共查询到20条相似文献,搜索用时 15 毫秒
1.
R.P. SiqueiraH.R.Z. Sandim T.R. OliveiraD. Raabe 《Materials Science and Engineering: A》2011,528(9):3513-3519
Composition and orientation effects on the final recrystallization texture of three coarse-grained Nb-containing AISI 430 ferritic stainless steels (FSSs) were investigated. Hot-bands of steels containing distinct amounts of niobium, carbon and nitrogen were annealed at 1250 °C for 2 h to promote grain growth. In particular, the amounts of Nb in solid solution vary from one grade to another. For purposes of comparison, the texture evolution of a hot-band sheet annealed at 1030 °C for 1 min (finer grain structure) was also investigated. Subsequently, the four sheets were cold rolled up to 80% reduction and then annealed at 800 °C for 15 min. Texture was determined using X-ray diffraction and electron backscatter diffraction (EBSD). Noticeable differences regarding the final recrystallization texture and microstructure were observed in the four investigated grades. Results suggest that distinct nucleation mechanisms take place within these large grains leading to the development of different final recrystallization textures. 相似文献
2.
M. AKITA M. NAKAJIMA Y. UEMATSU K. TOKAJI 《Fatigue & Fracture of Engineering Materials & Structures》2008,31(11):959-966
In order to understand the effects of annealing and quenching on fatigue behaviour in type 444 stainless steel, fully reversed axial fatigue tests have been performed using smooth specimens of heat‐treated materials in laboratory air and 3%NaCl aqueous solution. Three materials subjected to different heat treatments, annealing at 960 and 1000 °C, and water‐cooling at 960 °C, were prepared. In laboratory air, the fatigue limit of the annealed specimens was lower than that of the as‐received specimen and decreased with increasing annealing temperature. The subsequent grain coarsening from the heat treatments was primarily responsible for the lower fatigue strength in the annealed specimens. The fatigue strength of the water‐cooled specimen was lower than that of the corresponding annealed specimen. In the annealed specimens, cracks were generated within ferritic grains, while in the water‐cooled specimen, at or near grain boundaries. In 3%NaCl solution, the fatigue strengths of all specimens decreased compared with those in laboratory air. Only in the water‐cooled specimens, crack initiation at grain boundary and intergranular crack growth were observed, indicating the most sensitive to corrosion environment. 相似文献
3.
The microstructure, including grain size and precipitation, tensile strength and Charpy impact toughness of (Nb + V) 18Cr–2Mo ferritic stainless steel heavy plates with/without Ti were investigated by means of optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and standard tensile strength and Charpy impact toughness testing. It was found that for 18Cr–2Mo heavy plate, a good combination of Nb–V stabilized method without Ti induces refinement of grain sizes due to the precipitation of amounts of fine Nb carbonitrides and V nitrides. Meanwhile, the mechanical testing results indicate that optimal transformation of grain size, precipitation that Nb–V composition system brings to 18Cr–2Mo heavy plate is beneficial to improvement of strength and impact toughness. 相似文献
4.
Hoon-Hwe ChoHeung Nam Han Sung-Tae Hong Jong-Hwan ParkYong-Jai Kwon Seok-Hyun KimRussell J. Steel 《Materials Science and Engineering: A》2011,528(6):2889-2894
High-quality, defect-free welds were successfully produced in 409 ferritic stainless steel by friction stir welding. A remarkably fine-grained microstructure was observed in the stir zone, and the fraction of low angle grain boundary in the stir zone significantly increased as compared to that in the base material. An increase in plunging depth led to an increase of the fraction of low angle grain boundary, a decrease in grain size, and an increase in hardness in the stir zone. 相似文献
5.
