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为了揭示温变形工艺参数对双相钢拼焊板宏观力学性能及组织演变的影响规律,在不同变形温度和应变速率条件下对DP590双相钢拼焊板进行温拉伸试验和微观组织观察,将变形温度和应变速率对材料温成形过程的综合影响统一为Zener-Hollomon(Z)参数来研究材料宏观力学性能和微观组织演变.实验结果表明,随着Z参数的降低,材料越容易发生动态再结晶,流变应力-应变曲线越低,断后延伸率逐渐提高,平均晶粒尺寸有长大的趋势.本研究对于通过Z参数优化DP590双相钢拼焊板温变形宏观力学性能和微观组织具有一定的参考价值. 相似文献
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门内板是激光拼焊板应用于汽车车身的主要零件之一,通常由差厚板激光拼焊后经冲压成型。由于存在焊缝,且焊缝两侧的板料性能、厚度存在差异,在靠近焊缝的薄板侧很容易发生开裂,即随着板厚比例增大,破裂危险也相应增加,反之亦然。重要的是,门内板开裂问题会严重影响汽车质量,所以我们必须深入分析并解决问题。 相似文献
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目的研究某车型侧围加强板生产稳定性的材料性能。方法通过对某车型激光拼焊侧围加强板的主要用材TRIP800进行分析,研究不同3种生产批次材料性能和组织上的差异性,包括化学成分、显微组织、残余奥氏体含量、扩孔试验、力学性能、表面粗糙度的测量。结果 3种不同批次材料生产后,两种批次满足生产稳定要求,一种批次不能满足稳定生产要求,识别了TRIP800材料影响零件冲压开裂的关键性能指标,主要为材料伸长率及硬化指数。结论针对某侧围加强板的生产稳定性,材料伸长率大于25%,硬化指数n值不低于0.18的情况下,能够满足稳定生产。扩孔试验结果表明,该零件的成形过程中,扩孔率并不是唯一影响开裂的性能指标。 相似文献
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焊缝对拼焊板成形性能的影响 总被引:5,自引:0,他引:5
邱晓刚 《理化检验(物理分册)》2005,41(4):166-170
采用激光焊接技术对冷轧薄钢板进行拼焊,通过对拼焊板进行拉伸试验和模拟成形性能试验,研究分析了焊缝对拉伸性能参数和成形性能参数的影响,比较了拼焊板与母材性能的差异,分析了强度比和厚度比对塑性变形的影响及应变分布。 相似文献
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本研究通过等径通道挤压(ECAP)对孪晶诱导塑性变形钢(TWIP钢)在300℃下进行了晶粒细化,并运用金相显微镜、电子背散射衍射(EBSD)、透射电镜(TEM)观察了经不同道次挤压后TWIP钢的晶粒、孪晶形貌及位错组织。结果表明,在均匀化退火状态下,试样晶粒基本呈现等轴状态,通过测微尺测量晶粒尺寸,约为(90±30)μm。在1道次挤压后,晶粒沿剪切方向显著伸长,并有尺寸较小的新晶粒产生,许多形变孪晶在剪切带中产生。2道次挤压后新产生的细小晶粒增多,并开始产生许多微孪晶,孪晶易于在晶界处产生。经过4道次等径通道挤压,晶粒逐渐细化至超细晶状态,晶粒尺寸达到0.3~1μm,孪晶厚度随挤压道次的增多而不断减小,甚至达到几十纳米。在不同晶粒尺寸下,TWIP钢在高温ECAP过程中产生孪晶的机理不同。 相似文献
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为开展异种高熵合金激光焊接性研究,采用光纤激光对1.2 mm厚的异种高熵合金CuCoCrFeNi和AlCoCrFeNi实施了对接焊试验,利用金相观察、EDS、XRD和显微硬度计等方法对接头组织和性能进行测试.研究表明:在经历焊接热循环后,HAZ的金相组织没有发生明显变化;在FZ附近发现两种不同类型的显微组织(柱状晶和胞状晶),WM中心区由等轴晶组成;WM区内各元素均匀分布,FZ附近区域焊缝晶界处存在Cu、Al元素的偏聚,与母材相比,该偏聚现象明显减弱;焊缝横截面的显微硬度略高于CuCoCrFeNi合金,远低于AlCoCrFeNi合金;异种接头拉伸试样断裂位置发生在AlCoCrFeNi合金母材处,接头的抗拉强度σb为166 MPa,断口形式为解理断裂,其断口形貌为扇形花样与河流状花样(无撕裂棱).与母材组织相比,焊缝区晶粒明显细化,且焊缝仍为高熵合金. 相似文献
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针对2 mm厚的GH4169镍基合金板材进行激光对焊,研究热处理对GH4169激光焊接头组织和性能的影响。采用线切割方法制备激光焊接头试样,对热处理和非热处理激光焊接头进行拉伸实验、硬度测定、OM分析、SEM分析、EDS分析和XRD相分析。实验结果表明:热处理后接头抗拉强度为1372 MPa,延伸率为14%,焊缝平均硬度为473HV;较未热处理接头强度提高52%,延伸率降低71%,硬度提高69%。OM、SEM、EDS和XRD分析表明:对GH4169激光焊接头热处理能细化焊缝晶粒,改善枝晶形态,消除残余应力,析出δ相、γ′相和γ″相,使得焊接接头硬度和强度有所提高。 相似文献
