Coarse-grained Heat-affected Zone Research Articles

Influence of Interpass Temperature on the Simulated Coarse-Grained Heat-Affected Zone of a Circumferentially Welded 2.25Cr-1Mo Steel Pipe Joint

To reduce manufacturing costs, energy companies aim to maximize the deposition rate during welding operations by increasing the interpass temperature (IT), thereby minimizing the cooling time. However, IT can significantly affect weldment performance, particularly its Charpy V-notch (CVN) impact energy (toughness). The present study investigates the effect of increasing IT beyond the limit specified by the ASME B31.3 (315 °C) on the CVN impact energy (−30 °C) of the simulated coarse-grained heat-affected zone (CGHAZ) of a 2.25Cr-1Mo steel submerged arc welded (SAW). The CGHAZ thermal cycles were obtained through finite element method simulations and physically replicated using a Gleeble machine. The increase in IT beyond the ASME-specified limit significantly reduces the CVN impact energy of the CGHAZ. However, the values obtained remained above the minimum required threshold (NORSOK M630, 42 J). The main effect of increased IT was grain coarsening. Additionally, an inverse linear relationship was observed between effective grain size (EGS) and CVN impact energy. The steel’s microstructure showed non-significant sensitivity to variations in IT within the studied range. These findings suggest that, under the conditions studied, increasing IT could be a viable option for optimizing production by reducing welding time and potentially lowering costs.

Study on Microstructure and Low‐Temperature Impact Toughness in Coarse Grain Heat‐Affected Zone of EH460 Steel

Herein, the effects of peak temperature on the microstructure and low‐temperature impact toughness of coarse grain heat‐affected zone (CGHAZ) of EH460 steel are investigated by Gleeble simulation welding. The low‐temperature impact toughness of CGHAZ decreases with the increase of peak temperature. With the increase of peak temperature, the microstructure of CGHAZ gradually changes from bainite to a mixed structure composed of bainite, intragranular ferrite, side lath ferrite, and a small amount of grain boundary ferrite. The inclusions size decreases as the peak temperature increases. The existence of large‐sized inclusions is conducive to the initiation and propagation of cracks, reducing the low‐temperature impact toughness of the material.

Crystallographic Study of Transformation Products of Heat-Affected Zone and Correlation with Properties of FH690 Heavy-Gauge Marine Steel by Multi-Pass Submerged Arc Welding

In this work, the microstructure–property relationship of the heat-affected zone (HAZ) of a FH690 ultra-heavy marine steel plate was investigated based on insight of microstructure and crystallographic features. After multi-pass welding with a heat input of ~30 kJ/cm, an ~8 mm wide HAZ was obtained with a coarse grain HAZ (CGHAZ) of ~3.8 mm, fine grain HAZ (FGHAZ) of ~3.4 mm, and intercritical HAZ (ICHAZ) of ~1 mm. High impact toughness values of ~120 and 140 J at -60 °C were obtained for coarse grain HAZ and fine grain HAZ, respectively. The microstructure of the CGHAZ and FGHAZ was fine lath bainite. Although the average prior austenite grain size for the CGHAZ was ~75 μm, which was five times that of the FGHAZ (15 μm), a high density of high-angle grain boundaries (HAGBs) with misorientation higher than 45° was obtained in the CGHAZ. This is the underlying reason for the excellent low-temperature toughness of the HAZ. Thermo-dynamic calculations indicated that the high density of HAGBs in the CGHAZ was attributed to the decreased bainitic transformation temperature due to the reduced phase transformation driving force via the high nickel addition, leading to weak variant selection. In addition, the high nickel addition offered high hardenability for high hardness in the FGHAZ. The outcome of this study could provide an experimental and fundamental basis for designing high-strength ultra-heavy steel plates with excellent weldability.