In this work, microstructural characteristics and development within the heat affected zone (HAZ) of T4003 ferritic stainless steel (FSS) welded joint were investigated combining experimental measurement with finite element simulation of welding temperature field. The results indicate that the HAZ was characterized with heterogeneous microstructure due to the extensive peak temperature range which could be divided into three sub-zones named as HAZ1, HAZ2 and HAZ3. The HAZ1 (the region next to weld zone boundary) experienced peak temperatures of 1300–1500 °C during welding process. This region presented almost fully δ ferrite microstructure with irregular grain, which was attributed to the high element diffusion rate and the absence of elevated-temperature austenite. The HAZ2 (center region of HAZ) suffered the peak temperatures of 1150–1300 °C. It presented martensite + δ ferrite dual microstructure with limited grain growth due to the formation of γ phase at grain boundaries. The HAZ3 (the region closed to the base metal) was undergone the peak temperatures of 830–1150 °C and was characterized with both martensite and ferrite structure. 相似文献
6.
为探究一种新型铁素体不锈钢的深冲性能,在840~920℃不同温度下对新型铁素体不锈钢的冷轧板做再结晶退火处理,通过XRD、SEM和EBSD等分析方法研究了退火2 min或4 min后,材料微观组织、宏观织构的变化规律对深冲性能的影响及其内在机理.研究表明:保持退火时间2 min,退火温度900℃时,试验钢拥有较多的有利γ纤维织构,主要为{111}112取向,并有少量α纤维织构,此时平均塑性应变比r-=1.77,高于其他退火温度下的值;延长退火时间,在900℃下保温4 min,不同取向晶粒获得了长大机会,晶粒尺寸均匀性显著改善,r-值提高至1.82,试验钢有望取得理想深冲性能. 相似文献
7.
Correlation between ductile-to-brittle transition behaviour and twinning in ferritic stainless steel
F. Gao F.-X. Yu R. D. K. Misra H.-T. Liu Z.-Y. Liu 《Materials Science & Technology》2015,31(12):1462-1472
In this work, the 18Cr–2Mo ferritic stainless steel was treated with and without warm rolling at 573 K with 66.5% reduction after conventional hot rolling process. It was shown that ductile-to-brittle transition behaviour could be closely related to deformation twinning and parameters affecting critical temperature for twinning would also inevitably affect ductile-to-brittle transition temperature. This correlation between ductile-to-brittle transition behaviour and twinning was in good agreement with the Cottrell–Petch model. A lowered transition temperature and an improved toughness after introducing warm rolling process and corresponding annealing process could be mainly explained in terms of refining the recrystallised grains and reducing the volume fraction of grains having orientations favourable for twinning, which decrease the critical temperature at which twins form. 相似文献
8.
《Materials Science & Technology》2013,29(2):530-536
AbstractTraditional 11·5 wt-%Cr ferritic stainless steels are single stabilised with Ti or dual stabilised with Ti–Nb additions. A dual-stabilised ferritic stainless steel 409 with Zr–Ti additions was studied, which was selected through thermodynamic and kinetics analysis. The alloy was subjected to thermomechanical processing using both hot and cold rolling and annealing. The intergranular corrosion resistance and microstructure of this alloy was evaluated. Of particular interest was to study the stabilisation behaviour of this alloy under all processing conditions. The results showed that the precipitation of CrxCy was effectively prevented; hence, the alloy used in this investigation had an excellent resistance to intergranular corrosion. 相似文献
9.
Keum-Oh Lee Seong-Gu Hong Samson Yoon Soon-Bok Lee 《International Journal of Fatigue》2005,27(10-12):1559
Low-cycle fatigue tests on 429EM ferritic stainless steel and 316L austenitic stainless steel were carried out in a wide range of temperatures from room temperature to 750 °C. The Tomkins fatigue life model was applied to correlate the fatigue life with crack propagation rate and this model matched well with the fatigue life of 429EM stainless steel but not for the 316L stainless steel. A new life prediction model was developed to consider the temperature effect on fatigue life. The predictions show good agreement with experimental results for both materials. The predicted lives were within a±2X scatter band at all test temperatures. 相似文献
10.
