Powder Wire Research Articles

Production and Tensile Behavior of Novel Powder Wire Mesh Composite Porous Plates

A new type of powder wire mesh composite porous plate (PWMCPP) is successfully fabricated by the composite rolling and solid‐state sintering of stainless steel powder and wire mesh. Tensile tests are carried out, and the microstructure and fracture morphology are observed. The results show that the tensile strength of the PWMCPP decrease first and then increase with increasing mesh volume fraction and mesh diameter and increase with increasing sintering temperature. It is found that when the mesh volume fraction exceeds 65% and the sintering temperature exceeds 1310 °C, the tensile properties of the PWMCPP show the phenomenon of secondary plastic deformation work hardening with a saddle shape change. The tensile strength increased from 433 to 593 MPa, with an increase ratio of 36.95%, and the elongation increased from 33.17% to 55.7%, with an increase ratio of 67.92%. Herein, not only a method for preparing a composite of stainless steel powder and mesh is offered but also a useful reference for improving the tensile properties of the PWMCPP and expanding the application range (especially in the field of porous bearing) of porous metal materials is provided.

Charpy Impact Behavior of a Novel Stainless Steel Powder Wire Mesh Composite Porous Plate.

A novel powder wire mesh composite porous plate (PWMCPP) was fabricated with 304 stainless steel powders and wire mesh as raw materials by vacuum solid-state sintering process using self-developed composite rolling mill of powder and wire mesh. The effects of different mesh volume fractions, mesh diameters, and sintering temperatures on the pore structure and Charpy impact properties of PWMCPPs were studied. The results show that PWMCPPs have different shapes and sizes of micropores. Impact toughness of PWMCPPs decreases with increasing wire mesh volume fraction, and increases first and then decreases with increasing wire mesh diameter, and increases with increasing sintering temperature. Among them, the sintering temperature has the most obvious effect on the impact toughness of PWMCPPs, when the sintering temperature increased from 1160 °C to 1360 °C, the impact toughness increased from 39.54 J/cm2 to 72.95 J/cm2, with an increased ratio of 84.5%. The tearing between layers, the fracture of the metallurgical junction, and the fracture of wire mesh are the main mechanisms of impact fractures of the novel PWMCPPs.

Electric arc spraying of intermetalic Fe–Al coatings using different solid and powder wires

Electric arc spraying of intermetalic Fe–Al coatings using different solid and powder wires

Metallurgical processes and the mechanism of underwater wet cutting of steel with powder wire

Metallurgical processes and the mechanism of underwater wet cutting of steel with powder wire

Study of electrical stability parameters of the process of underwater wet cutting using powder wires with oxidized gas slash system

Study of electrical stability parameters of the process of underwater wet cutting using powder wires with oxidized gas slash system

Influence of introduction of titanium into the composition of a powder wire of type 25X5FMS

The effect of titanium introduction on the microstructure and physical and mechanical properties of metal deposited with flux-cored wire 25X5FMS has been studied. Surfacing of the investigated samples was carried out using a flux made from crushed slag produced by silicomanganese. The microstructure and non-metallic inclusions in the deposited layer have been studied. It is shown that with an increase in the concentration of titanium in the deposited metal, the hardness increases and the wear decreases.

Powder wires for resource-saving electric arc spraying

One of the promising methods of thermal spraying is the arc spraying. The use of electric arc spraying is particularly eff ective for the protection of metal structures from corrosion, receiving heat resistant, heat-resistant and wear-resistant coatings. This method is also eff ective in the recovery and hardening de tackles tractors, trucks and agricultural machinery. Signifi cantly extend the scope of the arc deposition can be using the new electrode materials in the form of fl ux-cored wires, the cost of which can be reduced by using materials for dying as a band , with factories producing cable products and iron shavings tion of machine-building enterprises.