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采用两种热输入不同的焊接工艺参数对3 mm壁厚的Inconel 617镍基高温合金进行激光焊接。通过光学显微镜和扫描电子显微镜对焊接接头显微组织进行观察分析,并测试了焊接接头在室温(25℃)及高温(900℃)下的拉伸性能。结果表明:激光焊接热输入对Inconel 617焊接接头显微组织及力学性能影响明显。在高热输入(200 J/mm)条件下,焊缝正面宽度3.88 mm,熔化区中部晶粒尺寸粗大,取向杂乱,树枝晶二次枝晶间距较大(6.71μm),枝晶间碳化物颗粒尺寸较为粗大,枝晶间Mo,Cr等合金元素的凝固偏析较为严重。焊接接头热影响区宽度约0.29 mm,在晶界和晶内形成了γ+碳化物共晶组织,这是由于焊接升温过程中,热影响区内球状碳化物颗粒与周边奥氏体发生组分液化,并在焊后凝固过程中形成共晶。低热输入(90 J/mm)工艺参数获得的焊缝正面宽度为2.28 mm,焊缝呈沿熔合线母材外延生长并沿热流方向定向凝固形成的柱状晶形态。焊缝中部树枝晶二次枝晶间距较小(2.26μm),枝晶间碳化物颗粒尺寸细小,热影响区宽度约0.15 mm。室温(25℃)拉伸测试表明:高热输入下获得的焊接接头由于焊缝中固溶元素偏析造成的局部组织弱化,从焊缝中部破坏,强度与伸长率有所降低,低热输入条件下获得的焊接接头从母材破坏。而高温实验条件下(900℃),母材晶界发生弱化导致所有试样均从母材破坏。 相似文献
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研究了激光焊对Fe-Mn-Si系形状记忆合金焊缝区组织和性能的影响,结果表明,激光焊焊缝区组织显著细化,大大提高基体的强度,同时,由于激光焊焊缝过冷度大,容易产生较多的层错,这些层错有利于应力诱发ε马氏体形核,从而显著提高焊缝区的形状记忆效应,和母材相比,提高幅度达40%~178%左右;在模拟油田介质情况下,激光焊焊缝耐腐蚀性能高于母材,这是因为,激光焊焊缝组织细小均匀,在腐蚀过程中产生钝化现象,同时也降低了腐蚀电池的电位差,从而降低了合金的腐蚀速度,提高耐腐蚀性能。 相似文献
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690 MPa级低合金高强钢焊接接头组织性能 总被引:1,自引:1,他引:0
为探讨690 MPa级低合金高强钢焊接接头组织与性能的关系,采用手工电弧焊(SMAW)和埋弧焊(SAW)获得成形良好的焊接接头,经过拉伸、冲击、弯曲试验及光学显微镜、扫描电镜和透射电镜分析,对两种焊接方法的接头组织性能进行研究.结果表明:两种焊接方法的焊缝组织主要为板条状贝氏体和少量针状铁素体,粗晶区为粗大贝氏体和少量马氏体;焊缝中含有大量分布均匀的微小球形夹杂物;两种焊接方法所得焊接接头都具有较高力学性能,-50℃的冲击断口形貌为韧窝、准解理混合型;埋弧焊焊缝冲击韧性低于手工电弧焊,手工电弧焊熔合线处冲击吸收功小于埋弧焊,但随距熔合线距离增加其值增加更快.显微组织和夹杂物是影响接头性能的主要因素. 相似文献
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Amir Abbas Zadpoor Jos Sinke Rinze Benedictus Raph Pieters 《Materials Science and Engineering: A》2008,494(1-2):281
This paper studies the microstructural features and mechanical properties of friction stir welds with dissimilar alloys and different thicknesses. The welds are produced in five different thickness/material combinations from 2024-T3 and 7075-T6 sheets with different thicknesses. A parametric study is conducted to optimize the welding parameters such that the different configurations can be compared. The paper is divided into two chapters: microstructural features and mechanical properties. In the first chapter, a study of the chemical composition and microstructure of the welds shows that a narrow chemical mixing zone is present in the dissimilar-alloy welds and that the stirring zone embodies the union rings and exhibits heterogeneous texture for most configurations. Study of the hardness, tensile properties and fracture surfaces in the second chapter shows that an asymmetric softened region, which is harder at the advancing side and extends more into the retreating side, is formed in the stirring zone and that the mechanical properties decrease as the thickness ratio increases. The fracture was partially ductile and partially brittle for all configurations. 相似文献
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《材料与设计》2015