《材料科学技术学报》2019,35(8):1787-1796
Intergranular corrosion (IGC) behavior of the stabilized ultra-pure 430LX ferritic stainless steel (FSS) was investigated by using double loop electrochemical potentiokinetic reactivation (DL-EPR) and oxalic acid etch tests to measure the susceptibility of specimens given a two-step heat treatment. The results reveal that IGC occurs in the specimens aged at the temperature range of 600–750 °C for a short time. The aging time that is required to cause IGC decreases with the increase of aging temperature. A longer aging treatment can reduce the susceptibility to IGC. The microstructural observation shows that M23C6 precipitates form along the grain boundaries, leading to the formation of Cr-depleted zones. The presence of Cr-depleted zones results in the susceptibility to IGC. However, the atoms of stabilizing elements replace chromium atoms to form MC precipitates after long-time aging treatment, resulting in the chromium replenishment of Cr-depleted zones and the reduction of the susceptibility to IGC. 相似文献
11.
The present work was performed to investigate the texture difference of an ordinary Ti-IF steel and a high-strength Ti-IF steel under ferritic hot rolling and high-temperature coiling. Comparing with the completely recrystallized textures of the ordinary IF steel, the textures of the high-strength IF steel were still deformed textures. The texture difference for the two steels is related to high P content in the high-strength IF steel which prevents the recrystallization during the coiling process. For the ordinary IF steel, the texture components were mainly very weak {001}110 orientation at the surface, and partial 110//RD (rolling direction) textures focused on {223}110 orientation and 111/ND (normal direction) texture at the mid-section and 1/4-section. For the high-strength IF steel, the texture components were mainly of {110}001 orientation at the surface and of a sharp 110//RD texture from {001}110 to {223}110 and weak 111/ND texture at the mid-section and 1/4-section. 相似文献
12.
In this study, microstructure and mechanical properties of a friction stir welded 18Cr–2Mo ferritic stainless steel thick plate were investigated. The 5.4 mm thick plates with excellent properties were welded at a constant rotational speed and a changeable welding speed using a composite tool featuring a chosen volume fraction of cubic boron nitride (cBN) in a W–Re matrix. The high-quality welds were successfully produced with optimised welding parameters, and studied by means of optical microscopy (OM), scanning electron microscopy (SEM), electron back-scattered diffraction (EBSD) and standard hardness and impact toughness testing. The results show that microstructure and mechanical properties of the joints are affected greatly, which is mainly related to the remarkably fine-grained microstructure of equiaxed ferrite that is observed in the friction stir welded joint. Meanwhile, the ratios of low-angle grain boundary in the stir zone regions significantly increase, and the texture turns strong. Compared with the base material, mechanical properties of the joint are maintained in a comparatively high level. 相似文献
13.
Microstructure, precipitates and fracture morphology in the coarse grained heat-affected zone CGHAZ) of a new high-purity
0Cr18Mo2Ti ferritic stainless steel were studied by means of optical metallography, SEM, TEM, X-ray diffractometer, etc. Experimental
results indicated that grain coarsening resulted in brittle fracture in the CGHAZ of 0Cr18Mo2Ti steel. The reduction of impact
toughness in the CGHAZ due to change of cooling rate can be attributed to the increase of nitrides (TiN, Cr2N, etc). These nitrides in the CGHAZ promote initiation and propagation of brittle cracks. The precipitated Cr2N nitrides in the grain boundaries decrease impact toughness in the CGHAZ of 0Cr18Mo2Ti steel by promoting crack initiation. In practical applications, the welding heat input (E) should be as low as possible to prevent toughness reduction in the CGHAZ. 相似文献
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16.
针对一种以Al作为主要强化元素的新型马氏体时效不锈钢,通过力学性能测试、光学显微镜观察和透射电子显微分析方法,研究不同的热处理温度对实验钢力学性能和微观组织的影响。结果表明:该实验钢的抗拉强度最高可达1876MPa,屈服强度可达1762MPa,具有良好的强韧性配合。固溶处理后形成了具有高密度位错的细小板条马氏体组织,在时效过程中,马氏体基体上弥散析出的NiAl相使其强度得到大幅度的提升。随着时效温度的提高,NiAl析出相颗粒逐渐长大粗化,从而使强度在到达峰值后迅速下降,出现了过时效现象。实验钢经过820℃固溶+(-70℃)冷处理+540℃时效处理后可获得良好的综合力学性能。 相似文献
17.
