Weld Hardfacing Research Articles

A Machinability Study of Hard-Facing Weld Metal on JIS-S50C Carbon Steel

The feasibility study of the face-milling performance of hard-facing weld metal on JIS-S50C carbon steel was investigated on microstructure, chip characteristics, wear properties, and surface roughness. Discontinuous chips were found in all machining conditions. No buffering weld metal (No buffering layer, NBL) produces longer and thicker chips than that of the buffering weld metal (Buffering layer, BL). The flank wear of the cutting tool edge increases with the cutting length of the test specimen. The maximum wear of 850 mm was found in a wet condition of the NBL weld metal which is about 4 times higher than that of the base metal. High hardness value of the NBL weld metal produces a higher flank wear of the cutting tool edge than that of the BL weld metal. After comparing the wear of the cutting tool edge in wet and dry conditions, it was found that the dry condition exhibits a smaller flank wear than that of the wet condition. In the wet condition, more amount of coolant oil droplets cannot penetrate into the chip-tool interface and then provides an insufficient amount of lubricant in order to decrease the cutting temperature. Therefore wet condition produces severe wear of the cutting.

Microstructure and Wear Resistance of Hard-Facing Weld Metal on JIS-S50C Carbon Steel in Agricultural Machine Parts

Hard-facing welding is one of the repairing methods for increasing hard metal on the agricultural machine part surfaces that caused by the wear mechanism. To this date, the investigation of an optimized welding process parameter that could produce high hardness and wear resistance of the hard-facing layer is still being developed and performed. This paper aims to study the effects of hard-facing welding layer on mechanical properties and microstructure of hard-facing weld metal on JIS-50C carbon steel. The summarized results are as follows: (a) an increase of hard-facing layer affected to increase the hardness of the layer, (b) the hardness of the welds showed a maximum hardness of about 750 HV at a top surface of 3rd welds layers with no-buffering layer and showed the minimum hardness of about 225 HV at a base metal, (c) microstructure investigation showed that the increase of the phase that contained higher chromium, molybdenum and manganese affected the increase of the hardness and the wear resistance of the weld metal, (d) The minimum mass loss of 0.2559 mg/m could be found when a welding current of 100A, non-buffering layer and 3 layers of hard-facing weld metal were applied, and (e) the buffering layer was able to produce a sound weld metal and might not be suited for the hard-facing welding of the medium carbon steel because it produced the dilution effect that deteriorated the mechanical properties of the weld metal.

Life Extension of Propeller Shafts by Hardfacing Welding

At present the Cut-stern Kolek Boats of local fishermen at Kaoseng Community on the Coast of Songkhla Lake have a high rate of shaft failure. Consequently, the fishermen have spent lots of money on maintenance program of repairing shafts for a few years. Besides, the repairing cost, each time of the failure also causes water pollution from the leakage of grease. The incomplete transmission of power leads to engine overloading and fuel wasting. The investigation of the high failure rate of propeller shafts which were major machine component in power transmission illustrated the failure in normal fracture caused by the mechanisms of metal fatigue. Using the welding repair by shield metal arc welding process did not give the satisfied outcome because it created the short service life of reused propeller shafts after repairing. This research was aimed to study the metal fatigue behavior of long tail shafts in the Cut-stern Kolek boats and introduce the new method of welding repair process to prolong their service life. The experiment revealed that specimens resulted from the new welding repair process and the conventional one possessed different service life. The new process used the flux core which arc welding can prolong the service life of the shafts of boats more than 1.6 times of using the conventional method which is the electric welding by flux core arc welding. The research result will be extended to fishermen, in order to encourage them to become a part of sustainable inshore fisheries.

