G.N.Polskiy
Chief engineer of “Interpipe Nizhnedneprovsk tube-rolling plant” OJSC, Dnepropetrovsk
A.P.Timoshchenko
Head of NDT tools department, “Interpipe Nizhnedneprovsk tube-rolling plant” OJSC, Dnepropetrovsk, specialist of III grade in ultrasound, eddy current and magnetic particle testing techniques
A.A.Nikonenko
Chief engineer of “Ultracon-Service” OJSC, Kiev
INTERPIPE pipe and wheel company is one of the major manufacturers of rail wheels in the world and supplies its wheel products to more than 60 countries of the world under KLW brand. Wheel rolling shop of “INTERPIPE Nizhnedneprovsk tube-rolling plant” OJSC (hereinafter referred to as “INTERPIPE NTRP” OJSC) – is one of the world leaders regarding the range and output of wheel production, has more than 40 years of experience in work with German railroads, cooperates with Ukrainian, Russian, Indian and Austrian railroads. Long experience of manufacture and delivery of wheel products allows the company to compete successfully in international markets.
In spite of world depression 2008-2009 in metallurgy branch, the products of “INTERPIPE NTRP” OJSC remain in demand what is proved by the contracts concluded at this time: in February the plant started the rail wheels delivery under KLW brand for Greek railroads and under the terms of the contract in 2009 it will supply the customer with the wheels of two dimension-types for coaches and freight cars produced according to the standard EN 13262 to the total sum of About Us 7 million euro; within the contract signed at the end of December 2008, INTERPIPE will supply Rustavi carriage works (Georgia) with 20 thousand wheels for new freight cars construction and for overhaul reconditioning of worn-out car fleet of Georgia, Armenia and Azerbaijan for 4 months; the company has won the tender for delivery of rail wheels of two dimension-types for rolling stock of National railroads of Marocco (ONCF) and it will supply the customer with 1100 rail wheels with diameters of 890 mm and 1200 wheels – 920 mm within 6 months. Today, INTERPIPE company supplies its clients all over the world with more than 240 dimension-types of rail wheels and About Us 80 dimension-types of rims. Taking into account a wide range of manufactured products (wheel diameter over the taping line: 650 – 1269 mm; rim width: 90 – 157 mm; hub length: 90 – 405 mm; diameter of hole in the hub: 90 – 190 mm; weight: 165 – 1050 kg), the most advanced manufacturing equipment is used during production.
Taking into consideration growing demands to wheel products quality, INTERPIPE company is constantly improving its engineering data: improving design, increasing the strength and accuracy of processing, developing unique dimension-types by special orders. The products are delivered to the customer by single source contracts, that is why, quality assurance and orders timing assurance are the starting points of our long-term cooperation with clients. Nowadays, INTERPIPE products are certified in all strategic markets. Public accountants who represent railroads of three European countries at once – Germany, Slovakia and Czech Republic – certified solid-rolled wheels manufactured in the plant for consumers in the EU countries for compliance with the requirements of the module Í1 TSI-WAG from 05.01.2005 “Generalized system of quality protection”. At the end of February 2008 on the basis of the performed testing results «EisenbahnCert» certifying organization (Germany) registered a high level of conformity of wheel products of “INTERPIPE NTRP” OJSC with the indicated requirements. The audit of rail wheels produced by the plant was also carried out by the following companies: “ZSSKCARGO” (Slovakia), “VUKZ” (Czech Republic), “VUZ”. While performing the testing, any nonconformities of wheel products, organization and production technology with the requirements of valid international standards have not been found.
Issues of quality assurance of rail wheels manufactured by “INTERPIPE NTRP” OJSC are principal in relations of company with customers. An automated line of complex wheels testing which assures a multistage process inspection in compliance with the requirements of international standards was put into operation in 2008 in the process of all-factory program of engineering manufacture upgrading in the export area of tube-rolling shop. The delivered automated line combined laser geometry testing, ultrasonic flaw detection, magnetic particle inspection, testing of wheel rim strength and allowed to provide 100% assurance of testing products quality. The equipment of well-known world firms was included in the line composition: “Starmans electronics s.r.o” (Czech Republic) – immersion tanks of ultrasonic testing, “AMEST” (Switzerland) – hardness tester, “ERNST” (Italy) – laser system of geometry measurement. Leading domestic manufacturer of ultrasonic and eddy current testing tools, “Ultracon-Service” scientific production association, Kiev, designed, manufactured and incorporated in the line UÌPK-1 magnetic particle testing system on a tight schedule.
UÌPK-1 system is intended for magnetic particle inspection of rail transport wheels with diameter from 650 to 1300 mm (stated range of dimension-types is more than 90 % of the range on the existing and perspective orders) for the presence of surface and subsurface defects of any direction on all wheel surfaces, except the hub hole.