Microstructure and tensile properties of the laser welded joint of Fe–18.8Mn–0.6C TWIP steel were investigated in this research. The microstructure of fusion zone (FZ) was characterized by means of X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). TEM and in-situ SEM observation were employed to investigate the microstructural evolution and strengthening mechanism of FZ during deformation. The welded joint with a fully austenitic structure was obtained by the laser welding. The granular divorced eutectic phases (Fe, Mn)3C and inclusions formed in the interdendritic regions during the solidification of FZ. The fully austenitic structure and coarse dendrite grains were responsible for the fracture at the weld seam. The FZ exhibited a good combination of strength (e.g. tensile strength up to 1000 MPa) and ductility (e.g. total elongation up to 73%). The microstructural evolution revealed that dislocation slip was the main deformation mechanism at low strains of FZ, while at relatively high strains, mechanical twinning was the domain deformation mechanism and played an important role in improving the strength and ductility as well as the work-hardening effect of FZ. 相似文献
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High strength low alloy (HSLA) and dual-phase DP980 (UTS ⩾ 980 MPa) steels were joined using fiber laser welding in similar and dissimilar materials combinations. The welded joints were characterized with respect to microhardness and tensile properties at three different temperatures: −40 °C, 25 °C, and 180 °C. Tensile properties of the welded joints were compared to those of the base metal (BM) obtained under similar conditions. A good correlation was found between the welded joints and the BM in relation to the tensile properties obtained at the different temperatures. A general trend of increase in the yield strength (YS), the ultimate tensile strength (UTS) and energy absorption (EA) with decreasing temperature was observed; however, work hardening coefficient was not altered and insignificant scatter was observed in case of the elongation. However, in the DP980 steel, dynamic strain ageing was observed only in the BM. 相似文献
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为实现直径为0.1 mm微孔的良好封接,采用低功率脉冲激光对0.40 mm厚的工业纯钛(CP-Ti Grade 1)进行了封焊,采用扫描电镜、显微硬度计及光学显微镜,研究了激光功率对焊缝表面成形、焊接接头横截面形貌和显微硬度的影响规律,分析了接头的微观组织结构.结果表明:当激光功率不低于19.2 W时,微孔可以实现完全封接,且熔核直径随着激光功率的增大而增大,但随着激光功率增大,焊缝凹陷和烧蚀现象越加严重;当激光功率增大时,焊缝表面显微硬度呈上升趋势,激光功率为19.2 W时,焊缝成形良好,且最大显微硬度值可以达到290 HV;焊缝中心微观组织为针状α、锯齿状α以及板条状α晶,焊缝上边缘为锯齿状α晶,而焊缝下边缘为细小的锯齿状α和针状α晶. 相似文献