Generating Compressive Surface Residual Stresses Using Hydraulic Autofrettage Process With Heat Treatment

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Rajkumar Shufen ◽  
Uday S. Dixit

Abstract Recently, a method of inducing compressive residual stresses in the vicinity of the walls of a thermally autofrettaged cylinder was proposed. In the proposed method, the thermally autofrettaged cylinder was heated in such a manner that its outer wall attained a temperature more than the lower critical temperature and the inner wall was at a sufficiently lower temperature. When the cylinder was quenched, compressive residual stresses were induced in the vicinity of the cylinder walls. This article investigates the feasibility of the same procedure for a hydraulic-autofrettaged cylinder made of AISI 1080 steel. A finite element method (FEM)-based analysis is carried out using commercial package abaqus by incorporating microstructure and temperature-dependent material properties. The results indicate that the heat treatment design proposed for the thermally autofrettaged cylinder to induce compressive residual stresses at the outer wall can also be adapted for a hydraulic-autofrettaged cylinder. However, for cylinders subjected to high percentage of autofrettage, heating of the outer wall needs to be carried out well below the lower critical temperature. In fact, this is an advantage in terms of energy saving and can be implemented even for cylinders subjected to a low percentage of autofrettage.

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Rajkumar Shufen ◽  
Nilkamal Mahanta ◽  
Uday S. Dixit

Recently, a heat treatment technique has been proposed to induce compressive residual stresses at the vicinity of the outer wall of a thermally autofrettaged cylinder. In the proposed technique, the outer wall of a thermally autofrettaged vessel is heated above the lower critical temperature while temperature of the inner wall is kept below it. The cylinder is then quenched, which induces compressive residual stresses both at the inner and outer walls. This article presents the construction and working of an experimental setup to carry out the proposed heat treatment coupled thermal autofrettage process. Experiments are carried out on AH36 mild steel cylinders to assess the presence of the compressive residual stresses. Measurement of microhardness and opening angle of cut in a thermally autofrettaged AH36 steel cylinder provided the evidence for compressive residual stresses at the outer wall of the cylinder. A finite element method (FEM) technique was used to predict the opening angle of cut. Predicted opening angle was fairly close to experimental observation.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.


2012 ◽  
Vol 723 ◽  
pp. 208-213 ◽  
Author(s):  
Yi Wan ◽  
Chen Li ◽  
Zhan Qiang Liu ◽  
Shu Feng Sun

Residual stresses generated in milling process affect the performance of machined components. Milling residual stresses correlate closely with the cutting parameters. In this paper, the generation and distribution of surface residual stresses in milling of aluminum alloy 7050-T7451 was investigated. The cutting speed changes from 300m/min to 3000m/min. In the experiments, the residual stresses on the surface of specimen are detected by X-ray diffraction technique. The result shows that compressive residual stresses are generated when cutting speed is under 500 m/min. In feed and its orthogonal direction, the effect of cutting speed and feed rate on residual stresses is similar. The formation of the residual stresses can be explained by thermo-mechanical coupling effects.


1959 ◽  
Vol 63 (578) ◽  
pp. 90-94
Author(s):  
G. A. Hawkes

Summary:An X-ray back reflection technique has been used to measure the surface residual stresses resulting from the cold and hot forming of certain high strength aluminium alloys. The alloys examined were to specifications DTD 683, DTD 687 and B.S.S. L65, and the residual stresses have been related to the residual strain in bending of these alloys. The results show that, apart from the degree of straining, the residual stresses are affected by the heat treatment (cold or hot quench) and the amount (if any) of controlled stretching that the alloy has had between solution treatment and precipitation.


