Effect of CBN Grinding on the Bending Strength of Carburized Gears

1998 ◽  
Vol 120 (4) ◽  
pp. 606-611 ◽  
Author(s):  
K. Inoue ◽  
H. Sonoda ◽  
G. Deng ◽  
M. Yamanaka ◽  
M. Kato
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
Bending Strength ◽  
Surface Condition ◽  
Ground Surface ◽  
Tooth Surface ◽  
Test Results ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Carburized Gear

The surface condition of a carburized gear is improved by CBN grinding, in addition to the generation of a compressive residual stress at the ground surface. To clarify the effect of these merits on the strength enhancement, a bending fatigue test is performed for the carburized and the CBN-ground gears. The fillet as well as involute tooth surface is ground by an electroplated threaded CBN wheel. The low axial feed rate and the spark-out treatment are effective in improving the surface finish and increasing the compressive residual stress, and the strengths of CBN-ground gears are increased from 100 MPa to 160 MPa in comparison with the carburized gears. Moreover, the test results are discussed on the basis of the fracture mechanics-based strength evaluation which has been proposed by the authors. This analysis demonstrates that the influence of CBN grinding on strength is smaller than the effects of surface-treatments such as shot peening and chemical polishing.

scholarly journals Experimental Analysis of Residual Stress and Bending Strength of Gear Tooth Surface after Shot Peening Treatment

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Dong Liang ◽  
Sheng Meng ◽  
Yi Chen ◽  
Chengli Hua
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Shot Peening ◽  
Bending Strength ◽  
Gear Tooth ◽  
Tooth Surface ◽  
Bending Fatigue ◽  
Gear Teeth ◽  
Tooth Surfaces ◽  
Bending Fatigue Strength

The fatigue strength of a gear tooth surface is affected by various factors, which subsequently impacts the transmission performance of gears. Usually, shot peening treatment is carried out during processing to improve the performance of gears. Most current studies focus on theoretical descriptions and simulation analyses of shot peening treatment. However, in this paper, the relationships among shot peening treatment, residual stress, and bending fatigue strength of a gear tooth surface are discussed, through experimental methods. Based on X-ray stress analysis, at select locations on the test samples, the residual stresses on gear tooth surfaces with and without shot peening treatment are determined and contrasted. The results show that shot peening treatment can effectively increase the residual stress on gear tooth surfaces. In addition, an electromagnetic resonance fatigue tester is used to analyze the bending fatigue strength of gear tooth surfaces. The test results indicate that the bending fatigue strength of the gear teeth with shot peening is higher than that of the gear teeth without shot peening. The obtained conclusions lay the foundation for further practical engineering applications of gears.

Bending Strength of Carburized Forged Spur Gear

2007 ◽  
Author(s):  
Masashi Yamanaka ◽  
Shinji Miwa ◽  
Katsumi Inoue ◽  
Yoshiki Kawasaki
Keyword(s):  
Fatigue Strength ◽  
Fatigue Test ◽  
Bending Strength ◽  
Surface Hardness ◽  
Spur Gear ◽  
Bending Fatigue ◽  
Precision Forging ◽  
Bending Fatigue Test ◽  
Bending Fatigue Strength ◽  
Gear Profile

This paper deals with the evaluation of influence of the manufacturing methods precision forging and conventional hobbing on the bending fatigue strength of carburized gears. The forging has advantages in productivity and strength. The forged gear has a continuous directed fiber flow which runs along the gear profile. To clarify the effect of strength enhancement, a bending fatigue test is performed for the forged and the hobbed gears. The material of test gears is SCr420H in the JIS and all gears are carburized. The electrohydraulic servo-controlled fatigue tester is used in the constant stress-amplitude fatigue test. The strength is expressed by the fillet stress level, which is calculated by FEM. The obtained strengths of forged and hobbed gear are 1613 MPa and 1490 MPa, respectively. The strength of forged gear is increased 8% in comparison with that of the hobbed gear. The surface hardness is higher and the surface roughness is smaller in the forged gear, however, the residual stress is approximately same. The effect of improvement of the roughness by forging on the strength is small in 1%, and the main reason of the improvement of fatigue strength is considered as the continuous fiber flow.

