The thermocouples were beaded at the tip and stuck at the measuring points with a silicate high temperature glue (TECHNICQLL, NALMAT, Trzebinia, Poland). 0000007965 00000 n
After cooling and applying the subsequent pressure, the process of recrystallization and growth takes place that results in fine grain structure as demonstrated authors in the papers [33, 48]. To see details of the matrix microstructure, specimens must be etched. A thin proeutectoid ferrite layer formed close to the weld interface in both central and peripheral zones (see Figs. During the friction welding process, wear generated heat and consequently increased the temperature at the weld interface. Martensite particles were approximately (2–6 µm) in size. The result shows that the hardness of the welded sample decreased more rapidly when the phase changed from a fully deformed zone to the HAZ. <]>>
Oxides and other foreign materials present on the original surface were broken up and dispersed. The ellipsoidal or even flake-shaped graphite in the HAZ acts as a stress concentration, which may prematurely cause a localized plastic flow at low stress and initiate fracture in the matrix at higher stress (Fig. 0000083177 00000 n
0000016643 00000 n
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The temperature curves of the weld center and peripheral zone during cooling phase (Fig. xref
Temperature identifiable in a close proximity to the interface of the joints was obtained with a TP202K1b2001 K-type thermocouple (NiCr–NiAl, CZAKI THERMO-PRODUCT, Raszyn, Poland) with the accuracy of ± 0.1 °C. AWS, Miami, Kou Sindo (2003) Welding metallurgy, 2nd edn. The combination of high friction welding parameters produced more axial shortening that played an important role in the mechanical properties of the joints, as reported by authors of other works [27, 28]. Difference in temperatures occurred due to the change of the yield strength stress of nodular cast iron with temperature (see Fig. Mater Des 56:572–578, Winiczenko R, Kaczorowski M (2012) Friction welding of ductile cast iron using interlayers. 12, the process of friction welding is difficult, because graphite particles, distributed in metal matrix without ductility, deteriorate the deformation plastic flow in high temperature and act as a lubricant, not allowing for a sufficient frictional heat to process the material. Similar results for the relationship between welding parameters, flash diameter, and tensile strength were achieved for different joints in other papers [25, 26]. Cavities arose from inclusions or coarser precipitates were enlarged and—during further yielding—the material between them was necked and sheared. Generally, a brittle fracture propagates through the grains. The hardness of the TMAZ, HAZ, and parent material region was measured. 3. 0000015391 00000 n
Figure 1 shows the microstructure of the as-cast nodular with graphite nodules in a matrix. CRC Francis & Taylor Group, New York, p 1149, Winiczenko R (2016) Effect of friction welding parameters on the tensile strength and microstructural properties of dissimilar AISI 1020-ASTM A536 joints. Figure 8 shows a Fe–C binary diagram with major transformation boundaries, as well as the associated phases and microstructures. Nodular cast iron (also called ductile or spheroidal graphite cast iron) is much stronger and has a notably higher elongation than other grade cast irons. J Braz Soc Mech Sci Eng 40(158):1–7, Baker H (1990) Alloy phase diagram. Magn. 11a). Arab J Sci Eng 39:5017–5023, Pineau A, Benzerga AA, Pardoen T (2016) Failure of metals I: brittle and ductile fracture. Effect of welding parameters on ultimate tensile strength of nodular cast iron joints. Only other materials, such as mild steels, have been considered in a friction welding of a truck axle-related application, where spindles are welded to axle housings [31]. Weld Cut 37:60–65, Dette M, Hirsch J (1990) Reibschweissen von Konstruieren aus Kugelgraphitguss mit Stahlteilen. Additionally, Fig. 0000008630 00000 n
As a result, this graphite morphology exhibits no elastic behavior and fails in tension without a significant plastic deformation [13, 47]. Fracture appearances of nodular cast iron welded joints for different welding parameters. Many techniques and special materials are available that allow for repair welding of nodular cast iron castings, for joining nodular cast iron to itself, as well as to other ferrous materials. However, the microstructure of nodular cast iron features spheres of graphite instead of flakes. During the cooling phase, heat was conducted away from the weld interface and lost to the surroundings through the ends of weld specimens. x�b```b``mg`e`�vga@ ��n� ���>g100��� �M,�rr B%������j�������%r�Y�@(4�q���&���*,�Bz�X6x&0 9, 12a). During friction welding of nodular cast iron, metal is heated above the eutectoid transformation temperature A1 (see Fig. The chemical composition and mechanical properties of a parent material selected for the study are shown in Table 1. 0000006794 00000 n
9). Eng Fail Anal 18:47–51, Kaczorowski M, Winiczenko R (2013) The microstructure and mass transport during friction welding of ductile cast iron. Journal of the Brazilian Society of Mechanical Sciences and Engineering All the specimens failed at the bondline during the executed tensile test without obvious plastic deformation. When the temperature of nodular cast iron exceeds the temperature of eutectoid, carbon in graphite spreads out to speed up the microstructure transformation by increasing carbon concentration in the base metal. A similar trend was observed by authors [49, 53]. Acta Metall Sin (Eng Lett) 28(10):1291–1298, Winiczenko R, Goroch O, Krzyńska A, Kaczorowski M (2017) Friction welding of tungsten heavy alloys with aluminium alloy. H��W�n7��W̺@�z�@�E�Ȣ�"������6����R�4]��;>&ϡ(�������9�i)9;��,!�ז��ߧ��%���ӏɺ��yN!,�z��8(V���/��d�~�j�ﯝ0�����E���M�˒�W���\�jݦ�//��/O_���������_>�f����Ϗ�yͷ��,��5ѯ�%��|��뷗)]��"C]2V�`�4�͒����u@��rE�)'�h�%,1��uɮ��+��`*���6���I���ҕ8O1�Kq5@�x���w���*fq�u@�1�����/�f2�YJK�1U��V�Me��"Y�J*]�f�v�'M���beX�J�o2^��5MfW�G�j뾒���V��m$��]���{㜦.Җ�F$�&�8F�v��WO|�"�`� J Mater Process Technol 246:42–55, Cheng CP, Lin HM, Lin JC (2010) Friction stir welding of ductile iron and low carbon steel. Fracture surface micrographs showing a mixture of dimple and a cleavage pattern mode for tensile test specimen with the optimum parameters a, b cleavage fracture with river markings; c, d shallow dimples with microvoid coalescence visible in the central part of the micrograph. In some areas of the micrograph, ultra-refined graphite particles (0.5–1 µm) were uniformly distributed in a pearlitic matrix (see Fig. 0000002610 00000 n
The effect of friction time on flash diameter is presented in Fig. xref
Time–temperature profiles at the axial center and the periphery are shown in Fig. The first is 4% alcoholic nitric acid ("nital") used at room temperature to reveal the ferrite grain boundaries and reveal phases and constituents such as cementite and pearlite. 0000018517 00000 n
Maximum temperature measurements in the axial center and periphery of the analyzed joints were equal to 950 and 840 °C, respectively. 3b). © 2020 Springer Nature Switzerland AG. As it can be seen, the marked areas are critical, because probably the highest stress can be identified there. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Moreover, the size of the weld flashes was dependent on friction welding parameters. Said phenomenon is also accompanied by a large decrease of the friction coefficient, which in turn decreases the amount of heat generated at the interface. There were noticeable differences in the width of the heat-affected zones and the amount of flash produced in the welds by opting for different welding conditions.