scholarly journals Effects of Substrate Preheating Temperatures on the Microstructure, Properties, and Residual Stress of 12CrNi2 Prepared by Laser Cladding Deposition Technique

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2401 ◽  
Author(s):  
Chenggang Ding ◽  
Xu Cui ◽  
Jianqiang Jiao ◽  
Ping Zhu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Laser Cladding ◽  
Nuclear Power ◽  
Steel Substrate ◽  
Residual Deformation ◽  
Deposition Technique ◽  
Analysis Model ◽  
Preheating Temperature ◽  
Uneven Heating

The 12CrNi2 alloy steel powder studied in the present paper is mainly used to manufacture camshafts for nuclear power emergency diesel engines. Laser cladding deposition is of great significance for the manufacture of nuclear power emergency diesel camshafts, which has the advantages of reducing material cost and shortening the manufacturing cycle. However, due to the extremely uneven heating of the components during the deposition process, a complex residual stress field occurs, resulting in crack defects and residual deformation of the components. In the present paper, 12CrNi2 bulk specimens were prepared on the Q460E high-strength structural steel substrate at different preheating temperatures by laser cladding deposition technique, and a finite element residual stress analysis model was established to investigate the effects of different preheating temperatures on the microstructure, properties, and residual stress of the specimens. The results of the experiments and finite element simulations show that with the increase of preheating temperature, the content of martensite/bainite in the deposited layer decreases, and the ferrite content increases. The proper preheating temperature (150 °C) has good mechanical properties. The residual stress on the surface of each specimen decreases with the increase of the preheating temperature. The longitudinal stress is greater at the rear-end deposition part, and the lateral residual stress is greater on both sides along the scanning direction.

Effect of Cooling Modes on Microstructure and Mechanical Properties of Cr18Ni8Mo2Si Cladding to 40Cr by Laser Cladding Technology

2019 ◽  
Author(s):  
Mingsan Xu ◽  
Simo Liu ◽  
Mingliang Mei ◽  
Bingbing Li
Keyword(s):  
Residual Stress ◽  
Laser Cladding ◽  
Temperature Control ◽  
New Technology ◽  
Scanning Speed ◽  
Structural Defects ◽  
Metallic Material ◽  
Orthogonal Experiments ◽  
Bonding Effect ◽  
Preheating Temperature

Abstract Laser cladding is a new technology to clad metallic material to substrate. The objective of this research is to find optimized process parameters such as preheating temperature of substrate, laser power, scanning speed, spot diameter for cladding Cr18Ni8Mo2Si on 40Cr substrate. Moreover, effects of different cooling modes, cooling in temperature control box or natural environment were studied. Orthogonal experiments are used to find optimized parameters and better cooling strategy. Experimental results are analyzed through measurements of residual stress, micro-hardness, and metallic microstructure. It was observed that parts cooling in temperature control box show better qualities: smaller residual stress, less cracks or other structural defects, better microstructure, and better bonding effect. This research provides a guideline for further researches in temperature control of laser cladding and expands application to rotary die cutting machine.

Numerical Simulation on Temperature Field in Single-Layer Laser Cladding Using Coaxial Inside-Beam Powder Feeding

2010 ◽  
Vol 426-427 ◽  
pp. 151-155 ◽  
Author(s):  
Ming Di Wang ◽  
Shi Hong Shi ◽  
Dun Wen Zuo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Laser Cladding ◽  
Moving Boundary ◽  
Single Layer ◽  
Layer By Layer ◽  
Analysis Model ◽  
Element Analysis ◽  
Powder Feeding

For the disadvantages of the lateral powder feeding and multi-lateral coaxial powder feeding process in laser cladding rapid prototyping process, a new process of hollow focusing laser, powder tube being middle and inside-beam powder feeding is put forward, which can be especially apply in laser cladding. In this paper, the finite element analysis model of temperature of the laser cladding using inside-beam powder feeding is established, temperature distribution of the single-layer in laser cladding is researched, which is theoretically useful for controlling the quality of microstructure and to prevent the cracks. When adopting finite element analysis software, Ansys, the layer unit is acted layer-by-layer, the full simulation of real cladding deposition process will be realized if moving boundary. Finally, some experiments validate the simulation results. Compared with the original mode, it can be found that if adopting the system of the laser cladding rapid manufacturing using inside-beam powder feeding, the temperature distribution is different and it will lead to a denser microstructure.

Study on Weld Residual Stress and Crack Propagation Evaluations for a Saddle-Shaped Weld Joint

2013 ◽  
Author(s):  
Jinya Katsuyama ◽  
Koichi Masaki ◽  
Kunio Onizawa
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Weld Joint ◽  
Power Plants ◽  
Structural Integrity ◽  
Piping System ◽  
Stress Distributions ◽  
Analysis Model ◽  
Element Analysis ◽  
Weld Residual Stress

Stress corrosion cracking (SCC) have been observed in reactor coolant pressure boundary piping system at nuclear power plants. When an SCC is found, the structural integrity of piping should be assessed according to a fitness-for-service rule. However, the rule stipulates the assessment procedures for crack growth and failure only for a simple structure such as cylindrical or plate-wise structure. At the present, the methodology even of an SCC growth evaluation for a geometrically complicated piping such as saddle-shaped weld joints has not been established yet. This may be because analyses on the weld residual stress distribution which affects the SCC growth behavior around such portion are difficult to conduct. In this study, we established a finite element analysis model for a saddle-shaped weld joint of pipes. The residual stress distributions produced by the tungsten inert gas (TIG) welding were calculated based on thermal-elastic-plastic analysis with moving and simultaneous heat source models. Analysis results showed complicated weld residual stress distributions, i.e., residual stresses in both hoop and radial directions were tensile at the inner surface near the nozzle corner in branching pipe. SCC growth simulation based on S-version finite element method (S-FEM) using the weld residual stress distributions in saddle-shaped weld joint was also performed. We confirmed an applicability and the accuracy of S-FEM to saddle-shaped weld joint.

