scholarly journals INVESTIGATION OF THE INFLUENCE OF PREHEATING ON THE STRUCTURE AND PROPERTIES TRANSITION ZONE BETWEEN HARDFACED WEAR-RESISTANT ALLOY AND 55NICRMOV5 STEEL

Author(s):  
S. A. Fastov ◽  
I. V. Zorin ◽  
V. I. Lysak ◽  
D. A. Murugov

The results of the experimental studies hardfacing of the 55NiCrMoV5 die steel of the three types of wear and heat-resistant alloys with preheating are presented. The effect of the preheating on the structure hardfaced alloys as well as on the heat affected zone formation of the base metal is estimated. It is revealed that the use of preheating under the considered conditions of surfacing causes the formation of a structural heterogeneity of the heat-affected zone of the base metal, which manifests itself as a variable distribution of chromium and molybdenum.

Author(s):  
O. V. Sych ◽  
E. I. Khlusova ◽  
U. A. Pazilova ◽  
E. A. Yashina

The paper presents the results of a comprehensive study of structural and properties changes in the most dangerous regions of the heat-affected zone of low-alloyed cold-resistant steel with a guaranteed yield strength of 355–390 MPa before and after the post-welding tempering, including when the heating temperature is subjected to tempering and deformation, comparing with the base metal. The simulation was performed on the dilatometer DIL 805 and the GLEEBLE 3800 complex. The results of the investigation of the structure and properties of real welded joints after welding with different linear energy (3.5 and 6 kJ/mm) are presented.


Author(s):  
Michael Santella ◽  
X. Frank Chen ◽  
Philip Maziasz ◽  
Jason Rausch ◽  
Jonathan Salkin

AbstractA 50.8-mm-deep gas tungsten arc weld was made with matching filler metal in cast Haynes 282 alloy. The narrow-gap joint was filled with 104 weld beads. Visual and dye-penetrant inspection of cross-weld specimens indicated that the cast base metal contained numerous casting defects. No visible indications of physical defects were found in the weld deposit. The weld heat-affected zone was characterized by microcracking and localized recrystallization. The cause of the cracking could not be determined. Hardness testing showed that a softened region in the as-welded heat-affected zone was nearly eliminated by post-weld heat treatment. Tensile testing up to 816 °C showed that cross-weld specimen strengths ranged from 57 to 79% of the cast base metal tensile strength. The stress-rupture strengths of cross-weld specimens are within 20% of base metal reference data. Failures of both tensile and stress-rupture specimens occurred in the base metal.


2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Payam Tayebi ◽  
Ali Fazli ◽  
Parviz Asadi ◽  
Mahdi Soltanpour

AbstractIn this study, in order to obtain the maximum possible formability in tailor-welded blank AA6061 sheets connected by the friction stir welding (FSW) procedure, the incremental sheet forming process has been utilized. The results are presented both numerically and experimentally. To obtain the forming limit angle, the base and FSWed sheets were formed in different angles with conical geometry, and ultimately, the forming limit angle for the base metal and FSWed sheet is estimated to be 60° and 57.5°, respectively. To explore the effects of welding and forming procedures on AA6061 sheets, experimental studies such as mechanical properties, microstructure and fracture analysis are carried out on the samples. Also, the thickness distribution of the samples is studied to investigate the effect of the welding process on the thickness distribution. Then, the numerical process was simulated by the ABAQUS commercial software to study the causes of the FSWed samples failure through analyzing the thickness distribution parameter, and major and minor strains and the strain distribution. Causes of failure in FSWed samples include increased minor strain, strain distribution and thickness distribution in welded areas, especially in the proximity of the base metal area.


2012 ◽  
Vol 581-582 ◽  
pp. 582-585
Author(s):  
Guo Dong Zhang ◽  
Ya Dong Xiao ◽  
Nian Liu ◽  
Min Hong

The welding between Fe-Al intermetallic compound and high-strength steel was done via SPS technology. Microstructure, elements concentration and micro-hardness of welding joint were examined. The results indicated that there was no obvious welding heat-affected zone in both Fe-Al intermetallic compound and high-strength steel. The HAZ microstructures of high-strength steel were mainly martensite. In Fe-Al intermetallic compound, the grain size of heat-affected zone was larger than that of base metal and the density of heat-affected zone was lower than that of base metal. Besides, the grains of base metal had deformation phenomena. The welding joint had steady performance and the connection was reliable. Under the influence of chemical potential differences, unidirectional impulses discharge current and axial pressure, elements diffused perfectly in a short period of time.


