Types Of Filler Metals Research Articles

Effect of heat input on the microstructure and hardness of AISI 321 stainless steel welds using ER 347 filler metal

Stainless steel is widely used in various fields, one of which is AISI 321, which is used for high-temperature applications because of its high resistance to creep and intergranular corrosion. The type of filler metal and heat input on stainless steel welds play an essential role in determining the microstructure and mechanical properties of the welded joints. The purpose of this experiment was to evaluate the microstructure and mechanical properties of AISI 321 stainless steel welds with variations in heat input. This study is expected to explore the performance of this weld joint, which can be anticipated in relevant fields. The welding method used in this experiment was Gas Tungsten Arc Welding (GTAW) with ER 347 as filler metal. Welding was carried out on three samples with a heat input of 0.92 kJ/mm, 0.64 kJ/mm, and 0.52 kJ/mm, respectively. The tests included tensile strength, Vickers microhardness, and microstructure observations. The tensile test results showed that a fracture occurred in the Base Metal (BM) area, indicating that the strength of the weld joint was higher than that in the BM. The Vickers microhardness test results showed that the Weld Metal's hardness (WM) was the highest, followed by the Heat-Affected Zone (HAZ) and BM. The welding experiment that used three variations in heat input demonstrated that higher heat input lowered the hardness of the weld joint. The microstructure observation results around the fusion line demonstrated the presence of step and ditch structures. The ditch structure indicates intergranular corrosion.

The Effect of Composition and Type of Metal Filler on Heat Resistance of Silica Rubber Matric Composites

Thermal Tensioning is one of the methods use to minimise the occurrence of residual stress and unwanted distorsion during welding. One of the thermal tensioning methods is Static Thermal Tensioning (STT), which involves countering thermal stress during welding. The STT method requires an active cooling behind the welding line. Several properties are required for the coolant material, such as thermal conductivity, heat resistance, and good flexibility. To achieve the desired properties, a mixture of different materials was used, commonly called a composite. The purpose of this study is to know the effect of filler metal composition and type on the heat resistance of silica rubber matric composites. This study used 2 independent variables: the filler composition in composites with variations of K1 (60%) and K2 (70%), and the type of filler metal, aluminium and copper powder with variation J1 (100%-0%), J2 (75%-25%), J3 (50%-50%), J4 (25%-75%), and J5 (0-100%). The testing process used Thermogravimetry Analysis (TGA) method with replication 2 times. The results of this study showed the specimens with K1;J1 composition,containing 60% pure aluminium filler metal, showed the best heat resistance with a final weight of 88,25%. While specimens with K2;J5 composition, containing 70% pure copper filler metal, showed the worst heat resistance with a final weight of 74,25%.

Retaining Mechanical Properties of GMA-Welded Joints of 9%Ni Steel Using Experimentally Produced Matching Ferritic Filler Metal

Motivated by the loss of tensile strength in 9%Ni steel arc-welded joints performed using commercially available Ni-based austenitic filler metals, the viability of retaining tensile strength using an experimentally produced matching ferritic filler metal was confirmed. Compared to the austenitic Ni-based filler metal (685 MPa), higher tensile strength in gas metal arc (GMA) welded joints was achieved using a ferritic filler metal (749 MPa) due to its microstructure being similar to the base metal (645 MPa). The microstructure of hard martensite resulted in an impact energy of 71 J (-196 °C), which was two times higher than the specified minimum value of ≥34 J. The tensile and impact strength of the welded joint is affected not only by its microstructure, but also by the degree of its mechanical mismatch depending on the type of filler metal. Welds with a harder microstructure and less mechanical mismatch are important for achieving an adequate combination of tensile strength and notched impact strength. This is achievable with the cost-effective ferritic filler metal. A more desirable combination of mechanical properties is guaranteed by applying low preheating temperature (200 °C), which is a more practicable and economical solution compared to the high post-weld heat treatment (PWHT) temperature (580 °C) suggested by other research.

