Nazia Afrin^a, Yijin Mao^a, Yuwen Zhang^a,*, J. K. Chen^a, Robin Ritter^b, Alan Lampson^b, Jonathan Stohs^c

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.7

Abstract A three-dimensional numerical simulation is conducted for a complex process in a laser-material system, which involves heat and mass transfer in a compressible gaseous phase and chemical reaction during laser irradiation on a urethane paint coated on a stainless steel substrate. A finite volume method (FVM) with a co-located grid mesh that discretizes the entire computational domain is employed to simulate the heating process. The results show that when the top surface of the paint reaches a threshold temperature of 560 K, the polyurethane starts to decompose through chemical reaction. As a result, combustion products CO₂, H₂O and NO₂ are… More >

Yanhua Zhao^1,3,*, Wenhao Tian¹, Jianhua Liu¹, Dongqing Qian², Wei Meng¹, Jiaming Wang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.2, pp. 451-470, 2023, DOI:10.32604/fdmp.2022.021035

Abstract The process parameters of laser additive manufacturing have an important influence on the forming quality of the produced items or parts. In the present work, a finite element model for simulating transient heat transfer in such processes has been implemented using the ANSYS software, and the temperature and stress distributions related to 316L stainless steel thin-walled ring parts have been simulated and analyzed. The effect of the laser power, scanning speed, and scanning mode on temperature distribution, molten pool structure, deformation, and stress field has been studied. The simulation results show that the peak temperature, weld pool size, deformation, and… More >

Xingguo Feng^1,2,3, Yiji Zhang¹, Xiangyu Lu^1,*, Yiwen Xu¹, Leyuan Zhang¹, Chao Zhu¹, Tong Wu¹, Yashi Yang⁴, Xuhui Zhao⁵

Journal of Renewable Materials, Vol.8, No.5, pp. 513-534, 2020, DOI:10.32604/jrm.2020.09549

Abstract Durability and ecological effects of the stainless steel reinforced coral waste concrete were compared with those of the carbon steel reinforced ordinary concrete. The results showed that the corrosion current densities of the stainless steel in the coral waste concrete were less than one-tenth of those of the carbon steel in the same grade ordinary concrete. The stainless steel in the seawater coral waste concrete maintained passivation even after more than two years of immersion in 3.5% NaCl solution, while the carbon steel counterparts in the ordinary concrete were seriously corroded under the same condition. Simultaneously, the corrosion current density… More >

Guocai Chai

Structural Durability & Health Monitoring, Vol.3, No.3, pp. 191-196, 2007, DOI:10.3970/sdhm.2007.003.191

Abstract Duplex stainless steels (DSS) are a group of steels consisting of approximately equal volume fraction of austenite and ferrite. In this study, the influences of the factors such as hydrogen, ferrite phase, cold deformation, grain size, and cluster due to the spinodal decomposition and precipitates or secondary phases in a super duplex stainless steel on the ductile to brittle transition (DBT) are investigated. Three types of DBT curves: toughness versus temperature, hardness and amount of precipitates, have been built to describe the DBT behavior in DSS. These curves are important to provide the information about the critical conditions or criteria… More >

Fuyao Yan^{1, #}, Yu hin Chan^2,#, Abhinav Saboo³ , Jiten Shah⁴, Gregory B. Olson^{1, 3}, Wei Chen^{2, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.3, pp. 343-366, 2018, DOI:10.31614/cmes.2018.04452

Abstract Predicting the mechanical properties of additively manufactured parts is often a tedious process, requiring the integration of multiple stand-alone and expensive simulations. Furthermore, as properties are highly location-dependent due to repeated heating and cooling cycles, the properties prediction models must be run for multiple locations before the part-level performance can be analyzed for certification, compounding the computational expense. This work has proposed a rapid prediction framework that replaces the physics-based mechanistic models with Gaussian process metamodels, a type of machine learning model for statistical inference with limited data. The metamodels can predict the varying properties within an entire part in… More >

T. Fu, C.P. Wang, B. Hou, X.D. Zhu, Z.F. Zhou, K.Y. Li, J. Lu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.20, No.3, pp. 91-92, 2011, DOI:10.3970/icces.2011.020.091

Abstract Structural steels are widely used in engineering fields. Generally, they have the advantage of lower prices due to less precious alloy elements contained; however, their properties, especially the surface properties are inferior to high alloy steels. Surface engineering are of importance in improving surface properties of steels, and even a 'new' surface layer with high performances can be produced by surface technologies on low cost structural steels with ordinary properties.
The researches of last decade have shown that surface nanocrystallization (SNC) can markedly improve surface mechanical properties of metallic materials and accelerate thermal diffusion of N, Cr, etc atoms. In… More >

K. Yamamoto¹, M. Tanaka¹, S. Tashiro¹, K. Nakata¹, K. Yamazaki², E. Yamamoto², K. Suzuki², A. B. Murphy³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.7, No.1, pp. 1-6, 2008, DOI:10.3970/icces.2008.007.001

Abstract Authors have used a numerical model of stationary helium TIG arc welding taking into account the iron, chromium and manganese vapors produced from the weld pool surface and have simulated the distribution of the metal vapors, plasma temperature, fluid flow velocity and the formation of the weld pool. The concentration of manganese vapor in arc plasma was much higher compared with the composition of manganese for stainless steel. More >

S. Aggoune¹, C. Abid², E.H. Amara^1,3

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 115-125, 2015, DOI:10.3970/fdmp.2015.011.115

Abstract This paper focuses on the vortex formation effect during the application of a laser-fusion cutting technique. This industrial technique is typically associated with the ejection of a film of molten stainless steel blown off by a subsonic laminar jet of nitrogen gas used to assist the process. Without taking into account the transverse movement of the workpiece, we consider a 4 mm thick stainless steel plate. The resulting molten metal flow is assumed to be laminar, steady, viscous and incompressible. The numerical results reveal vortex structures adjacent to the walls at the entrance of the kerf, and a pair of… More >

S. Aggoune¹, E.H. Amara¹, M. Debiane²

FDMP-Fluid Dynamics & Materials Processing, Vol.9, No.1, pp. 61-75, 2013, DOI:10.3970/fdmp.2013.009.061

Abstract The effects of inert assisting gas nature and velocity on laser cut quality are investigated. A pure fusion cutting process just above melting point is considered, where the molten steel velocity is given as a function of the two acting forces represented by the pressure gradient and the frictional forces applied by the laminar gas flow. In the case of nitrogen assisting gas, the stainless steel melt film exhibits a visible separation point. The point where the melt flow is separated out from the solid wall depends strongly on the gas velocity. It is pushed down the cut surface when… More >