钢铁
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
2017 Vol. 52 No. 9
Published: 2017-09-15
1
JIANG Zhou-hua，ZHANG Xin-fa，LIU Fu-bin，GONG Wei
Harmful impurities control of raw material used in Ni-based superalloy production
With increasing thrust-weight ratio and inlet temperature of turbine for the aircraft engine，higher comprehensive performance requirements are put forward for components operating in hot environment manufactured by premium Ni-based superalloy. The quality of high temperature alloy material depends on its chemical composition and structure. It is obligatory to strictly control the alloy composition and reduce the content of harmful elements firstly. Since the residual detrimental impurities such as Pb，Sn，As，Sb，Bi，Se，and O，N，S etc are difficult to remove through common refining technology in practice， the purity of superalloy products would greatly depends on purity of raw materials used in production. Along with improvement in equipment and technology of domestic alloy making enterprises，raw materials of high harmful impurity content has become the bottleneck，limiting stable production of premium Ni-based superalloy. Based on the analysis of sources of trace elements in primary raw materials used in production of superalloy，the approaches of quality control for raw materials are proposed including selecting superior ore resources，improving the level of extraction and refining，purifying scrap and spent alloy component and cleaning the raw materials before charging.
2017 Vol. 52 (9): 1-10 [
Abstract
] (
538
) [
HTML
0KB] [
PDF
0KB] (
62
)
11
ZHAO Lu-peng，WU Keng，ZHU Li，，CHEN Xiao-min，QIN Xuan-ke
Prediction model of sinter properties based on BP neural network
To solve the problem of neglevting the high temperature characteristics of iron ore powder in sinter forecast model， the assimilation reaction characteristic number and liquidity characteristic number which reflect the high temperature performance of iron power are added into the model. BP neural network is used to establish prediction model of sinter performance. The sinter indexes that affects the production of blast furnace were chose as the output. The high temperature and the physical and chemical properties of the iron ore powder were analyzed as input. Thus， the prediction model was established by BP neural network， and the algorithm of BP neural network was optimized. The structure of BP neural network for prediction model was 8-17-4. After training the neural network ， the prediction accuracy of the predicted characters was more than 85%， which meant that the neural network had good accuracy and adaptability.
2017 Vol. 52 (9): 11-15 [
Abstract
] (
558
) [
HTML
0KB] [
PDF
0KB] (
88
)
16
ZHANG Jian-liang，LIU Dong-hui，LIU Hao，LIU Zheng-jian，WANG Guang-wei，WANG Yao-zu
Effects of nuclei ores on granulation behavior of low-titanium magnetite concentrate
Effects of the nuclei ores on the granulation behavior of the low-titanium magnetite concentrate （LTC） were investigated using micro-drum granulation equipment in order to improve the granulation properties of the LTC. The results show that the LTC has coarse grain size， small specific surface area， and the granule morphologyof the LTC is mainly smooth irregular shape and the adhesion among granules is relatively week. The granulation index （GI） and uniformity index（UI）of the LTC are relatively high， the granulating efficiency and the uniformity of quasi-particles are not the restrictive link for the LTC granulation.There is no evident relationship between nuclei ores and the granulation index or uniformity index. Compared with other iron ores， the resistance index of the thermal disintegration （KI） of quasi-particlesis relatively high but the damage index （DI） exhibits the opposite behavior. The KI and DI of the quasi-particles varies greatly for the different nuclei ores. Given that there are three kinds of nuclei ores can be selected in the low-titanium magnetite concentrate granulation process， when the limonite acts as nuclei ore， the quasi-particles has the strongest capability of impact-resistance and hot pulverization resistance， but for the hematite， the capabilities of impact-resistance and hot pulverization resistance are comparatively worse， and the impact-resistance and hot pulverization resistance of the sinter return is the worst.
2017 Vol. 52 (9): 16-21 [
Abstract
] (
490
) [
HTML
0KB] [
PDF
0KB] (
63
)
22
GUO Pei-min，ZHAO Pei，WANG Lei，KONG Ling-bing
Oxidizing kinetics of reducing gas during iron oxide reduction process
To research the process of reducing gas oxidized by iron ore，gas efficiency of single or monolayer iron oxide particle during gas-based reduction process was calculated through formula and coupled kinetic model of iron oxide reduction and reducing gas oxidation was established by theory and experiment in different reactors.The results show that gas efficiency is relatively high when reduction fraction is low， and drops gradually with the reduction fraction increasing through the reduction experiments of single iron oxide reduction process with hydrogen and iron oxide at fixed and fluidized bed. It is advantageous to increase reduction fraction of iron ore and gas efficiency by pulverizing oreand increasing reaction rate constant （including temperature， high quality reducing gas， catalyst）.Increasing gas flow helps iron ore reduction， but it induces gas efficiency drop.