Experimental investigation of butt welded Ti/steel bimetallic sheets by using multi-principal powders as a single filler metal

Owing to the easy-to-crack in the weld zones (WZ) of titanium alloy/steel bimetallic sheets, sequentially layered-to-layered welding, by using various filler metals, is widely adopted to join the bimetallic sheets. In this study, multi-principal filler powders of FeCoCrNiMn, as only one type of filler metal, were used to join TA1/Q345 bimetallic sheets by laser deposition welding. Microstructure evolution, microhardness, and tensile properties in the joint of TA1/Q345 bimetallic sheets were studied. The results indicated that TA1/Q345 bimetallic sheets could be joined by using multi-principal filler metal when the groove root was opened in the Q345 base plate. Significant transition zones were found at the TA1/WZ and Q345/WZ interfaces. The structures of α-Fe, β-Ti, β-Ti + TiFe, and α-Fe + TiFe2 were formed in the transition zones. The solidified primary phases of TiFe2 and the eutectic structures of α-Fe + TiFe2 were observed in most regions of the WZ. Various intermetallic compounds (IMCs) of TiFe and TiFe2, as well as the snowflake-like structures of TiC, coexisted in the WZ near the flyer and base layers, which were significantly harmful to the formability of the WZ and caused a crack in the WZ. The markedly high hardness and low tensile strength were presented in the WZ. A sawtooth-like fracture line was observed. The fracture line was extended from the WZ/base metal (BM) interface to the WZ center, in which the minimum hardness (∼523 HV0.2) and many eutectic structures were presented.

Evaluation of dissimilar metal joining of aluminum alloy to stainless steel using the filler metals with a high-entropy design

Abstract Fe-Al intermetallic compounds (IMCs) have huge adverse effects on the dissimilar metal joining of aluminum to steel. High-entropy alloys can use high mixing entropy to promote the formation of single-phase solid solution structures, which would have significant advantages in inhibiting the formation of Fe-Al IMCs in the welding of Al/steel joints. In this study, three types of filler metals, including CoZnCuMn0.8Si0.2 powders with a high-entropy design, the FeCoCrNiMn high-entropy alloy powders, and the comparative Al-12Si powders, were used to join the dissimilar metals between Al 6061 alloy and 304 stainless steel by laser deposition welding. It was found that high-entropy filler metals, including CoZnCuMn0.8Si0.2 and FeCoCrNiMn powders, could successfully be used to join dissimilar metals of aluminum to steel. The high-entropy effect could be achieved in the weld zones (WZs) by using CoZnCuMn0.8Si0.2 and FeCoCrNiMn powders, which could significantly inhibit the formation of Fe-Al IMCs in the WZs, and promote the formation of fine and equiaxed grains, without element segregation, in the WZs. An unmixed zone with a width of 10−20 μm was formed between the WZ and HAZ in the Al 6061 alloy side for those two dissimilar joints. And some Fe-Al IMCs with submicron or nanoscale size were presented in the unmixed zones.

WPS Design of Dissimilar Metal Welds between Austenitic Stainless Steel and Carbon Steel for Building Thermal Power Plants

Dissimilar metal welding (DMW) is frequently used to join stainless steels to other metals in Thermal Power Plants (TPP) and industries. DMW process has been shown to have great advantages for many years. This approach is most often used where a transition in mechanical properties and/or performance in service are required. The objective of this research is to review the basic principles of fusion welding of dissimilar metals.In experiments, the two seamless pipes with 18 mm thick, one modified SS 304L austenitic stainless steel was welded to another modified carbon steel A 106B by means of shielded metal arc (SMAW) and gas tungsten arc (GTAW) welding processes using ER309L and E 309L-16 type of filler metal. Before welding, essential variables were analysed so that creating preliminary welding procedure specifications (pWPS). After welding, weldment was tested by NDT such as visual, penetrant and radiography. Microstructural examinations were carried out including macro and micrographs, grain size analysis, and hardness measurements. Transverse tensile, and face/ root bend testing were carried out. Finally, WPS was established conformance to standards of TPP structure toward to building Nuclear Power Plant in Vietnam.

