scholarly journals The Mechanism of Corrosion–Erosion in Steam Extraction Lines of Power Stations

1988 ◽  
Vol 110 (2) ◽  
pp. 180-184 ◽  
Author(s):  
L. E. Sanchez-Caldera ◽  
P. Griffith ◽  
E. Rabinowicz
Keyword(s):  
Material Removal ◽  
Metal Removal ◽  
Removal Rate ◽  
Low Carbon Steel ◽  
Mass Transfer Process ◽  
Diffusion Resistance ◽  
Low Carbon ◽  
Wear Rates ◽  
Power Stations ◽  
Steam Extraction

Corrosion-erosion occurs in steam extraction piping made of low carbon steel that conveys wet steam. The rate of metal removal peaks at 150°C and is most severe on the inside and outside of bends and in the vicinity of fittings. A theory is presented by which three processes are shown to give rise to the observed peak in the metal removal rate: (1) the oxidation reaction, (2) the mass transfer process, which governs at 150°C, and (3) the diffusion resistance of the oxide layer, which governs at higher temperatures. The results of the derived model agree well with the available experimental data in predicting wear rates and in establishing the temperature and the location of maximum material removal.

Influence of Polarity of Electro Discharge Machine (EDM) on Surface Roughness (SR) and Metal Removal Rate (MRR) of Low Carbon Steel

2020 ◽  
Vol 38 (7A) ◽  
pp. 975-983
Author(s):  
Shahad A. Taqi ◽  
Saad K. Shather
Keyword(s):  
Surface Roughness ◽  
Metal Removal ◽  
Removal Rate ◽  
Low Carbon Steel ◽  
Negative Electrode ◽  
Tool Electrode ◽  
Metal Removal Rate ◽  
Low Carbon ◽  
Discharge Machine ◽  
Multiple Variables

Electro discharge machining (EDM) is one of a thermal process that is used for remove of metal from the workpiece by spark erosion. The work of this machine depends on multiple variables. One of the more influential variants on this machine is the change of polarity and the use of this variable is not wide and the research depends on the polarity of the machinist. Essentially, the polarity of the tool (electrode) is positive and the workpiece is negative, this polarity can be reversed. This paper  focuses on the influence of changing the polarity (positive and negative) on the surface roughness and metal removal rate by using different parameters (current, voltages, polarity and Ton). Experiments show that the positive electrode gives (best surface roughness = 1.56 µm when the current = 5 Am and Ton = 5.5 µs) and (best metal removal rate = 0.0180 g/min when the current = 8 Am and Ton = 25 µs). Negative electrode gives (best surface roughness = 0.46 µm when the current = 5 Am and Ton = 5.5 µs) and (best metal removal rate = 0.00291 g/min when the current = 8 Am and Ton = 25 µs).

scholarly journals EFFECT OF TURNING PARAMETERS ON METAL REMOVAL AND TOOL WEAR RATES OF AISI 1018 LOW CARBON STEEL

2016 ◽  
Vol 35 (4) ◽  
pp. 847 ◽  
Author(s):  
C Mgbemena ◽  
C Mgbemena ◽  
G Etebenumeh ◽  
F Ashiedu
Keyword(s):  
Carbon Steel ◽  
Tool Wear ◽  
Metal Removal ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Wear Rates

scholarly journals Investigation an assisting electrode powder mixed electrical discharge machining of nonconductive ceramic

2021 ◽  
Author(s):  
Dragan Rodic ◽  
Marin Gostimirovic ◽  
Milenko Sekulic ◽  
Borislav Savkovic ◽  
Branko Strbac
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Material Removal Rate ◽  
Electrical Discharge ◽  
Material Removal ◽  
Metal Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Positive Effects ◽  
Assisting Electrode

Abstract It is well known that electrical discharge machining can be used in the processing of nonconductive materials. In order to improve the efficiency of machining modern engineering materials, existing electrical discharge machines are constantly being researched and improved or developed. The current machining of non-conductive materials is limited due to the relatively low material removal rate and high surface roughness. A possible technological improvement of electrical discharge machining can be achieved by innovations of existing processes. In this paper, a new approach for machining zirconium oxide is presented. It combines electrical discharge machining with assisting electrode and powder-mixed dielectric. The assisting electrode is used to enable electrical discharge machining of nonconductive material, while the powder-mixed dielectric is used to increase the material removal rate, reduce surface roughness, and decrease relative tool wear. The response surface method was used to generate classical mathematical models, analyzing the output performances of surface roughness, material removal rate and relative tool wear. Verification of the obtained models was performed based on a set of new experimental data. By combining these latest techniques, positive effects on machining performances are obtained. It was found that the surface roughness was reduced by 18%, the metal removal rate was increased by about 12% and the relative tool wear was reduced by up to 6% compared to electrical discharge machining with supported electrode without powder.

