ASTM A Research Articles

STUDY OF MATERIALS AND WELDING USED IN THE CONSTRUCTION OF RACKS FOR STORAGE OF FUEL ELEMENTS AT NUCLEAR PLANTS

This paper showed the technological innovations and the necessary requirements for the welding of ASTM A240 TP316L Austenitic Stainless Steel in the construction of racks used in the storage of Fuel Elements inside nuclear power plants. It presents the development of welding processes using coated electrode, SMAW and as addition metal rods EAS 2-IG / ER 308L. This study is divided into two stages, the preparation of technical documentation and the development of methods and manufacturing processes used in the qualification of welding processes. A sequence was outlined based on real situations used by nuclear component manufacturing companies, meeting the physical and mechanical properties required by the nuclear classification standards and their regulations. The results showed that the welding processes were satisfactory, that the destructive and non-destructive tests showed that there was no discontinuity in the surface and defects in the volume of the welding and that, in the present study, safety in the project for the operation of a Nuclear Power Plant was demonstrated.

Coconut Fiber Extraction using Soda Pulping Method as Green Corrosion Inhibitor for ASTM A36 Steel

Currently, the corrosion inhibitor is a method that is widely used to control the corrosion rate of inner pipe in the chemical industry. This study aims to utilize coconut fiber as a green inhibitor, determine the effect of adding inhibitor concentration, immersing time, and determine the inhibition efficiency of coconut husk extract. The extraction method used is the soda pulping method with a solid to liquid ratio of 1:8 (w/v). The method used for testing the corrosion rate is the weight-loss method, UV-Vis Spectrophotometry and FT-IR are also used to analyze the lignin produced. The lowest corrosion rate was obtained in 1 M HCl corrosive medium with the addition of 3 g/L inhibitors at 48 hours immersion, which was 49.691 mpy. The highest inhibition efficiency was in 1 M HCl corrosive media solution with the addition of 3 g/L inhibitors at 48 hours immersion, which was 78.11%.

Concentrically and eccentrically loaded high-strength concrete columns with high-strength reinforcement: An experimental study

The demand for high-strength steel (HSS) in concrete structures has been steadily increasing as it has potential to reduce congestion in heavily reinforced section, decrease steel quantity and lower the labour cost. Although typical design standards such as ACI 318 limit the design strength to 550 MPa, research focuses on developing design guidelines for using HSS. ACI ITG-6R-2010 has developed design procedures for the use of ASTM A1035 Grade 100 (690 MPa) steel bars as longitudinal reinforcement. ACI 318-2019 permits the use of 690 MPa bars as spiral transverse reinforcement in column. Australian Standards AS 3600-2018 allows HSS up to 600 MPa for longitudinal reinforcement and 800 MPa for transverse reinforcement (tie) in columns. While several design codes permit higher yield strength for steel bars, comprehensive test data are required to enhance the confidence in the application of the high-strength concrete (HSC) in conjunction with HSS in concrete columns. In this study, 39 HSC columns reinforced with HSS were tested under static loading. The compressive strength of concrete and yield strength of the longitudinal reinforcement varied between 100 and 115 MPa and 520–670 MPa, respectively, and tie was provided with 810 MPa steel. The ties were placed at a maximum spacing calculated based on AS 3600-2018 design model, resulting in 29% larger spacing than that for 500 MPa steel ties. The other test variables were section geometry, tie arrangement, tie bar areas and loading eccentricities. The columns section capacities were compared with AS 3600-2018 and ACI 318-2019 design models and ductility of the columns was studied too. It is shown that columns reinforced with HSS generally have a larger strength than that of the columns reinforced with 500 MPa Grade bars. The study also concluded that detailing HSS (810 MPa) tie reinforcement with HSS longitudinal bars meet the minimum confinement and the static ductility requirements of AS 3600-2018.

