Weld Hardfacing Research Articles

Analysis of Ballistic Capability in Making Bulletproof Multilayers Using Woven Ramie Fiber, Hardfacing Metal with Epoxy Matrix for Bulletproof Vests

Bulletproof material in level III bulletproof vests must be created using hard and soft materials to prevent bullet penetration. Kevlar and SiC + PE are imported materials used as armor in bulletproof vests. The use of Kevlar and SiC is very dependent on foreign sources with high prices. An innovation was carried out by making bulletproof material using cheaper multilayer methods involving metal from hardfacing welding as a hard layer and ramie fiber as a soft layer with an epoxy matrix. To see the level of penetration and surface morphology structure in the specimens, 9 variations were made: 3 layers of hardfacing welding and 3 epoxy volume fractions (40%, 45%, 50%). Ballistic test using NIJ 0101.06 level III standards with AK-47 of 7.62 mm x 39 mm bullets and the morphology of bulletproof multilayer material after impact was observed using SEM. The results showed all specimens failed to withstand bullet penetration at a distance of 15 meters. Meanwhile, at 50 meters, the S2-C specimen with a 60% epoxy volume fraction was able to withstand bullet penetration with a BFS value of 25.85 mm. This value is < 44 mm; thus, it complies with the NIJ 0101.06 body armor standard. According to SEM, most of the failures occurred because the resulting adhesion force was weak. It was necessary to add reinforcing material so that the adhesion force between the metal, ramie fiber, and adhesive increases; the materials must also have very light density to prevent the effectiveness reduction of the multilayer.

Analysis of variations in the number of layers of hardfacing overlay ABREX 500 material on hardness,impact strength and microstructure with the SMAW process

Hardfacing is a welding technique that functions to increase the surface hardness value of a material. Generally, hardfacing is done on low-carbon steel materials because low-carbon steel cannot be increased in hardness by heat treatment. For this reason, research will be carried out on the multilayer hardfacing process with the aim of obtaining optimal layer hardness. The methodology in this research is that multilayer hardfacing welding will be carried out consisting of 3 layers, 4 layers, and 5 layers, and each specimen has 2 buffer layer layers with E 309 electrodes for the hardfacing layer using HV 600 electrodes. This research reveals the influence of the number of layers of hardfacing on the hardness and toughness values. ABREX 500 material with a size of 150x150x10 mm was welded using the SMAW process using a current of 130 A. In this research, hardness and toughness tests were carried out. On test results. The base metal microstructure is dominated by a tempered martensite structure with a small amount of bainite and pearlite. In the structural area of the support layer, austenite and vermicular ferrite dominate. In the hardfacing layer area, austenite and vermicular ferrite, which are in dendritic form, dominate. The increase in hardness will occur significantly after hardfacing is carried out on the base metal. In a specimen, the more layers of hardfacing are added, the harder the material will be. The hardness of the specimen in 5 layers gets the most optimal value (higher) when compared with the hardness in 3 layers and 4 layers. In the 5-layer specimen, the resulting hardness value was 482.13 kgf/mm2, for the 4-layer specimen, the average value was 464.83 kgf/mm2, and in the 3-layer specimen, the hardness value was 444.13 kgf/mm2. For toughness testing, the highest toughness value was obtained, namely 1.32 (J/mm2) for the 3 layers specimen, compared to 4 layers with a toughness value of 1.25 (J/mm2) and 5 layer with a toughness value of 1.19 (J/mm2). The toughness value decreases as the hardness value increases.

The Effect of Mixing the Additive Material with the Substrate During the Renovation of the Foundry Mold by TIG Welding Hardfacing

The Effect of Mixing the Additive Material with the Substrate During the Renovation of the Foundry Mold by TIG Welding Hardfacing

Effects of flux-cored arc welding technology on microstructure and wear resistance of Fe-Cr-C hardfacing alloy

