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81.
Research efforts were given towards development of low carbon high strength steels since recent past. The present study deals with the development of a low carbon high strength steel alloyed with Mn, Ni, Mo, Cu and microalloyed with Ti and Nb. The steel was subjected to three stage controlled rolling operation followed by accelerated cooling. The structure and properties of the steel at various processing conditions were evaluated. Microstructural observation reveals predominantly lath martensite along with twinned martensite structure at all processing conditions. High strength values at higher finish rolling temperatures have been obtained due to fine martensitic structure along with tiny precipitates of microalloying carbide and carbonitride. The strength value increases marginally at lower finishing temperature due to comparatively finer lath size of martensite and increased precipitation density of carbides, carbonitrides along with Cu particles. The variation in impact toughness properties at different finish rolling temperatures is found to be negligible at ambient and subambient temperatures. The formation of stable and large TiN/TiCN particles during casting have impaired the impact toughness values at ambient and at ‐40°C temperatures. 相似文献
82.
张禄廷 《沈阳工业大学学报》1992,14(2):77-87
为M相变机制中K-S关系切变过程提供了直观的立体图解。利用矢量运算及矩阵等数学工具计算和校验了K-S关系切变过程中各阶段晶面指数和晶向指数以及在转变前后的对应关系。 相似文献
83.
84.
H. Berns 《Materialwissenschaft und Werkstofftechnik》2007,38(6):464-472
The wear resistance of martensitic, austenitic and duplex stainless steels is increased by carbon and nitrogen in solid solution and in addition by carbides and nitrides, which are formed during conventional ingot metallurgy or by powder metallurgical processing. High temperature and low temperature nitriding provide a hard surface zone. Characteristic alloys and applications are discussed, which try to optimize the resistance to wear and corrosion. 相似文献
85.
T. Michler Dr.‐Ing. 《Materialwissenschaft und Werkstofftechnik》2007,38(1):32-35
The formation of martensite in metastable austenitic stainless steels was investigated. The results showed that the formation of martensite in 304 grade stainless steels due to the exposure to cryogenic temperatures is negligible. The amount of formed martensite is dependent on the chemical composition of the actual heat but for standard grades the amount is not expected to exceed a very few percent. In welds the formation of martensite is not promoted by the presence of δ‐ferrite. The formation of martensite due to cold forming at room temperature can reach around 20 %. Cold forming with subsequent exposure to cryogenic temperatures does not lead to additional formation of martensite due to the exposure to low temperatures. Cold forming at low temperatures leads to the highest amount of martensite formed in metastable stainless steels. 相似文献
86.
Susil K. Putatunda 《Materials and Manufacturing Processes》2003,18(4):667-684
An investigation was carried out to examine the influence of microstructure on the stress corrosion cracking (SCC) growth behavior of an austempered high-carbon (1.00%), high-silicon (3.00%), and high-manganese (2.00%) cast steel. Compact tension specimens were prepared from this cast steel as per American Society for Testing Materials standard E-399 and were given four different heat treatments to produce different microstructures. The SCC behavior of these specimens was studied in 3.5% NaCl solution. The test results indicate the KISCCvalue of the material increases as the austenite content increases. Significant improvement in SCC resistance was achieved by using a novel two-step austempering process. Intergranular crack growth was observed in all these specimens. 相似文献
87.
88.
中碳钢马氏体组织温塑性变形力学行为 总被引:1,自引:0,他引:1
利用Gleeble 3500热模拟试验机对中碳钢淬火和完全退火组织的温加工流变应力在不同的变形参数条件下进行了对比研究,并根据其真σ ε曲线拟合了可反映该材料两种原始状态下压缩的稳态流变曲线和变形参数之间关系的中温压缩变形本构方程。结果表明:当为001 s-1时,室温压缩的σ ε曲线,淬火态的远高于退火态;350~550 ℃压缩,淬火态稍高于退火态;高于600 ℃压缩,淬火态的流变应力在变形初期略高于退火态,随应变的增加,淬火组织的流变曲线低于退火组织;在压缩温度为650 ℃,为1 s-1、01 s-1、001 s-1时,淬火和退火组织压缩的σ ε曲线有交点,在为0001 s-1时,淬火组织的σ ε曲线低于退火组织的σ ε曲线。 相似文献
89.
C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill. 相似文献
90.
Ultrahigh strength steels have been used increasingly in recent years for critical aircraft and aerospace structural applications.
In such applications, though materials performance is of prime consideration, cost and availability makes the low-alloy steels
an attractive option. This paper describes the development of an ultrahigh strength NiSiCrCoMo low-alloy steel, supported
by significant findings obtained from the basic studies that were aimed at understanding how solute additions influence fracture
resistance of iron, with and without the presence of carbon. The results of the basic studies, in combination with the work
of Garrison (1986) on a NiSiCr steel, have profitably been employed in the development of a NiSiCrCoMo low-alloy steel possessing
a strength-toughness combination quite comparable to the highly alloyed 250-grade maraging steel. Reproducibility of attractive
strength and toughness properties has been established in tonnage scale melts. This steel, in the softened condition, has
good formability and machinability. Weld parameters have also been established. The NiSiCrCoMo low-alloy steel thus meets
the requirements of performance and cost rendering it an attractive option for advanced structural applications. 相似文献