High-Strength Reinforcing Steel Bars: Low Cycle Fatigue Behavior Using RGB Methodology

Low cycle fatigue life of high-strength reinforcing steel bars (ASTM A706 Grade 80), using photogrammetry by RGB methodology is evaluated. Fatigue tests are performed on specimens under constant axial displacement with total strain amplitudes ranging from 0.01 to 0.05. The experimental observations indicate that buckling of high-strength reinforcing bars results in a damaging degradation of their fatigue life performance as the slenderness ratio increases, including an early rebar failure as the total strain amplitude increases since it achieves the plastic range faster. In addition to this, the results show that the ratio of the ultimate tensile strength to yield strength satisfies the minimum of 1.25 specified in ASTM A706 for reinforcement. On the other hand, the RGB methodology indicates that the axial strains measured by photogrammetry provide more accurate data since the registered results by the traditional experimental setup do not detect second-order effects, such as slippage or lengthening of the specimens within the clamps. Moreover, the RGB filter is faster than digital image correlation (DIC) because the RGB methodology requires a fewer computational cost than DIC algorithms. The RGB methodology allows to reduce the total strain amplitude up to 45% compared to the results obtained by the traditional setup. Finally, models relating total strain amplitude with half-cycles to failure and total strain amplitude with total energy dissipated for multiple slenderness ratios (L/d of 5, 10, and 15) are obtained.

Root cause analysis of a failure in a flange-pipe welded joint in a steam line in an ammonia plant: Experimental investigation and simulation assessment

This study aims to investigate the root cause of a failure in an ASTM A106 pipe-ASTM A105 flange welded joint, welded to a pump in an ammonia plant. Samples were taken from the failed joint. These joints were exposed to steam at the temperature of 148 °C and internal pressure of 7 bar. The changes in metal microstructures along the welded metal showed that root pass region consists of large grain-size structure, containing Widmanstätten, grain boundary and polygonal ferrite structures. On the other hand, the areas on the middle and upper sections of the weld mostly contained acicular ferrites. The results of hardness tests indicated that the root pass region has lower hardness compared to other areas which is due to large grain size structure in this region. In addition, simulation results showed that a rather large residual tensile stress exists at the root of the weldment. Besides, results of fractography showed that areas close to the weld root consisted of a quasi-cleavage structure. Based on the results, it can be postulated that the main reason for the failure was unsuitable welding parameters which have resulted in the formation of large grain structures with low strength.

Stress relaxation cracking failure in a high pressure steam pipeline in an ammonia plant

In this study, a failure in a high pressure steam pipeline, made of ASTM A335 P11 steel grade, has been investigated. The failure in this case appeared in the form of cracking in a 16 inch pipe, containing high pressure steam (47 bar) at 400 °C after eight years of service, which is considered as a relatively premature failure in comparison to the design service-life of the pipeline. Optical and electron microscopies were employed to investigate the microstructure of the failed pipe. Hardness measurement was also conducted to measure the hardness of samples. Results indicated that the main mechanism of the failure was stress-relaxation cracking (SRC). Formation of coarse carbide precipitates at grain boundaries appears to have a vital attribution to this failure. Failure mechanism and mitigation strategies are discussed in this paper.

Multiobjective Genetic Algorithm applied to inverse finite element analysis: T-joint welding case study

ABSTRACT Welding processes play as an important role in the manufacturing of a lot of products in most of industrial sectors. Despite its wide applicability, the welding process is subjected to some inconsistencies in quality due to controllable and uncontrollable variables. This work is aimed to use inverse Finite Element Analysis (FEA) to simulate the movement of the heat flow in the base metal submitted to the Gas Metal Arc Welding (GMAW) process. To this end, control limits were established, such as voltage and electric current (in the form of the heat source) and welding speed in order to obtain optimized values of deformations and stresses along the plates subjected to the GMAW welding process. For the numerical simulation process modelling, empirical data from weld beads applied on both sides of two ASTM A36 steel plates (thickness of 9.5 mm each) were used in a T-joint configuration. In this case, a multiobjective algorithm to find the optimized solution was used. Non-dominated Sorting Genetic Algorithm II (NSGA II) in conjunction with FEA was applied. The results presented are consistent with literature data within the pre-established limits, which are deformations and stresses less than 2 mm and 600 MPa, respectively. This demonstrates the potential of using FEA in conjunction with the NSGA II genetic algorithm to predict input variables in welding processes. This can be considered an important contribution to the industrial technological advancement for predicting welding process’s variables.