This research presented the effects of flux-cored arc welding (FCAW) with and without preheating, gas-shielding and buffering conditions on the microstructure and wear resistance of Fe-Cr-C hardfacing alloy. The flux-cored wires based on austenitic nickel and Fe-Cr-C alloyed steel were used as buffer and hardfacing layers. The welding quality was inspected by visual test (VT) and penetrant test (PT). The structural characteristics were analyzed by optical microscope (OM), X-ray diffractometer (XRD), and scanning electron microscope with energy dispersive X-ray spectrometer (SEM-EDS). The results exhibited that the preheating, gas-shielding and buffering could improve the quality, dilution and weldability of the hardfacing weld. The structural phase of the hardfacing weld was found in the form of (Fe,Cr)7C3 mixed with martensite-austenite matrix (MA matrix). The buffering could combine the interphase of hardfacing to structural steel base resulting in the reduction of crack and carbide precipitation (Fe3C) at the fusion line from the effect of elemental dilution. The combination of buffer and hardfacing layers affected to crystallite size and fraction ratio of (Fe,Cr)7C3 to MA matrix increasing the elemental diffusions. According to the wear testing results (hardness, impact and abrasion), it was found that the preheating, gas-shielding and buffering FCAW provided an excellent wear resistance of Fe-Cr-C hardfacing alloy due to the present of (Fe,Cr)7C3 eutectic carbide in a high fraction of MA matrix resulting in good toughness-hardness balance properties. In addition, the suitable FCAW condition from the study could be applied for hardfacing of the tooth plate of crushing roller that was used in the biomass energy industry with better service life than traditional FCAW.

MANUFACTURING AND CHARACTERIZATON OF WAAM-BASED BIMETALLIC CUTTING TOOL

Wire-arc additive manufacturing (WAAM) is a promising method to produce many functional components in different industries. In this method, the welding wires from the feedstock are melted by arc discharge and deposited layer by layer. Other welding wires having different chemical compositions can also be added to the top of the previously deposited layer by replacing the feed wire from the stock to produce bimetallic components. This study investigated the feasibility of using robotic wire arc additive manufacturing technology to produce a bimetallic cutting tool. The bimetallic cutting tool was produced by depositing MSG 6 GZ-60 hard-facing welding wire on top of the austenitic stainless-steel wall produced with ER 316LSi solid wire. The cutting-based equipment requires an increased abrasion resistance with the combination of ductility to provide adequate tool life and performance. Thus, detailed microstructural analysis and hardness tests were conducted to understand the general microstructural characteristic of the manufactured cutting tool, including interfaces between two different materials.

Wear resistance and microstructural evaluation of a hardfacing welded S355J2 steel pipe piles

Abstract Steel pipe piles are used to reinforce the grounds. Due to high hardness of the rocky materials, in some cases, the tip surface should be developed with new designs in terms of geometry, material and heat treatment. In this study, a hardfacing welding, which reinforces the application point of the tip surface, was applied on the steel pipe pile shoe tip which was manufactured from S355J2 steel. Wear tests were applied and hardness measurements were made to explain wear behavior. According to the results, the hardened surface of the 3rd layer which was welded with FCH-360 flux cored wire showed higher hardness than other layers. Similarly, the highest wear resistance was obtained in this layer. Martensitic and bainitic structures with ferrite islets were observed from the first layer to the second layer. The bainite and ferrite isles were gradually transformed to martensite and maintained itself from first to third layer. The martensitic structure mainly controlled the hardness and wear resistance. The sizes of the martensite highly affected the hardness and wear resistance of the layer itself.

Modelling of hardfacing layers deposition parameters using robust machine learning algorithms

The study presents a data-driven framework for modelling parameters of hardfacing deposits by GMAW using neural models to estimate the influence of process parameters without the need of creating experimental samples of the material and detailed measurements. The process of GAS Metal Arc Welding (GMAW) hardfacing does sometimes create non-homogenous structures in the material not only in deposited material, but also in the heat-affected zone (HAZ) and base material. Those structures are not fully deterministic, so the modelling method should account for this unpredictable component and only learn the generic structure of the hardness of the resulting material. Artificial neural networks (ANN) were used to create a model of the process using only measured samples without any knowledge of equations governing the process. Robust learning was used to decrease the influence of outliers and noise in the measured data on the neural model performance. The proposed method relies on modification of the loss function and several of them are compared and evaluated as an attempt to construct general framework for analysing the hardness as a function of electric current and arc velocity. The proposed method can create robust models of the hardfacing layers deposition or other welding processes and predict the properties of resulting materials even for unseen parameters based on experimental data. This modelling framework is not typically used for metallurgy, and it requires further case studies to verify its generalisability.