Microstructure and wear resistance performance of Cu–Ni–Mn alloy based hardfacing coatings reinforced by WC particles

A Cu–Ni–Mn alloy based hardfacing coating reinforced by WC particles is deposited on steel substrates by a manual oxy-acetylene weld hardfacing method. Microstructure and wear resistance performance of the fabricated hardfacing coatings are investigated. There are no cracks or other defects observed in the hardfacing coating. Uniform distributed WC particles in the composite hardfacing coating are not dissolved, and its volume fraction is up to about 63%. A sound bond is formed at the interface of WC and Cu–Ni–Mn alloy, and the bond between the coating and the steel substrate is reliable. With silica sands, the wear resistance performance of the composite hardfacing coatings is about 4 times better than that of the high-Cr cast iron, and its volume loss presents approximately a linear relationship with the sliding distance. The main wear mechanisms are the plastic extrusion of the Cu–Ni–Mn matrix and the fracturing of WC-reinforcement particles under three-body abrasive wear condition in this paper.

Influence of Particle Fracture on the Slurry Abrasion Behavior of Weld Deposited Martensitic Steel

The life of the components used under slurry abrasion conditions is governed by the process variables, properties of the abrasive materials in the slurry and the material properties. Slurry wear, abrasion occurs in Extruders, pumps and pipe transport slurry of minerals and ores in mineral processing industries. In the present research, the effect of operating variables such as abrasive particle size and shape, slurry concentration and normal load on the abrasive slurry wear behavior of the weld deposit martensitic steel surface produced by the Manual Metal Arc Welding Hard facing process was conceded out. The testing was conceded out using the slurry abrasion test rig. The silica sand particles were used as the abrasive medium. The qualitative nature of wear pattern and morphology of the worn out surface was examined under scanning electron microscope (SEM). These features were correlated with operating parameters.

Residual Stress Distribution in Hard-Facing of Pressure Relief Valve Seat

In this study, for the hard-facing of spring-loaded pressure relief valve seats, the residual stress distributions after the tungsten inert gas welding, (TIG) postwelded heat treatment and subsequent surface turning were investigated. The heat input parameters of welding were calibrated using an infrared imaging and thermocouples. The residual stress distributions were computed using three-dimensional finite element model. The neutron diffraction approach was employed to verify the finite element calculation. It is found that, the surface temperature during hard-facing welding shows a double ellipsoidal shape with the highest value of around 1570 °C. The high residual stress zones are located exactly under the welded joint except a slight deviation in the hoop direction. The magnitudes of tensile residual stresses in the three directions increase with their corresponding locations from the root of the joint into the base metal. The residual stresses in all of the three directions decrease significantly after the heat treatment. After surface turning, the residual stresses are tensile except for those close to the inner surface that are compressive in axial and radial directions.

Wear Behavior of Hardfacing Coatings Applied on Glass Processing Tools

AbstractWear is major life limiting factor of the glass processing tools. A complex interaction of hot viscous glass and oxide layers at tool surface, damages tool by cyclic contact. Hardfacing is one of the most useful and economical ways to improve the performance of components submitted to severe wear conditions. The specific wear behavior of a hardfacing coating depends on its chemical composition, the microstructure obtained after hardfacing process, and finally the harfacing technology used to apply them. The main objective of this study was to evaluate wear behavior for coatings applied by various hardfacing techniques consist of gas tungsten arc (TIG) welding, plasma transferred arc (PTA) welding, and chromizing. Two different commercial cobalt based hardfacing electrodes (Stellite 12 and Tribaloy T‐401) were employed to investigate the effect of the hardfacing alloys. In order to simulate real field conditions on a lab scale, tests were performed with a specially designed system and actual process parameters. The qualitative evaluation of wear behavior was supported by microstructural investigations using optical microscopy and scanning electron microscopy (SEM + EDS). The quantitative investigations were performed using profilometry and hardness tests. The results showed the superiority of PTA welding in comparison with other hardfacing techniques. The best wear resistance was obtained in PTA welding hardfacing with Stellite 12 alloy.

