scholarly journals Effect of Oxide Scale on Hot Dip Zn-Al-Mg Alloy Coating Prepared by Reduction Combined with Induction Heating

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1519
Author(s):  
Yijie Zhang ◽  
Minyun Xu ◽  
Ruina Ma ◽  
An Du ◽  
Yongzhe Fan ◽  
...  
Keyword(s):  
Oxide Scale ◽  
Surface Quality ◽  
Induction Heating ◽  
Ternary Eutectic ◽  
Alloy Coating ◽  
Eutectic Structure ◽  
Scale Thickness ◽  
Rapid Induction ◽  
Fe4al13 Phase

Hot dipping Zn-Al-Mg coatings were prepared by rapid induction heating combined with gas protection. The influence of oxide scale on the structure and surface quality of a hot-dip Zn-6Al-3Mg alloy coating was studied in this paper. The results showed that the reaction of Fe-Al was suppressed by the scale on the surface of the steel plate. When the thickness of scale was 10 μm and the steel entry temperature was 900 °C, the surface quality of the coating was good. The Zn-Al-Mg coatings mainly consisted of the ternary eutectic structure of Zn/Al/MgZn2 and Fe4Al13 at the interface. When the scale thickness was 2–3 μm with the same steel entry temperature, the surface quality of the coating was poor, and serious stripe-like protrusion defects were formed on the surface of the coating, which was mainly caused by the Fe4Al13 phase separating from the substrate / coating interface into the overlay.

scholarly journals Scale Formation on HSLA Steel during Continuous Casting Part I: The Effect of Temperature–Time on Oxidation Kinetics

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1243 ◽  
Author(s):  
Rosa Maria Pineda Huitron ◽  
Pavel Ernesto Ramírez López ◽  
Esa Vuorinen ◽  
Pooria Nazen Jalali ◽  
Leonardo Pelcastre ◽  
...  
Keyword(s):  
Water Vapor ◽  
Continuous Casting ◽  
Oxide Scale ◽  
Surface Quality ◽  
Hsla Steel ◽  
Effect Of Temperature ◽  
Dry Air ◽  
Oxidation Rates ◽  
Steel Slabs

The findings in this work enhance the understanding of oxidation mechanisms and scale growth at high temperatures of a high strength low alloy (HSLA) steel for improving surface quality during continuous casting. The oxidation phenomenon was investigated under dry air and water vapor atmospheres by heating specimens at 1000, 1100, and 1200 °C at different holding times. Temperature and time had great effects on the kinetics, where faster (i.e., parabolic) oxidation rates were present under water vapor when compared with the dry air condition. Temperature strongly influenced the number of defects, such as pores, voids, gaps and micro-cracks, formed in the oxide scale. A phase analysis confirmed the presence of FeO as the first phase formed at the steel surface, Fe3O4 as the middle and thicker phase, and Fe2O3 as the last phase formed in the oxide/air interface. The micromechanics of the oxides demonstrated that a combination of phases with high (wüstite) and low plasticity (magnetite and hematite) could also have been the reason for the uneven cooling during Continuous Casting (CC) that resulted in the undesired surface quality of the steel slabs. This work gives a good look at the oxide scale effect on the surface quality of steel slabs through an understanding the kinetics during oxidation.

scholarly journals Novel Terahertz Nondestructive Method for Measuring the Thickness of Thin Oxide Scale Using Different Hybrid Machine Learning Models

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 805
Author(s):  
Zhou Xu ◽  
Dongdong Ye ◽  
Jianjun Chen ◽  
Haiting Zhou
Keyword(s):  
Machine Learning ◽  
Oxide Scale ◽  
Surface Quality ◽  
Time Domain ◽  
Gaussian White Noise ◽  
Machine Learning Algorithms ◽  
Effective Control ◽  
The Novel ◽  
Thin Oxide

Effective control of the thickness of the hot-rolled oxide scale on the surface of the steel strip is very vital to ensure the surface quality of steel products. Hence, terahertz nondestructive technology was proposed to measure the thickness of thin oxide scale. The finite difference time domain (FDTD) numerical simulation method was employed to obtain the terahertz time-domain simulation data of oxide scale with various thickness (0–15 μm). Added Gaussian white noise with a Signal Nosie Reduction (SNR) of 10 dB was used when simulating real test signals, using four wavelet denoising methods to reduce noise and to compare their effectiveness. Two machine learning algorithms were adopted to set up models to achieve this goal, including the classical back-propagation (BP) neural network algorithm and the novel extreme learning machine (ELM) algorithm. The principal component analysis (PCA) algorithm and particle swarm optimization (PSO) algorithm were combined to reduce the dimensions of the terahertz time-domain data and improve the robustness of the machine learning model. It could be clearly seen that the novel hybrid PCA-PSO-ELM model possessed excellent prediction performance. Finally, this work proposed a novel, convenient, online, nondestructive, noncontact, safety and high-precision thin oxide scale thickness measuring method that could be employed to improve the surface quality of iron and steel products.

