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1.
The problems of surface hardening of high-carbon steels by alloying using laser radiation are considered. The effect of the laser treatment parameters on the thickness, the structure, the phase composition, the microhardness, and the residual stresses of the surface layer is studied, and the influence of alloying elements on the strength of the surface layer in carbon steels and their wear resistance is investigated. 相似文献
2.
Charudatta Pathak Prathamesh Dodkar 《Transactions of the Indian Institute of Metals》2020,73(3):571-576
This paper investigates the effect of shot blasting and shot peening parameters on residual stresses induced in connecting rod. Compressive residual stresses are induced using shot peening to increase fatigue life of connecting rod. Shot peening is also responsible for increase in surface roughness. Surface roughness is detrimental for fatigue life of the connecting rod. This necessitates shot blasting to reduce surface roughness. Shot peening and shot blasting processes are analysed to find optimum process parameters which will induce required value of compressive residual stress on the surface of connecting rod. Compressive residual stresses induced in the connecting rod specimen have been experimentally measured using X-ray stress analyser. The experimental results have been analysed using grey relational analysis to find optimum values of process parameters for target value of compressive residual stress and surface roughness. The experimental investigation and the analysis of it have resulted in achieving the desired value of compressive residual stress, which is 10.5% higher over the existing connecting rod. Surface roughness also decreases to 3.84 Ra which is 8.5% lesser than specified value to achieve better fatigue life. 相似文献
3.
硬质合金基体上金刚石膜粘附性能的影响因素探讨 总被引:3,自引:0,他引:3
采用压痕试验法的临界开裂(或剥落)载荷PCr和抗裂性参数dP/dX两指标系统,评定了硬质合金基体经不同预处理工艺和沉积工艺参数全盛的金刚石膜的粘附性能。探讨了粘附性能指标与基体表面钴相含量、表面粗糙度、主要沉积工艺参数(如甲烷浓度、沉积气压、沉积功率)、膜中残余应力之间的内在关系。适当的基体表面预处理、合适的甲烷浓度、较低的沉积气压、较高的沉积功率、适中的残余应力均有利于改善硬质合金基体上金刚石膜的粘附性能。 相似文献
4.
T. C. Totemeier R. N. Wright W. D. Swank 《Metallurgical and Materials Transactions A》2004,35(6):1807-1814
X-ray based residual stress measurements were made on type 316 stainless steel and Fe3Al coatings that were high-velocity oxy-fuel (HVOF) sprayed onto low-carbon and stainless steel substrates. Nominal coating
thicknesses varied from 250 to 1500 μm. The effect of HVOF spray particle velocity on residual stress and deposition efficiency was assessed by preparing coatings
at three different torch chamber pressures. The effect of substrate thickness on residual stress was determined by spraying
coatings onto thick (6.4 mm) and thin (1.4 mm) substrates. Residual stresses were compressive for both coating materials and
increased in magnitude with spray velocity. For coatings applied to thick substrates, near-surface residual stresses were
essentially constant with increasing coating thickness. Differences in thermal expansion coefficient between low-carbon and
stainless steels led to a 180 MPa difference in residual stress for Fe3Al coatings. Deposition efficiency for both materials is maximized at an intermediate (∼600 m/s) velocity. Considerations
for X-ray measurement of residual stresses in HVOF coatings are also presented. 相似文献
5.
Thomas K. Hirsch Alexandre Da S. Rocha Fabiano D. Ramos Telmo R. Strohaecker 《Metallurgical and Materials Transactions A》2004,35(11):3523-3530
Plasma nitriding of tool materials is common practice to improve the wear resistance and lifetime of tools. Machining-induced
compressive residual stresses in shallow layers of some tenths of microns are observed accompanied by other characteristic
properties of machined surfaces in these high-strength materials. After plasma nitriding of M2 high-speed steel, previously
induced compressive residual stresses remain stable and the depth of diffusion layers decreases with increasing compressive
residual stresses. This article reports investigations of plasma nitrided samples with different levels of residual stresses
induced prior to the nitriding process. For comparison, experiments with bending load stresses during plasma nitriding have
also been carried out. The plasma nitriding treatment was performed at constant temperature of 500 °C with a gas mixture of
5 vol pct N2 in hydrogen. Nitriding time was varied from 30 to 120 minutes. All samples were characterized before and after plasma nitriding
concerning microstructure, roughness, microhardness, chemical composition, and residual stress states. Experimental results
are compared with analytical calculations on (residual) stress effects in diffusion and show a clear effect of residual and
load stresses in the diffusion of nitrogen in a high-strength M2 tool steel. 相似文献
6.