Material Removal in WEDM of PCD Blanks

1994 ◽  
Vol 116 (3) ◽  
pp. 363-369 ◽  
Author(s):  
J. Kozak ◽  
K. P. Rajurkar ◽  
S. Z. Wang
Keyword(s):  
Material Removal ◽  
Thermal Stresses ◽  
Metal Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Polycrystalline Diamond ◽  
Advanced Materials ◽  
The Matrix ◽  
Diamond Grain ◽  
Pcd Tools

Polycrystalline diamond (PCD) tools are now widely used in machining a large variety of advanced materials. However, the manufacture of PCD tool blanks is not an economical and efficient process. The shaping of PCD blanks with conventional machining methods (such as grinding), is a long, labor-intensive and costly process. Wire electric discharge machining (WEDM) promises to be an effective and economical technique for the production of tools from PCD blanks. However, a knowledge base for wire electrical discharge machining of PCD blanks needs comprehensive investigations into the proper parameter setting, metal removal mechanisms, and surface integrity of machined blanks. This paper presents the results of experimental and theoretical investigations of the influence of discharge frequency and discharge energy on the material removal rate of WEDM of PCD blanks. The mechanism of removing diamond grains from the matrix during electrical erosion is also discussed on the basis of thermal stresses between the diamond grain and cobalt phase.

Effects of Electrical Process Parameters and Electrode Tool Geometries in EDM of Inconel825 Material Using Zirconium Copper Electrode

2015 ◽  
Vol 766-767 ◽  
pp. 668-673
Author(s):  
S. Senthamilperarasu ◽  
P. Padmini ◽  
B. Shanmuganathan ◽  
N.R.R. Anbusagar ◽  
P. Sengottuvel
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Metal Removal ◽  
Removal Rate ◽  
Optimization Technique ◽  
Copper Electrode ◽  
Experimental Result ◽  
Tool Geometry ◽  
Zirconium Copper ◽  
Inconel 825

The Electrical Discharge Machine (EDM), parameters are investigated during the machining of Inconel 825 by using different tool geometry of zirconium copper electrode. Demand for better MRR, SR, and lower Tool Wear Rate are increasing recently for all materials, the low rigidity and high material removal rate of Inconel alloy offers a challenging task in obtaining output responses. The analysis of output responses such as Metal Removal Rate (MRR) of Inconel 825 material is carried out an excellent result can be obtained by using Taguchi L16 Orthogonal Array under different conditions of Parameters. The response of MRR is considered for improving machining efficiency. Optimal combination of parameters was obtained Taguchi optimization technique. The confirmation experiments results shows that the significant improvement in output responses was obtained. ANOVA have been used to analyze the contribution of individual parameters on Material Removal Rate. The experimental result demonstrates that the Taguchi method satisfies the practical requirements.

Influence of Ultrasonic Wave, Argon Blowing and its Coordinated Treatment on the Nitrogen Content in Low Carbon Steel

2011 ◽  
Vol 402 ◽  
pp. 841-845
Author(s):  
Jie Li ◽  
Ling Li ◽  
Qi Xuan Rui ◽  
Jian Jun Wang ◽  
Hai Chuan Wang
Keyword(s):  
Carbon Steel ◽  
Nitrogen Content ◽  
Ultrasonic Wave ◽  
Nitrogen Removal ◽  
Molten Steel ◽  
Ultrasonic Treatment ◽  
Removal Rate ◽  
Low Carbon Steel ◽  
Low Carbon

Influence of ultrasonic wave, argon blowing agitating and their coordinated treatment on nitrogen content in low carbon steel was mainly studied. Results showed that ultrasonic wave, argon blowing or their coordinated treatment can all reduce the nitrogen content in low carbon molten steel. While treated with ultrasonic wave separately, removal rate of the nitrogen in molten steel is relatively low with 3.13%~9.04%. Using the argon blowing agitating separately, removal rate of the nitrogen in molten steel is relatively high with 6.89%~32.68%, when the argon blowing flow is 0.5 l/min, removal rate of nitrogen is 32.68%. The nitrogen removal effect of the ultrasonic wave-argon blowing agitating coordinated treatment is considerably improved than that of separately ultrasonic treatment. While 300 W ultrasonic wave and 0.5l/min argon blowing agitating cooperatively treatment on the low carbon molten steel, the removal rate of nitrogen is 26.95%.

Hydrodynamic Physical Modeling of Laser Drilling

2002 ◽  
Vol 124 (4) ◽  
pp. 852-862 ◽  
Author(s):  
D. K. Y. Low ◽  
L. Li ◽  
P. J. Byrd
Keyword(s):  
Material Removal ◽  
Laser Intensity ◽  
Low Carbon Steel ◽  
Laser Drilling ◽  
Low Carbon ◽  
Additional Energy ◽  
Complex Process ◽  
Threshold Time ◽  
Drilling Conditions ◽  
Melt Ejection

Laser drilling is a complex process that involves material removal through both vaporization and hydrodynamic melt ejection. The process is further complicated when an assist gas is incorporated, which is often the case under most practical drilling conditions. It is the intent of this article to investigate these effects through both experiments and theoretical analysis. The analysis accounts for conduction in the solid, vaporization, vaporization-induced recoil pressure melt ejection, convection due to the melt flow as well as the effects of using an O2 assist gas, which includes the effective assist gas pressure exerted on the melt surface, the forced convection cooling and the additional energy generated due to the oxidation of the melt surface by O2. The effects of the absorbed laser intensity on the melt surface temperature, melt ejection velocity and drilling velocity were studied for both cases of laser drilling with and without O2 assist gas and compared to experimental results obtained for EN3 low carbon steel. The dependence of threshold time on the absorbed laser intensity for either vaporization-dominated or melt ejection-dominated (hydrodynamic-dominated) material removal was studied and subsequently related to the threshold conditions for spatter formation. The model was subsequently optimized by examining the significance of the O2 effects considered.