Coupled effect of microstructure heterogeneity and hydrogen on local embrittlement of CGHAZ and IC-CGHAZ in X65 pipeline steel

The local embrittlement of the coarse-grained heat-affected zone (CGHAZ) and intercritically reheated CGHAZ (IC-CGHAZ) in X65 pipeline steel was investigated using an in situ crack-tip opening displacement test in air and H2S, combined with microstructure-based simulation. The IC-CGHAZ exhibited significantly lower cracking resistance, with the fracture toughness reduced by 50% compared to CGHAZ in both environments (0.160 mm in air and 0.017 mm in H₂S for IC-CGHAZ, compared to 0.307 mm in air and 0.034 mm in H₂S for CGHAZ). The martensite/austenite (M/A) constituents showed exceptionally higher intrinsic hardness than the ferrite matrix. The continuous distribution of M/As along the prior austenite grain boundaries resulted in local hardening and the formation of heterogeneous hard zones in IC-CGHAZ. Such microstructure heterogeneity resulted in the unique partitioning of plastic strain localization and stress triaxiality that promotes premature fracture, particularly with the coupled effect of hydrogen. This study provides a novel perspective on the fracture mechanisms and the typical fracture morphology of IC-CGHAZs in pipeline steel under the coupled effect of microstructure heterogeneity and hydrogen.

Microstructural evolution and hydrogen embrittlement in simulated reheated coarse-grained heat-affected zone of a high-strength naval steel

The influence of simulated reheated coarse-grained heat-affected zones (CGHAZ) on the microstructural evolution and hydrogen embrittlement in high-strength naval steel was investigated by scanning electron microscopy, microhardness testing, electron backscatter diffraction, slow strain rate tensile test and fracture morphology analysis. Twinned martensites were observed in both the intercritical and super-critically reheated CGHAZ, with a widely spaced region in the former. Intercritical reheated coarse-grained HAZ (ICCGHAZ) was the weakest zone of reheated CGHAZ when the peak temperature was 660 °C, exhibiting the intergranular cracking feature. Twinned martensite and coarsening grain size were therefore concluded to be the main reasons for high hydrogen embrittlement susceptibility in the reheated CGHAZ.

Multi-angle analysis of Mo on martensite–austenite component and toughness in SCGHAZ of X80 pipeline automatic ring welding

In order to solve the embrittlement problem of welded joint of pipeline steel, this paper proposes to study the influence of Mo on M-A component of the subcritically reheated coarse-grained HAZ (SCGHAZ), and Mo on bainite transformation. Through the welding thermal simulation experiment, two kinds of X80 pipeline steel with different Mo content were set different secondary thermal cycle peak temperatures to simulate the heat affected zone (HAZ). Samples in the SCGHAZ were selected to observe the microstructure, M-A component, microalloy-element distribution and fracture crack trend, and comprehensively analyze the reasons for the deterioration of impact toughness caused by the changes of Mo content. The results show that the increase of Mo content leads to the formation of twinning martensite, which is one of the reasons for the deterioration of toughness. Mo is enriched at the interface of ferrite and M-A component, reducing the binding energy at the interface, resulting in the desorption of M-A component from the matrix, the formation of pores and becoming the nucleation site of cracks, resulting in the generation of micro-cracks and the decrease of toughness.

Effect of heat input on the microstructure and hydrogen embrittlement susceptibility of the coarse-grain heat-affected zone of CrMo steels generated using a Gleeble 3500 welding simulator

The changes in microstructure and hydrogen embrittlement (HE) susceptibility of the simulated coarse-grain heat-affected zone (CGHAZ) of CrMo steels under three distinct heat input conditions were investigated. The cooling time from 800 °C to 500 °C, represented by t8/5, increased from 100 s to 200 and 400 s.. The sample with t8/5 = 100 s has a microstructure consisting of martensite and a small amount of lower bainite. When the t8/5 was increased to 200 s and 400 s, the HAZ consisted of 65.43 % martensite and 34.57 % lower bainite and 4.53 % martensite with 95.47 % bainite, respectively. The HE susceptibility was assessed by slow strain rate tensile (SSRT) testing of hydrogen-charged samples, and the HE susceptibility index (IHE) declined from 87.89 % to 61.37 % when t8/5 increased from 100 to 400 s. The high dislocation density and hydrogen concentration in the sample with t8/5 = 100 s led to intergranular fracture and incresaed HE susceptibility. The martensite lath and cementite/ferrite interface are the sites of crack initiation in the sample with t8/5 = 200 s. In the sample with a cooling time of 400 s, the martensite/ferrite interfaces are the main crack initiation sites under hydrogen charging.

