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Development of a New Welding Material for Arc Welding of As-cast Ferritic Ductile Iron
Daqian SUN,Zhenfeng ZHOU,Jingfei LUAN,

材料科学技术学报 , 1998,
Abstract: Using the nickel welding wire, the effect of alloying elements on the chilling tendency of partial fusion zone (PFZ) of arc-welded ferritic ductile iron and the mechanical properties of weld metal have been systematically studied. On this basis a new nickel electrode for arc welding of ferritic ductile iron (QT400-17) is developed for the first time. The mechanical properties of its weld metal can match those of ferritic ductile iron. The width of carbide layer (WCL) in PFZ is significantly decreased, the welded joint has excellent machinability and the weid metal has high hot cracking resistance
Mechanical properties and structure of austempered ductile iron -ADI
Kaczorowaki M.,Krzyńska A.
Archives of Foundry Engineering , 2007,
Abstract: The results of experimental study of austempered ductile iron are presented. The aim of the investigations was to look closer into the structure – mechanical properties relationships of this very attractive cast material. The experiment was carried out with 500 7 grade ductile iron, which was austempered using different parameters of heat treatment. The specimens were first solution treated 1 hour in 910oC and then isothermally quenched for different time in silicon oil bath of temperature 275, 325, 300 and 350oC. The mechanical properties heat treated specimens were tested in tensile to evaluate yield stress Re, 0.2, tensile strength Rm and elongation A10. Additionally hardness of heat treated samples was measured using Brinell-Rockwell hardness tester. Structure of the specimens was studied either with conventional metallography, scanning (SEM) and transmission (TEM) electron microscopy. It followed from the study that conventional grade ductile iron enabled to produce both low and high strength ADI, depend on heat treatment parameters. As expected the low temperature isothermal quenching produced higher strength ADI compare to the same ductile iron but austempered at 350oC. It was discovered however, that low yield strength ADI obtained for short time quenching at 275oC exhibited high strengthening effect while strained in tensile. So it was concluded that this had to by cause by large amount of untransformed austenite, which FCC lattice is characterized by high strengthening coefficient.
Calorimetric examinations of austempered ductile iron ADI  [PDF]
F. Binczyk,J. Furmanek,A. Smoliński
Archives of Foundry Engineering , 2007,
Abstract: The study presents the results of calorimetric examinations during heating and cooling of austempered ductile iron ADI after austempering at temperatures of 280, 330 and 380oC. The samples for examinations were taken from cast rods of 20 and 60 mm diameter. Examinations were carried out on a differential scanning calorimeter, type Multi HTC S60. During heating, on a DSC curve one strong exothermic effect has been noted to occur (it does not occur in the case of common-grade cast iron), accompanied by two endothermic effects. The exothermic effect occurs within the range of about 20oC. Depending on the temperature of austempering treatment, its beginning falls to the temperatures from 469 to 490oC. The heat of this effect is proportional to the austenite content in ADI matrix after austempering. The endothermic effects are related with decomposition of pearlite (or bainite) and with phase transformation α → γ (ferrite as a constituent of ausferritic matrix.
Fatigue Properties of Austempered Ductile Iron(ADI) in Water Environment

QZ Cai,BK Wei,Y Tanaka,

金属学报(英文版) , 2004,
Abstract: The acicular ferrite in austempered ductile iron (ADI) matrix around graphite was corroded preferentially in wet condition, promoting crack origination and propagation and resulting in the disappearance of ADI fatigue limit. ADI fatigue strength was gradually reduced with increasing the time of test and was reduced by 50% in wet condition at 10~7 cycles compared with the fatigue limit in dry condition. The fatigue strength variation of ferritic ductile iron in wet condition was similar to that of ADI. The ferritic ductile iron, however, has better corrosion resistance so that the fatigue strength was lowered only by 10% in wet condition at 10~7 cycles compared with the fatigue limit in dry condition. On the other hand, the fatigue limits of ADI and ferritic ductile iron were dropped by 32% and 25% in tap water dipping 480h/dry condition respectively compared with those in dry condition. The reduction of fatigue limit was attributed to corrosion pits formation correlated with stress concentration, resulting in origination and propagation of fatigue crack.
To Study the Effect of Austempering Temperature on Fracture Behaviour of Ni-Mo Austempered Ductile Iron (ADI)  [PDF]
Vikas Chawla, Uma Batra, D. Puri, Amita Chawla
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2008, DOI: 10.4236/jmmce.2008.74024
Abstract: Austempered Ductile Iron (ADI) can be as twice as strong as standard spheroidal iron at the same level of toughness. It responds to work-hardening surface treatments and exhibits excellent fatigue and wear property. There is extensive work done on the fracture of steel with ferrite or/and austenite structure, but little on fracture behaviour of ADI whose microstructure also comprises austenite and ferrite but with graphite nodules in the matrix. The present work is aimed in this direction. The fracture behavior of Ni-Mo ADI is studied. It is found that the crack always originates from graphite nodules and the matrix affects the propagation path.
Influence of Temper Temperature of Austenite on High-speed Cutting Properties of Austempering Ductile Iron (ADI)
奥氏体回火温度对等温淬火球墨铸铁(ADI) 高速切削加工性能的影响研究