Sliding wear performance of Fe-, Ni- and Co-based hardfacing alloys for PTA cladding

Abstract Stellite 6, Colmonoy 56, and SKS3 tool steel are typically the materials used as weld hardfacing claddings or as-cast to provide the needed wear resistance to a base material with the required mechanical properties. In this study, a series of Co- and Ni-based hardfacing alloys are successfully fabricated on a substrate of S45C carbon steel using the plasma transferred arc process with Stellite 6 and Colmonoy 56 powders. An Fe-based hardfacing alloy is used on commercial SKS3 tool steel for comparison. The microstructure, hardness and wear resistance of the three materials are investigated systematically. The two claddings and the as-cast SKS3 examined belong to the categories of Co-, Ni- and Fe-based hardfacing, respectively, with hard carbides/borides in their microstructures. The two different claddings are not only tested against SKS3 tool steel but also against each other using the ring-on-disk wear test. After the wear test, the worn surfaces are examined using scanning electron microscopy and energy dispersive spectroscopy to identify the dominant wear mechanisms. The experimental results show adhesive wear is confirmed by metal transfer from a hard surface to a softer one in Stellite 6 against SKS3, and in Colmonoy 56 against the Stellite 6 specimens, while surface deformation testifies to abrasive wear. The transfer layer formed on the surface prevents direct metal-to-metal contact and reduces the wear loss. For Colmonoy 56 against SKS3, adhesion does not occur; instead, Colmonoy 56 causes serious abrasion on SKS3 due to its greater degree of hardness and causes significant wear loss for SKS3.

Effect of Preheating and Buttering on Cracking Susceptibility and Wear Resistance of Hardfaced HSLA Steel Deposit

Hardfacing weld techniques apply mainly to improve the service life of engineering components either by rebuilding or fabricating a composite layer, which will protect the components from wear, erosion, and corrosion. However, hardfaced deposits are susceptible to cracks compared to the base metal due to thermal cycles and different chemical composition of hardfaced consumables. In addition, this method yields only marginal improvements in wear resistance performance. This investigation was attempted to eliminate the cracks by depositing a soft buttering layer by using austenitic stainless steel consumable in the area between base metal and hardfaced layer. Preheating was also applied at the joint. The result reveals that buttering and preheating reduce crack susceptibility and increase wear performance of hardfaced HSLA steel deposit.

Development of WC Hard-facing Welding Process using Pulse Heated Hot-wire Gas Tungsten Arc Welding System

Development of WC Hard-facing Welding Process using Pulse Heated Hot-wire Gas Tungsten Arc Welding System

Study of Carbonitride Precipitates in the Fe-Cr-Mn-N Hardfacing Alloy

The Fe-Cr-Mn-N hardfacing alloy was deposited on a low carbon steel substrate by the weld hardfacing technique. Ti and Nb as the most effective nitrogen-fixing elements were added in the hardfacing alloy. Carbonitride precipitates were systematically studied by canning electron microscopy and electron probe microanalyser. The thermodynamics and the effect on the matrix of the formation of carbonitride were also discussed. It was found that carbonitride precipitates were complex carbonitride of Ti and Nb distributing on grain boundary and matrix of the hardfacing alloy. In as-welded condition, primary carbonitride particles were readily precipitated from the hardfacing alloy with large size and morphology as they were formed already during solidification. In heat-treated condition, a large number of secondary carbonitrides can precipitate-out with very fine size and make a great secondary hardening effect on the matrix. As a result, precipitation of carbonitride in the hardfacing alloy can prevent the formation of chromium-rich phase on grain boundaries and increase the wear resistance of the hardfacing alloy. Keywords: carbonitride precipitate, hardfacing alloy, deposit, thermodynamics

A New Type of Submerged-Arc Flux-Cored Wire Used for Hardfacing Continuous Casting Rolls

It is expected that the welding hardfacing of continuous casting rolls has better welding performance and higher wear resistance. A new type of submerged-arc hardfacing flux-cored wire has been developed through nitrogen replacing part of carbon and addition of the nitrogen-fixing elements of niobium and titanium. And microstructure, degree of hardness and high-temperature wear resistance of its deposited metal samples were also investigated. It is found that the microstructure is martensite, residual austenite and carbonitride precipitates. As a result, the hardfacing metal with homogeneous distribution of very fine carbonitride particles had high hardness and excellent wear-resisting property during high-temperature wear, which could significantly extend the service life of continuous casting rolls.