2017 Vol. 52 (9): 22-26 [
Abstract
] (
392
) [
HTML
0KB] [
PDF
0KB] (
66
)
27
ZHANG Shuo，YANG Shu-feng，LI Jing-she，WANG Lin-zhu
Morphology of MnS inclusions in Y15 high sulfur free-cutting steel by tellurium treatment
For the purpose of investigating tellurium on the morphology of MnS in steel，aiming at Y15 high sulfur free-cutting steel， using scanning electron microscopy， combined with FactSage thermodynamic calculation， the effect of tellurium on morphology， size and aspect of MnS inclusions in steel was studied and the controlling mechanism of scattered metals tellurium in the morphology of MnS inclusions was discussed.The results show that， after tellurium added into liquid steel，the compound which is identified as complex phase containing Fe， Mn and Te by elementmapping forms. The morphology and distribution of MnS changes significantly by adding Te into liquid steel.MnS inclusions of chain shapearegreatly reduced and quantities of globular MnS inclusions increase when the ratio of Te content to S content reaches 0.05. MnS inclusions of chain shape almost entirely disappear when the ratio of Te content to S content reaches 0.2， andthe change of MnS inclusions morphologyis no longer obvious when[w(Te)/w(S)]reaches 0.5. The aspect of MnS inclusions reduces significantly by adding Te into liquid steel and the best ratio to control MnS inclusions is 0.2. FactSage calculation shows that the formation temperature of MnTe is 1 900 ℃.Solid solution occurs between MnS and MnTe during solidification. Solid solution growsspherical because of liquid MnTe.
2017 Vol. 52 (9): 27-33 [
Abstract
] (
625
) [
HTML
0KB] [
PDF
0KB] (
69
)
34
LIU Liu，FAN Jian-wen，WANG Pin，WANG Le
Generation mechanism of large inclusions during bearing steels refining process by tracer method
The generation mechanism of large size non-metallic inclusions has been studied by the method of adding tracer agent into the refining slag during Ladle Refining process. The results show that the large size inclusions in the high carbon chromium bearing steels mainly originate from primary de-oxidation reaction， intrinsic reaction and refining slag mixing. The three type inclusions occupy 10%-15% of all the oxides， 25%-40% and 50%-60% respectively. The primary de-oxidation inclusions linger in liquid metal without contact with the slag， therefore their contents have no BaO. The intrinsic reaction inclusions originate from interface reaction between steel and slag， and the BaO content of the inclusions increases with the refining process going on. By the refining process without slag， such as RH process， the formation of inner formed inclusions can be hold back. The slag-mixing inclusions originate from liquid steel stirring and most of them have some BaO. The size of the inclusions decreases with the refining process going on. Therefore， the methods for decreasing the number of large size inclusions are as follows， confining strictly the oxygen activity， a0，before deoxidizing process， decreasing[w(T[O])]in liquid metal， weakening and even avoiding slag-metal interface reactions and decreasing the reduction potential ability of slag as possible， and optimizing the liquid metal stirring intensity to decrease the slag involving and promote the tiny inclusions coagulating and floating upwards and being absorbed by the refining slag.
2017 Vol. 52 (9): 34-41 [
Abstract
] (
549
) [
HTML
0KB] [
PDF
0KB] (
64
)
42
DENG Xiao-xuan，，JI Chen-xi，，HE Wen-yuan，YANG Chun-bao，LUO Yan-zhao，，HUANG Cai-de
Periodic transient level fluctuations in continuous casting mold of slab
A full scale water modeling combined with industry experiments was carried out to investigate the transient characteristics in the continuous casting mold of slab. The results of water modeling show that the periodic level distortion exists in the traditional slab casting mold. This phenomenon involves about 5 s level distortions of the mold level every 20-30 s. The mold level near the narrow faces raises up but depresses at the quarter location with the maximum surface velocity during this distortion period. The distortion period is defined as the interval between the last distortion-ending to the latest distortion ending. The results also shows that increasing the casting speeds may decrease the distortion periods while raising the SEN depths and angles can promote these periods. Changing these casting parameters could not eliminate the level distortion，however can alter their periods. Furthermore，the effects on level distortion periods decreases from SEN angles，casting speed to SEN depths. The industrial experiments also confirms the existence of the periodic level distortions. Increasing the SEN angles may reduce the slag entrapments caused by the periodic distortions.