A finite-element method has been employed to calculate the effect of the prestrain, particle size, volume fraction, and yield
strength ratio of the constituent phases on the Bauschinger effect (BE) and residual phase stresses for ferrite-martensite
two-phase steels. The relationships be-tween the BE parameters and residual phase stresses are given, and the basics of inelastic
un-loading and the effect of reverse deformation on the BE and residual phase stresses are also discussed. Based on the decaying
of the residual phase stresses (commonly called “back stresses”) during reverse loading, the relationship between back stresses
and permanent softening has been elucidated. Some of the calculated results are compared with experimental ones, and good
agree-ment between them is found. 相似文献
7.
Induction Heat Treatment of Sheet‐Bulk Metal‐Formed Parts Assisted by Water–Air Spray Cooling 下载免费PDF全文
Hans‐Bernward Besserer Andrej Dalinger Dmytro Rodman Florian Nürnberger Philipp Hildenbrand Marion Merklein Hans Jürgen Maier 《国际钢铁研究》2016,87(9):1220-1227
In order to produce components with massive secondary functional elements from sheet metal bulk forming operations, termed sheet‐bulk metal forming, can be applied. Owing to high, three‐dimensional stress and strain states present during sheet‐bulk metal forming, ductile damage occurs in the form of micro‐voids. Depending on the material flow properties, tensile residual stresses can also be present in the components' formed functional elements. During service, the components are subjected to cyclic loading via these functional elements, and tensile residual stresses exert an unfavorable influence on crack initiation and crack growth, and therefore on the fatigue life. Following the forming process, temperature and microstructurally related compressive residual stresses can be induced by local heat treating of the surface. These residual stresses can counteract potential crack initiation on the surface or in the subsurface regions. In the present study, the adjustability of the residual stress state is investigated using a workpiece manufactured by orbital cold‐forming, which possesses an accumulation of material in its edge region. Based on residual stress measurements in the workpiece's edge region using x‐ray diffractometry, it is possible to verify the compressive residual stresses adjusted by varying the cooling conditions. 相似文献
8.
A new X-ray method for the evaluation of three dimensional (residual) stress states is demonstrated by studies of the effect
of grinding on Armco iron and a medium carbon steel. Although the penetration depth of the Cr-radiation employed in this study
is only 5 μm, there is evidence of residual stresses normal to the surface (normal and shear components). In the past it has
been assumed that these stress components can be neglected. Shear stresses normal to the surface are small in Armco iron,
but significant (± 60 MPa) in steel. From the sign of the shears, the direction of final grinding can be determined. Cooling
decreases the tensile stresses parallel to the surface in steel; surprisingly, the opposite result is found in Armco iron. 相似文献
9.
The aim of the current investigation is to examine the influence of carbonitriding in low-temperature plasma on forming macroresidual
stresses in the surface layer of the materials. Particular modes of ion carbonitriding are considered in which layers of different
depth and different surface microhardness are obtained. The residual stresses in the α-Fe in carbonitride layers are determined by the method of “sin2Ψ.” The results show that at different modes of ion carbonitriding, residual macrostresses are obtained that have different
values and depend on the qualitative characteristics of the formed carbonitrided layers. 相似文献
10.
B. L. Averbach Bingzhe Lou P. K. Pearson R. E. Fairchild E. N. Bamberger 《Metallurgical and Materials Transactions A》1985,16(7):1253-1265
Fatigue cracks were propagated through carburized cases in M-50NiL (0.1 C,4 Mo, 4 Cr, 1.3 V, 3.5 Ni) and CBS-1000M (0.1 C,
4.5 Mo, 1 Cr, 0.5 V, 3 Ni) steels at constant stress intensity ranges, ΔK, and at a constant cyclic peak load. Residual compressive
stresses of the order of 140 MPa (20 Ksi) were developed in the M-50NiL cases, and in tests carried out at constant ΔK values
it was observed that the fatigue crack propagation rates,da/dN, slowed significantly. In some tests, at constant peak loads, cracks were stopped in regions with high compressive stresses.