Effect of microstructure on slurry erosion behaviour of weld hardfacing alloys

In the present work, the slurry erosion behaviour of weld hardfacing alloys was investigated by systematic variation of identified test parameters and the response data were generated from a suitably designed experimental plan. The identified groups of parameters were operational parameters; velocity, slurry concentration, and particle size of the erodent; and relative hardness of erodent particle and the microstructural parameter, carbide volume fraction (CVF). The slurry erosion experiments of hardfacing alloys with different Cr and C content were conducted using a pot-type slurry erosion tester with silica sand slurry of different concentration over a range of velocities. The slurry erosion volume loss of hardfacing alloys exhibited different trends under different test conditions with identified parameters. The slurry erosion volume loss decreased with increasing CVF and He/ Ht, (ratio of hardness of erodent to hardness of target) except under severe erosion test conditions where the reverse trend was observed. An empirical correlation was proposed, in which the slurry erosion rate was expressed as a product of operational parameters, microstructural parameter, and relative hardness of erodent particles. Scanning electron microscopy observations were focused on gaining additional information associated with the mechanism of material removal under different experimental conditions.

Effect of microstructure on slurry erosion behaviour of weld hardfacing alloys

Effect of microstructure on slurry erosion behaviour of weld hardfacing alloys

Friction-induced work hardening of cobalt-base hardfacing deposits for hot forging tools

Cobalt-base materials are widely used as weld hardfacing deposits in hot forging industry. When the cobalt-base hardfacing alloys are deposited using the MIG welding process, the weld energy with the sequences of the welding are at least the two important variables which influence the behaviour of most hardfacing deposits in service conditions. The purpose of this work is to consider their role in connection with the work-hardening ability of Stellite 21 weld hardfacing deposits. An experimental parametric study of several welded-layers related to their friction behaviour is performed. The friction-induced work hardening (FIWH) ability of Stellite 21 deposits is considered to assess the influence of the two welding parameters. Results show that depending on the used welding sequences, the amount of the applied energy determines the dilution rates across the thickness of the deposits. Microscopic observations at the friction surface confirm that the highest FIWH rates, owing to stacking faults brought out, increase the wear resistance.

Selection of welding process for hardfacing on carbon steels based on quantitative and qualitative factors

Weld hardfacing techniques are employed mainly to extend or improve the service life of engineering components either by rebuilding or by fabricating in such a way as to produce a composite wall section to combat wear, erosion, corrosion, etc. In this paper, an attempt has been made to determine the best welding process to hardface boiler grade steels based on quantitative factors (by measuring percentage of dilution) and qualitative factors (using the analytic hierarchy process [AHP]). Five different welding processes including shielded metal arc welding (SMAW), gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), submerged arc welding (SAW), and plasma transferred arc welding (PTAW) have been compared. Based on the quantitative and qualitative factors, the PTAW process is found to be the best method to hardface boiler grade steels.

Optimisation of cobalt-based hardfacing in carbon steel using the fuzzy analysis for the robust design

In this paper, we present the application of the fuzzy logic analysis to a Taguchi orthogonal experiment for developing a robust model with high efficiency in multiple performance characteristics (MPCs) of the plasma transfer arc welding (PTAW) hardfacing process. It eliminates uncertain information and is a simple, effective, and efficient approach. A fuzzy logic system is used to simultaneously investigate relationships between various MPCs and to determine the efficiency of each trial of the Taguchi experiments. From the fuzzy inference process, we are able to determine the optimal setting of factor-levels for the MPCs. In addition, we also use the analysis of variance (ANOVA) to identify the significant factors, which coincide with findings from the fuzzy logic analysis and are found to account for about 79% of the total variance. Furthermore, a confirmation experiment of the optimal process is conducted, and it verifies that both individual performance characteristics and MPCs are successfully optimized and satisfy our desired levels of MPCs.

