Evolution of 52CrMoV4 from 51CrV4 material to withstand field severity of parabolic leaf spring suspension in heavy-duty commercial vehicles

2019 ◽  
Vol 43 (3) ◽  
pp. 387-397
Author(s):  
P. Thangapazham ◽  
L.A. Kumaraswamidhas ◽  
D. Muruganandam

This investigative study is mainly focused on improving the fatigue life of the leaf spring through the following protocols. In protocol 1, a parabolic leaf spring is manufactured with 51CrV4 material through normal production processes, which results in low residual compressive stress and high decarburization. The resulting proto sample does not support severe field application. This issue can be resolved by optimizing the heat treatment and the shot peening process. The proto part was prepared and tested under rough road conditions, and the vehicle withstood field severity up to 10% higher than the design load. However, under highly severe field operation, the severity was 30% higher than the design load. Hence, the above process improvements could not resolve the failures of the 51CrV4 material. Hence, an alternate material is identified, 52CrMoV4, and investigated. In protocol 2, the spring proto part is manufactured directly through an optimized process. The residual compressive stress, decarburization, and mechanical properties are obtained at desired levels. The proto part was tested under rough road conditions; the suspension system withstood a field severity of 30%. The vehicle was then tested on the test track and covered 335 000 km of off-road distance, with all durability requirements met.

2011 ◽  
Author(s):  
Murathan Soner ◽  
Metin Guven ◽  
Nilay Guven ◽  
Tolga Erdogus ◽  
Mustafa Karaagac ◽  
...  

Author(s):  
Junhong Zhang ◽  
Feiqi Long ◽  
Hongjie Jia ◽  
Jiewei Lin

Abstract Leaf springs play an important role in the handling stability and ride comfort of vehicle. End rubber gaskets are widely used to reduce the friction between leaves, but they also have considerable effect on the stiffness of the suspension assembly. The ride comfort may deteriorate with the stiffness of leaf spring changes. In this paper the influence of the end rubber gasket on the static stiffness performance of a parabolic leaf spring is studied. A finite element model of the leaf spring is developed and verified against the static stiffness test. Effects of the end rubber gasket parameters on the static stiffness of the leaf spring are analyzed based on an orthogonal experiment. The sensitivities of the five parameters are identified including the width, the length, the end thickness, the tail thickness and the distance to the end of the middle leaf. It is found that the contributions can be ranked in descending order as the tail thickness, the end thickness, the distance from end rubber gasket to the end of Leaf 2, and the width and length. The first two factors are considered of significant effects on the leaf spring stiffness. According to single-factor analysis, it is found that under the same load, as the tail thickness and the end thickness increase, the maximum deformation of the rubber gasket decreases, the stiffness of the rubber gasket increases, and the stiffness of the leaf spring increases, which provides a reference for the forward design of the end rubber gasket and the stiffness matching of leaf springs.


2014 ◽  
Vol 670-671 ◽  
pp. 52-55
Author(s):  
Yan Chai ◽  
Wei Feng He ◽  
Guang Yu He ◽  
Yu Qin Li

To solve the crack and fracture problem in blade made of K403 alloy, the samples of K403 are laser shock processed and then the microstructure, microhardness, residual compressive stress and surface roughness of the samples are tested. The test results show that some grains are observed refined in the grain boundary of shock region, the microhardness improves in a depth of 0.8mm from the surface and the surface microhardness improves 16%, a residual compressive stress which is more than 450MPa is developed in a depth of 1mm from the surface, and obvious changes of the surface roughness are not tested.


2012 ◽  
Vol 463-464 ◽  
pp. 1363-1367
Author(s):  
M.L. Zhang ◽  
J.M. Wang ◽  
Y.F. Jiang ◽  
Q.L. Zhang ◽  
Q.L. Zhou

The solution treatment and solution and aging treatment (T6) were disposed on 7050 aluminium alloy, then local processed by laser shock processing (LSP) with high-rate neodymium glass laser. The microhardness and residual stress on the surface of 7050 aluminium alloy were tested, then how the microstructure influences the residual stress on the surface of 7050 aluminium alloy by laser shock processing was analysed. The results show that the microhardness and residual compressive stress on the surface of 7050 aluminium alloy treated by solution and aging treatment was higher, and decreased obviously treated by solution treatment; the microhardness and residual compressive stress on the surface of 7050 aluminium alloy increased obviously by solution treatment and solution and aging treatment after laser shock processing; treated by solution treatment and solution and aging treatment, the microhardness and residual compressive stress of the material with uniform original structure was higher than the material with nonuniform original structure.


Author(s):  
Tao Mo ◽  
Jingqing Chen ◽  
Pengju Zhang ◽  
Wenqian Bai ◽  
Xiao Mu ◽  
...  

Ultrasonic impact treatment (UIT) is an effective method that has been widely applied in welding structure to improve the fatigue properties of materials. It combines mechanical impact and ultrasonic vibration to produce plastic deformation on the weld joints surface, which introduces beneficial compressive residual stress distribution. To evaluate the effect of UIT technology on alleviating the residual stress of welded joints, a novel numerical analysis method based on the inherent strain theory is proposed to simulate the stress superposition of welding and subsequent UIT process of 304 stainless steel. Meanwhile, the experiment according to the process was carried out to verify the simulation of residual stress values before and after UIT. By the results, optimization of UIT application could effectively reduce the residual stress concentration after welding process. Residual tensile stress of welded joints after UIT is transformed into residual compressive stress. UIT formed a residual compressive stress layer with a thickness of about 0.13 mm on the plate. The numerical simulation results are consistent with the experimental results. The work in this paper could provide theoretical basis and technical support for the reasonable evaluation of the ultrasonic impact on residual stress elimination and mechanical properties improvement of welded joints.


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