2017 Vol. 52 (9): 42-47 [
Abstract
] (
498
) [
HTML
0KB] [
PDF
0KB] (
68
)
48
LI Jian-min，，，JIANG Mao-fa，
Effect of mold fluxes on slab surface crack for 20Mn23AlV
In present work，the continuous casting（CC）production of high manganese steel 20Mn23AlV in the TISCO and the slab surface cracks of the 20Mn23AlV were investigated. By means of industrial samples and the slag-metal reaction experiment，the characteristics and forming process of slab surface crack were systematically studied through the metallographic microscope，the scanning electron microscopy and the energy spectrum analysis. While the variation of indexes such as the chemical compositions before and after mold fluxes were used，melting point，viscosity，heat transfer and so on were studied. The results showed that the SiO2 in mold fluxes was deoxidized by the Al in the molten steel，leading to changes of the mold fluxes composition during the continuous casting process，and properties of the lubrication and the heat transfer for mold fluxes also changed，which could increase slab surface cracks of high manganese steel 20Mn23AlV. Therefore，during CC production of the steel with strong reducibility element（Al），low SiO2 content mold fluxes should be used in order to reduce slab surface cracks，improve the surface quality of slab and ensure CC production of high manganese steel smoothly.
2017 Vol. 52 (9): 48-53 [
Abstract
] (
592
) [
HTML
0KB] [
PDF
0KB] (
71
)
54
SONG Guang-yi，YANG Quan，WANG Xiao-chen，ZHANG Xi-bang， WANG Feng-mei，WANG Qiu-na
Work roll wear law for hot strip temper mill
Because of special characteristics of process and structure of hot strip temper mill，the work roll wear evolution law is different from that of hot strip mill. However，researches on work roll wear mainly focused on hot strip mill and there was little research on work roll wear evolution law of hot strip temper mill. Accordingly，On the basis of the wear characteristics of hot strip temper mill，a large number of wear data were measured for analyzing the formation and development mechanism of work roll wear. For single-stand four-high hot temper mill，a roll-strip coupling model was established with ABAQUS finite element simulation software and effect of contact pressure on work roll wear evolution rule in different wear stages was obtained. Compared with the actual data of 1 580 mm hot strip mill，the results show that work roll wear evolution law can accurately reflect real wear condition. The conclusion lays the foundation for the development of the wear theory of hot strip temper mill and the further optimization of the wear prediction model.
2017 Vol. 52 (9): 54-59 [
Abstract
] (
443
) [
HTML
0KB] [
PDF
0KB] (
59
)
60
WANG Bing-xing，XIONG Lei，ZHANG Tian，WANG Zhao-dong，WANG Guo-dong
Influence on deformation permeability of plate by controlled rolling process with inter-pass water cooling technology
The differential temperature rolling method using inter-pass water cooling technology was introduced in this paper to reduce the internal defects of heavy plate，such as shrinkage and cracking，from the continuous casting slab in the hot rolling process. The influence of water cooling process on the temperature evolution and rolling deformation of steel plate was analyzed by numerical simulation and experimental study. The results show that the method of “temperature and deformation control” from water cooling process can effectively increase the deformation permeability inside heavy steel plate and improve its quality. The deformation inside the steel plate during high temperature rough rolling with the inter-pass cooling is significant，but is relatively small during the finish rolling process. In addition，for finish rolling with inter-pass water cooling technology，the rolling force is significantly increased and the rolling load is increased.
2017 Vol. 52 (9): 60-65 [
Abstract
] (
505
) [
HTML
0KB] [
PDF
0KB] (
66
)
66
YU Hui，ZHAI Jian-wei，ZHANG Chao-fan，LIU Shuai-shuai，LIU Li-gang
Microstructures and properties of nuclear carbon manganese steels P280GH after accelerated aging
P280GH carbon manganese steels used for the nuclear steam system and auxiliary system pipes in pressurized water reactor nuclear power plant are susceptible to thermal aging brittleness during long-term service at its working temperature from 280 to 350 ℃. In order to investigate its thermal aging behavior， P280GH carbon manganese steels have been thermally aged at 400 ℃ for up to 10 000 h. The micro-hardness of ferrite and pearlite phases， conventional tensile properties and impact properties at different aging duration have been measured. The results show that the micro-hardness of ferrite and pearlite gradually decreases with increasing thermal aging time. The tensile strength and yield strength increase within 300 h and then progressively and slightly decrease after 300 h with the long aging time， respectively. The charpy impact energy slightly decreases with the long aging time. The changes of all the above mechanical properties of P280GH carbon manganese steels are associated with the changes of the pearlite morphologies， dislocation configurations in ferrite and precipitates after different thermal aging time.
