物理测试
Home
|
About Journal
|
Editorial Board
|
Instruction for Authors
|
Subscriptions
|
Advertisement
|
Contacts Us
|
Chinese
Office Online
Author Center
Peer Review
Editor Work
Office Work
Editor-in-chief
Journal Online
Forthcoming Articles
Current Issue
Archive
Read Articles
Download Articles
Email Alert
Quick Search
Advanced Search
2022 Vol. 40 No. 4
Published: 2022-08-15
1
LI Zhilong,GAO Yifei,LIU Lanzhou,ZHAO Renwei
Characterization of residual stresses during machining of GH4169 fatigue specimens and the effect on low cycle fatigue life
In order to investigate the changes in surface residual stresses and the effect of residual stresses on the low cycle fatigue properties of GH4169 alloy specimens during the machining process, X-ray diffraction was used to characterize the surface residual stresses of specimens with different machining processes of "turning-grinding-polishing" and to test the depth of the residual stress layer of the finished specimens. The residual stresses were measured inside the specimens by neutron diffraction. Lowcycle fatigue tests were carried out using an electrohydraulic servo universal testing machine. The results show that the residual stresses on the machined surface of GH4169 alloy change from surface residual compressive stresses to residual tensile stresses as the cutting volume increases. According to the residual stress layer depth test, machining on the surface of the specimen caused residual stress layer depth less than 0.01 mm, the internal axial residual tensile stress decreases. According to the fatigue test results, GH4169 alloy fatigue life and surface axial residual compressive stress is positively correlated.
2022 Vol. 40 (4): 1-7 [
Abstract
] (
66
) [
HTML
1KB] [
PDF
0KB] (
138
)
8
YU Hongyao，QIN Hailong，SHI Songyi
Determination of residual stress in GH4169 alloy disc by neutron diffraction method and contour method
The distribution characteristics of residual stress of the GH4169 alloy disc parts on service were characterized by neutron diffraction method and contour method, respectively. The mechanism of two testing technologies was totally different. The measurements results were compared and verified to determine the value of residual stress with higher reliability. First, the stress in axial direction, radial direction, and hoop direction of GH4169 alloy disc after full heat treatment was accurately characterized by timeofflight neutron diffraction technique. The residual stress level was about -300 to 300 MPa. The stress was mainly in the hoop direction and radial direction, showing the distribution characteristics of "External pressure and internal tension". Then, the two-dimensional(2D) distribution map of residual stress in hoop direction along the cross section of dimeter was measured by contour method. The hoop residual stress in cutting section obviously showed the distribution characteristics of "external tension and internal pressure". The order of magnitude of residual stress was about -300 to 250 MPa. In the section of thickness center of alloy disc, the measuring results of neutron diffraction technique and contour method were basically consistent in both trend and absolute value. The reliability of measurement results was high.
2022 Vol. 40 (4): 8-13 [
Abstract
] (
81
) [
HTML
1KB] [
PDF
0KB] (
130
)
14
SHAO Zhubiao，LI Defa
Study on erosion-corrosion resistance of Ni-Cr-Mo alloyed HB500 grade wear resistant steel
In order to improve the service life of wear-resistant steel under corrosive wear conditions, the corrosion resistance, wear resistance and erosin-corrosion resistance of Ni-Cr-Mo alloy HB500 wear resistant steel were studied by immersion test, wear test and erosion-corrosion test.And the interaction mechanism of corrosion and wear was discussed. As a result, the pure corrosion, pure wear and erosion-corrosion interaction respectively 0.2%, 82.9%, 16.9% of the total corrosion and wear, shows that under the condition of corrosion wear performance deteriorated, the state of material surface change in the process of wear, and then corrosion and wear promote each other, is the main reason for the interaction between corrosion and wear. Reducing the interaction of corrosion and wear, is beneficial to improve the erosion-corrosion resistance.
