Investigation on Surface Finishing of Components Ground with Lapping Kinematics: Lapgrinding Process

2011 ◽  
Vol 223 ◽  
pp. 879-887 ◽  
Author(s):  
Arthur Alves Fiocchi ◽  
Luiz Eduardo de Angelo Sanchez ◽  
João Fernando Gomes de Oliveira ◽  
Ioan Marinescu
Keyword(s):  
Single Point ◽  
Surface Finishing ◽  
Grinding Wheel ◽  
Average Surface Roughness ◽  
Ultra Precision ◽  
Steel Aisi ◽  
Finishing Processes ◽  
Abrasive Process ◽  
Precision Finishing ◽  
Stainless Steel Aisi

Over the last three decades, researchers have responded to the demands of industry to manufacture mechanical components with geometrical tolerance, dimensional tolerance, and surface finishing in nanometer levels. The new lapgrinding process developed in Brazil utilizes lapping kinematics and a flat grinding wheel dressed with a single-point diamond dresser in agreement with overlap factor (Ud) theory. In the present work, the influences of different Ud values on dressing (Ud = 1, 3 e 5) and grain size of the grinding wheel made of silicon carbide (SiC = 800, 600 e 300 mesh) are analyzed on surface finishing of stainless steel AISI 420 flat workpieces submitted to the lapgrinding process. The best results, obtained after 10 minutes of machining, were: average surface roughness (Ra) 1.92 nm; 1.19 µm flatness deviation of 25.4 mm diameter workpieces and mirrored surface finishing. Given the surface quality achieved, the lapgrinding process can be included among the ultra-precision finishing processes and, depending on the application, the steps of lapping followed by polishing can be replaced by the proposed abrasive process.

scholarly journals SURFACE STATE EFFECT OF WELDED STAINLESS STEELS ON CORROSION BEHAVIOR

2016 ◽  
Vol 22 (1) ◽  
pp. 44 ◽  
Author(s):  
Tatiana Liptáková ◽  
Martin Lovíšek ◽  
Ayman Alaskari ◽  
Branislav Hadzima
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Passive Layer ◽  
Argon Atmosphere ◽  
Oxidation Products ◽  
Surface Finishing ◽  
Font Size ◽  
Steel Aisi ◽  
Stainless Steel Aisi

<p style="margin: 2pt 0cm; line-height: 12.5pt;"><span style="font-family: 'Times New Roman','serif'; mso-ansi-language: EN-US;" lang="EN-US"><span style="font-size: small;"><span style="color: #585858;">Welding joints of stainless steels are in practice very sensitive places attacked by local corrosion, such as pitting and crevice corrosion, mostly in chloride containing oxidizing environments. It is caused by different oxidation products created on the surface by welding. Corrosion resistance of stainless steels is affected by quality of passive layer (Cr<sub>2</sub></span></span><span style="color: #585858; font-size: small;">O</span><sub><span style="color: #585858; font-size: small;">3</span></sub><span style="color: #585858; font-size: small;">) which created at normal conditions on air. After welding the steels are heated and on the surface are originated different types of oxides which do not have the same protective properties. Resistance to </span><span style="letter-spacing: -0.2pt;"><span style="color: #585858; font-size: small;">intergranular</span></span><span style="color: #585858; font-size: small;"> and pitting corrosion of the welded stainless steels with different surface finishing was tested. Experimental materials are the austenitic stainless steel AISI 316L (welded by the TIG method in inert argon atmosphere with filler) and the ferritic stainless steel AISI CA6-NM (welded by the WPS method in inert argon atmosphere with filler and after welding heat treated). Character of the surface after welding and after finishing by grinding and pickling was evaluated by SEM microscopy, EDX analysis. Corrosion resistance to local forms of corrosion was investigated by electrochemical potentiodynamic test and by exposure tests in chloride solutions. The steel AISI CA6-NM was tested in fluvial water to simulate real operation environment. The evaluation is supported by microscopic analysis. Susceptibility to intergranular corrosion was tested too and results detect the dangerous localities for corrosion attack and show increasing of corrosion resistance by surface treatment. </span></span></p>

Finishing of Flat Parts Led by Lapping Kinematics on Abrasive Disc Dressed in Agreement With Overlap Factors

2008 ◽  
Author(s):  
L. E. A. Sanchez ◽  
N. Z. X. Jun ◽  
A. A. Fiocchi
Keyword(s):  
Single Point ◽  
Grinding Wheel ◽  
Additional Advantage ◽  
Workpiece Surface ◽  
Abrasive Grains ◽  
Set Up ◽  
Lapping Machine ◽  
Suitable Technique ◽  
Abrasive Process

This paper discusses the investigation of an abrasive process for finishing flat workpieces, based on the combination of important grinding and lapping characteristics. Instead of loose abrasive grains between the workpiece and the lapping plate, a resinoid grinding wheel of hot-pressed silicon carbide is placed on the plate of a device resembling a lapping machine. The resin bond grinding wheel is dressed with a single-point diamond. In addition to keeping the plate flat, dressing also plays the role of interfering in the behavior of the process by varying the overlap factor (Ud). It was found that the studied process simplify the set-up and can be controlled more easily than in lapping, whose is a painstaking process. The surface roughness and flatness deviation proved comparable to those of lapping, or even finer than it, with the additional advantage of a less contaminated workpiece surface with a shiny appearance. The process was also monitored by acoustic emission (AE), which indicates to be a promissing and suitable technique for use in this process.