A new understanding of hydrogen-assisted cracking of coarse-grained heat-affected zone in X65 pipeline steel through {110} lath bainite boundary texture

The susceptibility of subzones of the coarse-grained heat-affected zone (CGHAZ) in X65 pipeline steel to hydrogen embrittlement was studied through an in situ crack-tip opening displacement test in an H2S-containing environment. The intercritically reheated CGHAZ (IC-CGHAZ) exhibited the highest embrittlement factor of 89.4%, compared to 64.0% for the sub-critically reheated CGHAZ (SC-CGHAZ). Hydrogen transportation by dislocations to massive-slender martensite/austenite (M/A) constituents initiated cracks in IC-CGHAZ. Deterioration of lath bainite (LB) boundaries, with separation of M/A-ferrite interface, accelerated crack propagation across prior austenite grains and promoted hydrogen-assisted degradation of fracture toughness. Reheated CGHAZ at a peak temperature of 620 °C led to an increased intensity of the {110} LB boundary texture by up to 52% in SC-CGHAZ. This enhanced texture facilitated dislocation slipping along {110} LB boundary planes, thereby promoting deformation compatibility and preventing the deterioration of LB boundaries in the presence of hydrogen.

Corrosion fatigue cracking behaviors of Q690qE high‐strength bridge steel as a weld joint in simulated marine environment

AbstractCorrosion fatigue behavior and mechanism of the weld joint of Q690qE high‐strength bridge steel was investigated in a simulated marine environment. It reveals the sub‐critical heat‐affected zone (SCHAZ) and coarse‐grained heat‐affected zone (CGHAZ) are the most vulnerable sites to corrosion fatigue cracking. The CGHAZ of the Q690qE steel weld joint was prone to corrosion fatigue initiation mainly because of micro‐galvanic corrosion between CGHAZ and weld metal (WM). The corrosion fatigue failure in SCHAZ mainly resulted from local stress/strain concentration due to weld softening. The final fracture location was determined by the competition between these two effects.

Creep rupture properties of dissimilar welded joint of ferritic/martensitic P92 steel and Inconel 617 alloy

The dissimilar welded joint (DWJ) comprising P92 steel and Inconel 617 (IN617) is frequently utilized in advanced ultra-supercritical (AUSC) boilers. In present work the creep rupture behaviour, rupture mechanism and microstructure evolution of DWJ of P92 steel and IN617 with Ni-based ERNiCrCoMo-1 filler, were examined at 650 °C under the stress range of 120–200 MPa. The results of the creep test indicated that the location of creep rupture varied across different testing conditions, encompassing areas such as P92 base metal and the fine-grained heat-affected zone (FGHAZ). The creep tested specimens within the stress range of 180–200 MPa exhibited failure originating from P92 base metal, predominantly influenced by plastic deformation. The failure manifested in a transgranular mode, driven by the formation, growth, and eventually coalescence of microvoids. The creep tested specimens within the stress range of 120–150 MPa displayed the characteristic ofType IV failure, primarily attributed to matrix softening and the absence of adequate precipitates to pin the PAGBs. Microstructural characterization unveiled the presence of microvoids along the PAGBs, facilitating microvoid nucleation primarily owing to the existence of the coarse brittle carbide phase. The growth of these microvoids over a period of time during tertiary stage of creep which lead to their coalescence and the formation of microcracks, ultimately resulting in premature intergranular failure. The specimen creep exposed at 650 °C under the lower stress of 120 MPa exhibited higher creep rupture life for 432 h. The SEM/EDS study of the crept sample of 120 MPa is also confirmed the presence of intermetallic laves phases in regions near the fracture tip and in the heat-affected zones (HAZs). Although the creep tested specimens at 150 MPa and 120 MPa exhibited failure in the FGHAZ and their elemental SEM/EDS analysis confirmed the presence of an oxide layer and notch formation near the interface of P92 base metal and ErNiCrCoMo-1 filler weld. The FESEM study revealed the growth of the oxide layer in the notch region, and it also showed the presence of multiple cracks and microvoids in the oxide layer. The formation and propagation of the oxide notch mainly led to the interfacial failure. The crept specimens subjected to 180 MPa and 200 MPa did not exhibit any cracks or microvoids in HAZs. However, specimens that failed under applied stresses of 120 MPa and 150 MPa revealed the presence of a high density of microvoids in the FGHAZ, inter-critical heat-affected zone (ICHAZ), and in the region of the coarse-grained heat-affected zone (CGHAZ) adjacent to the interface attached with an oxide layer.