Effect of Superficial Residual Stresses on Abrasive Wear Resistance of Al2O3 / Al2O3+3Y-TZP Multilayers

2005 ◽  
Vol 502 ◽  
pp. 217-224
Author(s):  
Goffredo de Portu ◽  
L. Micele ◽  
D. Prandstraller ◽  
G. Palombarini ◽  
Giuseppe Pezzotti
Keyword(s):  
Residual Stress ◽  
Wear Resistance ◽  
Residual Stresses ◽  
Abrasive Wear ◽  
Compressive Stress ◽  
Compressive Residual Stress ◽  
Tape Casting ◽  
Cold Isostatic Pressing ◽  
Abrasive Wear Resistance ◽  
Test Results

Multilayered composite specimens consisting of Al2O3 / Al2O3+ 3Y-TZP (A/AZ) layers with different compositions and thicknesses were prepared starting from ceramic sheets obtained by tape casting. Residual stresses arisen from mismatch in thermal expansion coefficient during sintering were evaluated using luminescence piezo-spectroscopy. The stress in the superficial A layer was found to be compressive, and its value depended on the ratio between thickness of A and AZ layer. The influence of the superficial compressive stress on the abrasive wear resistance was investigated using microscale ball cratering test; results were correlated with the superficial compressive stress and compared with a specimen of pure unstressed Al2O3 prepared both by lamination and by cold isostatic pressing. Experiments show an improvement of performances in the samples containing compressive residual stress in the surface.

High Dynamic Mechanical Strength of Zirconium-Based Bulk Amorphous Alloys

1998 ◽  
Vol 554 ◽  
Author(s):  
Tao Zhang ◽  
Akihisa Inoue
Keyword(s):  
Residual Stress ◽  
Mechanical Strength ◽  
Amorphous Alloys ◽  
Compressive Residual Stress ◽  
Bending Strength ◽  
Tensile Fracture ◽  
Uniaxial Tensile ◽  
Cast Sample ◽  
Bulk Amorphous Alloys ◽  
Squeeze Cast

AbstractA bulk amorphous Zr55Al10Ni5Cu30 alloy prepared by squeeze casting was found to exhibit high mechanical strength values, i.e., uniaxial tensile fracture strength (σt) of 1850 MPa, three-point bending strength (σb) of 3200 MPa, bending fatigue strength (σf) of 1100 MPa, Charpy impact fracture energy (Ef) of 135 kJ/m2 and fracture toughness of 68 MPa√m. The σb, σf and Ef are about two times higher than those for the corresponding bulk amorphous alloys prepared by unidirectional solidification and powder consolidation techniques, though the σt of the squeeze cast sample is higher by about 15 % than those for the other samples. The remarkable increases in the σb, σf and EF are presumably due to the introduction of high compressive residual stress of about 1240 MPa in the outer surface region only for the squeeze cast sample. The finding of the effectiveness of the compressive residual stress on the increase in the mechanical strength under the bending stress mode is important and expected to be widely used as a new strengthening mechanism for bulk amorphous alloys, as is the case for reinforced oxide glasses subjected to strengthening treatment.

A Study on the Improvement of Durability of Gear Steel by Shot Peening

2006 ◽  
Vol 321-323 ◽  
pp. 662-665 ◽  
Author(s):  
Dong Sun Lee ◽  
Tae Hyung Kim ◽  
Jae Heon Lee ◽  
Tae Kun Lee ◽  
Seong Kyun Cheong
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Spur Gear ◽  
Sem Image ◽  
Gear Steel ◽  
Ball Velocity ◽  
Bending Fatigue Test ◽  
Fatigue Characteristics

In this paper the fatigue life of spur gear was investigated by changing the shot peening condition. From bending fatigue test depending on various shot peening intensity, fatigue characteristics were investigated. The causes of reduction in fatigue life were analyzed by observing the surface of gear with Scanning Electron Microscope(SEM), and impact of residual stress to fatigue characteristics was identified by measuring compressive residual stress depending peening intensity by depth. The results show that the optimum shot ball velocity is 65 m/s and optimum peening time is 8 minutes. From SEM image, the micro-crack was observed at the surface in case of over peening. This seems to be the factor which reduces fatigue life by decreasing compressive residual stress of surface.