Finite Element Simulation of Temperature Field on Laser Cladding Layers Regulated by Micro-Forging

2011 ◽  
Vol 328-330 ◽  
pp. 1417-1420
Author(s):  
Ju Zhou ◽  
Chang Jun Qiu ◽  
Xi Yang Cheng
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Temperature Field ◽  
Thermal Stress ◽  
Laser Cladding ◽  
Cladding Layer ◽  
Element Simulation ◽  
Preheating Temperature ◽  
Deform 2D ◽  
Cladding Layers

Micro-plastic deformation was produced on the surface of the laser cladding layer by micro-forging, thus cracks were healed in cladding layer; in order to reduce the thermal stress, preheating the substrate was needed to reduce the temperature gap between cladding layer and substrate. In this paper, temperature field by micro-forging on laser cladding Ni60 layer was simulated on software named DEFORM-2D. Compared the width of cracks, the results showed that reasonable and effective preheating temperature could ensure to reduce or eliminate cracks on laser cladding layer.

ANALYSIS OF RESIDUAL STRESS FOR NARROW GAP WELDING USING FINITE ELEMENT METHOD

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2797-2802 ◽  
Author(s):  
CHOON YEOL LEE ◽  
JAE KEUN HWANG ◽  
JOON WOO BAE
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Nuclear Power ◽  
Power Plants ◽  
Large Diameter ◽  
Narrow Gap ◽  
Narrow Gap Welding ◽  
Welding Processes ◽  
Element Method

Reactor coolant loop (RCL) pipes circulating the heat generated in a nuclear power plant consist of so large diameter pipes that the installation of these pipes is one of the major construction processes. Conventionally, a shield metal arc welding (SMAW) process has been mainly used in RCL piping installations, which sometimes caused severe deformations, dislocation of main equipments and various other complications due to excessive heat input in welding processes. Hence, automation of the work of welding is required and narrow-gap welding (NGW) process is being reviewed for new nuclear power plants as an alternative method of welding. In this study, transient heat transfer and thermo-elastic-plastic analyses have been performed for the residual stress distribution on the narrow gap weldment of RCL by finite element method under various conditions including surface heat flux and temperature dependent thermo-physical properties.

Influence of Preheating Temperature on Mechanical Properties of Laser Cladding Layer

2016 ◽  
Author(s):  
Jibin Jiang ◽  
Guofu Lian ◽  
Mingsan Xu ◽  
Chunyu Li ◽  
Bingsan Chen ◽  
...  
Keyword(s):  
Residual Stress ◽  
Laser Cladding ◽  
Heat Affected Zone ◽  
Processing Parameters ◽  
Cladding Layer ◽  
Laser Cladding Process ◽  
Preheating Temperature ◽  
Substrate Preheating ◽  
Physical And Chemical ◽  
Cladding Layers

Physical and chemical changes always occur in the process of laser cladding, and the cladding quality is directly affected by processing parameters. This paper mainly focused on effects of temperature field of preheating substrate on the cladding quality. Laser cladding process has the following experimental parameters: laser power, powder feeding rate and rotational speed. Three types of cladding powders were used: Ni60A, Cr12MoV and WC-Co. Experiments were conducted by using different substrate preheating temperatures and cladding materials, which affect the quality of cladding layers. Comparison and analysis of the three types of powders showed that under different preheating temperatures, the cladding layer is mainly affected by tensile stress. Besides that, the residual stress of cladding layer is always higher than that of heat affected zone and substrates. The best preheating temperature to test the residual stress for three types of powders are: 600°C, 400°C and 300°C. For all three types of powders under different preheating temperatures, cladding layer and substrate have compact and uniform structures. However, when substrate is overheated the cracking will occur in the substrate. Under different preheating temperatures, the Vickers hardness is higher than that of heat affected zone and the substrate for all three materials. The preheating temperatures for getting the maximum hardness are respectively 300°C, 600°C and 400°C.

scholarly journals Finite Element Analysis and Experimental Evaluation of Residual Stress of Zr-4 alloys Processed through Swaging

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1281 ◽  
Author(s):  
Gaurav Singh ◽  
Bijit Kalita ◽  
K. I. Vishnu Narayanan ◽  
Umesh Kumar Arora ◽  
Manas M. Mahapatra ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Nuclear Power ◽  
Zirconium Alloy ◽  
True Strain ◽  
Three Dimensional ◽  
Element Model ◽  
Hole Drilling ◽  
Element Analysis ◽  
Hole Drilling Method

Zirconium alloy has been extensively used as a cladding material in nuclear power reactors due to its low neutron absorption cross section, excellent mechanical properties, and corrosion resistance. The influence of the swaging parameter, feed rate (0.7, 1.25, 2 m/min) on residual stress induced in Zr-4 alloy is investigated in the present work. A three-dimensional finite element model was implemented in the Deform 3D software to simulate the rotary swaging (RS) process over a circular rod of Zr-4 alloy. The simulation results based on the 3D framework provide a detailed insight of residual stress, true stress versus true strain and force applied over the rod during the multiple pass swaging process; the results are compared with experimental results. The experimental hole drilling method is used to determine the residual stresses on swaged zirconium alloy at different feed rates (0.7, 1.25, and 2 m/min). A similar trend of residual stress between experimental and numerical results from the surface to the center on the swaged rod samples is observed. The same magnitude of residual stress at the surface of the swaged Zr-4 rod is also observed. It is found to be compressive at the surface and tensile in the center of the samples, as observed in the present work.

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