Increasing Durability of Transport Rollers for Sawmill Equipment

A test procedure has been developed that models the wear of a material at friction against timber with abrasive particles impregnated into it. The procedure considers the kind and grain structure of an abrasive, timber species, technique of impregnating timber with abrasive particles, and testing configuration, temperature, and modes. The building up of the lateral surfaces of roller thorns with electrodes UONI-13/NZH and powder wire PP-Np-30Х4G2М is a more expedient method to make them more durable. It is shown that the grade 30 steel wear is characterized by the plastic straining of micro-volumes in the surface layer in the presence of individual marks and scratches, whereas the buildup wear is attended only by elastoplastic straining. The influence of such factors, as contact pressure, sliding speed, test temperature, and quartzy particle grain structure on the wear resistance of the studied surfacings is revealed. It is noted that the wear resistance of buildups UONI-13/NJ and PP-NP-30X4G2M for various test conditions is approximately equal to and 2.5–3 times as high as that of grade 30 steel; however, the preferable option for practical use on feed rollers is UONI-13/NJ due to its enhanced anticorrosion properties.

Повышение окалиностойкости валков горячей прокатки наплавкой порошковой проволокой

The application of PP30N8H6M3STYu powder wire is considered which ensures high scale-resistance of welded metal. It is defined that the scale formation indices of 30N8H6M3STYu metal are much better than those in 30H2V8F steel at the temperature of 900ºC. It is shown that the scale base of 30N8H6M3STYu metal is chemical compounds of Fe2O3, Fe3O4, Cr2FeO4, Fe2NiO4 and Fe3N.

Формування структури плазмово-дугових покриттів, одержаних із порошкових дротів зі сталевою оболонкою і наповнювачем B$_4$C+(Cr,Fe)$_7$С$_3$+Al

Формування структури плазмово-дугових покриттів, одержаних із порошкових дротів зі сталевою оболонкою і наповнювачем B$_4$C+(Cr,Fe)$_7$С$_3$+Al

Вплив діаметра електродних порошкових дротів на механічні характеристики електродугових покриттів

The influence of the diameter of the electrode flux-cored wires on the mechanical characteristics of the electric arc coatings is carried out in the work. Electric arc coatings were obtained on the original equipment, developed and manufactured at the Institute of Physics and Mechanics. GV Karpenko NAS of Ukraine. For spraying, model flux-cored wires of basic doping systems Fe – Cr – C and Fe – Cr – B with a diameter of 1.6 and 2.4 mm were used. The influence of the diameter of flux - cored wires on the structure, electric arc coatings from model flux - cored wires of different diameters is investigated. The dependence of porosity, microhardness, adhesion to the steel base, abrasive wear resistance of electric arc coatings sprayed from flux-cored wires with different amounts of charge on the thickness of the lamellae in the coating structure has been established. The influence of the thickness of the lamellae in the structure of coatings sprayed from flux-cored wires with different amounts of charge (depending on their diameter 1.6 and 2.4 mm) on their abrasive wear resistance was determined. It was found that the thickness of the lamellae in the coatings of all analyzed alloying systems increased with increasing volume of molten metal at the ends of flux-cored wires with the corresponding formation of droplets of larger diameter during its dispersion by air jet. shell charge and high arc current. It is shown that the amount of oxide phase in the structure of coatings doubles with increasing spray distance of flux-cored wires from 80 to 120 mm. More oxide phase (40… 100%) was found in coatings formed of flux-cored wires with a diameter of 2.4 mm with a higher filling factor of its shell charge compared to coatings formed of flux-cored wires with a diameter of 1.6 mm with lower filling. This is due to the larger volume of the charge in the powder wires of larger diameter, the cavities between the powders in which are filled with air, which intensively oxidizes the melt droplets inside the powder wires and at their ends during spraying. It is established that the porosity and microhardness of coatings from the developed flux-cored wires increase with the increase of the thickness of the lamellae in their structure and, accordingly, the diameter of the flux-cored wires. The increase in micro hardness is due to less evaporation and burnout of alloying elements from the droplets forming the coating, and the increase in porosity is caused by intensive spraying of droplets when hitting the sprayed surface, which contributes to micro cavities between the lamellae of the coating. It was found that with increasing the thickness of the lamellae in the structure of coatings of flux-cored wires 250H21VFGS and flux-cored wires 50HN2R5GS their adhesion to the steel base decreased slightly due to the occurrence of tensile stresses in coatings, which cause micro cracks or cracks. At the same time, the adhesion of 50X6MG2C flux-cored wire coatings to steel increased due to the higher carbon content of large lamellae and favorable conditions for the formation of high-carbon martensite, which has the lowest coefficient of thermal expansion and causes the lowest residual tensile stresses. It was found that the abrasive and gas-abrasive wear resistance of coatings from flux-cored wires 250Х21ВФГС decreased, and from flux-cored wires 50ХН2Р5ГС increased due to the increase in the thickness of the lamellae in their structure using a larger diameter.