Studying on the Propagation Behavior of Bent Crack Bending from Slant Pre-Crack with Compressive Residual Stress

2012 ◽  
Vol 433-440 ◽  
pp. 6558-6564
Author(s):  
You Li Ma
Keyword(s):  
Residual Stress ◽  
Mixed Mode ◽  
Compressive Residual Stress ◽  
Intensity Factors ◽  
Slant Angle ◽  
Fracture Angle ◽  
Bending Fatigue ◽  
Stress Criterion ◽  
Propagation Behavior ◽  
Discontinuous Displacement

For a slant pre-crack under mixed-mode conditions, a method is proposed in which mode Ⅰ and mode Ⅱ stress intensity factors ‹KI›mes and ‹KII›mes can be directly evaluated from the discontinuous displacement along it. The effect on fatigue pre-crack deformation behavior was discussed by comparing fatigue and annealed cracks. In general, using the biggest tangential stress criterion the direction propagating from the pre-cracks can be predicted by ‹KI›mes and ‹KII›mes calculated above. So testing for bending fatigue crack propagation under mixed-mode conditions was carried out using fatigue and annealed slant pre-cracks with slant angle β=450 defined as the angle between loading and pre-crack direction in a rectangular plate. As a result, for annealed pre-crack, the estimated fracture angle θestcorresponded to the measured oneθmes ; On the other hand, for fatigue pre-crack,θmes is bigger than θest because of the compressive residual stress around the pre-crack .

Residual Stress in a Quenched Gear Shaft Treated by Water Cavitation Peening

2005 ◽  
Vol 490-491 ◽  
pp. 364-369 ◽  
Author(s):  
H. Tsuda ◽  
Dong Ying Ju ◽  
T. Uchiyama ◽  
Y. Sunayama ◽  
R. Oba
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Compressive Residual Stress ◽  
Diffraction Method ◽  
Tooth Surface ◽  
Material Surface ◽  
Process Conditions ◽  
Strengthening Effect ◽  
Surface Strength ◽  
Surface Strengthening

Water cavitation technique can be applied to modify the surface strength of materials as an attractive new peening route. By inducing cavitation of ultrahigh speed water due to water-jet, the numerous impacts induced by the cavitation bubbles impact can produce compressive residual stress on material surface in the similar way as that by shot peening. In the present paper, an automobile part of steel gear shaft with complex shape is processed by water peening process. Compressive residual stress induced by water peening was measured to investigate the surface strengthening effect as a quantitative factor. The residual stresses on the tooth surface of the gear are measured by X-ray diffraction method. The effect of process conditions such as water outlet pressure, standoff distance of the nozzle, and peening time are discussed. To investigate the effect of heat treatment, carburizing-quenching is implemented to the gear shaft. By comparing the residual stresses of the tooth before and after water peening, the effectiveness of water peening process on surface strengthening is verified for a quenched gear shaft.

Improvement of Fatigue Properties in a Cast Aluminum Alloy by Roller Burnishing and Friction Stir Processing

2014 ◽  
Vol 891-892 ◽  
pp. 662-667 ◽  
Author(s):  
Yuki Nakamura ◽  
Masaki Nakajima ◽  
Hiroaki Masuda ◽  
Toshifumi Kakiuchi ◽  
Yoshihiko Uematsu
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Friction Stir Processing ◽  
Compressive Residual Stress ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Bending Fatigue ◽  
Friction Stir

Roller burnishing (RB) and friction stir processing (FSP) were applied to a cast aluminum alloy, AC4CH-T6 (equivalent to A356-T6), to improve the fatigue properties. In roller burnished specimens, Vickers hardness was increased until the depth of 60μm compared with that of the as-cast specimens, resulting in work-hardening by RB. The compressive residual stress on the surface of the roller burnished specimens was also increased from 35MPa to 132MPa. In order to investigate the effect of RB on the fatigue properties, rotary bending fatigue tests have been performed using the roller burnished and the as-cast specimens. The roller burnished specimens exhibited higher fatigue strength than the untreated specimens. It is due to the increase in hardness and compressive residual stress by RB. In addition, plane bending fatigue tests have been performed using the friction stir processed and untreated specimens. Fatigue strengths of the friction stir processed specimens were highly improved compared with untreated specimens as the results of the elimination of casting defects by FSP. However, the crack growth rates of the friction stir processed specimens were faster than those of untreated specimens. It is due to the softening of the material by heat input during the FSP.

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