Development of NiCrSiBC Weld Hardfacing Approach for P91 Steels Used in Steam Turbine Components

Abstract: P91 steels are used as substrate material for steam turbine components like bush, valve seat internals, and engineering valves. These components have hardfacing of cobalt-based material to reduce the high temperature wear loss and to improve the surface hardness. However, delamination failure and higher heat affected zone (HAZ) hardness were identified challenges for P91 steels. Hence, this demands the development of a suitable weld hardfacing approach to resolve the said challenges. In this work, NiCrSiBC (Colmonoy 6) has been considered as a hardfacing material to replace cobalt-based Stellite 6 material due to elimination of radiation activity, lower cost, and higher coating hardness. FCAW and PTA techniques were used to deposit buffer layer (SS-309L) and hardfacing layer (NiCrSiBC) respectively. Sample WBL (with deposition of buffer layer) and sample WOBL (without deposition of buffer layer) are considered approaches to study the metallurgical characterization for each case. Higher coating hardness, lower HAZ hardness and lower Fe dilution were observed in sample WBL. Cr7C3, Cr2B, and Cr5B3 hard phases in block shape together with ϒ- nickel matrix solid solution was observed in coating region of sample WBL. Overall, sample WBL approach was considered to overcome weld hardfacing challenges for steam turbine industries.

New submerged arc welding flux for hardfacing of Hardox steels

Abstract In this study, the usability of a new submerged arc welding flux was investigated to develop the surface properties of Hardox steels. In the hardfacing welding processes for Hardox 400 steel, four welding speeds resulting in varied heat inputs were applied. Through an analysis of the chemical composition, microstructure examinations, hardness measurements and wear tests, the possibility of hardfacing properties control due to the change of process parameters were determined. In the experimental studies, the hardness of the hardfacing obtained at a welding speed of 30 cm × min-1 was measured as 42 HRC while the hardness of the hardfacing obtained at a welding speed of 48 cm × min-1 was measured as 57 HRC. Moreover, in the wear tests, results consistent with the hardness values were obtained. It was understood in the light of the results that the use of high carbon ferro-chromium 20 wt.-% in a submerged arc welding flux mixture may be useful in improving hardness and wear properties of Hardox steels through hardfacing welding processes.

New submerged arc welding flux for hardfacing of Hardox steels

Abstract In this study, the usability of a new submerged arc welding flux was investigated to develop the surface properties of Hardox steels. In the hardfacing welding processes for Hardox 400 steel, four welding speeds resulting in varied heat inputs were applied. Through an analysis of the chemical composition, microstructure examinations, hardness measurements and wear tests, the possibility of hardfacing properties control due to the change of process parameters were determined. In the experimental studies, the hardness of the hardfacing obtained at a welding speed of 30 cm × min-1 was measured as 42 HRC while the hardness of the hardfacing obtained at a welding speed of 48 cm × min-1 was measured as 57 HRC. Moreover, in the wear tests, results consistent with the hardness values were obtained. It was understood in the light of the results that the use of high carbon ferro-chromium 20 wt.-% in a submerged arc welding flux mixture may be useful in improving hardness and wear properties of Hardox steels through hardfacing welding processes.

Characterisation of Electrode Drying Effect on the Tungsten Carbide Hardfacing Microstructure

This study addresses characterization of ED (electrode drying) effect on WC hardfacing welding microstructure. Medium carbon steel blade which used as CD (continuous digester) blade to mix up sulphuric acid together with ilmenite ore in a digester tank as a major part of production. Microstructure of WC hardfacing, elemental composition alongside hardness analyses are executed to investigate the effect of ED (electrode drying). The ED (electrode drying) effect on microstructure and hardness values of WC hardafcing coating are characterized by SEM (scanning electron microscope) analysis and micro-Vickers hardness tester correspondingly. Results revealed that ED (electrode drying) effect less significant in the larger carbides at overall coating zone. However, the absence of ED (electrode drying) led to distribution of uniform smaller carbide in non-carbide zone. The uniform carbide distribution increases the hardness of the WC hardfacing coating.

Microstructure and wear resistance of (Nb,Ti)C carbide reinforced Fe matrix coating with different Ti contents and interfacial properties of (Nb,Ti)C/α-Fe

In this work, the (Nb,Ti)C reinforced Fe matrix coatings were prepared by gas metal arc welding (GMAW) hardfacing technology. The microstructure, hardness and wear resistance of (Nb,Ti)C reinforced coatings with different Ti contents were investigated by experiments. The interfacial properties of (Nb,Ti)C/α-Fe interfaces were calculated by first principles method based on density functional theory (DFT). The experiment results show that as the Ti content in the coating changes from 0.15 to 0.41 wt%, the average diameter of NbC primary carbide grains decreases from 3.2 μm to 1.7 μm and their amount increase from 0.35 to 0.51 μm−2. The coating with 0.15 wt% Ti performs the lowest wear loss, which is 0.47 g/N ∗ cm2. From the calculated results, the interfacial combination between carbide and matrix are improved after Ti addition. The adhesion work of (Nb,Ti)C/Fe interfaces show the following order: CNb-Fe < NbC-Fe < CTiNb-Fe < CNbTi-Fe < NbTiC-Fe < TiNbC-Fe. In CTiNb-Fe, CNbTi-Fe and CNb-Fe surfaces, weak Fe-M covalent bonds are formed at the interfaces. In NbC-Fe, NbTiC-Fe and TiNbC-Fe surfaces, strong FeC and M-C covalent bond can be found at (Nb,Ti)C/α-Fe interfaces, besides, FeC ionic bonds are also formed.