Effect of Electrolyte on the Surface Smoothness Obtained by Electropolishing of Stainless Steel

2012 ◽  
Vol 713 ◽  
pp. 55-60 ◽  
Author(s):  
M. Hernando ◽  
Pedro Jose Núñez López ◽  
Eustaquio García Plaza ◽  
R. Trujillo
Keyword(s):  
Stainless Steel ◽  
Surface Finish ◽  
Chromic Acid ◽  
Bath Temperature ◽  
Surface Finishing ◽  
Initial Surface ◽  
Surface Finishes ◽  
Finishing Process ◽  
Steel Aisi ◽  
Stainless Steel Aisi

Electropolishing is a surface finishing process of metals and alloys that enhances brilliant surface finishes with low surface roughness values. The most widely used electrolytes for the electropolishing of stainless steel are varying concentrations of phosphoric and sulphuric acid, and occasionally additives such as chromic acid. The objective of this study was to assess the performance of three commonly used industrial electrolytes in terms of the surface finish of electropolished stainless steel AISI 316L. Each electrolyte had varying sulphuric-phosphoric acid combinations with or without chromic acid. The following electropolishing conditions were assessed: current density, bath temperature, electropolishing time, and initial surface texture. The results revealed that adding chromic acid to the electrolyte did not significantly enhance surface finish, and electropolishing ranges were quite similar for all three electrolytes.

Improvement of Machined Surface Flatness in Ultra-Precision Plane Honing

2005 ◽  
Vol 291-292 ◽  
pp. 359-364 ◽  
Author(s):  
Shinya Suzuki ◽  
Nobuhito Yoshihara ◽  
Tsunemoto Kuriyagawa
Keyword(s):  
Large Diameter ◽  
Contact Length ◽  
Optimum Shape ◽  
Surface Finishing ◽  
Grinding Wheel ◽  
Glass Wafer ◽  
Wheel Surface ◽  
Machined Surface ◽  
Surface Flatness ◽  
Ultra Precision

In recent years, there has been a great demand for large-diameter wafers with high flatness of hard and brittle materials that are used as optical and sensor elements. To meet these demands, we have developed an ultra-precision plane honing method as a highly efficient surface finishing technique using a fixed abrasive. This technique offers good finish surface roughness, shallow subsurface damage and high machining efficiency. However, there is a need to improve the surface flatness, which is dependent on the grinding wheel surface flatness and the tilt of the spindles. In this paper, the relationship between grinding wheel surface flatness and the shape of a truer is investigated by calculating the contact length of a point on the grinding wheel with the truer. It was found that there is an optimum shape of the truer to make the grinding wheel surface flat, and the machined 3-inch glass wafer is controlled to a flatness of less than 1µm by using the optimum truer.

Review of several precision finishing processes for optics manufacturing

2018 ◽  
Vol 1 (2) ◽  
pp. 170-188 ◽  
Author(s):  
Gourhari Ghosh ◽  
Ajay Sidpara ◽  
P. P. Bandyopadhyay
Keyword(s):  
Surface Finish ◽  
Single Point ◽  
Diamond Turning ◽  
Free Form ◽  
Shape Accuracy ◽  
Optical Components ◽  
Finishing Processes ◽  
Optics Fabrication ◽  
Free Form Surfaces ◽  
Precision Finishing

The ultrasmooth optical components with atomic-order surface roughness and nanometre-level shape accuracy are in immense demand with the rapid advancement of modern optical technology. In recent years, aspherical and free-form surfaces are gaining more interest for its favorable properties. Moreover, the new optical materials with immensely enhanced mechanical properties are being developed to meet the stringent requirements of modern optics. Fabrication of complex-shaped ultrasmooth optical components becomes a significant challenge as conventional finishing techniques are unable to machine aspherical or free-form surfaces precisely. This situation demands some highly deterministic finishing processes. Mostly, the optical components are fabricated by shaping or pre-finishing methods followed by final finishing processes. In the shaping or pre-finishing methods, the rigid abrasive tools are used to remove the material at an enhanced rate and near net shape of the elements can be attained. Surface finish and shape accuracy can also be improved to some extent. Owing to the presence of residual finishing marks generated by shaping methods, the application of the components is limited to the infrared (IR) optics. Final finishing processes include more deterministic and flexible polishing techniques that can achieve desired surface finish, figure accuracy and surface integrity to make it suitable for shorter wavelength applications. In recent years, single point diamond turning, precision grinding, plasma chemical vaporization machining and magnetorheological fluid-based finishing are widely used for fabricating ultrasmooth optics. In this article, principle, mechanism of material removal and applicability of the aforementioned precision finishing processes to different materials are discussed.