Author(s):  
Emre Korkmaz ◽  
Cemal Meran

In this study, the effect of gas metal arc welding on the mechanical and microstructure properties of hot-rolled XPF800 steel newly produced by TATA Steel has been investigated. This steel finds its role in the automotive industry as chassis and seating applications. The microstructure transformation during gas metal arc welding has been analyzed using scanning electron microscope, optical microscope, and energy dispersive X-ray spectrometry. Tensile, Charpy impact, and microhardness tests have been implemented to determine the mechanical properties of welded samples. Acceptable welded joints have been obtained using heat input in the range of 0.28–0.46 kJ/mm. It has been found that the base metal hardness of the welded sample is 320 HV0.1. On account of the heat-affected zone softening, the intercritical heat-affected zone hardness values have diminished ∼20% compared to base metal.


2014 ◽  
Vol 22 (1) ◽  
pp. 93-98
Author(s):  
Pavol Švec ◽  
Viliam Hrnčiar ◽  
Alexander Schrek

AbstractThe effects of beam power and welding speed on microstructure, microhardnes and tensile strength of HCT600X laser welded steel sheets were evaluated. The welding parameters influenced both the width and the microstructure of the fusion zone and heat affected zone. The welding process has no effect on tensile strength of joints which achieved the strength of base metal and all joints fractured in the base metal.


2021 ◽  
Author(s):  
Nafisa Nuzhat ◽  
Kristof Van Schil ◽  
Sandra Liakopoulos ◽  
Miriam Bauwens ◽  
Alfredo Dueñas Rey ◽  
...  

Ciliopathies often comprise retinal degeneration since the photoreceptor outer segment is an adapted primary cilium. CEP162 is a distal end centriolar protein required for proper transition zone assembly during ciliogenesis and whose loss causes ciliopathy in zebrafish. CEP162 has so far not been implicated in human disease. Here, we identified a homozygous CEP162 frameshift variant, c.1935dupA (p.(E646R*5)), in retinitis pigmentosa patients from two unrelated Moroccan families, likely representing a founder allele. We found that even though mRNA levels were reduced, the truncated CEP162-E646R*5 protein was expressed and localized to the mitotic spindle during mitosis, but not at the basal body of the cilium. In CEP162 knockdown cells, expression of the truncated CEP162-E646R*5 protein is unable to restore ciliation indicating its loss of function at the cilium. In patient fibroblasts, cilia overcome the absence of CEP162 from the primary cilium by delaying ciliogenesis through the persistence of CP110 at the mother centriole. The patient fibroblasts are ultimately able to extend some abnormally long cilia that are missing key transition zone components. Defective transition zone formation likely disproportionately affects the long-living ciliary outer segment of photoreceptors resulting in retinal dystrophy. CEP162 is expressed in human retina, and we show that wild-type CEP162, but not truncated CEP162-E646R*5, specifically localizes to the distal end of centrioles of mouse photoreceptor cilia. Together, our genetic, cell-based, and in vivo modeling establish that CEP162 deficiency causes retinal ciliopathy in humans.


2021 ◽  
pp. 276-281
Author(s):  
E.V. Ageeva ◽  
E.V. Ageev ◽  
A.A. Sysoev

The results of experimental studies of the structure and properties of electroerosive high-chromium powders obtained in kerosene are presented. The high efficiency of using the electrodispersing technology is shown, which provides for obtaining new corrosion-resistant powder materials suitable for industrial use at low energy costs.


Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 408 ◽  
Author(s):  
Lidong Dai ◽  
Haiying Hu ◽  
Jianjun Jiang ◽  
Wenqing Sun ◽  
Heping Li ◽  
...  

In this paper, we present the recent progress in the experimental studies of the electrical conductivity of dominant nominally anhydrous minerals in the upper mantle and mantle transition zone of Earth, namely, olivine, pyroxene, garnet, wadsleyite and ringwoodite. The main influence factors, such as temperature, pressure, water content, oxygen fugacity, and anisotropy are discussed in detail. The dominant conduction mechanisms of Fe-bearing silicate minerals involve the iron-related small polaron with a relatively large activation enthalpy and the hydrogen-related defect with lower activation enthalpy. Specifically, we mainly focus on the variation of oxygen fugacity on the electrical conductivity of anhydrous and hydrous mantle minerals, which exhibit clearly different charge transport processes. In representative temperature and pressure environments, the hydrogen of nominally anhydrous minerals can tremendously enhance the electrical conductivity of the upper mantle and transition zone, and the influence of trace structural water (or hydrogen) is substantial. In combination with the geophysical data of magnetotelluric surveys, the laboratory-based electrical conductivity measurements can provide significant constraints to the water distribution in Earth’s interior.


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