Study on the wetting interface of Zr-Cu alloys on the SiC ceramic surface.

A Zr–Cu alloy, as a new type of filler metal, is proposed for brazing SiC ceramic under special working conditions. The wetting angle of Zr–Cu alloy/SiC ceramic at different temperatures and holding times was investigated by a high-temperature wetting tester. The composition of the wetting interface was tested by XRD, and the interfacial reaction layer was analyzed with SEM and EDS. The results show that the wetting angle decreases sharply with the change in temperature from 1100 °C to 1175 °C and remains unchanged when the temperature is higher than 1175 °C, about 34 ± 1°. The dynamic wetting angle of Zr–Cu/SiC at 1200 °C with the increase in holding time conforms to the law of exponential decay, and the equilibrium wetting angle is 5°. The transition layer with a certain thickness is formed during the spreading process of the Zr–Cu alloy at a high temperature, and the microstructure of the interfacial reaction layer mainly consists of ZrC and Zr2Si.

MICROSTRUCTURE AND HARDNESS PROFILE OF DISSIMILAR LAP JOINT OF TYPE 304 STAINLESS STEEL TO SS400 CARBON STEEL

Dissimilar metal welds between austenitic stainless steel and carbon steel are commonly used in oil and gas industries for certain reasons. The objective of this research is to asses the effect of filler metal and shielding gas on the microstructure and hardness of dissimilar lap joint of type 304 austenitic stainless steel to JIS SS400 low carbon steel. For the purpose of this investigation, the weldments were produced using flux-cored arc welding (FCAW). Three types of filler metals (E316L, E309L and E308L) and two different gas compositions (100%CO2 and 90%Ar+10%CO2) were selected to be used. Each of the weldments were analyzed on the microstructure characteristic and hardness profile of base metal (BM), heat affected zone (HAZ) and weld metal (WM) using optical microscope and microhardness Vickers. The metallographic examination revealed HAZ-SS400 contains martensites. Both HAZ-304 and WM show austenitic microstructure, with columnar and cellular sub-structures present at WM. The hardness profile of HAZ-304 is higher than BM-304, it may be attributed to the presence of the fine grains in HAZ-304 due to high temperature during welding. The hardness profile of WM-E309L exhibited the hardness from HAZ to WM tend to decrease linearly, while WM-E316L and WM-E308L showed the hardness from HAZ to WM also decreased but drastically dropped at fusion line (FL). The welds using E309L offer the best result in the point of view homogeneity of the hardness profile.

The Effect of Weld Metal Composition on Microstructural and Mechanical Properties of Dissimilar Welds Between Monel 400 and Inconel 600

The current work was carried out to characterize welding of Inconel 600 superalloy and Monel 400. In the present study, gas tungsten arc welding (GTAW) with four types of filler metals (ENiCu, ENiCu-7, ENiCr-3 and ENiCrFe-3) was utilized. The filler metals were categorized into two groups based on the presence of Cr and Nb in their chemical composition. This paper describes the selection and application of welding consumables in manufacturing dissimilar metal combinations. It was found that (Nb/Cr) ratio and Fe content can affect on the size and amount of carbides. During solidification of ENiCr-3 and ENiCrFe-3 filler metals, Nb leaves dendritic cores and is rejected to inter-dendritic regions because of its high tendency for segregation. However, No brittle Laves phase was detected in the welds. The interface between weld metal and base metal and gradual changes in alloying elements were also investigated by scanning electron microscopy. EDX analysis was also applied for different samples. Microhardness measurements and tensile test were performed on the joints. The average hardness value in the weld metal obtained from ENiCrFe-3 is higher than the other welds. ENiCu-7 weld exhibited the highest tensile strength of 540 MPa and percent elongation of 53% in contrast to ENiCrFe-3 weld with the lowest tensile strength (518 MPa) and percent elongation (39%).

