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1.
The effect of heat treatment on the properties and structure of molybdenum and vanadium dual-phase steels 总被引:1,自引:0,他引:1
A. R. Marder 《Metallurgical and Materials Transactions A》1981,12(9):1569-1579
A systematic study was made of the effect of the heat treating parameters,(i.e., temperature, time, and cooling rate) on the properties and structure of molybdenum and vanadium bearing dual-phase steels.
The volume percent martensite was found to be the major structural factor that controls the strength and ductility of these
steels. The relationship between strength and ductility was independent of alloy addition for the alloys studied. Annealing
temperature was shown to be very important in these alloys, especially at high quench rates. The molybdenum alloy exhibited
better hardenability than the vanadium alloy for equivalent heat treating conditions. Therefore, for a given set of annealing
conditions the molybdenum alloy generally had the highest tensile strength and lowest total elongation. A minimum in the 0.2
pct yield strength was found at a specific volume fraction martensite. The increase in yield strength at the lowest volume
fraction studied can be related to a jog or discontinuity in the stress-strain curve during tensile testing. This jog was
found to be the result of the lack of a sufficient amount of free dislocations. The causes of this deficiency of the dislocations
may be: 1) an insufficient amount of transformed martensite, 2) a large martensite interparticle spacing, 3) dynamic recovery
of dislocations during cooling, and 4) pinning of dislocations by precipitates during cooling. 相似文献
2.
The bainite-martensite-ferrite steels (tri-phase steels) were made in the laboratory by intercritical annealing, bainite transformation and oil quenching in sequence. With bainite inclusions, ductility was improved substantially without significant reduction of tensile strength. The ductility increase was found to be due to large deformation after necking and increased work-hardening. 相似文献
3.
M. Yu. Matrosov O. P. Talanov I. V. Lyasotskii D. L. Dyakonov E. I. Khlusova V. V. Orlov A. M. Korchagin D. S. Tsvetkov S. D. Popova 《Metallurgist》2011,55(7-8):489-495
The effect of heat treatment on mechanical properties and microstructure of high-strength low-alloy ferrite-bainite pipe steels is studied. Specimens are heated in a laboratory furnace up to a temperature in the range 100?C850°C. Dependences for the change in mechanical properties on heating temperature and the main features of steel structure are determined. TEM is used to study excess phase precipitation, including Nb and V carbonitrides, during heating. Unfavorable temperature ranges are determined for heating pipe steels with a ferrite-bainite structure. The results obtained may be used in industrial production and during development of new technology for thermomechanical treatment. 相似文献
4.
Dual-phase structures were produced in three steels (designated A1, A2 and A3) using two different heat-treatment cycles which incorporate intercritical annealing at a temperature of 750°C. In general, alloy A2 contains the maximum and alloy A1 the minimum volume fraction of martensite, with alloy A3 coming in between. All the cold-rolled alloys show elongated cell-like structures and also some deformation bands. Recrystallisation anneals were carried out at 650°C and 800°C. At the lower recrystallisation temperature of 650°C, the cold-worked ferrite starts to recrystallise, whereas, at the higher temperature of 800°C, re-austenitisation of martensite and recrystallisation of cold-worked ferrite take place simultaneously. During the recrystallisation anneal strain free ferrite grains are found to nucleate at both the deformed ferrite-martensite interfaces as well as inside the deformed ferrite grains. The process of recrystallisation in all three alloys, irrespective of the initial heat-treatment as well as annealing temperature, can be described as an in-situ process. The kinetics of primary recrystallisation of ferrite in the cold-rolled dual-phase steels was analysed from the relevant microhardness data using an Avrami-type relationship. In general, the Avrami plots show straight line segments with two distinct slopes, indicating two different processes during recrystallisation. The activation energies measured from the Arrhenius plots range between 66.88 and 83.6 kJ K mole?1 which are close to the value 84.02 kJ K mole?1 for the diffusion of carbon in α-Fe. 相似文献
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采用不同的热处理工艺研究了残留奥氏体对中碳双相钢冲击韧性的影响。利用金相显微镜、扫描电镜、透射电镜和摆锤式冲击试验机,对不同试样的显微组织与冲击韧性进行观察、检测和分析。试验结果表明:中碳贝氏体钢的冲击性能显著高于Q/P马氏体钢(室温冲击功是57J对应15J,-40℃冲击功是33J对应9J),可能的原因是贝氏体钢中薄膜状残留奥氏体,对裂纹扩展的阻止效应更显著。 相似文献
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One- step and two- step isothermal low temperature bainitic transformation were designed. The effects of heat treatments on the microstructures, mechanical properties and stirring wear resistance of low temperature bainite were discussed. The results show that the microstructures of samples under different heat treatments all consist of micro- and nano- scale bainite lath and austenite. The size of bainite lath decreases from 95 nm to 65 nm with the decrease of isothermal temperature from 300?? to 250?? under the one- step isothermal bainitic transformation. Moreover, the volume fraction of austenite likewise decreases from 28??1% to 19??9%. The unstable block austenite is apparently refined by the two- step isothermal bainitic transformation. The optimal balance between the tensile strength (1857MPa) and elongation (10??59%) is obtained in the sample treated by two- step isothermal bainitic transformation. Also, the V- notch impact absorbed energy of the sample treated by two- step isothermal bainitic transformation reaches 11J. Compared with the one- step isothermal bainitic transformation (300, 250??), the sample treated by two- step isothermal bainitic transformation shows the optimized wear resistance and increases by 11??8% and 31??4%, respectively, which is attributed to the better ductility and toughness. 相似文献
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A thermal model for the grinding of quenched alloy roll steels has been developed. The temperatures in the cutting area are calculated by this model, and the effect of grinding conditions on the structure and hardness of the surface layers of a roll steel quenched for martensite is studied. 相似文献
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A. M. Glezer V. V. Rusanenko O. P. Zhukov M. A. Libman A. D. Klippenshtein 《Russian Metallurgy (Metally)》2012,2012(10):869-872
The effect of rolling at a temperature of 77 K and subsequent tempering on the structure and properties of chromium-nickel 05Kh14N14T2 and 15Kh14N14Yu1 steels is investigated. The formation of a nanocrystalline martensite phase in an austenitic matrix has been established. It is shown that additional hardening of the metal occurs due to the precipitation of intermetallic phases during heat treatment. The steels under study are high-strength and hard-magnetic after cryogenic deformation and heat treatment. 相似文献
13.