Schwingungsüberlagertes Axialformen/Superimposed Oscillated Axial Forming

2020 ◽  
Vol 110 (11-12) ◽  
pp. 838-843
Author(s):  
Philipp Müller ◽  
Bernd-Arno Behrens ◽  
Sven Hübner ◽  
Hendrik Vogt ◽  
Daniel Rosenbusch ◽  
...  
Keyword(s):  
Surface Quality ◽  
Economic Importance ◽  
Combined Effect ◽  
Wird Eine ◽  
Forming Force ◽  
Forming Process ◽  
Forming Technology ◽  
Great Economic Importance ◽  
Gear Geometry

Techniken zur Steigerung der Formgebungsgrenzen in der Umformtechnik sind von hoher wirtschaftlicher Bedeutung. In dieser Arbeit wird eine Schwingungsüberlagerung im Krafthauptfluss eines Axialformprozesses zur Ausprägung einer Verzahnungsgeometrie untersucht. Die Auswirkungen der Schwingung auf die erzielbare Ausfüllung der Zahnkavitäten werden analysiert sowie die Parameter Schmierung und Oberflächengüte der Halbzeuge in ihrer kombinierten Wirkung untersucht. Es konnte eine Reduzierung der mittleren Umformkraft sowie eine Erhöhung der Formfüllung festgestellt werden. Techniques for extending the production limits in forming technology are of great economic importance. In this research, a superimposed oscillation in the main force flow of an axial forming process to form an axial gear geometry is investigated. The effects of the superimposed oscillation on the achievable form-filling of the tooth cavities are analyzed and the parameters lubrication and surface quality of the semi-finished products are investigated in their combined effect. A reduction of the averaged forming force as well as an increase of the form-filling could be achieved.

scholarly journals Face Grinding Surface Quality of High Volume Fraction SiCp/Al Composite Materials

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Xu Zhao ◽  
Yadong Gong ◽  
Guiqiang Liang ◽  
Ming Cai ◽  
Bing Han
Keyword(s):  
Friction Coefficient ◽  
Surface Morphology ◽  
Surface Quality ◽  
Volume Fraction ◽  
High Volume ◽  
Spindle Speed ◽  
High Volume Fraction ◽  
Machining Parameters ◽  
Al Composite

AbstractThe existing research on SiCp/Al composite machining mainly focuses on the machining parameters or surface morphology. However, the surface quality of SiCp/Al composites with a high volume fraction has not been extensively studied. In this study, 32 SiCp/Al specimens with a high volume fraction were prepared and their machining parameters measured. The surface quality of the specimens was then tested and the effect of the grinding parameters on the surface quality was analyzed. The grinding quality of the composite specimens was comprehensively analyzed taking the grinding force, friction coefficient, and roughness parameters as the evaluation standards. The best grinding parameters were obtained by analyzing the surface morphology. The results show that, a higher spindle speed should be chosen to obtain a better surface quality. The final surface quality is related to the friction coefficient, surface roughness, and fragmentation degree as well as the quantity and distribution of the defects. Lower feeding amount, lower grinding depth and appropriately higher spindle speed should be chosen to obtain better surface quality. Lower feeding amount, higher grinding depth and spindle speed should be chosen to balance grind efficiently and surface quality. This study proposes a systematic evaluation method, which can be used to guide the machining of SiCp/Al composites with a high volume fraction.

Simulation and Productive Practice of 60 Tons Huge Rectangular Ingot by Wind Cooling

2011 ◽  
Vol 233-235 ◽  
pp. 2714-2717
Author(s):  
Xin Gang Ai ◽  
Sheng Li Li ◽  
Dong Wei Zhang ◽  
Nan Lv ◽  
Jun Tao
Keyword(s):  
Mathematical Simulation ◽  
Surface Quality ◽  
Solidification Time ◽  
Special Method ◽  
Cooling Process ◽  
Heavy Plate ◽  
Simulation Results

Huge rectangular ingots becomes crying needs in the condition of lots of heavy plate mills more than 5m have been in operation. In this paper, a special method of wind cooling outside mould has been presented and applied to produce 60t rectangular ingot. Mathematical simulation results tell us that by wind cooling, the solidification time of the 60t ingot can be shortened by 67 minutes, internal soundness can be ensured. The wind cooling process can obviously improve microstructure and preventing skull patch by increasing the thickness of solidified shell. A 60 tons huge rectangular ingot is successfully produced by wind cooling, the surface quality of is very well and the internal soundness should be improved further.

Synthesis of high-temperature thermally expandable microcapsules and their effects on foaming quality and surface quality of foamed ABS materials

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 519-527
Author(s):  
Wei Gong ◽  
Xianglin Pei ◽  
Xiaogang Yin ◽  
Daming Ban ◽  
Hai Fu ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Quality ◽  
Volume Fraction ◽  
Crosslinking Agent ◽  
Acrylonitrile Butadiene Styrene ◽  
Foaming Agent ◽  
Blowing Agent ◽  
Good Surface ◽  
Butadiene Styrene

AbstractIn this paper, acrylonitrile and hydroxypropyl acrylate are used as the binary polymerization monomers, and isooctane is used as the foaming agent to prepare high-temperature thermally expandable microcapsules. Analysis of the effect of blowing agent and crosslinking agent on the expansion properties of high-temperature thermally expandable microcapsules, the effects of foaming agent azodicarbonamide (ADCA) and micro-expansion capsule on the surface quality and foaming quality of foamed acrylonitrile–butadiene–styrene (ABS) products were investigated. The foamed product prepared by the high-temperature microcapsule has a good surface quality, the gloss is 52.3, the cell is not easily deformed, and the volume fraction is 4%; the foamed ABS/ADCA material has poor cell uniformity, the cell is easily deformed, the volume fraction is 6.5%, the surface quality is poor, and the gloss is only 8.7.

Laser polishing to improve the surface quality of CoCr and Ti6AL4V additively manufactured parts

2017 ◽  
Author(s):  
Wojciech S. Gora ◽  
Yingtao Tian ◽  
Marcus Ardron ◽  
Philip Prangnell ◽  
Nicholas J. Weston ◽  
...  
Keyword(s):  
Surface Quality ◽  
Laser Polishing
Sign in / Sign up

Export Citation Format

Share Document