FATIGUE CHARACTERISTICS OF SM490A WELDED JOINTS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4141-4146 ◽  
Author(s):  
YONG HUH ◽  
HYUNG ICK KIM ◽  
JAE SIL PARK ◽  
CHANG-SUNG SEOK
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Weld Metal ◽  
Heat Treated ◽  
Weld Toe ◽  
Fatigue Characteristics ◽  
Profile Change ◽  
Better Than

We compared the fatigue characteristics of weld metal with those of base metal heat-treated and non heat-treated. Also, we examined the influence of bead on fatigue life. From the experimental results of this study, it has been seen that the fatigue characteristics of welded specimens grinded the toe of bead are slightly better than those of welded specimens not grinded. Fatigue life is affected more by the stress concentration due to the profile change in the weld toe rather than by the residual stress, and heat-treatment had almost no influence on the fatigue characteristics.

Research about the Effect of Residual Stress on the Fatigue Life of Cruciform Joint of 16MnR Steel

2011 ◽  
Vol 382 ◽  
pp. 400-403 ◽  
Author(s):  
Ying Xia Yu ◽  
Bo Lin He ◽  
Huang Huang Yu ◽  
Jian Ping Shi
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Fatigue Life ◽  
Impact Machine ◽  
Ultrasonic Impact Treatment ◽  
Heat Treated ◽  
Impact Specimen ◽  
Weld Toe ◽  
The Impact ◽  
Cruciform Joint

Surface treatment was carried out on the cruciform joint of 16MnR steel by using the HJ-II-type ultrasonic impact machine. The impact current is 1.2A, impact amplitude is 30 microns. Fatigue experiments were carried out for impact treated specimen, impact treated and heattreated specimen and un-heattreated specimen. The effect of ultrasonic impact on the hardness of the weldment and weld toe was researched. The experimental results show that the fatigue life of the cruciform joint of 16MnR steel can be significantly improved through the ultrasonic impact treatment and the hardness of weld toe can also be promoted. Compared to the sample without impact treatment, its fatigue life was increased 692.52%. The hardness of weld toe was increased 31%. Compared to the sample with heat treatment, the fatigue life of impact specimen was increased 316.67%. Compared to the sample without impact treatment, the fatigue life of impact and heat treated specimen was increased 218.69%.

Influence of Air Heat Treatment on Bonding Strength and Microstructure of Al2O3-13wt%TiO2/NiCrAl Coating

2015 ◽  
Vol 817 ◽  
pp. 158-163
Author(s):  
Guo Wei Wang ◽  
Ze Hua Zhou ◽  
Ze Hua Wang ◽  
Han Liu ◽  
Jia Shao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Bonding Strength ◽  
Holding Time ◽  
Micro Structure ◽  
Cooling Method ◽  
Heat Treated ◽  
Heating Up ◽  
Cooling Methods ◽  
Better Than

Owing to typical weaknesses of Al2O3-13wt%TiO2/NiCrAl coating (AT13), appropriate air heat treatment is an effective method in improving the bonding strength and microstructure of AT13. AT13 was air heat-treated with varying holding times and cooling methods. The aims are not only to ascertain the changes of the bonding strength and micro-structure of AT13 under various conditions, but also to understand the influence of holding time and cooling method on the bonding strength and microstructure of the coating. The experimental results showed that the best bonding strength and lowest porosity of AT13 were obtained using proper heat treatment of heating up to 560°C for 6 h along with two-step cooling. The two-step cooling is better than normal furnace cooling in improving properties of the coating, which is attributed to the densification of AT13 and release of residual stress.

Finite Element Analysis of the Rolling Contact Fatigue Life of Railcar Wheels

2008 ◽  
Vol 575-578 ◽  
pp. 1461-1466
Author(s):  
Byeong Choon Goo ◽  
Jung Won Seo
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Element Analysis ◽  
Railway Vehicles ◽  
Contact Fatigue Life

Railcar wheels and axles belong to the most critical components in railway vehicles. The service conditions of railway vehicles have been more severe in recent years due to speed-up. Therefore, a more precise evaluation of railcar wheel life and safety has been requested. Wheel/rail contact fatigue and thermal cracks due to braking are two major mechanisms of the railcar wheel failure. One of the main sources influencing on the contact zone failure is residual stress. The residual stress in wheels formed during heat treatment in manufacturing changes in the process of braking. Thus the fatigue life of railcar wheels should be estimated by considering both thermal stress and rolling contact. Also, the effect of residual stress variation due to manufacturing process and braking process should be included in simulating contact fatigue behavior. In this paper, an evaluation procedure for the contact fatigue life of railcar wheels considering the effects of residual stresses due to heat treatment, braking and repeated contact load is proposed. And the cyclic stressstrain history for fatigue analysis is simulated by finite element analysis for the moving contact load.

