Residual stresses in surface layers of carbide tool tips after diamond grinding

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

Structural transformation and residual stresses in surface layers of α + β titanium alloys nanotextured by femtosecond laser pulses

Applied Physics A ◽

10.1007/s00339-014-8954-6 ◽

2014 ◽

Vol 119 (1) ◽

pp. 241-247 ◽

Cited By ~ 20

Author(s):

Yu. R. Kolobov ◽

E. V. Golosov ◽

T. N. Vershinina ◽

M. V. Zhidkov ◽

A. A. Ionin ◽

...

Keyword(s):

Femtosecond Laser ◽

Residual Stresses ◽

Titanium Alloys ◽

Structural Transformation ◽

Laser Pulses ◽

Femtosecond Laser Pulses ◽

Surface Layers

Application of the Finite Element Method for Modelling of the Spatial Distribution of Residual Stresses in Hybrid Surface Layers

Mechanical and Materials Engineering of Modern Structure and Component Design - Advanced Structured Materials ◽

10.1007/978-3-319-19443-1_5 ◽

2015 ◽

pp. 51-69

Author(s):

Tomasz Tański ◽

Krzysztof Labisz ◽

Wojciech Borek ◽

Marcin Staszuk ◽

Zbigniew Brytan ◽

...

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Spatial Distribution ◽

Residual Stresses ◽

The Finite Element Method ◽

Surface Layers ◽

Element Method

Macro and micro scale modeling of thermal residual stresses in metal matrix composite surface layers by the homogenization method

Computational Mechanics ◽

10.1007/s004660050168 ◽

1997 ◽

Vol 19 (3) ◽

pp. 188-202 ◽

Cited By ~ 41

Author(s):

D. Golanski ◽

K. Terada ◽

N. Kikuchi

Keyword(s):

Residual Stresses ◽

Metal Matrix Composite ◽

Matrix Composite ◽

Metal Matrix ◽

Homogenization Method ◽

Surface Layers ◽

Composite Surface ◽

Micro Scale ◽

Thermal Residual Stresses ◽

Scale Modeling

A method of determining axial residual stresses in metal surface layers

Wear ◽

10.1016/0043-1648(69)90499-2 ◽

1969 ◽

Vol 13 (1) ◽

pp. 75-76

Keyword(s):

Residual Stresses ◽

Metal Surface ◽

Surface Layers

Effect of residual stresses in surface layers on the properties of steel 30KhGSA

Metal Science and Heat Treatment ◽

10.1007/bf00769423 ◽

1987 ◽

Vol 29 (4) ◽

pp. 258-261

Author(s):

V. A. Cheremkhin

Keyword(s):

Residual Stresses ◽

Surface Layers ◽

Steel 30Khgsa

Hot-filament Chemical Vapour Deposition of Microcrystalline Diamond Layers for Grinding Applications

10.14293/p2199-8442.1.sop-matsci.pxdfui.v1 ◽

2015 ◽

Author(s):

Jan Gaebler ◽

Markus Höfer ◽

Markus Armgardt ◽

Sven Pleger ◽

Lothar Schäfer

Keyword(s):

Chemical Vapour ◽

Cvd Diamond ◽

Grit Size ◽

Grinding Wheel ◽

Work Piece ◽

Carbide Tool ◽

Grinding Wheels ◽

Micro Cutting ◽

Diamond Grinding ◽

Hot Filament

Rough, microcrystalline CVD diamond layers are under research for many years for grinding applications. This contribution will present an overview about the results, both for film development and for application tests. The crystallite protrusions of microcrystalline CVD diamond layers act as micro cutting edges. Thus, the CVD diamond film forms a grinding layer on tools for abrasive machining, like grinding wheels or abrasive pencils (burrs, points). Such grinding layers have significant advantages compared to conventional diamond grinding layers, which are formed by bonding of diamond grains onto the tool base body. The development comprises CVD diamond layers that have been deposited on silicon nitride and silicon carbide tool base bodies with diameters up to 290 mm to form grinding wheels. For the preparation of the diamond layers our unique large-scale hot-filament CVD reactor with a coating area of 1000 mm × 500 mm was used which is already industrialized for the production of diamond electrodes, face seals, and bearings, respectively. The process was adjusted to achieve film thicknesses of 20 µm with tolerances below ±1 µm over the full grinding wheel area. The height of the crystallite protrusions was up to 4 µm; this protrusion corresponds to a grit size of D 12 for conventional bonded diamond grinding layers. The grinding wheels achieved a much better workpiece roughness in the machining of glass, alumina, and cermets. It is assumed that this is due to the number of protrusions, which is by factor of 2 to 7 higher compared to bonded grinding layers, depending on the grit size. Additionally the CVD diamond grinding wheels showed a strongly reduced wear rate. It was 10 to 80 times lower compared to conventional bonded diamond grinding layers. This improvement is due to the much higher number of diamond micro cutting edges and the larger diamond volume that can withstand the wear for a longer time. Furthermore a process technique was developed to regenerate worn CVD diamond layers. During machining the diamond crystallite tips are flattened. It was shown that a short epitaxial-like CVD process is able to recreate the crystallite tips without a significant increase of crystallite size. In such a way the CVD grinding tool can be re-sharpened and re-used. Grinding tests have shown that the machining performance is the same as for newly coated CVD grinding layers. The contribution will also present the development of micro abrasive pencils with CVD diamond coating. Microcrystalline CVD diamond layers have been deposited on cemented carbide tool base bodies with cylindrical tip shape. Due to the ability of the CVD process to coat complex substrate geometries the tools have been coated very uniformly. The abrasive pencils were tested and showed low work piece roughness and very long tool life times. The smallest abrasive pencil that was developed and tested successfully had a diameter of 0.05 mm. The presentation will be complemented by results of the development of honing tools.

Fatigue improvement of welded elements by ultrasonic impact treatment

Zavarivanje i zavarene konstrukcije ◽

10.5937/zzk2004179k ◽

2020 ◽

Vol 65 (4) ◽

pp. 179-190

Author(s):

Yuir Kudryavtsev

Keyword(s):

Mechanical Properties ◽

Fatigue Life ◽

Fatigue Strength ◽

Residual Stresses ◽

Large Scale ◽

Fatigue Testing ◽

Fatigue Improvement ◽

Surface Layers ◽

Ultrasonic Impact Treatment ◽

Stress Relieving

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of tensile residual stresses and introducing of compressive residual stresses into surface layers of a material. The secondary factors in fatigue improvement by UIT/UP are decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. Fatigue testing of welded specimens showed that UIT/UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UIT/UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The results of fatigue testing of large-scale welded specimens in as-welded condition and after application of UIT/UP are considered in this paper. It is shown that UIT/UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.