2017 Vol. 52 (9): 66-72 [
Abstract
] (
476
) [
HTML
0KB] [
PDF
0KB] (
63
)
73
YE Shuai，ZHAO Fei，，HUANG Fang，HE Jing，WANG Jia-lin
Creep behavior of CLAM steel at high temperature
In order to protect the security of CLAM steel under service condition and avoid the damage of theequipmentfrom creep， the creep behavior of CLAM steel was studied. First of all， the creep test of CLAM steel was conducted usinghigh temperature lasting creep testing machine， the creep curve was drawn and the creep deformation properties of CLAM steel under test conditions were discussed.The result showed that CLAM steel was highly sensitive to temperature，and the strengthening mechanism of the second phase particles was main creepmechanism. Secondly， the creep life of CLAM steel was predicted using double logarithmic isothermal extrapolation method and Larson-Miller parametric method， and two kinds of creep life prediction models were confirmed. Atlast， the resultsfromthe two models were compared， and result showed the extrapolation accuracy of Larson-Miller parametric method was higher， matchingwith the actual situation much closer.
2017 Vol. 52 (9): 73-78 [
Abstract
] (
487
) [
HTML
0KB] [
PDF
0KB] (
50
)
79
HUANG Le-qing，，WANG Yan-feng，DI Guo-biao，YANG Yong-da，HAN Cheng-liang
Influence of tempering temperature on microstructure and mechanical properties of F/B structural steel
In order to study the influence of tempering temperature on mechanical properties of F/B steel，420 MPa structural steel produced by Controlled Rolling， Relaxation and ACC processing was topics of research and studied by means of mechanical property test and microstructure observation with optical microscope and transmission electron microscopy. The results show that there is no change in the proportion of ferrite and bainite during the tempering process. With the increases of tempering temperature， M-A island decomposes and grain of ferrite grows up. At the same time， yield strength increases obviously but the tensile strength increases slowly， thereby yield ratio rises from 0.80 to 0.88. Changes of properties are caused by recovery， grain growth， interaction between dislocation and precipitation. In order to relieve stresses and meet technical requirements， the recommended tempering process is （400±10） ℃， （2×thickness） min.
2017 Vol. 52 (9): 79-83 [
Abstract
] (
458
) [
HTML
0KB] [
PDF
0KB] (
47
)
84
LI Xin-yu，，YANG Mao-sheng，ZHOU Xiao-long，GUO Jun，
Torsion fatigue characteristics and crackpropagation behavior of 15Cr14Co12Mo5Ni2 gear steel
The crack propagation behavior oftorsion fatigue fracture and the relationship between inclusions size and torsion fatigue lifeof 15Cr14Co12Mo5Ni2 steel were researchedthroughtorsion fatigue test. Torsional fatigue limit strength and[τ-N]cure was obtained， and the value of 15Cr14Co12Mo5Ni2 steel was 350 MPa，whosedispersion was large. Through observed fractures，the surface failure mode and subsurface failure mode as the main failure mode of the test steel， and the fracture mainly resulting from oxide inclusions were found. Thefracture mechanics conditions of fatigue crack propagation of 15Cr14Co12Mo5Ni2 steel were analyzed by calculating stress strength factor[ΔK] and crack propagation threshold value[ΔKth.] The load process of test steel in fracture was： type II load，type I load，type II load， and type I＋II load， which corresponded to crack sourcezone， fiber zone， fatigue crack propagation zone and instantaneous fracture zone. When the large crack formed， fiber zone would not appear， andthe load process was type II load， andtype I＋II load. The relationship between the size of the inclusions and the torsional fatigue life of the 15Cr14Co12Mo5Ni2 steel was obtained by eliciting formulas and fitting dates. It wasfound that[τ-N]cure of the test steel moved toward the high life zone， andwhen the size of inclusion in crack initiation was less than 5 μm， torsional fatigue life of 15Cr14Co12Mo5Ni2 steel would be more than 107 cycles with 350 MPa stress.