Frictional Strength of Electric Spark Coatings from Powder Wires under Friction without Lubrication

Frictional Strength of Electric Spark Coatings from Powder Wires under Friction without Lubrication

ПЕРСПЕКТИВЫ ПРИМЕНЕНИЯ ТЕХНОЛОГИИ ЛАЗЕРНОЙ НАПЛАВКИ ДЛЯ ВОССТАНОВЛЕНИЯ РОЛИКОВ МАШИН НЕПРЕРЫВНОГО ЛИТЬЯ ЗАГОТОВОК

The article considers the possibility of applying laser cladding technology to restore the rollers of continuous casting machines. Effective methods of restorative surfacing of rollers of continuous casting machines are briefly presented. The paper describes the process of forming coatings for rollers using laser and electric arc surfacing methods. Laboratory equipment for preparing experimental samples for metallographic studies is described. The method of preparation of laboratory samples of coatings obtained by laser and electric arc surfacing is described. Electric arc surfacing of 20X13 steel samples is performed with PP-NP-25X5FMS powder wire. Laser surfacing of samples made of 20X13 steel is performed with an economically alloyed powder based on Fe-Co-Cr-Mo iron. The structure and composition of surfaced coatings by electric arc and laser surfacing methods for rollers of continuous casting machines are studied. The mechanical properties of the applied coatings for the rollers are studied. Tribological characteristics of coatings applied by electric arc and laser surfacing methods are investigated. To evaluate the properties of coatings, a structural and phase analysis is performed, and the friction coefficients and wear rate are determined. Graphic images of the deposited layer structures are presented. The dependences of the friction coefficient of the deposited layers are presented and their differences for each of the surfacing methods are analyzed. An explanation of the differences in the properties of coatings based on the analysis of their formation conditions is offered. The efficiency of using the laser surfacing method for restoring parts of metallurgical equipment is evaluated.

Properties of new-generation hybrid layers combining hardfacing and nitriding dedicated to improvement in forging tools\u2019 durability

This article deals with the subject of layers produced in a hybrid process combining hardfacing and nitriding. These layers are characterized by improved resistance to wear, which arises from the synergy between favorable materials during hardfacing and nitriding treatment. Tests were conducted on hot-work tool steel (H11) samples. Hardfaced layers consisting of three layers were applied to these samples, where layers were made from two materials—Robotool 46 and Hardface VMolc powder wires. Next, samples of both materials were nitrided using ZeroFlow gas nitriding technology, with control of potential aimed at obtaining a diffusion layer without a white zone of nitrides on the surface. The next step was to investigate the properties of hardfaced layers and of layers hardfaced after nitriding treatment. Conducted tests covered observations of the microstructure, microhardness measurements as a function of distance from the surface, measurement of stresses in the surface layer by means of X-ray diffraction, and tribological tests. Obtained test results show that hybrid layers combining hardfacing and nitriding may be suitable for improving the lifetime of tools applied in hot forging processes.

Влияние режимов термической обработки на структуру, свойства и фазовый состав стали 10Г7М3С2АФТЮ, наплавленной порошковой проволокой

There are investigated peculiarities of hardening through ageing of steel 10G7M3S2AFTYu weld with powder wire. It is defined that ageing at the temperature of 550ºC during 6 hours ensures the highest degree of strengthening of ferrite steel 10G7M3S2AFTYu. It is proved that the mechanism of steel strengthening as a result of ageing is determined with the Ti2CN, V1.98Ti0.02, VC combinations mainly.

Анализ внутренних напряжений методами рентгеновской дифрактометрии в наплавленном металле и околошовной зоне легированными редкоземельными элементами

Through the methods of X-ray diffractometry there are defined values of residual stresses in a weld metal and a periweld area obtained by hand arc welding deposition with experimental powder wires with the different rare-earth element composition of the Tomtorsky deposit (Yakutia, Russia). It is revealed that in the deposited metal and in the periweld area (PWA) with REM there are formed tensile inner stresses. In weld metal and in the PWA deposited with wire containing 0.7% of REMs there are revealed tensile inner residual stresses which cam serve as an additional mechanism restraining a formation stage and delaying a process of post-welding cracks propagation. An optimum composition of powder wires with the modifying REM admixture is offered.

