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1.
. Yu. Matrosov A. A. Kichkina A. A. Efimov L. I. Éfron O. A. Bagmet 《Metallurgist》2007,51(7-8):367-376
The technology of combining controlled rolling with accelerated cooling (CR + AC) makes it possible to produce thick plates
having a unique combination of strength, toughness, cold resistance, and weldability. This technology is characterized by
several key parameters (cooling rate, the temperature at which accelerated cooling is ended, etc.), which should be determined
and substantiated from the viewpoint of the structure-forming processes that take place in the plate metal. Values of the
parameters for CR + AC were obtained by analyzing the results from a study of the phase transformations and structure-forming
processes which occur during accelerated cooling.
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Translated from Metallurg, No. 7, pp. 52–58, July, 2007. 相似文献
2.
随着矿井深度的增加,对锚杆支护强韧性的要求越来越高,为了应对这一情况,需要研发出更高强度的锚杆钢。利用锚杆钢研究了轧制工艺、冷却工艺与珠光体、铁素体相比例,析出相析出行为及力学性能的关系。研究结果表明,在中轧后、精轧前采用适当水冷+回复段处理的复合工艺可使晶粒更细小、组织更均匀。对超高强度锚杆钢进行热压缩变形试验,由热模拟试验结果确定相转变温度为Ac1=737 ℃、Ac3=886 ℃。最终筛选出入精轧温度为810 ℃、回复段温度为800 ℃时,可获得的晶粒尺寸达4 μm,珠光体体积分数为66.8%,铁素体体积分数为33.2%,珠光体片层间距达200 nm;另外调整V、Cr、N等析出以提高锚杆钢的强韧性,较低的回复温度有利于细小、弥散、V(C/N)析出相的析出,V(C/N)的析出可进一步改善锚杆钢的力学性能。由该控轧控冷工艺轧制的锚杆钢屈服强度为780 MPa、抗拉强度为930 MPa、硬度为291HV、伸长率为20%。 相似文献
3.
随着矿井深度的增加,对锚杆支护强韧性的要求越来越高,为了应对这一情况,需要研发出更高强度的锚杆钢。利用锚杆钢研究了轧制工艺、冷却工艺与珠光体、铁素体相比例,析出相析出行为及力学性能的关系。研究结果表明,在中轧后、精轧前采用适当水冷+回复段处理的复合工艺可使晶粒更细小、组织更均匀。对超高强度锚杆钢进行热压缩变形试验,由热模拟试验结果确定相转变温度为Ac1=737 ℃、Ac3=886 ℃。最终筛选出入精轧温度为810 ℃、回复段温度为800 ℃时,可获得的晶粒尺寸达4 μm,珠光体体积分数为66.8%,铁素体体积分数为33.2%,珠光体片层间距达200 nm;另外调整V、Cr、N等析出以提高锚杆钢的强韧性,较低的回复温度有利于细小、弥散、V(C/N)析出相的析出,V(C/N)的析出可进一步改善锚杆钢的力学性能。由该控轧控冷工艺轧制的锚杆钢屈服强度为780 MPa、抗拉强度为930 MPa、硬度为291HV、伸长率为20%。 相似文献
4.
应用控轧控冷工艺开发低碳贝氏体高强度钢板 总被引:2,自引:0,他引:2
设计了强度级别为685MPa的工程机械用低碳高强度焊接用钢,利用Gleeble热模拟实验机研究了实验钢奥氏体高温变形行为、应变诱发析出行为和连续冷却相变行为。在此基础上利用实验轧机研究了轧制和冷却工艺参数对实验钢力学性能和显微组织的影响。结果表明,实验钢通过适当的控制轧制和控制冷却可以得到以细小的贝氏体为主的显微组织,达到强度和韧性的良好匹配。 相似文献
5.