Improvement of ASTM A53 Steel Durability Using Agrowastes as Carburizing Agent

The importance of steel in manufacturing and construction over the past century cannot be over-emphasized and easy accessibility couple with excellent mechanical properties make it preferable over others. However, the problem of durability has posed a serious concern as majority of steel application are meant for long term use. Several attempts have been made to improve the durability of steel in the past and increase of carbon content in low carbon steel was found to be a suitable agent. Although getting carbon is not the challenge rather obtaining it from a sustainable source that has zero environment impact. This research identified two separate agrowaste that has high carbon content the issue of sustainability brought about the development of carburizing agent from agrowaste that are easily accessible namely palm kernel and eggshell which is employed in this research. The use of agrowaste was found to be effective as there was notable increase in grain structure of the carburized steel when compared to the control sample without carburized agent in it.

Analisis Variasi Arus Pengelasan Kombinasi SMAW-FCAW dengan Kampuh Double V-Groove terhadap Kekerasan dan Struktur Mikro Dissimilar Material JIS G3101-SS400 dan ASTM A36

This study aims to determine the effect of variations of the current with combining two welding techniques SMAW and FCAW in double v-groove against the hardness and microstructure of the dissimilar material of JIS G3101-SS400 and ASTM A36. JIS G3101 SS400 and ASTM A36 each with a thickness of 10 mm were used as the materials. The combination of SMAW welding with E7018 electrodes and FCAW with E71T-1 were used as the welding techniques. The current used in SMAW welding were 60 A, 75 A, and 90 A. While in FCAW welding the current used were 190 A, 205 A, and 220 A. Hardness and microstructure tests were carried out on each sample. The results of the study showed that the current in welding process affect the hardness value and microstructure of material. The higher the welding current, the value of hardness of the material going to decrease and vice versa. The highest hardness values in SMAW and FCAW welding are at currents of 60 A and 190 A. Then the current in the welding process also affect the microstructure produced in the weld and HAZ. The formed microstructure containing pearlite and ferrite. The higher welding current, the percentage of pearlite produced increase and the percentage of ferrite decrease.

Analisis Statis Konstruksi dan Lance Tube Sootblower Tipe Motorised Rotary Menggunakan Software Solidworks 2016

Sootblower is a boiler support equipment that works to clean soot. Sootblower requires a strong construction to support the components in order to work optimally. Sootblower is also not free from several failures on its components, the main component that causes failure on the sootblower is the lance tube. This study aims to analyze the static construction and lance tube motorized rotary sootblower type sootblower using Solidworks software. The method used in this research is a simulation based on the finite element method. The material applied to the construction is St 37 and the material on the lance tube is ASTM A213 T92. The static simulation results show that the construction design of the angle iron measuring 35×35×6 mm has a max stress value of 57,50 N/mm2 that occurs in the bolt hole, a value of max displacement of 0,0146 mm on the rod supporting the bearing, and a factor of safety value of 4,08 so it is safe to use. Static simulation on the design of 40 NB diameter lance tube with four thickness variations shows the highest max stress value, the highest max displacement, and the lowest factor of safety occurs in the lance tube thickness of 10,2 mm, which has a max stress value of 276,24 N/mm2, max displacement of 335,53 mm and a factor of safety 1,59. Lance tubes with a thickness of 10,2 mm can be declared safe because the value of the factor of safety meets the minimum limit for static loading.

Liquid Metal-Assisted Cracking During Hot-Dip Galvanizing of Complex Structures: A Case Study

A pipe rack assembly uses hot-dip galvanized trusses joined together by screw connections. The welded trusses were manufactured with ASTM A572 gr.50 W steel profiles. Two of them fractured during the galvanizing bath. The fractures presented typical characteristics of the LMAC — liquid metal-assisted cracking mechanism. In both cases, the fracture was located in the structural element base metal and followed the fillet weld to the neighboring elements at a distance beyond the heat-affected zone. The trusses height was greater than the depth of the molten zinc vat, and double immersion is required for complete galvanization. The failed trusses had a particular geometry, distinct from the others. The design of the trusses was verified taking into account the thermal stresses generated by the partial immersion in the zinc bath. Among all, only the two broken trusses were exposed to stresses of thermal origin substantially higher than the material yield strength. Metallographic analysis revealed secondary intergranular cracks near the fracture surface. The crack roots contained zinc. In addition, the secondary cracks had a large opening in relation to the depth, which indicates material plasticization in the root region.