Role of M-A constituents in bainitic microstructure on crack propagation behavior in the ICCGHAZ of HSLA steels for offshore applications

The objective of the study is to understand the effect of martensite-austenite (MA) constituents along with the neighbouring bainitic matrix and its effect on low-temperature impact toughness in the thermo-mechanically simulated inter-critically reheated coarse-grained heat-affected zone (ICCGHAZ) of offshore High Strength Low Alloy (HSLA) steels. ICCGHAZ was simulated using a Gleeble 3500 thermomechanical simulator between the inter-critical temperature near Ac1 (lower ICT) and at a temperature 50 °C higher (upper ICT) for two different steels (steel A and steel B) with predominant microstructures composed of granular bainite (GB) and bainitic ferrite (BF), respectively. MA constituents were observed in the form of necklaces along prior austenitic grain boundaries (PAGB) of simulated ICCGHAZ for both steel A and steel B. Steel A combrised of discrete island MA constituents inside the GB grains and steel B consists of lath shaped MA constituents inside BF grains. Fractographical analysis showed that secondary cracks were initiated at the MA constituents along PAGB and propagated linearly into the GB/BF grains in the ICCGHAZ. The cracks initiated at the bulky MA at grain boundaries of steel A moved towards the pre-cracked or de-bonded discrete MA inside the grains and propagated through the interlinking of microcracks. In contrast, for steel B a notable percentage of cracks were initiated through the necklace-like MA at the grain boundaries and propagated through the BF lath. Pre-cracking of the slender MA present at the lath boundaries facilitated crack propagation in steel B. Furthermore, increasing the inter-critical temperature improved the impact toughness of steel A with a predominantly GB microstructure, whereas impact toughness improvement was limited in steel B with a BF microstructure.

Cooling Rate Dependency of Retained δ-Ferrite in the Coarse-Grained Heat-Affected Zone of P92 Heat-Resistant Steel

Cooling Rate Dependency of Retained δ-Ferrite in the Coarse-Grained Heat-Affected Zone of P92 Heat-Resistant Steel

Stress-Corrosion-Cracking Sensitivity of the Sub-Zones in X80 Steel Welded Joints at Different Potentials.

X80 steel plays a pivotal role in the development of oil and gas pipelines; however, its welded joints, particularly the heat-affected zone (HAZ), are susceptible to stress corrosion cracking (SCC) due to their complex microstructures. This study investigates the SCC initiation mechanisms of X80 steel welded joints under practical pipeline conditions with varying levels of cathodic protection. The SCC behaviors were analyzed through electrochemical measurements, hydrogen permeation tests, and interrupted slow strain rate tensile tests (SSRTs) conducted in a near-neutral pH environment under different potential conditions (OCP, -1.1 VSCE, -1.2 VSCE). These behaviors were influenced by microstructure type, grain size, martensite/austenite (M/A) constituents, and dislocation density. The sub-zones of the weld exhibited differing SCC resistance, with the fine-grain (FG) HAZ, base metal (zone), welded metal (WM) zone, and coarse-grain (CG) HAZ in descending order. In particular, the presence of coarse grains, low dislocation density, and extensive M/A islands collectively increased corrosion susceptibility and SCC sensitivity in the CGHAZ compared to other sub-zones. The SCC initiation mechanisms of the sub-zones within the X80-steel welded joint were primarily anodic dissolution (AD) under open-circuit potential (OCP) condition, shifting to either hydrogen-enhanced local plasticity (HELP) or hydrogen embrittlement (HE) mechanisms at -1.1 VSCE or -1.2 VSCE, respectively.

Crystallographic study on microstructure evolution and mechanical properties of coarse grained heat affected zone of a 500 MPa grade wind power steel

The effect of different welding heat inputs on the microstructure and mechanical properties of the simulated coarse grained heat affected zone (CGHAZ) of high-strength wind power steel with yield strength of 500 MPa has been investigated using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Charpy impact tests have demonstrated that there exists an optimum heat input of ∼20 kJ/cm that allows optimum impact toughness to be obtained for the CGHAZ. It was shown that this is related to the refined bainitic structure and the highest density of high-angle grain boundaries (HAGBs) with misorientation angle of more than 45°. In crystallographic visualization studies, it was shown that the weakest variant selection occurs for the bainite transformation in the optimal heat input, leading to the highest density of HAGBs with each Closed-packet group containing two or three Bain groups and showing a staggered arrangement structure. The contribution that can effectively deflect and prevent crack propagation during impact experiments has to come from the block boundary. However, it was also found that the center segregation induced by C and Mn reduces the low-temperature impact toughness of the core sample before and after simulated welding, and affects the fluctuations of impact toughness and fatigue performance of simulated CGHAZ. Mn segregation can have a genetic effect on the welding heat affected zone, inducing a lower temperature martensitic transformation, which in turn leads to a decrease in low-temperature toughness and fatigue crack arrest performance.