The parameters estimation of pulse-arc welding by high-chromium flux-cored wire

ABSTRACT The analyses of the pulse-arc welding process influence on the macro characteristics of the melting process of high-chromium powder wires type 55 × 18 with a diameter of 1.2 and 1.4 mm is carried out in this work. It is established that at a modified pulse combination during the drop relief period and the flux-cored wire with a diameter of 1.2 mm, the waste of metal and spattering is 1.5 times lower, and the deposition coefficient is 1.5 times and the productivity is 1.6 times higher than for welding with natural short circuits. Oscillography of the arc current and voltage showed that in the pulsed mode, along with small-drop transfer, periodic formation of larger drops occurs. An explanation on the basis of the difference in the thermophysical properties of the core and the flux-cored wire shell, as well as the reduction in heat input during impulse welding in comparison with welding without impulse is proposed.

Methods for Increasing the Corrosion Resistance of Coatings Deposited under a Flux Layer from High-Chromium Powder Wires

We propose to improve the corrosion resistance of the coatings deposited from PP-Np-30Kh20MN fluxcored wires under a flux layer by changing the procedure of preparation of the charge, by introducing modifying additions to the charge, and by the ultrasonic impact treatment of the deposited surface. It is shown that the influence of charge materials from the flux-cored wires refined by electroslag remelting on the analyzed characteristic is more pronounced. The corrosion resistance becomes higher as a result of the addition of a small amount of yttrium to the charge. The ultrasonic treatment of the deposited surface may improve the corrosion resistance of the metal but this problem requires additional investigations.

Improving the efficiency of hardening of tillage machine working bodies by arc surfacing using wear-resistant rollers

Reducing operating costs during soil processing and increasing the wear resistance of parts and components is an important condition for reducing the cost of agricultural products, increasing its efficiency and competitiveness. The development of materials with increased wear resistance and new effective technologies for strengthening working bodies in their manufacture is now becoming an urgent task. (Research purpose) The research purpose is increasing the wear resistance of the working bodies of soil-processing machines by electric arc surfacing. (Materials and methods) During the experimental study, it has been performed testing of modes and surfacing of a pilot batch of working bodies from Kverneland for field tests in VIM on an automated installation for electric arc surfacing. Authors used eutectic CastolinEnDotec DO*30 powder wire with a diameter of 1.2 millimeters and a boron content of up to 4 percent for surfacing wear-resistant rollers, which allows to obtain wear-resistant rollers with a hardness of up to 65 HRC without pores and cracks. (Results and discussion) It has been revealed that hardened ploughshares that have passed field tests are subject to lower wear rates compared to non-hardened ones. It was found that when operating time is 24.785 hectares per ploughshare, the wear of the linear size of the cutting edge along the width of hardened ploughshares is on average up to 10-11 millimeters less than that of non-hardened ones. It was found that when processing 228 hectares, the wear of the linear size of the cutting edge along the width of hardened bits is on average up to 9-10 millimeters less than that of non-hardened ones. (Conclusions) The technology of surfacing with intermittent wear-resistant rollers provides an increase in the efficiency of hardening of Kverneland working bodies according to the criterion of wear resistance by an average of 20-30 percent. The adjusted technological parameters of the surfacing process will reduce the wear rate and increase the service life of the blade part of the working bodies, as well as reduce the amount of surfaced material by an average of 60 percent. The continuation of work on strengthening the working bodies should be aimed at changing the surfacing scheme and choosing a cheaper domestic cored wire.

Formation of Structure in Clad Abrasion-Resistant Alloys of the Fe – Cr – C – Mo – Ni – Ti – B System Under the Effect of Ultrafine Particles of Titanium Nitride

The behavior of the structure of abrasion-resistant alloys of the Fe – Cr – C – Mo – Ni – Ti – B system during electric arc cladding with introduction of ultrafine particles of titanium nitride into the welding pool in the composition of both the electrode and the filling powder wires is considered. The effect of titanium nitride on the hardness and wear resistance of the experimental clad alloys at normal and elevated temperatures is studied, and the values of the operating properties of the alloys are compared to the respective properties of the commercial counterparts.