2022 Vol. 40 (4): 14-17 [
Abstract
] (
69
) [
HTML
1KB] [
PDF
0KB] (
131
)
18
ZHANG Xiaomin,QIN Heyong,YU Ping,TIAN Qiang,DUAN Ran,ZHANG Wenyun
Study on the microstructure and properties of a new type of nickel-based superalloy
GH4742 (Russian ЭП742) alloy is a typical high-alloyed hard-to-deform nickel-based superalloy turbine disk material. In this paper, GH4742 alloy is improved by adjusting the composition of Al, Ti and Nb, and a new type of nickel-based superalloy was invented. Use JMatPro to simulate the equilibrium phase diagram, and then use optical metallographic microscope and field emission scanning electron microscope to observe the alloy′s grain structure, carbides and γ′ phase distribution, and at the same time to detect the mechanical properties.The results show that the phase transition of the alloy in the equilibrium state from 1 400 ℃ to 300 ℃ during the cooling process can be summarized as L → L+γ → L+γ+MC →γ+MC+γ′ → γ+γ′+MC+μ → γ+γ′+μ+MC+M23C6 → γ+γ′+μ+MC+M23C6+σ. The volume fraction of γ′ phase precipitated at 780 ℃ is 40.88%. The forging deformation process is γ+γ′ dual phase zone deformation. After solution at 1 120 ℃, the microstructure after standard double aging treatment (850 ℃/6 h/AC+ 780 ℃/6 h/AC) clearly shows two different size grains. Small crystal grains (13 μm) are distributed around large crystal grains (100 μm) in a necklace shape. The carbides in this alloy are mainly MC (NbC, TiC, VC) of large size and irregular shape. The distribution state of the strengthening phase γ′ phase also has two different sizes. The average diameter of γ′I phase is 600 nm, the average diameter of γ′II phase is 150 nm. The good matching of the two sizes of γ′ phase strengthening makes the alloy have high strength and high plasticity at the same time, and excellent mechanical properties. The tensile strength at room temperature is 1 478 MPa, and the durability at 650 ℃/863 MPa is 194 h, which far exceeds the standard of 50 h at 650 ℃/823 MPa for GH4742 alloy.
2022 Vol. 40 (4): 18-23 [
Abstract
] (
75
) [
HTML
1KB] [
PDF
0KB] (
138
)
24
CHENG Xu,JIANG Xiaojun,DONG Xinlong,LI Xinxi
Fatigue life analysis of crane steel girder based on hysteresis nondestructive technology
Aiming at the fatigue issues of steel girder structure of crane, three groups of samples made of steel used for crane were selected for testing. Three positions were marked in middle scale distance part of each group of samples. The specimens were then subjected to tensile tests. Coercivity tests were performed before and after stretching. The tensile test process was simulated, and the simulated stress cloud map was compared with the coercivity cloud map. The test and simulation results showed that the value of coercive force (Hc) of the material increased gradually with the increase of external stress. The value of coercive force showed the trend of periodic change, which was possibly related to the pinning effect of residual stress due to the dislocation inside the material. The coercive force cloud map showed that the internal crystal structure of sample was destroyed with varying degrees of damage, and meanwhile, the coercive force increased accordingly. The coercivity and strain data were analyzed theoretically to obtain the fitting curve and fitting equation between the coercivity and strain.
2022 Vol. 40 (4): 24-28 [
Abstract
] (
98
) [
HTML
1KB] [
PDF
0KB] (
148
)
29
YAO Liu，ZHU Haiyang，ZHANG Xinyu，YANG Weishu, ZHANG Haoyue，MA Mingyu
Design of high efficiency electrical energy conversion device based on piezoelectric crystal
The equipment which could convert the energy of wind or rain into electric energy via piezoelectric sensor module ′a′ was designed for the high-efficiency utilization of wind energy and rain energy. This equipment could supply power for the load and accumulator. Its resolving power was high, and even the micropressure generated by weak wind and light rain could be also converted to the electric energy. When the piezoelectric crystal plate ′d′ or ′e′ was pressed, the pinion would be rotated clockwise or counterclockwise. When the piezo-electric crystal ′b′ or ′c′ was pressed, the hydraulic cylinder would elongate or shrink. Under the actions of hydraulic cylinder and pinion, the normal of plane for piezoelectric crystal plate a could be adjusted automatically to be consistent with the direction of wind and rain, which could improve the conversion rate of electric energy.