Effect of Welding Heat Input on the Simulated Heat-Affected-Zone Toughness for Yield Strength 390MPa Class TMCP Steel Plate

In this study, the influence of heat input on the microstructure and toughness of the simulated heat-affected zone (HAZ) of YP390 MPa grade steel with a thickness of 80 mm was investigated. The weld coarse-grained HAZ was simulated using a Gleeble 3500 simulator, with heat input levels ranging from 30 to 650 kJ/cm. Following the HAZ simulation test, the microstructures and Charpy impact properties were examined. For heat inputs ranging from 30 to 50 kJ/cm, the microstructure consisted of bainitic ferrite/acicular ferrite, resulting in an impact toughness exceeding 200 J at -20 ℃. Conversely, in the higher heat input range of 130 to 650 kJ/cm, the simulated HAZ exhibited a lower impact toughness value due to the formation of coarse grain boundary ferrite. A high proportion of acicular ferrite with minimal grain growth was found to be the key metallurgical factor contributing to the improvement of impact toughness.

Effect of Pre-Weld Heat Treatment on the Microstructure and Properties of Coarse-Grained Heat-Affected Zone of a Wind Power Steel after Simulated Welding

The effect of pre-weld heat treatment on the microstructure and low-temperature impact toughness of the coarse-grained heat-affected zone (CGHAZ) after simulated welding was systematically investigated through the utilization of scanning electron microscopy (SEM) and electron back-scattering diffraction (EBSD). The Charpy impact test validated the presence of an optimal pre-weld heat treatment condition, resulting in the highest impact toughness observed in the CGHAZ. Three temperatures for pre-weld heat treatment (690, 720 and 750 °C) were used to obtain three different matrices (Steel 1, Steel 2, Steel 3) for simulated welding. The optimal pre-weld heat treatment is 720 °C for 15 min followed by water quench. Microstructure characterization showed that there is an evident microstructure comprising bainite (B) in Steel 1 and Steel 2 after pre-weld heat treatment, while the addition of martensite (M) with the pre-weld heat treatment temperature exceeds Ac1 by almost 60 °C (Steel 3). These differences in microstructures obtained from pre-weld heat treatment influence the refinement of high-temperature austenite during subsequent simulated welding reheating processes, resulting in distinct microstructural characteristics in the CGHAZ. After the optimal pre-weld heat treatment, Steel 2 subjected to single-pass welding thermal simulation demonstrates a refined microstructure characterized by a high density of high-angle grain boundaries (HAGBs) within the CGHAZ, particularly evident in block boundaries. These boundaries effectively prevent the propagation of brittle cracks, thereby enhancing the impact toughness.

Revealing the mechanism of crack initiation and propagation in CGHAZ of S690QL welded joints through low-temperature impact tests with gradient setting of pendulum angle

As the most brittle areas of welded S690QL high-strength steel structures, coarse-grained heat-affected zone (CGHAZ) was crucial for the structural integrity of components. This paper designed an innovative low-temperature impact testing method with a gradient setting of pendulum angle to investigate the micro-mechanism of crack initiation and propagation in the CGHAZ of S690QL welded joints. The results reveal that continuous blocky M−A constituents were distributed along prior austenite grain boundaries (PAGBs), leading to stress concentration and crack initiation. During low-temperature impact processes, cracks propagate in a transgranular mode along {100} or {110} crystal planes. Due to the interaction between compressive stress and the crack tip, regions with high kernel average misorientation (KAM) such as PAGBs can divert the crack. The coarsening of prior austenite grains in the CGHAZ leads to a diminished hindering effect of PAGBs on crack propagation. The findings elucidate the complex relationship between microstructure and impact toughness of CGHAZ, providing insights into crack behavior and mechanisms in CGHAZ.

The Dominant Role of Recrystallization and Grain Growth Behaviors in the Simulated Welding Heat-Affected Zone of High-Mn Steel.