Effect of DCRP and DCSP Polarity on SMAW Welding on the Depth of Penetration with E7018 Electrodes using Low Carbon Steel ASTM A36

The study aims to determine the level of penetration depth using SMAW (Shielded Metal Arc Welding) Process based on the polarity type of DCRP (Direct Current Reverse Polarity) and DCSP (Direct Current Straight Polarity). This research used ASTM A36 low carbon steel plate with thickness of 6 mm and length of 200 mm, Electrode E7018 LB-52-18 ∅ 3.2 mm, and with current parameters of 90 A, 100 A, 110 A, 120 A and 130 A and 70° welding arc angle. The method used the experimental research. Data collection techniques applied direct observation techniques and descriptive statistical data analysis techniques. Testing the penetration depth of the welds with a macrographic test was conducted by an optical microscope. The test results show that DCRP has more depth than DCSP when the current is 90 A with a difference of 0.38 mm. When the current is 100 A, DCRP is deeper with a difference of 0.312 mm compared to DCSP. The third experiment, with a current of 110 A DCRP, was deeper with a difference of 0.05 mm compared to DCSP. During the fourth and fifth experiments, DCRP was deeper with a difference of 0.21 mm compared to DCSP at 120 A and DCRP was 0.324 mm deeper than DCSP at 130 A. It can be concluded that the effect of DCRP and DCSP polarity on the depth of penetration using E7018 electrodes and ASTM low carbon steel A36, DCRP polarity has a deeper penetration depth compared to DCSP.

Fracture behavior of high-strength bolted steel connections at elevated temperatures

In fire events, to utilize catenary effect and accommodate large deformation in beams demands a sufficient deformation capacity and ductility in steel bolted connections, which is not well considered in design practice. Therefore, for performance-based fire safety design, it becomes very essential to accurately predict the fracture behavior of steel bolted connections at elevated temperatures. However, experimentally predicting their fracture behavior is very costly at elevated temperatures and limited by the scale of structural components. Therefore, this paper proposes a numerical analysis approach and investigates the fracture behavior of high-strength bolted steel connections at elevated temperatures based on the validated numerical analysis approach. The temperature-dependent material properties including true stress-strain curves and fracture parameters in a three-stage fracture model (describing the pure tension, pure shear, and combined tension and shear fracture behavior) for high-strength ASTM A325 bolt and A572 Grade 50 steel are firstly calibrated from and validated against their tensile and shear test results. They are further validated against the test results on single-bolted and multi-bolted connections at elevated temperatures, which were not used in the calibration of these material properties. The validated material properties and fracture parameters are finally proposed for fracture prediction of different types of bolted connections under various loading conditions at elevated temperatures. This study shows the potential of reasonable prediction of the fracture behavior for the steel bolted connections at elevated temperatures and under complicated loading conditions using a numerical analysis approach. According to the numerical analysis results, the degradation of shear fracture resistance of A325 bolts at elevated temperatures is more significant than that of A572 Grade 50 steel plate, which may lead to a bolt shear failure mode for these connections with a large end distance at high temperatures (>400 °C). It is also found that the fracture failure mode can significantly influence the degradation of the load and deformation capacities of high-strength steel bolted connections at elevated temperatures. With the bolt shear failure mode, the degradation of load and deformation capacities of steel bolted connections are more significant than that with plate tearing-out failure mode.

Modifikasi Mesin Las Gesek Cakram

The purpose of this research is to improve the performance of the disc friction welding machine that has been built and is operated, but there is a drawback, namely that there is no measuring device for process parameters such as rotational speed and forging load. In addition, during operation there is a vibration of 1.5 mm / s to 4.9 mm / s which is unacceptable according to ISO-2372 standards, so that these deficiencies can affect the quality of weld production. Repair or modification of this the friction welding machine is carried out by selecting and installing a rotating speed sensor (RPM) and load cell forging loads and installing rubber to dampen vibrations. Furthermore, the function test was carried out with the load, it was obtained that the rotational speed read on the LCD was 3.7% greater than the tachometer and the vibration decreased up to a value of 0.9 mm/s where this value was acceptable according to ISO-2372, while the performance test resulted in welding production for 3 workpieces with plate sheet material AA-110, ASTM A36 and CU-DHP copper with the same thickness, namely 1mm. From the results of the specimen tensile test of the three materials, it was found that the breakdown location was in the welding area where the tensile test value was around 1.2 to 5.1% of the tensile value of the workpiece material. 