Refining effect of nitrogen on M7C3 carbides in hypereutectic Fe–25Cr–4C–0.5Ti–0.5Nb hardface coatings

ABSTRACTHypereutectic Fe–Cr–C–Ti–Nb coatings with N additives were developed by surface-hardening welding (hardfacing). The experimental results showed that the primary M7C3 carbides were refined by the N additives in the coatings. Based on the micro-morphologies of M7C3 and (Ti,Nb)(C,N), the (Ti,Nb)(C,N) was present inside the primary M7C3 carbides, and they were tightly combined. The mismatch between the (010) crystal plane of M7C3 and the (110) crystal plane of (Ti,Nb)(C,N) was 6.15%, which indicated that (Ti,Nb)(C,N) was moderately effective as a heterogeneous nucleus of M7C3 carbides. Therefore, the preferentially precipitated (Ti,Nb)(C,N) in the Fe–Cr–C–Ti–Nb coating was the heterogeneous nucleus of the primary M7C3 carbides and thereby refined the primary M7C3 carbides .

Influence of Oxidation on the High-Temperature Tribological Properties of Tungsten-Carbide-Reinforced Cu-Ni-Mn Composite Coatings

Cu-Ni-Mn alloy coatings and their associated composite coatings reinforced with tungsten-carbide (WC) particles were deposited onto a steel substrate using the manual oxy-acetylene weld hardfacing method. The sliding wear behaviors in air at 350 °C were investigated. The relative wear-resistance values of the as-deposited and the age-hardened WC/Cu-Ni-Mn hardfacing coatings with regard to the commercial Fe-Cr-C hardfacing coatings at 350 °C were 1.90 and 2.39, respectively. The excellent sliding wear-resistance performance of the WC/Cu-Ni-Mn hardfacing coatings was mainly ascribed to the hard and thermally stable WC particles embedded uniformly in the Cu-Ni-Mn metal matrix. The high-temperature wear mechanisms of the coatings were determined to be mainly abrasion and adhesion. The oxidation of the metal matrix improved sliding wear-resistance performance at high temperatures. Compared to the results at room temperature, the friction coefficients of the coating decreased, whereas the sliding wear volume loss increased slightly under dry sliding wear conditions at high temperatures.

Wear characteristic of wc hardfacing on carbon steel: effect of weldment current and layer

Tungsten carbide (WC) hardfacing is performed to improve the wear resistance and operating life of the carbon steel blade which operates under acidic and abrasive environment. The effect of weldment current and layer number on wear characteristic of WC hardfaced carbon steel are the focus of this study. Different hardfacing welding parameters such as 200 A and 150 A weldment current and 1, 2 and 3 layer numbers are studied in detail. Microstructure and elemental composition are characterized by scanning electron microscope (SEM). Meanwhile, hardness test is performed using micro-Vickers hardness tester. The abrasive slurry wear test is implemented to investigate WC coating wear behaviour. The results revealed that the coating is made up of carbide and non-carbide region. The carbide region has higher hardness compared to non-carbide region. Carbide region has highest W content, while non-carbide region consists of combination of Fe and W. High weldment current and higher number of layers can enhance the wear resistance of WC hardfacing.

The investigation of wear properties of different hard filling welding electrodes used in repair welding

The surface of tamping machine's digger is covered with a filler material because it is a material that is continuously used in TCDD (The State Railways of the Turkish Republic) lines and it is a material that needs to be constantly changed because it is exposed to abrasion. For many years, this process with the same method and same electrodes. In our work, we aimed to produce a variety of welding electrodes with a more efficient, longer-lasting and less labor-intensive method for production tamping machine’s digger. Considering factors such as applicability, easy availability, cost, welding method and hard facing welding electrodes to be used in our work have been determined. The necessary materials were then provided. The diggers of tamping machines were welded with 5 different welding electrodes. Then, the effect of each of these electrodes on the mechanical properties and strength was compared. Used tamping machine’s diggers processing was carried out with different hardfacing welding electrodes. Mechanical properties and strength effects of different welding electrodes was analyzed.