2022 Vol. 40 (4): 29-32 [
Abstract
] (
49
) [
HTML
1KB] [
PDF
0KB] (
120
)
33
LIU Kexiu,FENG Xiaoliang,LI Maodong,MA Kuo,LI Lushui
Experimental research on the mechanical properties of gray cast iron used in paper drying cylinders
In order to make a more accurate judgment on the mechanical properties of the gray cast iron paper dryers that have been in service for a long time, different methods were used to conduct hardness tests and tensile tests on a 62-year continuous service dryer gray cast iron material, and the test results perform comparative analysis. The test results show that there is a large deviation between the test results of the D-type impact device Leeb hardness tester and the laboratory bench-top Brinell hardness tester. It is not suitable to use the D-type impact device Leeb hardness tester for the gray cast iron paper dryer on-site inspection. The test results of the G-type impact device Leeb hardness tester are relatively close to those of the laboratory bench-top Brinell hardness tester, and the deviations of the test results of different parts are also quite different. There is no difference between the hardness and strength of gray cast iron materials obvious linear correspondence, it is recommended to combine microstructure inspection and other methods to comprehensively judge the material performance status.
2022 Vol. 40 (4): 33-36 [
Abstract
] (
74
) [
HTML
1KB] [
PDF
0KB] (
133
)
37
QI Weiwei，SUN Jianwei，LIU Hongyin，YANG Xu，KANG Jia，YANG Hongbo
Effect of aluminum on composition control and inclusion formation of microalloyed steel containing titanium
Microalloyed steels containing titanium with different Al contents were designed independently, and the chemical composition of each furnace steel was detected by spark source photoelectric direct reading spectrometer. The influence of Al, O and Ti contents in the tested steel was analyzed. Optical microscope (OM) and scanning electron microscope (SEM) were used to observe the morphology of inclusions, and energy spectrum analysis was carried out to study the influence of Al content on the formation of inclusions. The results show that with the increase of Al content, Ti oxide inclusions in steel gradually decrease.Ti mainly exists in the form of TiN and TiC, and the rendimiento of Ti was increased. When Al content was higher than 0.033 7%, the rendimiento of Ti was higher than 90%.When the Al content was controlled at 0.033 7%-0.060 6%, the de-oxidation effect was good, and the number and size of inclusions were reduced.
2022 Vol. 40 (4): 37-41 [
Abstract
] (
93
) [
HTML
1KB] [
PDF
0KB] (
137
)
42
WANG Yanyang,YU Nengli,HOU Zongbao,XIA Bing,WANG Huaiwei,CHENG Yanan
Application of extreme value analysis method to speculate the maximum inclusion size in wheel steel
With the improvement of steel purity, the occurrence probability of large-size brittle non-metallic inclusions in steel gradually decreases. It is difficult to be detected by the conventional inclusion detection methods, but these large-size brittle inclusions have an important impact on the fatigue life of steel. An analysis method for the maximum size of inclusions in steel, i.e., extreme value analysis method, was introduced. The maximum size of brittle inclusions in wheel steel was estimated by the method. Moreover, the elemental composition of large-size brittle inclusions was analyzed by energy spectrometer. The results showed that the extreme value analysis method based on Gumbel distribution function could be used to estimate the maximum inclusion size in wheel steel. When the method was used in the actual production and testing, the selection of cumulative distribution probability F(x) should be paid attention to, that was, the total sample quantity had a great impact on the evaluation results. The chemical composition of large-size Class B inclusions in wheel steel was generally CaO + Al
2
O
3
.
