共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
3.
4.
BAINITE IN SOME ALLOY STEELS AND ITS MECHANICAL BEHAVIOUR 总被引:9,自引:0,他引:9
合金钢中温转变组织计有:粒状组织、上贝氏体和下贝氏体,有时可获准贝氏体。与马氏体回火后比较,准贝氏体、粒状组织、粒状贝氏体或它们的复合往往具有低屈服强度、一定高的抗拉强度,高的韧性、高的疲劳寿命和相当的疲劳强度。 相似文献
5.
钢中贝氏体及其力学行为 总被引:2,自引:0,他引:2
合金钢中温转变组织计有:粒状组织、上贝氏体和下贝氏体,有时可获准贝氏体。与马氏体回火后比较,准贝氏体、粒状组织、粒状贝氏体或它们的复合往往具有低屈服强度、一定高的抗拉强度,高的韧性、高的疲劳寿命和相当的疲劳强度。 相似文献
6.
使用热处理风冷炉模拟研究了大型汽轮机转子内外径处的冷却速率对转子材料30CrMoNiV511钢的组织转变及强韧性的影响。结果表明,淬火冷却速率对转子材料的强度影响不明显,而对冲击韧性的影响显著。随着淬火冷却速率从50℃/min逐渐降低至7℃/min,淬火组织由下贝氏体逐渐向上贝氏体、粒状贝氏体及其混合组织转变,冲击韧性由66 J急剧降低到16 J;当冷却速率降低到5℃/min以下时,组织中出现先共析铁素体,且上贝氏体铁素体粗大,碳化物分布极不均匀,冲击韧性极差。不同冷却速率转子钢的微观组织及碳化物析出形态和分布是决定其冲击韧性的主要原因之一。 相似文献
7.
8.
9.
采用焊接热模拟技术和显微组织分析等方法,对Mg处理X100管线钢在连续冷却转变下的显微组织的变化规律进行了研究。通过对Mg处理X100管线钢CCT曲线的建立和显微组织分析结果表明:对比焊接CCT模拟工艺和常规950℃保温的CCT工艺,前者AC1、AC3相变点要分别高于后者25℃,奥氏体晶粒显著大于后者,冷却相变点要低于后者50~80℃。在焊接热模拟工艺下,当冷却速度在0.1~3℃/s之间时,组织以准多边形铁素体(QF)和粒状贝氏体为主;在3~30℃/s的冷却速度范围,主体组织为粒状贝氏体(GB)和针状铁素体(BF);当冷却速度为30~50℃/s,组织以贝氏体铁素体(BF)为主;大于50℃/s的冷却速度,将形成马氏体(M)组织。 相似文献
10.
为提高低合金高强铸钢(HSLA)的综合力学性能,满足恶劣环境下的使用要求.采用光学显微镜、扫描电镜、透射电镜、冲击试验机、万能材料试验机研究了3种不同冷速及高温回火对HSLA铸钢组织与力学性能的影响.结果表明:随冷速增加,淬火组织发生由多边形铁素体+针状铁素体+粒状贝氏体→粒状贝氏体+板条贝氏体→准上贝氏体+板条马氏体的演变.冷速为1℃/s的空冷样,具有最高的塑韧性;冷速最大的水冷样,其强度、硬度最高.冷却样经580℃回火,其晶界、板条界均有粒状、短棒状的纳米第二相析出,EDS分析表明,100~200 nm的析出相为合金渗碳体(M3C),而50 nm以内的析出相为(V,Ti)(C,N).空冷样回火后有较高强度、最高的塑韧性;油冷、水冷样回火后,Re提高,Rm略有下降,AkU降低与高温回火脆性的发生有关,但-40℃的AkU仍有60、40 J,具有较好的低温冲击韧性.可见,试验HSLA铸钢表现出良好的综合力学性能,能满足在恶劣环境下的使用要求. 相似文献
11.
《International journal for numerical methods in engineering》2018,113(9):1488-1506
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method. 相似文献
12.
13.
Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
14.
A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa. 相似文献
15.
On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.…… 相似文献
16.
Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß. 相似文献
17.
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
18.
Dimiter Hadjistamov 《材料科学与工程:中英文B版...》2019,(2):56-65
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ... 相似文献
19.
《中国标准化(英文版)》2014,(4)
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from 相似文献
20.
《中国标准化(英文版)》2014,(5)
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively. 相似文献