The testing on the system is carried out using “wet” magnetic and luminescent technique. The testing conform to the requirements of regulatory documents on magnetic particle inspection PrEN 13262, ISO 6933, ÀÀR M107, DIN EN ISO-9934-1,2,3, GOST 21105 and provides conditional sensitivity level “V” according to GOST 21105.
The system is an automated system which provides operation by two independent lines in general, in testing workflow and consists of four distant sites, functionally combined by one control system. All testing operations are automated, the system equipment is integrated in one system of control, registration and archiving of wheels testing results. Actuating mechanisms are operated from industrial sequence control by the program or (in manual control mode) operator’s remote control. The operator selects the system operation program corresponding to the testing wheel on the panel of controller and presses the button “Start”.
The programs differ by exciting current setups and wheel speed during testing. The transportation system equipment is reset up for testing wheel dimension-type manually by an operator. On command of the processor the wheel arrives to the loading site from testing line workflow, from where it is input on the testing site by transportation system equipment where it is gripped and held in vertical position by thrust rollers. Magnetization yoke is brought to the rim to make a closed magnetic circuit. Then, the wheel is premoistened with magnetic particle suspension, and combined magnetization is switched on while constantly rotating and oiling it with suspension. The wheel makes a full turn in the course of which every operator examines the testing surface directed to him using ultraviolet radiation sources. If additional testing of separate sections is necessary, an operator in manual rotation control mode sets the wheel in convenient position, locally oils it with magnetic suspension by means of remote control and retests it. On the basis of visual testing results an operator enters testing results from controller panel (“Flaw by magnetic particle flaw detection”, “In-order”) and the system generates the testing report in the line of automatic control system. The wheel is unloaded from the testing site and moved by transportation system equipment to the drying site and then on the unloading site.
Magnetic particle inspection of rails is carried out by the technique of impressed magnetic field. On each testing site magnetization is performed with the application of stationary coil and Ï-shaped electromagnet surrounding the rim. Performed magnetization schemes allowed to reduce considerably the system power consumption in comparison with its analogues where the principle of circular magnetization is used. At the expense of wheel rotation in the coil while magnetizing and oiling it with suspension, every elementary wheel section makes a turnover relative to stationary directed magnetic-field vector what is equivalent to the rotation magnetic-field vector and provides the most favorable conditions – reciprocal perpendicularity of defect and magnetic inductance vector – for detection of possible defects of any orientation. The defects on the taping line surface directed perpendicular to the wheel rotation axis are an exception with the present magnetization scheme; polar magnetization by electromagnet surrounding the rim is applied for their detection. The density of created variable magnetic field in each point of testing wheel surface is programmatically controlled and is at least 30 À/cm. Operation on alternative current of mains frequency and object demagnetization function performed programmatically after testing assures declination of remanent magnetization to the value of at least 0,7 mT.
Application of “Lumor J” high-contrast magnetic and luminescent powder («ELY Chemical Company Limited», Great Britain) and developed powerful ultraviolet lamps UFO-400 and UFO-100 provides accurate visual detection of defect by an operator. In the course of trial performance aiming to reduce the detrimental effect of ultraviolet radiation on operators, UFO-400 lamps design was modernized: protective shutter is automatically closed on the lamps if there is no wheel on the testing site; the system of forced ventilation of working chamber is upgraded what allowed to extend the operation life of ultraviolet lamps 1,5 times more.
To decrease operating costs, the system of preparation and application of reusable suspension is performed in the instrument. The suspension is prepared in two 160-litre tanks by dissolving magnetic and luminescent powder in water which was mechanically precleaned. Non-stop suspension stirring to achieve constant powder concentration during testing and exclusion of its packing is solved by constant suspension pumping by means of hydraulic pump. The suspension is atomized on the testing wheel in the form of water mist through eddy current spray burners placed on adjustable ally arms on each wheel side and over the taping line surface. Suspension surpluses from the wheel on the testing site and on the blow-off site, on the system exit is gathered into the tank and from there for excluding the mechanical particle pollution – they are pumped over back into the tanks of the major system loop through filters. Operational consumption of powder when testing the wheels with taping line diameter of 825 mm is 0,4 kg on an average per 1000 tested wheels.
Over a period of trial performance and commercial operation more than 290 thousand wheels of various dimension-types have been tested on the system. Operational experience showed high sensitivity of technique to characteristic technological defects. The majority of wheels rejected on the system had defects like “fold” on the sections of near-rim area of the disk and rim; there were also cases of subsurface defects detection on the taping line surface in the area of surface transition on the flange proved by metallographic analysis.
Today, even the cursory analysis of expert data shows that a new line of complex wheel testing introduced in the wheel rolling shop has already returned the expenses invested in its development, and its performance has exceeded the expected forecasts. The performed program of modernization of technological testing line will enable “INTERPIPE NTRP” OJSC to guarantee the highest standards of rail wheels quality, and experience of effective cooperation of domestic enterprises – developer and consumer of NDT technologies – leads to mutual benefit of two companies, and in tote – to effective model of the whole Ukrainian economy development.