Characterization of Mechanical and Metallurgical Notch Effects of DP980 Steel Weld Joints in Fatigue Performance

This work investigates the use of 980 MPa grade dual-phase (DP) steel joints with pulsed current gas metal arc welding (P-GMAW) for reliable weld performance by comparing actual welded joints with thermo-mechanical simulations. We focus on the weldment characteristics that can cause mechanical and metallurgical notch effects, which impact the fatigue performance of welds. For this purpose, we conduct experiments investigating the use of two types of filler metals and three heat inputs as variables. We find that HAZ regions in the actual weldments have varied microstructures caused by different phase transformations of martensite corresponding to various peak temperatures experienced. We confirm that improved weld geometry plays a key role in enhancing fatigue performance. We identify and discuss the degradation of mechanical properties arising from increasing heat input, in terms of transformation kinetics investigated by means of HAZ thermo-mechanical simulations and thermodynamic calculations. This study provides an overall understanding of the welded joints of DP steel and suggests a way to improve weldability by adjusting the mechanical and metallurgical parameters of various regions in the weldments.

Transient liquid phase bonding of Inconel 617 superalloy: effect of filler metal type and bonding time

Transient liquid phase (TLP) bonding has enormous potential to repair cracks in the gas turbine hot section parts that are made of Ni-based alloys. The experiments were carried out by BNi-1 and BNi-2 filler metals in a vacuum furnace at the bonding times of 45 and 300 min. The shear strength, microhardness, microstructure, and homogeneity of chemical composition during TLP bonding of Inconel 617 superalloy, which is the base metal, were evaluated. The shear strength of about 620 MPa was obtained using the BNi-1 filler metal. Hence, the BNi-1 filler metal and the bonding time of 300 min are recommended for repair of hot section components of a gas turbine. The gap size is an important parameter on the diffusion especially at the lower bonding times but the preliminary difference in the chemical composition may play an important role at the longer bonding times. The results show that the type of filler metal is an important parameter in this process.

Evaluating the Properties of Dissimilar Metal Welding Between Inconel 625 and 316L Stainless Steel by Applying Different Welding Methods and Consumables

The current work was carried out to characterize welding of Inconel 625 superalloy and 316L stainless steel. In the present study, shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW) with two types of filler metals (ERNiCrMo-3 and ERSS316L) and an electrode (ENiCrMo-3) were utilized. This paper describes the selection of the proper welding method and welding consumables in dissimilar metal joining. During solidification of ERNiCrMo-3 filler metal, Nb and Mo leave dendritic cores and are rejected to inter-dendritic regions. However, ERSS316L filler metal has small amounts of elements with a high tendency for segregation. So, occurrence of constitutional super-cooling for changing the solidification mode from cellular to dendritic or equiaxed is less probable. Using GTAW with lower heat input results in higher cooling rate and finer microstructure and less Nb segregation. The interface between weld metal and base metal and also unmixed zones was evaluated by scanning electron microscopy and energy dispersive X-ray (EDX) analysis. Microhardness measurements, tensile test, and Charpy impact test were performed to see the effect of these parameters on mechanical properties of the joints.

Effect of post weld heat treatment (PWHT) on the microstructure, mechanical properties, and corrosion resistance of dissimilar stainless steels

The dissimilar austenitic stainless steel (AISI304L) and ferritic stainless steel (AISI430) have been welded with two types of filler metals (316L and 2594L) by GTAW. Then, the effect of heat treatment on the microstructure, mechanical properties, and corrosion properties of welded joint was investigated. Due to remove chromium carbide created during welding process and homogenize the microstructure, heat treatment was carried out on the whole series of the samples at 860°C and 960°C. The microstructural, fracture cross-section and corrosive areas of the samples were investigated by SEM. Tensile, bending and potentiodynamic polarization tests were employed to characterize mechanical and corrosion performance of the samples. The results indicate that the welded joints had good mechanical properties after heat treatment so that the best tensile strength was obtained at 960°C. Due to reduce grain size, the heat treatment samples show minimum corrosion resistance at 960°C in comparison to 860°C.