Hardfacing of Wear-Resistant Deposits by MAG Welding with a Flux-Cored Wire Having Graphite in Its Filling

ABSTRACT A high carbon content in a ledeburite-martensite deposit provides high wear resistance. This can be accomplished in hardfacing by MAG welding with covered electrodes, alloying fluxes, and flux-cored wires. Hardfacing with covered electrodes is not efficient, whereas application of alloying fluxes is suitable only for the flat welding position. Hardfacing by flux-cored MAG welding, however, is efficient and suitable also for out-of-position welding, i.e., in the horizontal-vertical and overhead positions, which is particularly important in maintenance. The paper deals with the investigations of the influence of hardfacing-weld alloying by means of the cored-wire filling in hardfacing both by CO 2 welding and welding with no externally supplied shielding medium. The efficiency of alloying the hardfacing weld depended on the composition and the filling ratio of the wire. In hardfacing of martensite-ledeburite deposits, the high carbon content in the deposit was provided by the addition of graphite to the cored-wire filling. A result of the high graphite content in the filling was a reduction of the filling ratio of the wire, and, consequently, weaker alloying of the hardfacing weld. As little as 10 wt.% graphite in the wire filling substantially affects alloying of the hardfacing weld. In this case, the amount of carbide-forming elements in the hardfacing weld will be reduced by around 4 wt.% whereas the carbon content will increase by as little as 1%, which, however, is enough to obtain high-quality martensite-ledeburite wear-resistant deposits with S-BC3 cored wires and with no externally supplied shielding medium of which the chemical composition, structure, and wear resistance were quite comparable to those obtained with a CrWC 600 covered wire (produced by SZ-Elektrode, Jesenice). Advantages of the cored wire over the covered electrode are substantially higher performance and lower consumption of the electric current.

Effects of Mn and C Addition on the Wear Resistance for the Recycled WC Dispersed Fe-base Hardfacing Weld

The abrasion and impact wear resistance were investigated on the hardfacing weld dispersed with the recycled hard metal(HM). The HM was composed of the tungsten carbide(WC) reinforced metal matrix composite. The cored wire filled with the 25-35wt.% HM and 2-8wt.% of the alloying element, Fe-75Mn- 7C(FeMnC), was used for the gas metal arc(GMA) welding. By using the cored wire of the 25wt.% HM and FeMnC addition, the weld showed mostly constant wear loss for the abrasion as a function of the FeMnC content. This was due to the insufficient amount of the tungsten carbide formed during the GMA welding. The FeMnC addition to the 35wt.% HM did not improve the abrasion wear property since the amount of the tungsten carbide formed was decreased with respect to the FeMnC amount. The 6wt.% FeMnC addition to the 35wt.% HM exhibited the better impact wear resistance than the hardfacing weld by 40wt.% HM.

Abrasion Wear Behavior of Recycled Tungsten Carbide Reinforced Metal Matrix Composite

The abrasion wear behavior on the hardfacing weld was investigated by performing abrasion wear, hardness, and microstructural tests. The gas metal arc(GMA) weld was produced by using the cored wire which was filled with the hard metal, i.e., the recycled tungsten carbide (WC) reinforced metal matrix composite. For 30% addition of the hard metal, the abrasion wear resistance was significantly improved comparing with that for 20% addition of the hard metal. Above 30% addition of the hard metal, however, there was no significant improvement of the wear resistance. The improvement of the wear resistance was due to the increased amount of eutectic carbides(W<TEX>$_{6}$</TEX>C) which was formed during GMA welding. For the weld in which the hard metal was added to 30-40%, an optimum level of abrasion wear resistance was performed.