Residual Stress Analysis Considering Phase Transformation and Transformation Plasticity for Heat-Treated Large Size Shaft

2016 ◽  
Vol 725 ◽  
pp. 647-652 ◽  
Author(s):  
Yusuke Yanagisawa ◽  
Yasuhiro Kishi ◽  
Katsuhiko Sasaki
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Phase Transformation ◽  
Air Cooling ◽  
Water Cooling ◽  
Stress Distributions ◽  
Transformation Plasticity ◽  
Large Size ◽  
Heat Treated ◽  
Good Agreement

The residual stress distributions of the forgings after both water-cooling and air-cooling were measured experimentally. The residual stress occurring during the heat-treatment was also simulated considering the phase transformation and the transformation plasticity. A comparison of the experiments with the simulations showed a good agreement. These results shows that the transformation plastic strain plays an important role in the heat treatment of large forged shafts.

scholarly journals Study on Fatigue Life of Heat-treated Aluminium alloy coated with Castor oil.

2018 ◽  
Vol 172 ◽  
pp. 03004
Author(s):  
A. Sivasubramanian ◽  
T.S. Kirubasankar ◽  
S. Vinoth kumar
Keyword(s):  
Heat Treatment ◽  
Fatigue Life ◽  
Aluminium Alloy ◽  
Castor Oil ◽  
Cyclic Load ◽  
Heat Treated ◽  
Al 7075 ◽  
Number Of Cycles ◽  
Uncoated Specimen ◽  
Scanning Electron

This paper involves the study of fatigue life of coated aluminium alloy Al 7075-T651 that is heat-treated under 100oC soaked in castor oil for three days. The specimen after heat treatment is subjected to fatigue test using rotary bending machine for number of cycles to fail under cyclic load of 15kgf, 25Kgf, and 50kgf.The life of the specimen is found and compared with uncoated specimen and improved life in number of cycle is noticed. The crack propagation and its type is analysed using scanning electron microscope for knowing the point of fracture and its initiation to failure.

A Study on the Fatigue Characteristics of Al6061-T651 by Shot Peening Velocity

2006 ◽  
Vol 326-328 ◽  
pp. 1093-1096 ◽  
Author(s):  
Won Jo Park ◽  
Sun Chul Huh ◽  
Sung Ho Park
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Fatigue Life ◽  
Shot Peening ◽  
High Speed ◽  
Compressive Residual Stress ◽  
Velocity Increase ◽  
Fatigue Characteristics ◽  
Height Increase ◽  
Small Steel

Small steel ball is utilized in Shot peening process. Called “shot ball” are shot in high speed on the surface of metal. When the shot ball hit the surface, it makes plastic deformation and bounce off, that increase the fatigue life by compressive residual stress on surface. In this study, the results of observation on the tensile strength, hardness, surface roughness, compressive residual stress and fatigue life of a shot peened Al6061-T651 were obtained. Experimental results show that arc height increase tremendously by shot velocity. Also, it shows that surface roughness, hardness, compressive residual stress and fatigue life increase as shot velocity increase.

Consistent and Repeatable Property and Residual Stress Control in Forged and Heat Treated Railway Wheels

2011 ◽  
Author(s):  
Jay Galbraith ◽  
George Ames ◽  
Scott Leister
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Pressure Control ◽  
Innovative Technology ◽  
Heat Treat ◽  
Heating And Cooling ◽  
Statistical Variation ◽  
Heat Treated ◽  
Railway Wheels ◽  
Process Controls

Consistent process control of wheel hardness and residual stresses developed during heat treatment are particularly important considerations for service life and safety of railway wheels. This paper details the process controls strategically located throughout an integrated, fully automated heat treatment system that can heat treat up to 65 railway wheels per hour. New, innovative technology such as in-line temperature measurements that control key process steps, uniform wheel heating and cooling, and quench water temperature and pressure control have resulted in wheel hardness and residual stress values with less statistical variation than older, traditional heat treat methods. Automatic serial number tracking and temperature measurement allow for statistical analysis of heat treat processes. Two years after the commissioning of this $18M facility, the quality and productivity benefits realized are discussed.

Fatigue Behavior of the Low-Strength Steel Welded Joints Treated by TIG Dressing and Ultrasonic Peening Combined Method

2011 ◽  
Vol 295-297 ◽  
pp. 1885-1889
Author(s):  
Sen Li ◽  
Dong Po Wang ◽  
Hai Zhang ◽  
Bo Tan
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Compressive Stress ◽  
Stress Level ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Combined Method ◽  
Ultrasonic Peening ◽  
Weld Toe

Butt-joint specimens of Q235B low-strength steel were treated by TIG dressing and ultrasonic peening combined method. The paper presents comparative fatigue test for welded specimens in the as-welded condition and specimens treated by TIG dressing, ultrasonic peening treatment (UPT) and the combined method. When the ratio of stress R=0.1, contrasted with the specimens in as welded condition, the fatigue strength of the specimens treated by TIG dressing is increased by 36%. The fatigue strength of the specimens treated by the combined method and UPT are almost the same, which are increased by 57% and 56% respectively. In the high stress level, weld toe treated by the combined method has smaller stress concentration factor than that of UPT, resulting in less release of residual compressive stress. So it's more effective to improve the fatigue life by the combined method. While in the low stress level, the residual compressive stress of weld toe treated by the combined method and UPT are nearly the same. Besides, the effect of stress concentration factor is smaller, thus the fatigue life of the two methods have little difference.

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