Analisis Keretakan pada Sambungan Las antara Pipa ASTM A106 dengan Globe Valve

Crack failure often occurs in piping installations, especially in the welding area which can be caused by excessive stress or corrosion of the material. In this case, the crack failure in the HAZ area will be discussed near the pipe connected to the valve for the heat transfer fluid line. The method used in this paper is the inspection of the attached materials using OES (Optical emission spectroscope), observation of pipe and valve joints and failure analysis. From the results of material inspection, it was found that the pipe used was ASTM A106, then from the microstructure it was seen that the grain dimensions were not homogeneous, it would cause the strength of material heterogeneity, then from visual observation, it could be seen that pipe joints and valve misalignment occurred.

Study of cracking susceptibility in similar and dissimilar welds between carbon steel and austenitic stainless steel through finger test and FE numerical model

Hot cracking susceptibility and the formation of brittle martensite phase are the main factors that limit the weldability of a dissimilar joint between carbon steel (CS) and austenitic stainless steel (SS). In this study, the self-constraint finger test was used to correlate the welding thermo-mechanical field with the crack susceptibility of a dissimilar weld between the CS ASTM A36 and SS AISI 304L. The finger test allowed to intercalate fingers (portions) of tested materials in the weld samples to produce dissimilar welds. The heat dissipation and the distortion behavior were related to the crack susceptibility, critical weld regions extension, and chemical species diffusion. Four samples were welded (two similar welds and two dissimilar welds) using the filler metals ER70S-6 and EC410NiMo. Welds were analyzed through light optical microscopy (LOM) and scanning electron microscopy (SEM) to characterize phases, detect cracks, microstructural changes, and element diffusion. A finite element (FE) numerical model was applied to simulate the welding thermo-mechanical field. FE estimations of distortion and residual stress helped to predict induced crack propagation (the initial gap between fingers) towards the fusion zone. Additionally, electrochemical tests were carried out to assess the corrosion susceptibility of the dissimilar welds. The observed cracks were produced due to different factors such as residual stress distribution, the formation of brittle and untempered martensitic phase in the fusion zone (FZ), and hot cracking associated with the weld sample distortion behavior. According to the FE estimations, the high thermal expansion of the SS was responsible for the bending curvature change in welds 2 and 4, which produced a gap between fingers and increased the crack extension in the FZ of weld 4. The dilution contributed to the formation of δ-ferrite in the FZ, which limited the growth of cold and hot cracks. The decarburization and sensitization were not observed in dissimilar welds due to the low element diffusion.

Behaviour of slender concrete shear walls with high-strength reinforcement under reverse cyclic loading

Research on seismic behaviour of shear walls with high-strength steel is limited. A combined experimental and analytical investigation was conducted to assess seismic behaviour of flexure-dominant shear walls. A large-scale concrete shear wall with Grade 690 MPa (ASTM A1035) reinforcement and 84 MPa concrete was tested under simulated seismic loading. The wall represented a 6-story building shear wall with 4.53 m height and 1.45 m length. It sustained a lateral drift of 1.8% prior to developing failure due to the rupturing of longitudinal reinforcement. This is 35% less than the drift capacity of a companion wall reinforced with 400 MPa reinforcement tested earlier. VecTor2 software was used to conduct an analytical parametric study to expand the experimental findings. The results indicate that the reinforcement grade has a significant impact on strength, ductility, and hysteretic behaviour of shear walls.

EFFECT OF MIG WELDING PROCESS PARAMETERS ON EROSION AND CORROSION BEHAVIOR OF ASTM A106 GRADE-B PIPE WELDMENTS

Evaluating the integrity of the welded pipes used for fluid transportation in processing industries demands certain investigations on the erosion and corrosion behavior under various environmental conditions. ASTM A106 Grade-B pipes are butt welded using an automated MIG welding setup to obtain the optimum output response such as Reinforcement Form Factor (W1), Penetration Shape Factor (W2), and Tensile Strength (W3) in the weldments. The slurry erosion test is conducted on the weldment surface by varying the velocity and erodent concentration in acidic (0.1M H2SO[Formula: see text] and alkaline (3.5%[Formula: see text]wt. NaCl) conditions. Correspondingly, the samples are subjected to electrochemical corrosion test in 0.1[Formula: see text]M H2SO4 and 3.5% wt. NaCl solutions. The SEM investigations carried out on the eroded weldment surface show glimpses of erosion mechanisms such as shallow and deep ploughing, oxide cracks, ridges and valleys, scale formation at some areas attributing to sulphide deposition. The corrosion that occurred on the weldment surface tested under acidic conditions is relatively high compared to the alkaline conditions. The reinforcement form factor is the most preferable weld bead characteristic to obtain better erosion and corrosion resistant weldments in the investigated pipe material.