Effect of hot-rolling temperature on microstructure and texture of an ultra-low carbon Ti-interstitial-free steel 总被引:2,自引:0,他引:2
W.C. Jeong 《Materials Letters》2008,62(1):91-94
Effect of finishing temperature in hot-rolling on the microstructure and texture of a cold-rolled and continuously annealed ultra-low carbon Ti-interstitial-free steel has been investigated. The finishing temperature in hot-rolling was varied from 900 °C in austenite region to 750 °C in ferrite region. Lankford value of the annealed sheet was decreased with a decrease in the finishing temperature to the ferrite region. This might be related to both the stronger {100} <011> texture of the annealed sheet and the texture inhomogeneity in the through-thickness direction of the hot bands rolled in ferrite region. The major component of the recrystallization texture was near {554} <225> irrespective of the hot-rolling temperature, but the intensity of {100} <011> texture was increased with the decrease in the finishing temperature in hot-rolling. 相似文献
18.
Dae Jin Ha Chang-Young Son Joon Wook Park Jong Seog Lee Yong Deuk Lee Sunghak Lee 《Materials Science and Engineering: A》2008,492(1-2):49-59
Effects of high-temperature hardness and oxidation on sticking phenomena occurring during hot rolling of two STS 430J1L ferritic stainless steels were investigated in this study. Hot-rolling simulation test was conducted using a high-temperature wear tester. The sticking started from the initial nucleation stage in which the rolled materials were stuck onto the roll specimen surface, proceeded to the growth stage in which stuck fragments grew further, and reached the saturation stage. The modified 430J1L steel had a smaller number of sticking nucleation sites and slower growth rate than the conventional 430J1L steel because of higher high-temperature hardness, thereby leading to less serious sticking. When the simulation test was conducted at 1070 °C, Cr oxides were formed on the surface of the rolled materials, and thus the sticking was drastically reduced because of the increased surface hardness of the rolled materials. In order to prevent or minimize the sticking, thus, it was suggested to improve high-temperature properties of stainless steels in the case of hot rolling at 900–1000 °C, and to promote the formation of oxides in the case of hot rolling at temperatures higher than 1000 °C. 相似文献
19.
The precipitation behavior of inhibitors and their influence on final Goss texture formation in grain-oriented electrical steels produced by compact strip processing technology with a reheating temperature lower than 1200 °C were investigated under two distinct intermediate annealing methods: conventional intermediate recrystallization annealing and a new intermediate decarburizing and recrystallization annealing method without final decarburizing after the second cold rolling. The initiation of secondary recrystallization, the distributions of second phase particles, the final Goss texture, and the grain structure were observed. The new technology could maintain higher inhibitor densities because the deformed matrix could provide higher site densities for inhibitor nucleation before secondary recrystallization, resulting in a relatively higher inhibition effect of the second phase particles. The new technology could also compensate for the disadvantages of fewer inhibitors induced by fewer dissolved Mn and S elements in the matrix during lower reheating temperature for hot rolling. The final sheet produced after the secondary recrystallization annealing obtained stronger Goss texture, larger grain size, and better magnetic properties. 相似文献
20.
V. Kuzucu M. Aksoy M.H. Korkut M.M. Yildirim 《Materials Science and Engineering: A》1997,230(1-2):75-80
The effect of different amounts of Nb and of homogenization on the ferritic stainless steels containing 17–18 wt.% Cr was investigated with scanning electron microscopy (SEM), optical microscopy, energy-dispersive spectrometry (EDS), X-ray diffraction (XRD) and differential thermal analysis (DTA). It was observed that M23C6, NbC and sigma phase formed in these steels. In addition, the formation of Nb2C was observed in the sample containing 3.0 wt.% Nb. While the amount of Nb increased from 0.5 to 3.0 wt.% Nb, the microhardness of the matrix and the amount of M23C6 decreased and the toughness of the samples increased. After homogenization, the increase in the toughness of the samples containing 1.5–3.0 wt.%Nb was considerable and impressive. 相似文献