspection equipment. The processing instruments include an automatic video diameter gauge of the TAIR 1-5 type installed after the sizing mill and planned for initial use in the third quarter of 1982, and a magnetic gauge to measure tube wall thickness. So far, we only have the prototype of the gauge, which was developed by the Chelyabinsk Polytechnic Institute. Work is currently proceeding on development of a commercial thickness gauge, however. The production of cold-reduced seamless lO0-450-mm-diameter tubing also involves the use of processing-type nondestructive inspection instruments: "Kvarts-6" devices for periodic real-time checks of tube wall thickness and corresponding mill adjustment, and a mechanized ultrasonic inspection device to check the quality of semifinished tubes and intermediate tube sizes. The ultrasonic unit, which effects 100% control of the wall thickness of high-precision carbon-steel tubing and was developed and mastered by the plant on the basis of the "Metall2M" ultrasonic thickness gauge, can be considered as both a processing and a delivery inspection tool. The unit checks tubes by the resonance method at a rate of i0 linear meters/ min with an accuracy to 1% over the entire length and area of the tube immediately after rolling. The inspection results can be used to correct rolling regimes on a real-time basis. The "Sigma" mechanized ultrasonic unit, developed by the Chelyabinsk Pipe Mill itself, provides delivery checks of tube integrity and wall thickness. Its electronics are based on DUK-6 PM instruments with AS-3 adapters. It has a unique acoustic component, a system for automatically recording defects, and a self-inspection capability. The L~D-30T unit, Chelyabinsk Pipe Mill.
Translated from Metallurg, No. i0, pp. 39-40, October, 1982.
0026-0894/82/0910-0381507.50
9 1983 Plenum Publishing Corporation
381
developed for the Scientific Institute of Automotive Transport and the REMZ, effects delivery magnetic-particle inspection of tube quality. The thickness of these tubes is checked selectively by a special ultrasonic technique using "Kvarts-6" thickness gauges. General-use 10-60-mm and 0.5-3" diameter furnace- and rf-welded tubes are produced on a 0.5-2" continuous-weld mill equipped with an ITKh-6170 X-ray-thickness gauge for the skelp and an ITG-5688 x-ray double-wall-thickness gauge for the hot-rolled tubes. Besides allowing the operator to correct rolling regimes from instrument readings, these devices can be used in automatic tube-thickness control system. The 0.5-2" and 0.5-3" mills are also equipped with automatic lines to realize 100% delivery eddy-current inspection of tube quality after the straightening machine. The 0.5-2" mill has five such flow lines and one line off the production line for final rejection of tubes. The 0.5-3" mill has three and one such lines, respectively. All of the lines are equipped with "EZTM-IM" flaw detectors which have been modernized by the Chelyabinsk plant. Also, in conjunction with the Tomsk Polytechnic Institute, work is proceeding on equipping the 0.5-2" mill with ED-I.02 flaw detectors for eddy-current processing control of the quality of continuous hot-rolled tubing at the exit end of the forming--welding mill. The rf-welding stands of the 10-30" and 10-60" mills are also equipped with EZTM-IM flaw detectors. The latter check the continuous tube afterwelding, so the inspection can be considered to serve both processing and delivery functions. The problem here is rejecting tubes from the results of machine checks of tubes cut to measured lengths. This problem is being solved with the aid of a special system of secondary automatic devices, also developed by the Tomsk Polytechnic Institute. Electric-resistance-welded gas and oil pipeline 520-1220 mm in diameter has always received emphasis at the plant with regard to quality control, due to the large output of this product and the stringent requirements set for it. The following nondestructive inspection methods are currently in use here: There is a fully mechanized and automated section to effect 100% processing control of the welds on 1220-mm-diameter tubes by a combination of ultrasonic and x-ray-video (XRV) means. The operation of the section is based on two ultrasonic units with DUK-70M instruments modernized by the plant and on two RTU devices based on the "Luch-ZM" instrument (designed by the "Gazpriboravtomatika" special design office). The tubes are checked immediately after welding, and the data is used to correct welding regimes when necessary. The section which effects 100% delivery inspection of the welds of 1220-mm-diameter tubing (ultrasonic and XRV) has the same basic flaw detection equipment, but differs from the first section in the mechanization and organization of its lines and in the presence of three ultrasonic units. The tubes are checked at the end of expansion. Another section which checks all tubes on a delivery basis, using the x-ray method, checks the end sections of the welds on the 1220-mm-diameter tubes. This section is equipped with two dual radiographic instruments based on the "Luch-ZM" apparatus. The section which realizes 100% delivery inspection of the welds on the 530-820-mmdiameter tubes employs automatic ultrasonic inspection of the welds and manual ultrasonic checking of any flaws that are found. The section is equipped with three automatic flow lines based on "DUK-70M." Each line has its own manual inspection station equipped with a DUK-66PM flaw detector with a special indicator attached. The indicator was designed by the All-Union Scientific Research Institute of Pipes and displays the horizontal coordinate of the defects during manual inspections. The structure and mechanical properties of tube metal are also being checked on a nondestructive basis at the plant. For example, an ultrasonic unit was successfully introduced in 1973 to check the grain size of austenitic-steel tubing. The unit employs a DSK-I instrument. To ensure problem-free and reliable operation of the nondestructive inspection equipment at the plant, most of the ultrasonic and electromagnetic transducers employed have been repaired or modified, and the control procedures are checked and made to conform to metro!ogical standards. The use of nondestructive inspection methods at the plant presently brings up to two million rubles in savings a year. Savings to the national economy amount to five million rubles.
382