Optimization of Cutting Conditions of YG15 on Finish Cutting in WEDM Based on Taguchi Method

2014 ◽  
Vol 887-888 ◽  
pp. 1195-1199
Author(s):  
Zhi Chen ◽  
Zhen Zhang ◽  
Wu Yi Ming ◽  
Hao Huang
Keyword(s):  
Taguchi Method ◽  
Material Removal Rate ◽  
Material Removal ◽  
Metal Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Machining Process ◽  
Machining Performance ◽  
Finish Cutting ◽  
Cutting Operation

Wire electrical discharge machining (WEDM) is extensively used in the mold, instrument and manufacturing industries, and rough cutting operation in WEDM is treated as a challenging process because improvement of more than one machining performance measures viz. metal removal rate (MRR), roughness (Ra) are sought to obtain a precision work. In this paper, first of all, a set of Taguchi experiment (L18 21×34) is carried out based on the Taguchi method. Secondly, two groups of ANOM are completed to obtain the influence trends of each parameters on material removal rate (MRR) and roughness (Ra), respectively. Eventually, three groups of best process parameters combination are acquired to meet high material removal rate (MRR) and low roughness (Ra) simultaneously, it can provide guiding significance to actual machining process.

scholarly journals Boride-Carbon Hybrid Technology for Ultra-Wear and Corrosive Conditions

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 475
Author(s):  
Nina Baule ◽  
Young S. Kim ◽  
André T. Zeuner ◽  
Lars Haubold ◽  
Robert Kühne ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Contact Fatigue ◽  
Low Carbon Steel ◽  
Single Layer ◽  
High Hardness ◽  
Low Carbon ◽  
Wear Properties ◽  
Wear Rates ◽  
Duplex Treatment ◽  
1045 Steel

This work discusses a study on a surface treatment for creating extremely durable low-friction, wear and corrosion-resistant surfaces for tribological components in harsh conditions. A duplex surface treatment was developed that combines the advantages of ultra-fast electrochemical boriding with those of hard tetrahedral amorphous carbon coatings. The friction and wear properties of the duplex treatment are compared to the boride-only treatment of AISI 1045 steel, while corrosion and contact fatigue behaviors of the duplex layer are compared to that of the single-layer carbon coating on low carbon steel. The duplex treatment yields wear rates as low as 6 × 10−8 mm3·N−1·m−1 and a coefficient of friction of 0.14 when tested against a steel counter face. The contact fatigue impact tests reveal that the high hardness of 1200 HV0.05 of the borided layer in the duplex treatment leads to higher resistance against indentation but is accompanied by a higher incidence of crack initiation, being in good agreement with the finite-element modeling of nanoindentation results. The duplex coatings exhibit resistance to pinhole corrosion as evidenced by a 3 h exposure to 15% HCl at room temperature.

Experimental investigation and multi-objective optimization approach for low-carbon milling operation of aluminum

2016 ◽  
Vol 231 (15) ◽  
pp. 2753-2772 ◽  
Author(s):  
Chaoyang Zhang ◽  
Weidong Li ◽  
Pingyu Jiang ◽  
Peihua Gu
Keyword(s):  
Performance Indicators ◽  
Regression Models ◽  
Material Removal ◽  
Carbon Emission ◽  
Removal Rate ◽  
Depth Of Cut ◽  
Optimization Approach ◽  
Low Carbon ◽  
Multi Objective Optimization ◽  
Milling Operation

In the past, milling operations have been mainly considered from the economic and technological perspectives, while the environmental consideration has been becoming highly imperative nowadays. In this study, a systemic optimization approach is presented to identify the Pareto-optimal values of some key process parameters for low-carbon milling operation. The approach consists of the following stages. Firstly, regression models are established to characterize the relationship between milling parameters and several important performance indicators, i.e. material removal rate, carbon emission, and surface roughness. Then, a multi-objective optimization model is further constructed for identifying the optimal process parameters, and a hybrid Non-dominated Sorting Genetic Algorithm-II algorithm is proposed to obtain the Pareto frontier of the non-dominated solutions. Based on the Taguchi design method, dry milling experiments on aluminum are performed to verify the proposed regression and optimization models. The experimental results show that a higher spindle speed and feed rate are more advantageous for achieving the performance indicators, and the depth of cut is the most critical process parameter because the increase of the depth of cut results in the decrease of the specific carbon emission but the increase of the material removal rate and surface roughness. Finally, based on the regression models and the optimization approach, an online platform is developed to obtain in-process information of energy consumption and carbon emission for real-time decision making, and a simulation case is conducted in three different scenarios to verify the proposed approach.

Sign in / Sign up

Export Citation Format

Share Document