Journal of Welding Science

Cellulose is a natural biopolymer with the general (C6H10O5)n formula, which according to AWS A5.5 standard, more than 40wt% of coating of cellulosic electrodes is consisted of cellulose. In this study to evaluate the effect of cellulose type on the performance of E8010-P1 cellulosic electrode, equal  amounts  of two celluloses with the same commercial properties but produced by two different companies, were used for production of two E8010-P1 electrodes.Experimental studies illustrate significant difference between structural and mechanical properties of deposited weld metals from these electrodes. FTIR, DTA and XRD testes of as-received celluloses show despite the same brandforthese celluloses, their properties such as bonds types,thermal behavior and crystallinity are different that cause variation ofweld metal penetrate and tensile strength around 25±2% and 5±2%respectively.

The aim of this study was to evaluate the mechanical properties and corrosion behavior of friction stir welding (FSW) connection of A517 (B) steel plate. Mechanical properties and corrosion behavior of weld zone were evaluated after reaching to optimum FSW microstructure with the lowest martensite phase. Thus, after the identifying phase microstructure by SEM and XRD analysis, mechanical properties were analyzed by micro-hardness and tensile test. Micro hardness data shows slight increases in stir zone (SZ) compared with the base metal (BM); although a reduction of about 17% in hardness of heat-affected zone (HAZ) was sensible. Reduction of hardness in the HAZ was appeared as drop by about 12 percent of the yield strength and 19 percent of ultimate strength compared with BM. SEM images from fracture surface of the tensile sample showed bi-modal distribution of large and small Dimples being sings of softness of HAZ .Comparing corrosion behavior in solution consist of 3.5 wt% of NaCl showed that there was no passive layers to prevent dissolution of the metal in the SZ and BM. while BM and SZ had fairly similar corrosion rates, Difference of 50 mV between corrosion potential of SZ and BM showed that in galvanic condition, corrosion resistance of BM could be lower than SZ.

In this study, microstructural features and mechanical properties of Incoloy 825-316L stainless steel dissimilar joints have been investigated. For this purpose, pulsed gas tungsten arc welding method was employed and 316L, Inconel 82 and Inconel 625 alloys were used as filler metal. First, specimens were cut. Pulsed gas tungsten arc welding was performed using peak and base currents of 220 A and 110 A, respectively. Microstructure of welded joints was studied using metallographic observations and energy dispersive spectroscopy (EDS) analysis. In order to evaluate the mechanical properties, tensile and microhardness measurements were done on the joints. In all specimens, dendritic and equiaxed and/or cellular growth of austenite phase was observed. Incoloy 625 weld metal had the finest dendritic structure. Tensile test results revealed the ductile fracture with a high percent of elongation for all specimens. The highest tensile strength and percent of elongation of 610 MPa and 48% were obtained for specimen welded using Inconel 625 filler metal. Inconel 625 and 316 stainless steel weld metals showed the highest and lowest microhardness with values of 232 HV and 224 HV, respectively.  

The aim of this study is to reach an increased service life for parts using in sour environment by weld overlaying process. In this investigation, two successive layers of ER410NiMo were clad on low alloy steel substrates. To reduce the likelihood of Hydrogen Induced Cracking (HIC) and producing stable hydrogen traps, Post Weld Heat Treatment (PWHT) was conducted. Microstructural analysis, X-ray diffraction studies, and mechanical tests show significant increase for austenite volume fraction after second stage of PWHT. In fact, not only two-stage PWHT  reduce the samples hardness, but it also increases austenite volume fraction which is a more resistant microstructure against hydrogen cracking.