采用中碳非调质钢制造的轴类等零件常承受交变载荷,因而对钢材疲劳性能具有高的要求。为了评估控轧控冷工艺生产的非调质钢棒材的疲劳性能,利用旋转弯曲疲劳试验机研究了一种常用的钒微合金化中碳非调质钢38MnVS及对比钢38MnS的高周疲劳性能。结果表明,与38MnS钢相比,38MnVS钢中铁素体体积分数增加,组织明显细化;相分析表明约有54%的钒处于M(C,N)相中,且尺寸小于10 nm的M(C,N)粒子质量分数为32%,这些细小粒子的析出强化增量约为116 MPa。38MnVS钢的疲劳极限较38MnS钢提高了62 MPa,提高幅度约为18%;疲劳极限比从38MnS钢的0.43提高到38MnVS钢的0.48。M(C,N)相的析出强化及组织细化是38MnVS钢较38MnS钢具有优异疲劳性能的主要原因,但其疲劳性能仍低于锻态非调质钢。根据试验结果及文献数据,给出了预测铁素体+珠光体型非调质钢疲劳极限的简便方法。 相似文献
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High temperature deformation experiments were conducted to monitor the recrystallization process in the austenite phase of a vanadium and columbium-treated HSLA steel alloy. The results show that columbium is much more effective than vanadium in retarding recrystallization. As the austenitizing temperature, above 2000°F, or time is increased the austenite recrystallization in the 1500° to 1700°F hot working temperature range is correspondingly increased. If, following the austenitization, the samples are held in the hot working temperature range for up to 5 min before hot working recrystallization occurs at a much faster rate. Several mechanisms are offered to explain the experimental results. 相似文献
8.
微合金高强度钢连续冷却转变及显微组织研究 总被引:3,自引:0,他引:3
以国内某厂新型微合金高强度钢的开发研究为背景,在THERMECMASTOR-Z热模拟试验机上对试验钢种进行了不同变形程度、变形速率和冷却速度等工艺条件下的热模拟实验.分析比较了不同变形工艺参数对微合金高强度钢相变及组织的影响.实验结果表明,提高轧后冷却速度使 Ar3温度降低;高温加热抑制相变,变形促进相变;变形速率越大,相变开始温度越高,变形程度越大,相变开始温度越高.增大变形程度和轧后快速冷却有助于铁素体晶粒的细化和减少珠光体的含量.试验钢种的γ+α两相区的温度范围大于130℃. 相似文献
9.
Some design guidelines for improving strength-toughness combinations in medium car-bon structural steels are critically reviewed.
From this, quaternary alloy development based on Fe/Cr/C steels with Mn or Ni additions for improved properties is described.
Transmission electron microscopy and X-ray analysis reveal increasing amounts of retained austenite in these alloys with Mn
content up to 2 wt pct and Ni additions at 5 wt pct after quenching from 1100°C. A corresponding improvement in toughness
properties is also found. Grain refining results in a further increase in the amount of retained austenite. In addition, the
excellent combinations of strength and toughness in these quaternary alloys are attributed to the production of dislocated
lath martensite from a homogeneous austenite phase free from undissolved alloy carbides. The question of thermal instability
of retained austenite following tempering is considered in detail and it is shown that the decomposition of retained austenite
is closely related to the ease of nucleation and growth of cementite. Thus, graphitizing alloying elements such as Ni are
beneficial in postponing the decomposition of retained austenite.
Formerly with the Lawrence Berkeley Laboratory, Berkeley, CA
This paper is based on a presentation made at a symposium on “Precipitation Processes in Structural Steels” held at the annual
meeting of the AIME, Denver, Colorado, February 27 to 28, 1978, under the sponsorship of the Ferrous Metal-lurgy Committee
of The Metallurgical Society of AIME. 相似文献
10.
Donald Webster 《Metallurgical and Materials Transactions B》1971,2(7):1857-1862
It has been found possible to increase the strength and toughness of two high-strength stainless steels, AFC 77 and AFC 260, by austenitizing at temperatures that are in the range where both austenite and δ ferrite are stable. The δ ferrite is then removed by isothermal transformation in the range 1800° to 2000°F. This technique results in a greater solution of carbides and intermetallic particles and consequently in a greater amount of retained austenite than is possible at austenitizing temperatures below the δ-ferrite range. In addition, the technique permits optimum mechanical properties to be obtained over a wider compositional range. 相似文献
11.