2017 Vol. 52 (9): 84-91 [
Abstract
] (
633
) [
HTML
0KB] [
PDF
0KB] (
83
)
92
FENG Hao，JIANG Zhou-hua，LI Hua-bing，HAN Yu，LUO Yi，DING Wei
Influence of austenitizing temperature on microstructure and mechanical properties of high nitrogen bearing steel 30Cr15Mo1N
The effect of austenitizing temperature on the microstructure and mechanical properties of high nitrogen bearing steel 30Cr15Mo1N was investigated by means of optical microscope， scanning electron microscope， Thermo-Calc calculation， hardness and impact energy measurements. The results show that with the increment of austenitizing temperature， precipitates （M23C6 and M2N） in the steel gradually dissolve and the distribution of elements in the matrix tends to be uniform. There is no significant difference in the prior austenite grain size when the austenitizing temperature is lower than 1 050 ℃. However， when the samples are austenitized at higher temperatures， the austenite grains grow up sharply. The hardness of 30Cr15Mo1N increases with the increment of austenitizing temperature， then decreases when the temperature is above 1 000 ℃. The hardness of the steel is remarkably improved after subzero treatmentand does not decline significantly with the increment of austenitizing temperature. The impact toughness of 30Cr15Mo1N is the best when austenitizing at 900 ℃， and it is greatly reduced after austenitizing at 1 000 and 1 100 ℃.
2017 Vol. 52 (9): 92-98 [
Abstract
] (
518
) [
HTML
0KB] [
PDF
0KB] (
60
)
99
LI Jun，ZHANG Ling-ling，ZHAO Gui-zhou，CANG Da-qiang
Pilot practice of direct modification of molten blast furnace slag and preparation of mineral wool fiber
Molten blast furnace slag flowed into electric furnace through the slag runner and siliceous additives as modification agent were simultaneously added into the electric furnace to remelt the slag. The modified slag was heated to 1 400-1 500 ℃ by electric furnace and then the molten slag with proper viscosity and fluidity was prepared into fireproof，thermal insulation and sound absorbing slag wool fiber through high-speed centrifugation method. Parameters of the slag wool fiber met the?national standards，with shot content of 4.7%，average diameter of 5.5 μm and water-absorption rate of 0.2%. Energy consumption and cost decreased by 40%-60% compared with traditional cupola furnace method. The new technology of preparing mineral wool fiber using direct modification provided a high value added method for the direct utilization of molten blast furnace slag.
2017 Vol. 52 (9): 99-103 [
Abstract
] (
522
) [
HTML
0KB] [
PDF
0KB] (
70
)
104
XU Ren-ze，ZHANG Jian-liang，ZHANG He-shun，LIU Chang-jiang， FAN Xiao-yue，WANG Zhi-yu
Influence of TiO2 on properties of Jingtang blast furnace slag and thermodynamic analysis
In order to clarify the impact mechanism of TiO2 on the performance of Jingtang blast furnace slag， based on the actual composition of Jingtang blast furnace slag， the influences of TiO2 on viscosity and melting temperature of slags were investigated through viscosity test. Furthermore， the activity， liquidus temperature， liquid region and phase change of slag from 1 500 to 1 000 ℃ were calculated by using FactSage thermodynamic software. The viscosity experimental result indicates that the viscosity and melting temperature of slag decrease with the increase of mass percent of TiO2.The calculation results from FactSage show that the viscosity decreases with the increase of TiO2 activity； the increase of mass percent of TiO2 could reduce the liquidus temperature and expand the liquid region in MgO and Al2O3 region， however the slag liquid region in CaO region isreduced when TiO2 changes from 4.2% to 5.6%. The transformation of the crystalline phase indicatesthat the perovskite is easy to generate at high temperature when TiO2 is too much， which can increase the viscosity of the slag and it is not conducive to the blast furnace operation. In order to ensure the fluidity of Jingtang slag and meet the requirement of furnace maintenance， the mass percent of TiO2 in slag should be controlled within 5%.
2017 Vol. 52 (9): 104-108 [
Abstract
] (
530
) [
HTML
0KB] [
PDF
0KB] (
66
)
钢铁
News
·
·
·
·
·
More
Author Center
Instruction for Authors
Template
Copyright Agreement
Links
·
Links
More
Copyright © IRON AND STEEL
Supported by: Beijing Magtech