1999 ◽  
Vol 122 (4) ◽  
pp. 642-649 ◽  
Author(s):  
Jeffrey D. Thiele ◽  
Shreyes N. Melkote ◽  
Roberta A. Peascoe ◽  
Thomas R. Watkins

An experimental investigation was conducted to determine the effects of tool cutting-edge geometry (edge preparation) and workpiece hardness on surface residual stresses for finish hard turning of through-hardened AISI 52100 steel. Polycrystalline cubic boron nitride (PCBN) inserts with representative types of edge geometry including “up-sharp” edges, edge hones, and chamfers were used as the cutting tools in this study. This study shows that tool edge geometry is highly influential with respect to surface residual stresses, which were measured using x-ray diffraction. In general, compressive surface residual stresses in the axial and circumferential directions were generated by large edge hone tools in longitudinal turning operations. Residual stresses in the axial and circumferential directions generated by large edge hone tools are typically more compressive than stresses produced by small edge hone tools. Microstructural analysis shows that thermally-induced phase transformation effects are present at all feeds and workpiece hardness values with the large edge hone tools, and only at high feeds and hardness values with the small edge hone tools. In general, continuous white layers on the workpiece surface correlate with compressive residual stresses, while over-tempered regions correlate with tensile or compressive residual stresses depending on the workpiece hardness. [S1087-1357(00)00304-X]


Author(s):  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith ◽  
M. R. Daymond

This paper presents results from an experimental and numerical study examining the creation of highly triaxial residual stresses in stainless steel. This was motivated by a need to model and understand creep in aged power plant. The residual stresses were introduced by rapid spray water quenching of heated solid stainless steel spheres and cylinders. Finite element (FE) simulations predicted high compressive residual stresses around the surface of the specimens and tensile residual stresses near the centre. Surface residual stresses were measured using the incremental centre-hole drilling (ICHD) technique. Neutron diffraction (ND) was used to measure the interior residual stresses. The measurements were in good agreement with FE predictions. The ND measurements confirmed that a highly triaxial residual stress state existed in the core of the specimens.


2014 ◽  
Vol 996 ◽  
pp. 609-614 ◽  
Author(s):  
Lin Peng Ru ◽  
Johan Moverare ◽  
Pajazit Avdovic ◽  
Annethe Billenius ◽  
Zhe Chen

In this paper we investigated the influence of vibratory stress relieving technique, which is widely used for stress relaxation of weld and casting components/structure, on machining residual stresses in a ring-component of 12%Cr-steel. It was shown that the employed vibratory treatment, without significantly altering the microstructure, turned the surface layer from tension into compression but retained the compressive residual stresses in the subsurface. In comparison, a stress relieving heat treatment, included as a reference in the study, removed completely the surface tensile residual stresses and reduced the subsurface compressive residual stresses to a low level. Significant microstructural changes in the form of recrystallization also occurred in a thin surface layer of the machining affected zone after the heat treatment.


2020 ◽  
Vol 5 (4) ◽  
pp. 29-35
Author(s):  
Valentin Fyodorovich Pavlov ◽  
Vladimir Stepanovich Vakulyuk ◽  
Vyacheslav Petrovich Sazanov ◽  
Arsenij Vital'evich Efrosinin

The influence of roller strengthening on endurance limit under bending of the 25 mm and 50 mm diameter shafts made of steel 20 and 25 mm diameter shafts made of steel 40X with a pressurized hub has been examined. It’s been stated that the endurance limit of roller strengthened shafts with a pressurized hub depends not only on a value of compressive residual stresses in their dangerous section but on the character of its distribution. The valuation of a surface hardening influence on the endurance limit of shafts by the surface residual stresses criterion and the average integral residual stresses criterion has been shown that the average integral residual stresses criterion calculated through the part’s dangerous section surface layer thickness equal the critical depth of the non-propagating fatigue crack can be recommended for the hardened shafts with a pressurized hub endurance limit increase prediction. It’s been shown that on a diameter of a shaft with a pressurized hub raising it is necessary to increase a thickness of a hardened surface layer with compressive residual stresses.


1987 ◽  
Vol 109 (3) ◽  
pp. 203-205 ◽  
Author(s):  
H. K. To¨nshoff ◽  
F. Hetz

The surface residual stresses produced by grinding may have a strong influence on the life of highly stressed components. Different abrasives such as aluminum oxide (Al2O3) and cubic boron nitride (CBN) may lead to very different results. While CBN produces compressive residual stresses in nearly all combinations of machining parameters, the use of Al2O3 normally leads to tensile residual stresses. Fatigue tests carried out in alternating bending showed a remarkable increase in fatigue strength for CBN ground specimens compared with Al2O3 ground ones.


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