Single-pass-welding thermal cycles with different peak temperatures (Tp) were reproduced by a Gleeble 3800 to simulate the heat-affected zone (HAZ) of a Fe-24Mn-4Cr-0.4C-0.3Cu (wt.%) high manganese austenitic steel. Then, the effect of Tp on the microstructure and mechanical properties of the HAZ were investigated. The results indicate that recrystallization and grain growth play dominant roles. Based on this, the HAZ is proposed to categorize into three zones: the recrystallization heat-affected zone (RHAZ) with a Tp of 700~900 °C, the transition heat-affected zone (THAZ) with a Tp of 900~1000 °C, and the coarse grain heat-affected zone (CGHAZ) with a Tp of 1000~1300 °C. The recrystallization fraction was 29~44% in the RHAZ, rapidly increased to 87% in the THAZ, and exceeded 95% in the CGHAZ. The average grain size was 17~19 μm in the RHAZ, slightly increased to 22 μm in the THAZ, and ultimately increased to 37 μm in the CGHAZ. The yield strength in the RHAZ and THAZ was consistent with the change in recrystallization fraction, while in the CGHAZ, it satisfied the Hall-Petch relationship with grain size. In addition, compared with the base material, the Charpy impact absorbed energy at -196 °C decreased by 22% in the RHAZ, but slightly increased in the CGHAZ. This indicates that the theory of fine grain strengthening and toughening is not entirely applicable to the HAZ of the investigated high-Mn steel.

Microstructure and mechanical properties of a dissimilar metal welded joint of Inconel 617 and P92 steel with Inconel 82 buttering layer for AUSC boiler application

The application of the novel dissimilar metal welded (DMW) joint, utilizing Inconel 617 and P92 steel, was showcased in the advanced ultra-supercritical (AUSC) boiler. The work has been performed to investigate the effect of Inconel 82 (ERNiCr-3) buttering layer on microstructure and mechanical properties (high-temperature tensile strength, impact strength and microhardness) of gas tungsten arc welded (GTAW) dissimilar joint between Inconel 617 and P92 steel fabricated using the Inconel 617 (ERNiCrCoMo-1) filler. For optical microscopy and scanning electron microscopy (SEM), samples were machined along a transverse direction which comprised the butter layer, weld metal, and heat-affected zone of both sides. The energy-dispersive X-ray spectroscopy (EDS) was used to map the interface of the buttering layer and weld metal and butter layer and P92 steel. The high-temperature tensile testing and Charpy impact testing at room temperature were conducted for the integrity assessment of the welded joint. The examination of microstructure and hardness revealed that the buttering layer of Inconel 82 filler successfully mitigated a significant portion of the brittle martensitic microstructure from the coarse-grained heat-affected zone (CGHAZ), along with hardness peaks on the side of P92 steel. The conventional method of DMW joint fabrication, without the use of a buttering layer, has been demonstrated to be less favourable compared to the new fabrication method, which incorporates a buttering layer. The TiC/NbC carbides were identified in the Inconel 82 buttering layer, whereas M23C6 and Mo6C carbides were found in the Inconel 617 filler weld. Near the interface of the Inconel 82 buttering layer and P92 steel, the formation of peninsula and island structures, as well as Type I and Type II boundaries, were confirmed. Additionally, element diffusion of Ni, Cr, and Fe was observed. The tensile test results indicated an ultimate tensile strength of 620 ± 4 MPa and % elongation of 19 ± 4 % at room temperature, with fracture occurring in the buttering layer near the interface of the buttering layer and P92 steel. At temperatures of 550 °C and 650 °C, the ultimate tensile strength decreased to 448 MPa and 326 MPa, respectively, with fractures occurring in the P92 steel, irrespective of temperature. The hardness of the Inconel 82 buttering layer and Inconel 617 filler weld were 219 ± 10 HV and 248 ± 11 HV, respectively. The Charpy impact toughness of the Inconel 82 buttering layer and Inconel 617 filler weld were 138 ± 6 J and 115 ± 4 J, respectively. The study comprehensively investigates and discussed the correlations between microstructure and mechanical properties.

Effect of Welding Heat Input on the Mechanical Properties of Mild Steel at Coarse Grain Heat Affected Zone (CGHAZ)

Effect of Welding Heat Input on the Mechanical Properties of Mild Steel at Coarse Grain Heat Affected Zone (CGHAZ)