The residual stresses in the cases in CBS-1000M steel were predominantly tensile, probably because of the presence of high
retained austenite contents, andda/dN was accelerated in these cases. The effects of residual stress on the fatigue crack propagation rates are interpreted in
terms of a pinched clothespin model in which the residual stresses introduce an internal stress intensity, Ki where Ki, = σid
i
1/2
(σi = internal stress, di = characteristic distance associated with the internal stress distribution). The effective stress intensity becomes Ke
= Ka
+ Ki where Ka is the applied stress intensity. Values of Ki were calculated as a function of distance from the surface using experimental measurements of σi and a value of di
= 11 mm (0.43 inch). The resultant values of Ke were taken to be equivalent to effective ΔK values, andda/dN was determined at each point from experimental measurements of fatigue crack propagation obtained separately for the case
and core materials. A reasonably good fit was obtained with data for crack growth at a constant ΔK and at a constant cyclic
peak load. The carburized case depths were approximately 4 mm, and the possible effects associated with the propagation of
short cracks were considered. The major effects were observed at crack lengths of about 2 mm, but the contributions of short
crack phenomena were considered to be small in these experiments, since the two steels were at high strength levels, and short
cracks would be expected to be of the order of 10 μm. Also, the two other steels behaved differently and in a way which followed
the residual stress patterns. Both M-50NiL and CBS-1000M have a high fracture toughness, with Klc = 50 MPa · m1/2 (45 Ksi · in1/2), and the carburized cases exhibit excellent resistance to rolling contact fatigue. Thus, M-50NiL, carburized, may be useful
for bearings where high tensile hoop stresses are developed, since fatigue cracks are slowed in the case by the residual compressive
stresses, and fracture is resisted by the relatively tough core. 相似文献
11.
Masoud Ahmadi Bagher Mohammad Sadeghi Missam Irani Farhad Rahimi 《Russian Journal of Non-Ferrous Metals》2016,57(6):565-571
Shot peening is a surface engineering process acknowledged for its potential to develop fatigue strength and erosion-corrosion resistance of metallic materials. In the present study, a 3-D finite element model is employed to predict the effective parameters through a single shot impact and the accuracy of the simulation is validated using previous literatures. In order to induce uniform compressive residual stress patterns across the specimen, processing parameters such as shot velocity, impact angle and friction coefficient should be controlled. It is observed that by increasing the shot velocity and the friction coefficient, the depth of compressive residual stress increases. Moreover, a comparative study between isotropic and kinematic hardening models is performed to evaluate the significant role of the hardening models on the compressive residual stress. It is observed that the kinematic hardening model shows better compatibility with the experimental results compared to the isotropic hardening. 相似文献
12.
B. B. Bartha J. Zawadzki S. Chandrasekar T. N. Farris 《Metallurgical and Materials Transactions A》2005,36(6):1417-1425
High-precision machining such as hard turning changes the surface and the material properties of steel alloys. The near-surface
material properties have been predicted from the known hard-turning cutting conditions. The effect of the predicted hard-turned
surface and material properties on wear performance was analyzed in detail to develop a process-performance model. A sliding
block-on-cylinder wear tester was used for the purpose of testing the wear performance of AISI 52100 bearing steel. The microstructure,
surface roughness, residual-stress field, and loading conditions from each wear test were used to develop the process-performance
model. The effect of microstructure on the wear performance of hard-turned steel showed that the white layer and overtempered
martensite (OTM) had a higher wear resistance than martensite. The wear-mechanism dependence on the surface hardness was attributed
to this increase in wear performance. The near-surface residual stress of the material was shown to become more compressive
as the material wore down. The applied normal loads affected the surface roughness, residual stresses, and, in turn, the wear
performance of the material. A process-performance model was developed to predict the wear performance of hard-turned steels,
which considers the machining process and the operating conditions in sliding wear. 相似文献
13.
