25 Years in the World of Flux-Cored Wires

Decomposition of the USSR and emergence of independent republics in the post-Soviet space at the start of 1990s was accompanied by upsetting of industry operation, breaking up and loss of production links, mass stoppage of production. In 1993 in Kiev a joint Russian-Ukrainian Company «TM VeldTek Ltd.» was set up by the initiative of PWI staff. The Company was successfully developing in the direction of flux-cored wire manufacture. This was promoted by the support of «Dnepropetrovsk Hardware Production Association», where the management appreciated the idea of restoring flux-cored wire manufacturing in Ukraine. In 2001 flux-cored wire manufacturing was moved to a separate subdivision – «TM.WELTEC Ltd.».

     Over 25 years of operation the Company implemented a number of important engineering measures on repair and upgrading of the main equipment, in particular, flux-cored wire production lines, charge section improvement, has mastered modern forms of product supply, has optimized technologies of manufacturing wires of 1.0—6.0 mm diameter. Series of modern welding and surfacing flux-cored wires have been developed and are manufactured at present. Such results have been achieved owing to dedicated efforts of highly qualified engineering and technical staff and workers.
     Positive result of cooperation with enterprises is achieved owing to application of comprehensive approaches to order fulfillment, including, if required consultative assistance on selection of material, optimum technology and equipment for its application and engineering support. High scientific and technical potential of the Company, irrespective of the range and volume of batches, allows fulfilling the orders in the shortest time, taking into account customer requirements. Such an approach allowed occupying a quite large market segment in Ukraine, ensuring stable foreign contacts and becoming a firm partner for many enterprises. Experience of interaction and cooperation with research institutes and universities of Ukraine and Russia is to the company’s credit.

     By their applications and performance WELTEK wires now are not inferior to the products of leading foreign companies, that is confirmed by their high evaluation in the local and foreign exhibitions and independent ratings, company’s recognition as a reliable supplier by leading enterprises of Ukraine and CIS, continuous widening of consumption regions and growth of sales.
     «TM.WELTEC» developed a number of new flux-cored wires for building-up by surfacing. WELTEK-N470 flux-cored wire of 2.0—4.0 mm diameter in combination with fluxes AN-20 and AN-26 and WELTEC-H470S self-shielded wire of 2.0—2.4 mm diameter are manufactured for building-up by welding of CCM rolls. These wires ensure self-separation of slag crust, absence of pores or cracks in the deposited metal in case of following the technological recommendations. Comparative testing of WELTEC-H470 and WELTEC-H350-RM wires showed that they are on the level of those of leading foreign companies. Built-up rolls have the service life of not less than 1.5 mln t.

     «TM.WELTEC» together with metallurgical plants «Krivorozhstal», «Dneprovsky F.E. Dzerzhinsky» and «Zaporozhstal» performed a package of work aimed at improvement of surfacing consumables, technology and equipment for mill roll surfacing. Standard flux-cored wires of FCW-Sw-35W9Cr3SiVand FCW-Sw-25Cr5VMoSi grades were used to optimize the alloying systems and develop new flux-cored wires WELTEK, allowing for mill roll operating conditions, namely WELTEC-H370-RM, WELTEC-H460, WELTEC-H500-RM, WELTEC-H505-RM, WELTEC-H550-RM. Surfacing by these wires is performed using AN-20, AN-26 and AN-348-A fluxes. Application of the proposed wires improved the effectiveness of mill roll operation.
     In cooperation with Nikopol Plant of Seamless Pipes «Niko Tube» performed work on introduction of hardsurfacing of continuous mill rolls by WELTEC-H350-RM flux-cored wire with C—Si—Mn—Cr—V—Mo—W alloying system. The wire provides a stable process of DCRP surfacing using AN-20S and AN-26P fluxes, easy separation of slag crust, absence of cracks and pores in the deposited metal. Deposited metal hardness is HRC 50—56.

     Self-shielded flux-cored wire WELTEC-H250-RMof 1.6—3.0 mm diameter is successfully applied at reconditioning of mill stand and shear pads, spindels and couplings of roll drives, sprockets, bushings, shafts, hubs, etc. Surfacing of dogging crane cores and striper crane jaws, exposed to impact and compressive loads at high temperatures in service, was implemented. For this purpose, 2.0 mm self-shielded flux-cored wire of WELTEC-H480S grade with C—Cr—W—Mo—V—Ti alloying system was applied, which ensures deposited metal hardness after surfacing equal to HRC 50—54, and hot hardness of HRC 40—44 at 600 °C. Application of mechanized surfacing with WELTEC-H480Swire instead of T-590 and T-620 electrodes allowed extending core service life 4—5 times. The problem of core reconditioning was solved in a comprehensive manner (equipment—material—technology).
     Flux-cored wires of WELTEC-H350-RM and WELTEC-H350-RM grades of 1.6—4.0 mm diameter are proposed for crane wheel surfacing. Surfacing is performed with AN-348 and AN-60 fluxes or in CO2. Over the recent years WELTEC-H300-RMwire has been successfully applied instead of solid wire Np-30KhGSA. Technology of surfacing using AN-348 flux and 3.6 mm fluxcored wire of WELTEC-H285 grade has been developed for heavy-duty crane wheels. Chromiummanganese deposited metal with the structure of metastable austenite ensures high wear resistance of the wheels through development of the process of self-strengthening at cold working. The Company is taking an active social stand, providing financial support to local sports, medicine and science.

Originally published at The Paton Welding Journal №01 2014 (View PDF)