研究了高强度含铜钢HSLA80和HSLA100奥氏体连续冷却转变产物的强度和韧性随冷却速率的变化规律,探讨了连续冷却过程中形成的Cu沉淀的特征和熟化规律.在Gleeble3800热模拟试验机上进行0.1℃·s-1至20℃·s-1的连续冷却实验,利用扫描电镜和透射电镜分析了显微组织和Cu沉淀.结果表明,随冷却速率提高,HSLA80的连续冷却转变组织由多边形铁素体向块状铁素体和贝氏体转变,在冷速0.1~1℃·s-1范围内Cu发生沉淀,两者综合作用造成随冷却速率提高钢的硬度分阶段变化,而韧性逐渐提高;HSLA100的连续冷却转变组织以贝氏体为主,且不发生Cu的沉淀,随冷却速率提高钢的硬度基本保持不变,但韧性发生剧烈变化.连续冷却过程中形成的Cu沉淀在等温过程中的熟化符合Ostwald熟化规律,半径随时效时间t1/3变化. 相似文献
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Microstructural basis for the effect of chromium on the strength and toughness of AF1410-based high performance steels 总被引:4,自引:0,他引:4
The variation in strength and Charpy impact toughness as a function of tempering temperature in the range of 200 ‡C to 650
‡C was investigated in AF 1410 and AF 1410 + 1 pct Cr steels produced in a laboratory-scale, and a commercially produced AerMet
100 steel. The tensile test results showed that AF 1410 + 1 pct Cr had lower strength compared to AF 1410, while AerMet 100
had the highest strength of the three steels examined. Transmission electron microscopy (TEM) studies demonstrated that the
strength variations among the steels can be attributed to differences in the matrix/carbide coherency strain and the volume
fraction of the strengthening M2C carbides. The toughness values of the three steels were comparable when tempered up to 424 ‡C. Tempering at and above 454
‡C resulted in a relative enhancement of toughness in AF 1410 + 1 pct Cr steel compared to AF 1410. This toughening was attributed
to the destabilization of cementite at lath and prior austenite boundaries and the formation of reverted austenite. 相似文献
15.
The effect of warm rolling on upper bainitic structures is to promote the development of a spherodized carbide structure and
a clearly defined dislocation substructure. An investigation of the mechanical properties of as transformed and warm rolled
structures in SAE 4340 steel revealed that the microstructural changes result in an increase in the strain to fracture and
in fracture toughness for the plate thickness studied in this work. These factors are related using a simple model based on
the critical strain to fracture. The detailed microstructural features are incorporated by examining the strain to cause void
nucleation and growth at carbide particles in terms of their size shape and volume fraction. 相似文献
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17.
XU Guang CHEN Ting LI Guangqiang LUO Feng ZHANG Cong Key Laboratory for Ferrous Metallurgy Resources Utilization of Ministry of Education Wuhan University of Science Technology Wuhan China 《Baosteel Technical Research》2010,(Z1)
The pipeline steel is usually produced by adding niobium and vanadium alloying elements.The titanium alloyed pipeline steel was studied in the paper to reduce the production cost and enhance the competitive ability of pipeline steel.The steel containing 0.070%Ti was refined in the laboratory vacuum refine furnace.The dynamic CCT curve of developed steel was conducted on Gleeble-1500 thermal simulator and multi-pass deformation tests of studied pipeline steel were performed to simulate the CSP hot-rolling... 相似文献
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The accuracy of mathematical modelling is strongly influenced by the boundary conditions assumed. A shape rolling mill was instrumented to provide on-line temperature measurements during hot rolling of steels. An inverse heat conduction technique was used to convert the measurement data to surface heat fluxes and heat transfer coefficients. The heat transfer coefficient or heat flux could then be used as the necessary boundary condition for the computation of temperature field in the entire roll and workpiece by means of conventional heat transfer analysis. The heat transfer phenomena involved and the influence of the major operating parameters on the heat transfer results have also been discussed. Finally, the paper has shown that the numerical evaluation procedure adopted has at least the same influence on the results as the accuracy of temperature sensors and the properness of experiment design. 相似文献