Numerical Simulation of Continuous Tension Leveling Process of Thin Strip Steel and Its Application 总被引:1,自引:0,他引:1
Cold rolled thin strip steel of high flatness quality undergoes multistage deformation during tension leveling. Thus, the parameters of set up and manipulating are more difficult. With the aid of FE code MSCMARC, the tension leveling process of thin strip steel was numerically simulated. Concentrating on the influence of the roll intermeshes in 2# anti cambering on the distribution and magnitude of residual stresses in leveled strip steel, several experiments were done with the tension leveler based on the results from the simulation. It was found from the simulation that the magnitude of longitudinal residual stresses in the cross section of the leveled strip steel regularly presents obvious interdependence with the roll intermeshes in 2# anti cambering. In addition, there is a steady zone as the longitudinal residual stresses of the surface layers in leveled strip steel vary with the roll intermeshes of 2# anti cambering, which is of importance in the manipulation of tension levelers. It was also found that the distribution of strains and stresses across the width of strip steel is uneven during leveling or after removing the tension loaded upon the strip, from which it was found that 3D simulation could not be replaced by 2D analysis because 2D analysis in this case cannot represent the physical behavior of strip steel deformation during tension leveling. 相似文献
14.
Residual stress measurements by x-ray diffraction in the ferritic-austenitic interface weldment 总被引:1,自引:0,他引:1
N. Sarafianos 《Metallurgical and Materials Transactions A》1993,24(9):2095-2106
A mathematical model of calculating residual stresses at the weld interface of ferritic-austenitic steels has been developed.
The Kurdjumov-Sachs orientation relationship (110)bcc[111]// (11 l)fcc[011] was determined at the interface of the transition joint. The resultant bcc-fcc lattice misfit gives rise to significant
residual stresses. The performed X-ray analysis establishes macro- and microstress profiles extending up to 22 mm and 55 μm,
respectively. The profiles indicate the development of compressive and tensile stresses on either side of the weld interface.
With respect to this, tensile stresses in increasing sequence were computed from the parent metal toward the interface and
compressive stresses were determined from the interface inward toward the weld bead in decreasing sequence. A remarkable stress
discrepancy between the two profiles was observed, with the macrostresses falling in the range of +185 to −245 MPa and the
microstress level ranging between +340 and −420 MPa. While the developed interfacial residual stresses are due to the difference
in the bcc-fcc lattice parameters, the discrepancy observed in the determined stress level has its origin in the varying percentage
of the two phases involved within a narrow mixing zone at the weld interface. 相似文献
15.
Bartlomiej Winiarski Richard M. Langford Jiawan Tian Yoshihiko Yokoyama Peter K. Liaw Philip J. Withers 《Metallurgical and Materials Transactions A》2010,41(7):1743-1751
Residual stresses in crystalline or glassy materials often play a key role in the performance of advanced devices and components.
However, stresses in amorphous materials cannot easily be determined at the micron scale by diffraction, or by other conventional
laboratory methods. In this article, a technique for mapping residual stress profiles in amorphous materials with high spatial
definition is presented. By applying a focused ion beam (FIB)–based semidestructive mechanical relaxation method, the stresses
are mapped in a peened and fatigued bulk metallic glass (BMG) (Zr50Cu40Al10 at. pct). The residual stresses are inferred using finite element analysis (FEA) of the surface relaxations, as measured
by digital image correlation (DIC), that occur when a microslot is micromachined by FIB. Further, we have shown that acceptable
accuracy can in most cases be achieved using a simple analytical model of the slot. It was found that the fatigue cycling
significantly changes the distribution of compressive residual stresses with depth in the plastically deformed surface layer.
Our observations point to the scalability of this method to map residual stresses in volumes as small as 1 × 1 × 0.2 μm3 or less. 相似文献
16.
17.
C. C. Aydiner E. Ü:Ustü:UndaG J. C. Hanan 《Metallurgical and Materials Transactions A》2001,32(11):2709-2715
The viscoelastic nature of bulk metallic glasses (BMGs), their low thermal conductivity, and the fast cooling used in their
processing subject them to thermal tempering. This process leads to a residual stress state in which compression on the surface is balanced by tension in the interior.