Study of Ultra-precision Finishing Techniques for Brittle Materials

2018 ◽  
Vol 6 (6) ◽  
pp. 197
Author(s):  
Partap Singh Samra ◽  
Sehijpal Singh ◽  
Lakhvir Singh
Keyword(s):  
Brittle Materials ◽  
Dimensional Accuracy ◽  
Electronic Industry ◽  
Finishing Process ◽  
Hard And Brittle Materials ◽  
Ultra Precision ◽  
Finishing Processes ◽  
Final Surface Finish ◽  
Precision Finishing ◽  
Crucial Parameter

Wide application of hard and brittle advanced ceramics, glasses and semiconductors in Mechanical, Optical and Electronic industry has led to the development of new ultra-precision finishing processes. With an increase in the applications of these materials, the need of finishing these materials has also become a great challenge. Dimensional and finish accuracies are the parameters that needs to be focused and improved with minimum time and cost. Another crucial parameter is the subsurface damages that are quiet common with these materials during finishing process.  New processes have been developed to overcome the drawbacks of the existing processes for Nano finishing. These processes can be classified as Conventional, Precision and Ultra-precision finishing based on the degree of dimensional accuracy and final surface finish. Both loose and bonded abrasives have been used for these processes. This paper deals with the study of some of the significant advances in ultra-precision finishing processes of hard and brittle materials.

Synthesis and characterization of TiN / Ti / AISI 410 coatings

2018 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
S Chirino ◽  
Jaime Diaz ◽  
N Monteblanco ◽  
E Valderrama
Keyword(s):  
Synthesis And Characterization ◽  
Photoemission Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Columnar Grains ◽  
Tin Thin Films ◽  
Steel Aisi ◽  
Interacting Surfaces ◽  
Stainless Steel Aisi

The synthesis and characterization of Ti and TiN thin films of different thicknesses was carried out on a martensitic stainless steel AISI 410 substrate used for tool manufacturing. The mechanical parameters between the interacting surfaces such as thickness, adhesion and hardness were measured. By means of the scanning electron microscope (SEM) the superficial morphology of the Ti/TiN interface was observed, finding that the growth was of columnar grains and by means of EDAX the existence of titanium was verified.  Using X-ray diffraction (XRD) it was possible to observe the presence of residual stresses (~ -3.1 GPa) due to the different crystalline phases in the coating. Under X-ray photoemission spectroscopy (XPS) it was possible to observe the molecular chemical composition of the coating surface, being Ti-N, Ti-N-O and Ti-O the predominant ones.

AL TECH MIAMI

Alloy Digest ◽  
1983 ◽  
Vol 32 (11) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Heat Treating ◽  
Good Resistance ◽  
Aisi Type ◽  
Steel Aisi ◽  
Resistance To Wear ◽  
Specialty Steel ◽  
Stainless Steel Aisi ◽  
Plastic Mold

Abstract AL TECH MIAMI is both a hardenable stainless steel (AISI Type 420) and a tool steel for making molds for plastic. A major requirement for plastic mold steel is corrosion resistance. Certain plastics, such as poly-vinyl chlorides, are very corrosive and stored molds often rust from sweating water lines and/or humid environments. AL TECH MIAMI has good resistance to wear. It is melted and AOD refined to assure the mold-maker of cleanliness and freedom from internal imperfections. It provides exceptionally good polishability for lens-quality molds. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: SS-435. Producer or source: AL Tech Specialty Steel Corporation.

scholarly journals Influence of Activated Fluxes on the Bead Shape of A-TIG Welds on Carbon and Low-Alloy Steels in Comparison with Stainless Steel AISI 304L

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 530
Author(s):  
Jerzy Niagaj
Keyword(s):  
Stainless Steel ◽  
Penetration Depth ◽  
High Strength ◽  
Tig Welding ◽  
Low Alloy Steels ◽  
Aisi 304L ◽  
A Tig Welding ◽  
Alloy Steels ◽  
Steel Aisi ◽  
Stainless Steel Aisi

The article presents results of comparative A-TIG welding tests involving selected unalloyed and fine-grained steels, as well as high-strength steel WELDOX 1300 and austenitic stainless steel AISI 304L. The tests involved the use of single ingredient activated fluxes (Cr2O3, TiO2, SiO2, Fe2O3, NaF, and AlF3). In cases of carbon and low-alloy steels, the tests revealed that the greatest increase in penetration depth was observed in the steels which had been well deoxidized and purified during their production in steelworks. The tests revealed that among the activated fluxes, the TiO2 and SiO2 oxides always led to an increase in penetration depth during A-TIG welding, regardless of the type and grade of steel. The degree of the aforesaid increase was restricted within the range of 30% to more than 200%.

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