Cyclic flexural test and loading protocol for steel wind turbine tower columns

A round hollow steel section (HSS) is generally used in a wind turbine tower column. Experimental studies on the cyclic flexural behavior of round HSS columns with large diameter-to-thickness (D/t) ratios are very limited. Three steel round HSS column specimens with a D/t ratio of 240 were planned for tests. The specimens, made from ASTM A36 steel, had a clear height of 4390 mm, diameter of 1440 mm and thickness of 6 mm. In addition, one specimen was wrapped with the Glass Fiber Reinforced Polymer (GFRP) material. Specimen 1 was tested under an increasingly monotonic loading, and Specimens 2 and 3 were tested under an increasingly cyclic loading. Specimens 1 and 2 exhibited inward local buckling at a drift angle of 0.0025 rad.; Specimen 3 with GFRP wrapping at the bottom end exhibited inward local buckling at a drift angle of 0.003 rad., slightly later than the timing when the local buckling occurred in Specimens 1 and 2. Test results indicated that the ductility of Specimen 1 under the monotonic loading is larger than that of Specimens 2 and 3 under the cyclic loading due to slower strength degradation. Specimen 2 has a ductility of 1.02–1.65 before the lateral load decreases more than 10%. The maximum flexural strength of the GFRP-wrapped column increases 6%–10% compared to that without GFRP wrapping. The AISC (2016) and EN1993-1-6 (2017) standards reasonably predict the flexural strength of specimens, but the ASME (2006) and ASCE (2011) standards underestimate the flexural strength by 18%–25%. Nonlinear time–history analyses were conducted on a 10-MW wind turbine tower to develop a cyclic displacement protocol for the tests.

Role of the Ni-based filler composition on microstructure and mechanical behavior of the dissimilar welded joint of P22 and P91 steel

The manuscript described the effect of Ni-based filler on microstructure and mechanical properties of the dissimilar welded ASTM A335 grade P22 and P91 alloy steel plate. The dissimilar welds joint (DWJ) was produced using the Gas Tungsten Arc Welding (GTAW) process. The DWJ was characterized for metallographic and mechanical testing for as-welded and post-weld heat treatment (PWHT) conditions. For mechanical properties, microhardness, tensile test and Charpy impact test were performed. The DWJ showed the heterogeneity in microstructure and mechanical properties (microhardness, impact toughness) along the welded joint. The weld metal showed the formation of the austenitic microstructure consisted of the equiaxed dendrite along with segregation of the alloying elements like Cr, Mo, and Ti at the inter-dendritic boundaries, while P91 and P22 HAZ showed the formation of coarse-grained, fine-grained, and inter-critical heat-affected region depends on the temperature experienced during the welding cycle. The region of P91 HAZ was characterized by untempered and tempered martensite, while P22 HAZ was characterized by coarse and fine bainitic microstructure. The PWHT showed a negligible effect on the microstructure of the weld metal, while a significant change in microstructure of P91 HAZ and P22 HAZ was observed. PWHT also led to the formation of the soft and hard zone along the interface of the P22 steel due to the carbon diffusion. At the interface of the weld metal and base material, a sharp gradient was observed for the elements Cr, Fe, Ni and Mo. The weld metal near the interface showed the columnar dendritic structure having segregation of the alloying elements Mo, Ti and Cr along the inter-dendrite boundaries. A variation in hardness was measured along the weldments for as-welded and PWHT conditions. The peak hardness was measured in P91 coarse-grained heat-affected zone (CGHAZ) for both as-welded and PWHT, while the poor hardness of 202 HV and 195 HV was measured for weld metal in as-welded and PWHT conditions. The strength of the welded joint was measured higher than the strength of P22 steel for both conditions; however, the fracture was observed in P22 base metal for the as-welded joint, while in PWHT, it was in P22 HAZ near the interface. A variation in Charpy impact toughness was observed along the weldment for both as-welded and PWHT conditions. In as-welded, the minimum Charpy impact toughness (CIT) of 95.8 J was measured in weld metal, while the maximum was 152 J in P91 HAZ. After the PWHT HAZ region of P22 and P91 steel showed a drastic increase in CIT, however reduction in CIT of the weld metal was measured.