Quenching and one- and two-stage aging conditions are found for a high-strength Al-Li-Cu cast alloy with a low density from
the results of studying its structure, mechanical properties, and aging kinetics. 相似文献
14.
分析了双相钢冷变形过程中形变织构的演变规律以及合金元素对双相钢形变织构的影响规律。分析结果表明,虽然存在有少量珠光体,但双相钢冷变形织构与体心立方金属相近;非碳化物形成元素Si的加入对形变织构没有明显的影响;碳化物形成元素Cr和Nb导致形变织构在α取向线的{112}<110>取向位置上的取向密度增强。测试分析了双相退火过程中钢的织构演变规律。结果表明,退火时晶粒的取向将沿着α取向线向γ取向线位置转变,Si或Cr对晶粒取向改变的阻碍作用不明显,微合金元素Nb明显阻碍晶粒取向改变,退火织构仍保持很高的α取向线织构组分。对上述的实验结果进行了理论分析。 相似文献
15.
R. G. Davies 《Metallurgical and Materials Transactions A》1979,10(1):113-118
A study has been made of the influence of up to 2 pct Si and 0.42 pct P upon the strength and ductility of ferrites over a
wide grain size range; the grain size was varied fromd
−1/2 mm−1/2 = 4 to 14. Although the ductility decreased with increasing strength for all the alloys, the 2 pct Si alloy had the best
combination of strength and ductility. The ferrites containing 2 pct Si and 0.2 pct P had greater uniform elongations than
conventional HSLA steels at the same tensile strength; it is thought that the ductility of the ferrites is enhanced by the
presence of Si while the ductility of conventional HSLA steels is reduced by the presence of carbide precipitates. With the
theory for a composite of two ductile phases and the results for the fine-grained alloyed ferrites, the change in uniform
elongation as a function of tensile strength was predicted for dual-phase (martensite plus ferrite) steels. Good agreement
was found between the prediction and experimental results for dual-phase steels containing up to 0.2 pct P or 2 pct Si; the
2 pct Si alloy had the best combination of strength and ductility of all dual-phase steels so far reported. This study again
emphasizes the importance of the high strength, high ductility ferrite in controlling the properties of dual-phase steels. 相似文献
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V. M. Blinov O. P. Tchernogorova E. I. Drozdova I. A. Afanas’ev 《Russian Metallurgy (Metally)》2006,(2):161-171
The structure and hardening of austenitic steels subjected to shock-wave treatment have been studied. This treatment is shown to form a structure whose cell size decreases with increasing pressure. The treatment-induced hardening of the steels can be estimated using the Hall-Petch relation. At the same degrees of residual deformation, shock-wave treatment results in a significantly higher degree of hardening of the austenitic steels as compared to cold rolling. The degree of hardening increases with decreasing stacking-fault energy in austenite. 相似文献
19.
P. J. Wray 《Metallurgical and Materials Transactions A》1984,15(11):2009-2019
The effect of composition on the dynamic recrystallization behavior of plain carbon steels has been examined in the temperature
range 850 to 1300 °C and the strain-rate range 6 × 10-6 to 2 × 10-2 s-1. With increasing solute content, the onset of dynamic recrystallization is delayed and the rate of recrystallization is decreased.
At 1000 °C the elements can be ranked in order of increasing effectiveness as C, Ni, Mn, Si, P. At higher temperatures the
effect of composition is complicated by its effect on grain coarsening, which itself postpones the onset and slows the rate
of recrystallization. Similarly, for steels in which precipitation may occur, a fine-grain structure can promote the earlier
onset and faster rate of recrystallization. Thus, out of an examination of the effect of composition comes an appreciation
of the influence of initial grain size. Another factor which can complicate any explanation of the compositional dependence
of dynamic recrystallization is grain-boundary segregation, which is probably responsible for the strong retarding influence
of phosphorus. 相似文献
20.
V. A. Vlasov A. N. Pityulin G. N. Komratov A. F. Belikova 《Powder Metallurgy and Metal Ceramics》1995,33(11-12):563-566
A study has been made to ascertain how high-temperature vacuum annealing affects the structure, strength, and chemical resistance of the material STIM-3B/3, which is based on titanium-chromium carbide and is obtained by self-propagating high-temperature synthesis. Annealing at a temperature above 1000°C reduces the average TiC grain size, increases the strength of the material, and makes it more soluble in nitric acid. The composition of TiC grains is not changed by annealing while the Cr content in the Cr3C2 grains decreases as the Ti, C, and Ni content rise. The changes in the structure and properties of STIM-3B occur because Ti, Cr, and C have different solubilities in nickel. 相似文献