Papers by Keyword: HAZ

Abstract: Corrosion is a natural occurring phenomenon which exists as a part of our everyday life. Generally stainless steel is having good corrosion resistance which undergo some specific type of corrosion. Corrosion problem in stainless steel has a huge economic and environmental impact on virtually all facts of world’s infrastructure, from highways, bridges, and buildings to oil and gas, chemical processing, and finally it play an ever increasing role in the largest industry in the world is food industry and automotive industry. The corrosion problem is quite costly and it has no easy solution so large amount of money is utilized to analyse the corrosion damage and also to replace the corroded components. The focus of this paper is to investigate the intergranular corrosion studies of industrially important stainless steel of AISI 430 by two different corrosive solutions were 40% Nitric acid (ASTM-A262-Practice C) and copper – copper sulphate 50% Sulphuric acid (ASTM-A262-Practice E) of Gas tungsten Arc welded Metal which were weighted and immersed in test solutions. After immersion, these weldments were removed, washed, and then weighted to determine the weight loss. The analysis of experimental data obtained on intergranular corrosion and the micrographs by Scanning Electron microscope were carefully analysed, monitored, and revealed to study the behaviour of intergranular corrosion of AISI 430, Stainless steel weldments.

Abstract: One of the decisive criteria in the selection of material between steel and aluminium could be the welding RS (residual stresses), which play an important role for the fatigue behavior of the structures under cycling loading. In the current paper simulations in commercial FE software ANSYS were carried out, in order to calculate the welding RS field for three different materials: structural steel S355 and the aluminum grades EN AW-6060 and EN AW-5754. In the case of EN AW-6060 influence of recrystallization on the yield strength of the HAZ (heat affected zone) was taken into consideration.

Abstract: Deflections at the serviceability limit state are often decisive in the design of aluminium structures due to the low elastic modulus. Where design is based on deflections, it may not be necessary to calculate the resistance exactly and simple conservative methods are sufficient. The proposed method may be used to generate a quick, approximate and safe solution, perhaps for the purpose of initial member sizing, with the opportunity to refine the calculation for final design. Another reason for the simple method is enhancing ease of use of Eurocode 9.The principal of the proposed method is to eliminate calculation of effective cross-sections by reducing the elastic resistance with the reduction factor for the most slender part of the cross-section or the factor for HAZ softening whichever is less. This means that you don’t need to define the cross-section class. The disadvantage is that you don’t utilize the plastic reserve for class 1 and 2 cross-sections, nor the redistribution of stresses in the post-buckling range of class 4 cross-sections or sections with HAZ. The procedure is similar to the method with permissible stresses familiar to most engineers.

Abstract: This work focuses on welding repair of aluminium alloy 6082 T6 by TIG welding process. Two types of filler, 4043 and 5356 were used. A comparison at I= 120A,140A, welding speed 20cm/min and gas flow rate 15 L/min was studied. Physical characteristics, macrostructure and microstructure at weld metal and Heat Affected Zone (HAZ) were investigated. Which at 140A can welding repair. The parameter 140A have complete melting and fail area at HAZ and mechanical properties more than 120A.

Abstract: A process design tool is proposed for parametric optimization of laser forming based on integrated Finite Element Method, Response Surface Method and grey Relation analysis. A sequentially integrated FEM-RSM-GRA framework has been developed and implemented to determine the optimum parameters for maximum bend angle, minimum heat affected zone (HAZ) and minimum residual stress. Four process parameters namely power, scanning velocity,spot diameter and sheet thickness had been consideredhave been optimized to minimize the distortion of the structure. The optimization results revealed the effectiveness of the methodology for process design of laser forming of AISI stainless steel sheet with reduced haz and residual stress.

Abstract: The simulation of cooling curves of the heat affected zones (HAZ) of API 5L X80 steel was based on the cooling rates of welds made by the process named FCAW-S (Flux Core Arc Welding Self-Protecting). The specimens were analyzed by macroscopy, light microscopy (LM) and scanning electronic microscopy (SEM) to investigate the effects of cooling conditions on the tensile test and Vickers hardness. A thermo-mechanical simulator showed be able to reproduce the different thermodynamics conditions of points in the HAZ and allowed the reproduction of the thermal cycle obtained by welds were applied to the specimens of API 5l X80 steel. The values of the yield strength, ultimate strength and hardness found in the specimens were lower than those presented by the material as received.

Abstract: Longitudinally welded steel pipe piles are not as commonly used as seamless steel pipe piles in offshore platform. Although longitudinally welded steel pipe piles are considerably cheaper than seamless steel pipe piles, yet many feared that longitudinally welded steel pipe piles are prone to fail because of non-uniformity in the heat affected zone (HAZ), especially when receiving impact loads during the installation process. In this paper, a finite element model is developed to study the deformation and failure of the longitudinal welded piles. Two modelling cases are performed: single and double piles, with two different failure parameters: maximum stress and maximum plastic displacement.

Abstract: This study describes the effects of machining parameters on the thermal affected zone (heat-affected zone; HAZ) of carbon fiber reinforced plastic using fiber laser. The HAZ described in this study was defined as the area where only resin was removed. In three experiments, the HAZ area and the removal shape of carbon fiber were investigated. The study revealed that pulsed laser reduces the HAZ more than continuous-wave laser does, but it causes the swelling of the carbon fiber tip. Furthermore, the HAZ decreased as the scan speed increased, even if the number of scans was increased. In addition, it was found that nitrogen could restrain the HAZ and the swelling of carbon fiber.

Abstract: This paper discusses the modeling of gas-tungsten arc welding (GTAW) process being adopted for maraging steel plates used in aerospace applications. Primary objective of this work is to predict the temperature profile of heat affected zone in a maraging steel weld. Finite element modeling was done utilizing a gaussian heat flux distribution on a weldment. Model also incorporated a moving heat source along with provision for heat sinks in the form of copper backup plates. For validating the model, welding experiments were conducted on 2 mm and 8 mm thick 250 grade maraging steel plates. Thermal profiles were acquired at different locations of heat affected zone using thermocouples and compared with the predictions from the model.

Abstract: Stellite 6 was deposited by laser cladding on a martensitic stainless steel substrate with energy inputs of 1 kW (MSS-1) and 1.8 kW (MSS-1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was assessed using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the MSS steel substrate with the lower heat input (MSS-1). Further, the Stellite coating for MSS-1 was significantly harder than that obtained for MSS-1.8. The wear test results indicated that the weight loss for MSS-1 was much lower than for MSS-1.8. It is concluded that the lower hardness of the coating for MSS-1.8, markedly reduced the wear resistance of the Stellite 6 coating.