Research on GTAW/SMAW Weldability of ADI/DI Using Electrodes ENi-Cl and ENiFe-Cl-A

The present research is dedicated to weldability of Austempered Ductile Iron (ADI) and Ductile Iron (DI) using Shielded Metal Arc Welding (SMAW) and Gas Tungsten Arc Welding (GTAW) methods. The welds were done using the arc welding process with Nickel base filler materials: ENi-Cl and ENiFe-Cl-A. Each weldment was examined visually, with X-rays and mechanical tests. After the mechanical tests, tensile test and impact properties of the welded joint are lower than mechanical properties of the ADI base material using ENiFe-Cl-A filler metal and GTAW process. This type of filler metal ENiFe-Cl-A can be applied successfully only for repair by welding of ADI parts. Using ENi-Cl filler metal with GTAW process applied to DI, the mechanical tests, tensile test and hardness of the welded joint are greater than mechanical properties of the DI base material. This procedure can be applied for welding. In case on DI welded using SMAW with ENi-Cl electrodes, the hardness of the welded joint is lower than the hardness of base material. This procedure can be applied only for repair by welding.

Strength of 316FR Joints Welded by Type 316FR/16-8-2 Filler Metals

Type 316 stainless steel with low-carbon and medium-nitrogen contents called 316FR stainless steel is a candidate structural material for reactor vessels and internals of future-generation fast breeder reactors (FBRs). The reactor vessel cannot be manufactured from rolled or forged steel, but can be built at reasonable cost by welding rolled steel plates. In this manufacture approach, the reliability of the welded joint must be indicated. Two types of filler metals are candidates for 316FR welded joints: types 316FR and 16-8-2 filler metals. The chemical composition of type 316FR filler metal is close to that of the stainless steel; type 16-8-2 filler metal contains lower amounts of Ni, Cr, and Mo than that of the stainless steel. This study evaluated the need to consider the welded joint strength reduction factors in 316FR welded joints under design of future-generation FBRs. To this end, the tensile and creep strengths of types 316FR and 16-8-2 weld metals were measured, and the effect of δ-ferrite in weld metals was evaluated in creep strength tests of 316FR welded joints. In tensile and creep strengths of 316FR welded joints welded by both metal types, the welded joint strength reduction factors were immaterial. The creep strength of 316FR welded joints was negligibly affected by δ-ferrite levels from 4.1 to 7.0 ferrite number (FN) in the Welding Research Council-1992 diagram. Furthermore, the tensile and creep strengths of 316FR welded joints by two methods (gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW)) were the same. Therefore, the tensile and creep strengths of 316FR welded joints in above condition are ensured the reliability of similar to 316FR stainless steels.

FEASIBILITY STUDY ON JOINING DISSIMILAR ALUMINUM ALLOYS AA6061 AND AA7075 BY TUNGSTEN INERT GAS (TIG)

The aim of this paper is to study the feasibility of welding dissimilar aluminum alloys AA6061 and AA7075 using different types of filler metals which are ER4043 and ER5356. The tungsten inert gas (TIG) welding method was used to butt joint these alloys. The effect of ER4043 (Si-rich) and ER5356 (Mg-rich) on weldability of the joint were studied through visual appearance, microstructures and hardness. It was found that, welding using filler ER5356 produced deeper penetration compared to filler ER4043. The depth of penetration obtained using filler ER5356 was 1.74 mm, while only 0.9 mm of penetration was obtained using ER4043. Microstructures at different zones of dissimilar TIG joints such as the fusion zone (FZ), the partially melted zone (PMZ) and the heat affected zone (HAZ) were identified. The grain size at FZ from filler ER5356 samples was finer compared to filler ER4043 which was 11.4 µm and 19.5 µm, respectively. The average hardness welding value of filler ER5356 samples was higher compared to filler ER4043 samples, which were 100HV and 86HV, respectively at HAZ of AA 6061, 110HV and 88HV, respectively at FZ, while 113HV and 85HV, respectively at HAZ of AA 7075. It can be concluded that TIG welding using the ER5356 filler yields better joint compared to ER4043.