For the first time, we have calculated such stresses in metallic glasses by adapting an analytical instant-freezing model
previously developed for silicate glasses. This model has been demonstrated to be reasonably accurate in predicting the final
residual stresses, although, due to its very nature, it neglects transient effects. For an infinite plate geometry and employing
processing parameters often used for metallic glasses, we predict that significant residual stresses can be generated in these
materials during thermal tempering. Preliminary measurements conducted using the layer-removal method yield compressive residual
stress values close to model predictions. 相似文献
18.
����ξ ����ϣ ʯ�� �˲� 《钢铁研究学报》2013,25(9):24-29
MS980 is one of advanced high-strength steels, which has a great potential for producing square tubes. Residual stress plays a significant role in determining roll-formed members?? behavior and strength. An experimental study on transverse residual stress of roll-formed shape with square section was conducted via X-ray diffraction method. The distribution of transverse residual stresses at different position in sections was measured and studied, and influence of cold-rolled-sheet and hot-rolled-sheet, different fillet radius, different processes, and different pickling time on circumferential residual stress distribution for square section was investigated. The experimental results show the transverse residual stresses are compressive stress in the corner portion and the tensile stress in the straight edge. Fillet radius, sheet, and process have a significant impact on the distribution of residual stress, but the conventional pickling hardly affects residual stress. 相似文献
19.
A variant selection model for predicting the transformation texture of deformed austenite 总被引:1,自引:0,他引:1
M. P. Butrón-Guillén C. S. Da Costa Viana J. J. Jonas 《Metallurgical and Materials Transactions A》1997,28(9):1755-1768
The occurrence of variant selection during the transformation of deformed austenite is examined, together with its effect
on the product texture. A new prediction method is proposed based on the morphology of the austenite grains, on slip activity,
and on the residual stresses remaining in the material after rolling. The aspect ratio of pancaked grains is demonstrated
to play an important role in favoring selection of the transformed copper ({311}〈011〉 and {211}〈011〉) components. The extent
of shear on active slip planes during prior rolling is shown to promote the formation of the transformed brass ({332}〈113〉
and {211}〈113〉) components. Finally, the residual stresses remaining in the material after rolling play an essential part
by preventing growth of the {110}〈110〉 and {100}〈uvw〉 orientations selected by the grain shape and slip activity rules. With the aid of these three variant selection criteria
combined, it is possible to reproduce all the features of the transformation textures observed experimentally. The criteria
also explain why the intensities of the transformed copper components are sensitive to the pancaking strain, while those of
the transformed brass are a function of the cooling rate employed after hot rolling. 相似文献
20.
Seokmin Hong Junghoon Lee Sunghak Lee Wanchuck Woo Sung-Kyu Kim Hyoung Seop Kim 《Metallurgical and Materials Transactions A》2014,45(4):1953-1961
In Twinning Induced Plasticity (TWIP) steels, delayed fracture occurs due to residual stresses induced during deep drawing. In order to investigate the relation between residual stresses and delayed fracture, in the present study, residual stresses of deep drawn TWIP steels (22Mn-0.6C and 18Mn-2Al-0.6C steels) were investigated using the finite element method (FEM) and neutron diffraction measurements. In addition, the delayed fracture properties were examined by dipping tests of cup specimens in the boiled water. In the FEM analysis, the hoop direction residual stress was highly tensile at cup edge, and the delayed fracture was initiated by the separation of hoop direction and propagated in an axial direction. According to the neutron diffraction analysis, residual stresses in 18Mn-2Al-0.6C steel were about half the residual stresses in 22Mn-0.6C steel. From the residual strain measurement using electron back-scatter diffraction, formation of deformation twins caused a lot of grain rotation and local strain at the grain boundaries and twin boundaries. These local residual strains induce residual stress at boundaries. Al addition in TWIP steels restrained the formation of deformation twins and dynamic strain aging, resulting in more homogeneous stress and strain distributions in cup specimens. Thus, in Al-added TWIP steels, residual stress of cup specimen considerably decreased, and delayed fracture resistance was remarkably improved by the addition of Al in TWIP steels. 相似文献