Thermal model of the Gas Metal Arc Welding hardfacing process

The article presents the application of the CFD FVM model for thermal simulation of the GMAW hardfacing process. The paper focuses on heat transfer aspects of welding process like distribution of temperatures, heat transfer from electric arc, thermal effects of melting and solidifying of metal. Because detailed CFD and thermal analysis of welding process is computationally expensive, the modified, faster approach has been proposed to obtain realizable compromise between accuracy and calculation efforts for engineering heat transfer analysis. It allows getting the thermal simulation closer to engineering practise as a base for structure analysis. The model has been tested and validated against thermography measurements. The procedure of thermography measurements and validation has been presented in the article. Results showed high reliability of proposed approach, particularly for heat transfer around electric arc. The developed model can be applied for various FVM codes and useful as a part of multi physics analysis.

Effect of welding conditions on erosive wear of hard-faced Co-based alloy layer

Degradation of materials due to the impact of solid particle is a major material wastage process. Modifying the surface of materials can be considered to be a potential method of improving the resistance to erosion. In the present days, weld hard-facing is a popular surface modification process. Engineering industries are opting for hard-facing because of its low capital cost, low operational cost, and operational simplicity. In the context of erosion-resistant hard materials, a series of Co-based alloys that can be deposited by hard-facing is one of the most suitable materials. The present analysis has been carried out to evaluate the influence of processing conditions of hard-faced Co-based alloyed layer on solid particle erosion response at ambient temperature. These layers were deposited on mild steel substrate by weld hard-facing. The mechanical properties and microstructural features of these coatings were evaluated by means of X-ray diffraction technique, optical microscopy, scanning electron microscopy, and microhardness tester. Erosion rate was measured using an air jet erosion test rig. The eroded surface morphology and the transverse section of eroded surfaces were viewed using scanning electron microscopy. The results showed that hard-facing improves erosion resistance of the substrate. The erosion responses of most of the coatings were ductile. Material loss from hard-faced coating was by formation of lips followed by their fracture which initiated in the interdendritic regions.

Hardfacing of 3.5% Chromium Cast Steel by Flux Cored Wire Arc Welding Process

Hardfacing weld is a technique which mainly improves and extends the useful life of engineering components. The purpose of this research is to improve welding procedure for one layer and three layers hardfacing of 3.5% Chromium cast steel and to study wear behavior of hardfacing layers. Flux Cored Wire Arc Welding (FCAW) process has been used as a welding process of this research by choosing austenitic stainless steel and martensitic hardfacing wire to weld the buffer and hardfacing layer respectively. Preheating was also used in this study. Abrasive wear test of hardfacing deposit were conducted in accordance with procedure “A” standard of ASTM G65. In addition, microstructures and macrostructure of worn surface deposits were analyzed by using optical microscope. These results showed that there is no crack and defect in the Heat Affected Zone (HAZ) and other regions. The hardness of preheating sample in HAZ regions was lower than the ones without preheating. Therefore, preheating samples should be done before welding. The abrasive wear resistance of three layers hardfacing deposit was better than one layer hardfacing deposit because one layer hardfacing deposit was more diluted from buffer layer than three layers hardfacing deposit. Moreover, weight loss of one hardfacing layer was also higher than three layers.

Effect of Age-Hardening Treatment on Microstructure and Sliding Wear-Resistance Performance of WC/Cu-Ni-Mn Composite Coatings

The Cu-Ni-Mn alloy-based hardfacing coatings reinforced by WC particles (WC/Cu-Ni-Mn) were deposited on a steel substrate by a manual oxy-acetylene weld hardfacing method. A sound interfacial junction was formed between the WC particles and the Cu-Ni-Mn alloy metal matrix binder even after the age-hardening treatment. The friction and wear behavior of the hardfacing coatings was investigated. With the introduction of WC particles, the sliding wear resistance of the WC/Cu-Ni-Mn hardfacing coatings was sharply improved: more than 200 times better than that of the age-hardening-treated Cu-Ni-Mn alloy coating. The sliding wear resistances of the as-deposited and the age-hardening-treated WC/Cu-Ni-Mn hardfacing coatings were 1.83 and 2.26 times higher than that of the commercial Fe-Cr-C hardfacing coating, which is mainly ascribed to the higher volume fraction of carbide reinforcement. Owing to the precipitation of the NiMn secondary phase in the Cu-Ni-Mn metal matrix, the age-hardening-treated coating had better wear resistance than that of the as-deposited coating. The main sliding wear mechanisms of the age-hardening-treated coatings are adhesion and abrasion.