WU Shao-hu,GUO Xu-hong,SHI Gao-lian,

摩擦学学报 , 2009,
Abstract: 等温淬火球墨铸铁(Austempering Ductile Iron,以下简称ADI)是一种新型的耐磨球铁材料.结合现有ADI材料的生产情况,选取300、350、400 ℃3个奥氏体回火温度,制备3组试样并测定力学性能.通过高速切削试验,研究了CC650陶瓷刀具高速干式切削不同性能ADI材料时刀具磨损形态和磨损机理,探讨了奥氏体回火温度对ADI高速切削时刀具磨损性能的关系.试验结果表明,奥氏体回火温度对ADI材料组织和力学性能有较大影响;奥氏体回火温度和ADI试件材料与CC650刀具磨损之间具有相关性;高速切削时,CC650刀具对ADI切削的磨损机制以磨粒磨损和扩散磨损为主.
Development of a new coated electrode with low nickel content for welding ductile iron and its response to austempering  [PDF]
Tapan Sarkar,Ajit Kumar Pramanick,Tapan Kumar Pal,Akshay Kumar Pramanick
- , 2018, DOI: https://doi.org/10.1007/s12613-018-1660-1
Abstract: Coated Electrodes with small amounts of nickel were developed for welding ductile iron (DI) and conversion of the same into austempered ductile iron (ADI) after austempering. Among six electrodes, Trials 3 and 4 were selected for establishing crack-free weld deposits via preheating and post-weld heat treatment. Austenitization was performed at 900°C for 2 h and austempering at 300 or 350°C for three different holding times to observe the results of austempering with respect to the microstructure, hardness, and austempering kinetics of the samples. The microstructures of the weld deposits showed needle-like bainitic ferrite with small amounts of retained austenite when treated at 300°C and feathery bainitic ferrite with large amounts of retainedaustenite when treated at 350°C. The electrode labeled with Trial 3 revealed greater austenite contents than that labeled with Trial 4 when treated with a 2 h holding time regardless of the austempering temperature applied. The transformation rate of the bainitic ferrite of Trial 3 was relatively higher than that of Trial 4 and showed a lower rate constant, leading to a higher diffusion rate of carbon in austenite.
Study on Ceramic Cutter''s Wear Mechanism When Dry Cutting Austempered Ductile Iron (ADI)

GUO Xu-hong,RUI Yan-nian,ZHU Sheng-ling,DONG Gui-yan,

摩擦学学报 , 2006,
Abstract: 采用陶瓷刀具(CC650)和YG6硬质合金刀具对等温淬火球墨铸铁(以下简称ADI)材料进行干式精车切削试验, 采用带有X射线能谱分析的扫描电子显微镜观察刀具磨损表面形貌, 用能谱仪对刀具磨损微区和工件表面成分进行分析, 用X射线衍射仪对刀具、 ADI材料和切屑等试样进行物相分析, 研究陶瓷刀具磨损形态及其磨损机理. 结果表明: 刀具磨损的主要形式为磨粒磨损、粘着磨损、 扩散磨损及微崩和脱落; ADI材料中含有微量Al和Ti元素, 在较高速度下切削ADI材料时, 刀具与工件之间的亲和性增加而导致粘着磨损; 在刀具前刀面平均切削温度大于800 ℃以上时,ADI材料中的元素Fe和Si扩散到刀面,刀具中的元素Al和Ti扩散到ADI材料表面,从而加剧刀具的磨损;切削后ADI材料表面出现的Al2O3相及切屑中的FeCr相等高硬度化合物颗粒是造成CC650刀具磨粒磨损的主要原因.
Residual Stresses and Micro-Hardness Testing in Evaluating the Heat Affected Zone’s Width of Ferritic Ductile Iron Arc Welds  [PDF]
Georgios K. Triantafyllidis, Dimitrios I. Zagliveris, Dionysios L. Kolioulis, Christos S. Tsiompanis, Titos N. Pasparakis, Athanasios P. Gredis, Melina L. Sfantou, Ioannis E. Giouvanakis
Materials Sciences and Applications (MSA) , 2016, DOI: 10.4236/msa.2016.71007
Abstract: Shielded Metal Arc Welding (SMAW) in Ductile Irons (DI) is often required by foundries for practical manufacturing reasons. The mechanical properties of the welded structures are strongly dependent on their HAZ’s width. A model based on the behaviour of the ferritic matrix of high-Si DIs in order to make an approach in measuring their HAZ’s width is developed in this study. A series of thermal treatments on 3.35 and 3.75 wt% Si as-cast DIs and spot SMAWs is applied on these materials. The applied SMAWs are done on non-preheated and preheated samples (150 - 300). For welding we modify the amperage (100 - 140A). The micro-hardness Vickers changes in the ferrite of the as-cast samples and inside the HAZ of the welded ones can be attributed to the existence of residual stresses (RS) in the ferritic matrix and assist in estimating the HAZ’s width.
The mystery of ADI  [PDF]
A. Krzyńska,M. Kaczorowski
Archives of Foundry Engineering , 2007,
Abstract: The considerations of ADI strengthening mechanisms based on results of previous structure investigations are presented. The aim of this elaboration was to discuss which mechanism looks to be most responsible for strengthening of ADI. It was concluded that the high strength of ADI which matrix consist mostly ferrite, austenite and sometimes some amount of martensite is caused by strengthening these three phases. Neglecting high carbon martensite which strength properties are nothing surprising, it is proposed that different mechanism of strengthening are responsible for ferrite and austenite strength increase. In case first of these phases strengthening is caused mainly by strain hardening. It is evidenced with very high dislocations and dislocation loops density which are typical in case of ferrite grains. The mechanism of austenite strengthening is more complicated. First of all hardening of austenite is connected with high supersaturation with carbon. The effect of strengthening is additionally increased with grains refinement caused by twinning and formation of stacking faults. The first of them supply extra coherent grain boundaries and the second lead to distortion of perfect lattice structure. It looks from the analysis, that strengthening rather soft and ductile phases which are ferrite and austenite is high enough to explain high strength properties of ADI.
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