Mechanical Properties and Microstructure of Welded Dissimilar Metals Using Buttering & Non-Buttering Layer

Joining of dissimilar metals is to compose different properties of metals in order to minimize material costs and at the same time to maximize the performance of the equipment and machinery. There are a lot of methods of joining of dissimilar metals. However, the fusion welding is mostly used in a wide range of industries. This research is carried out for the process of dissimilar welding between carbon steel plates of ASTM A516-70 and austenitic stainless steel plates ASTM A214-316L by using gas metal arc welding (GMAW). Welding design used is a V-groove by using the buttering process and without buttering (non-buttering) process. Types of filler metals used are ER309L and ER316L-Si. The weldment is then tested by using destructive test (DT) and non-destructive test (NDT). Weldment is also characterized by using X-Ray Diffraction (XRD). The results show that the mechanical properties of weldment with buttering process are better compared with the weldment with a non-buttering process. The macro and microstructure of weldment with buttering process revealed finer grained and homogeneous structures compared with the one by using a non-buttering process. Moreover, welds characterization by using XRD show that the precipitation of chromium carbide on HAZ of weldment with buttering process is lower than that of weldment with a non-buttering process.

Mechanical and Microstrutural Characterization of Weldments of Ferritic Stainless Steel AISI 444 Using Austenitic Stainless Steels Filler Metals

Abstract The objective of this study was to investigate the influence of the filler metal on the microstructure and mechanical properties of ferritic stainless steel AISI 444 welded using two types of filler metal of austenitic stainless steel. Microstructure examinations showed that in both welded joints grain growth occurred in the heat affected zone (HAZ). The results also showed that the fusion zone of the weld joints using E309L filler metal presented a discontinuous network of delta ferrite unlike the fusion zone of the weld joint using E316L. Tensile tests showed that the failures of specimens always occurred in the HAZ and that the weldments using E316L filler metal presented tensile strength lower than that of the weldment using E309L filler metal. In the fusion zone of the weldments using E316L filler metal, values for hardness were found to be higher than those found in the fusion zone of the E309L filler metal.

Investigation on Wettability and Metallurgical and Mechanical Properties of Cemented Carbide and Steel Brazed Joint

In this study the wettability, microstructure and mechanical properties of joining between cemented carbide and CK35 steel which brazed with two filler metals, L-Ag40Cd and L-Ag34Cd, were investigated. Wettability test shows that with increase of brazing time, the contact angle decreases and the best situation was resulted in the 20 minute brazing. Microscopic investigation of the brazed area with both filler metal shows that there is a copper enriched primary phase and eutectic microstructure in the silver enriched matrix which composed of copper enriched particles. The amount and the dispersion of precipitates are depended upon type of filler metal and brazing temperature. The results show that brazing with L-Ag34Cd filler metal at 800 °C exhibit superior shear strength in the level of 108 MPa.

Investigation on Wettability and Metallurgical and Mechanical Properties of Cemented Carbide and Steel Brazed Joint

In this study the wettability, microstructure and mechanical properties of joining between cemented carbide and CK35 steel which brazed with two filler metals, L-Ag40Cd and L-Ag34Cd, were investigated. Wettability test shows that with increase of brazing time, the contact angle decreases and the best situation was resulted in the 20 minute brazing. Microscopic investigation of the brazed area with both filler metal shows that there is a copper enriched primary phase and eutectic microstructure in the silver enriched matrix which composed of copper enriched particles. The amount and the dispersion of precipitates are depended upon type of filler metal and brazing temperature. The results show that brazing with L-Ag34Cd filler metal at 800 °C exhibit superior shear strength in the level of 108 MPa.