2022 Vol. 40 (4): 42-48 [
Abstract
] (
60
) [
HTML
1KB] [
PDF
0KB] (
130
)
49
XU Yan，GUO Zhan，WANG Debao,SONG Zufeng
Cause analysis and improvement of brittle fracture #br# of HRB400 hot rolled ribbed steel bar
The brittle fracture of HRB400 hot rolled ribbed steel bar was inspected and analyzed by the means of chemical in-situ measurement, scanning electron microscopy (SEM) and metallographic structure examination. The results showed that the severe C and P segregation occurred in steel bar. Moreover, due to the rapid cooling rate after rolling in winter, many upper bainite structures with high strength and low plasticity were caused. There were some microcracks in local region of steel bar. In the case of bending, the stress concentration was formed at the cracks, which would expand rapidly. After repeated bending processing, the toughness of steel bar was reduced. These factors resulted in the brittle fracture of steel bar. On this basis, we put forward the corresponding improvement measures to the problem of brittle fracture of steel bar. The quality of HRB400 steel bar products had been improved, the brittle fracture phenomenon of steel bar did not occur in use.
2022 Vol. 40 (4): 49-53 [
Abstract
] (
70
) [
HTML
1KB] [
PDF
0KB] (
130
)
54
LIU Yanning,LI Jikang,CHEN Ying,DU Min,LI Lingxia,WU Zhaobo
Common problems and improvement suggestions of ISO4967-2013 in practical application
ISO4967-2013 Steel-Determination of Content of Nonmetallic Inclusions was deeply analyzed. The existing problems in standard spectrum diagram, classification of type and series of inclusions, rating and inspection method were compared with ASTM E45-2018a. Some specific suggestions were proposed, e.g., the evaluation method of coexisting coarse and fine inclusions in the same field of view should be improved and clear, the divergence in evaluation of DS inclusions and oversized D inclusions, as well as the revision and modification of incorrect images for standard rating. The study was to standardize the evaluation method and eliminate the ambiguity, thus advancing the revision of standards, and improving the scientificity and accuracy of inclusion rating.
2022 Vol. 40 (4): 54-60 [
Abstract
] (
78
) [
HTML
1KB] [
PDF
0KB] (
152
)
61
ZHU Guifeng,ZANG Lili,LI Shuai,JIAO Zhongbin,WANG Yan,MENG Quansheng
Determination of equivalent coefficient of digital
radiography for AZ ceramics and aluminum alloy
AZ ceramic (ZrO
2
toughens Al
2
O
3
) is a kind of ballistic material. The nondestructive testing should be strictly conducted to ensure its protective performance. At present, it is usually detected by X-ray method. However, AZ ceramic belongs to nonstandard material, and there is lack of evidence in the determination of exposure conditions. In the study, 6063 aluminum alloy was selected as the standard material. The X-ray digital imaging of step samples of AZ ceramic and 6063 aluminum alloy were performed at same tube voltage. The relation curve and fitting formula between the thickness and image gray value were obtained by fitting. Then the equivalent coefficient between AZ ceramic and 6063 aluminum alloy at this tube voltage was calculated. The results showed that the equivalent coefficient between AZ ceramic and 6063 aluminum alloy was 3.03-3.79 when the tube voltage was in range of 75-95 kV. The study had certain guiding significance for the determination of X-ray digital radiographic testing conditions for AZ ceramics.
2022 Vol. 40 (4): 61-65 [
Abstract
] (
66
) [
HTML
1KB] [
PDF
0KB] (
144
)
66
ZHANG Yu
Technical improvement of FT equipment for petroleum pipes
In view of the problems and shortcomings found in the use of domestic oil pipe magnetic flux leakage testing equipment, this paper introduces the solutions and improvement measures adopted. This paper focuses on the analysis of the reasons for the large blind area of pipe end detection caused by edge effect, and innovatively introduces constant current source technology from the perspective of stabilizing magnetization current, which improves the magnetization effect of pipe end. According to the characteristics of equipment signal transmission, new materials are selected to make brush contacts, which improves the coupling ability and service life. In view of the electromagnetic interference prevalent in equipment field, comprehensive measures such as reasonable wiring, isolating power supply, PLC grounding, frequency converter filtering, and selecting grounding point are taken to ensure the reliability of flaw detection.
2022 Vol. 40 (4): 66-69 [
Abstract
] (
60
) [
HTML
1KB] [
PDF
0KB] (
116
)
物理测试
News
·
·
·
·
·
More
Author Center
Instruction for Authors
Template
Copyright Agreement
Links
·
Links
More
Copyright © PHYSICS EXAMINATION AND TESTING
Supported by: Beijing Magtech
