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Dissimilar Metal Welding

Apr 28, 2015

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Dissimilar Metal Welding, aluminum, steel, magnesium, alloy

M.Ekaditya Albar Rangga Agung Rhidiyan Waroko Rudiyansah

1106154305 1106108942 0806331935 0806331973

Master Degree Program Metallurgy and Material Engineering Department Universitas Indonesia7-Jan-13 1

Outline Dissimilar Metal Welding Journal Review Enhanced mechanical properties of friction stir welded dissimilar AlCu joint by intermetallic compounds Dissimilar friction welding of induction surface-hardened steels and thermochemically treated steels Dissimilar friction stir welding between 5052 aluminum alloy and AZ31 magnesium alloy

Weldability and mechanical properties of dissimilar aluminumcopper lap joints made by friction stir welding

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Dissimilar Metal Welding The joining of dissimilar materials is becoming increasingly important in industrial applications due to their numerous advantages. These include not only technical advantages, such as desired product properties, but also benets in terms of production economics. Dissimilar metals are difcult to join with conventional fusion welding due to their different chemical and physical characteristics, thus solid state joining methods have received much attention.

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Journal 1:Enhanced mechanical properties of friction stir welded dissimilar AlCu joint by intermetallic compounds (May 2010)Introduction: FSW has been shown to be an effective way of joining materials with poor fusion weldability, such as high-strength aluminum alloys and magnesium alloys. In Al-Cu joints, an intermetallic compound (IMC) layer usually formed on the AlCu interface. IMCs were easily formed in the nugget zone due to severe plastic deformation and thermal exposure. IMCs have been used as reinforcing particles in metal matrix composites (MMCs). Control of the IMC layer between dissimilar metals and the size and distribution of the IMC particles in the nugget zone becomes a key factor for FSW of dissimilar metals. Experiment: 1060 Aluminum + Pure Copper (99.9%) Plate (p x l x t : 300 x 70 x 5 mm) FSW machine (China FSW Center) Tool traverse speed : 100 mm min1 ; Rotation rate : 600 rpm Microstructural Analysis : EPMA, XRD, SEM, TEM, EDS Mechanical Testing : Tensile Test, Vickers Microhardness, Three-point Bending Test Results and Discussions: The nugget zone consists of a mixture of the aluminum matrix and Cu particles. A continuous and uniform interface layer is formed with a thickness of 1 m. Reinforcing particles were mainly composed of Al2Cu, Al4Cu9, and few AlCu particles. UTS of the composite structure was as high as 210 MPa. The hardness increased substantially due to the strengthening effect of the AlCu IMC particles.7-Jan-13 4

Journal 1:Enhanced mechanical properties of friction stir welded dissimilar AlCu joint by intermetallic compounds (May 2010)XRD Result SEM Result

EPMA Result PRZ

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Journal 1:Enhanced mechanical properties of friction stir welded dissimilar AlCu joint by intermetallic compounds (May 2010)Hardness Vickers

TEM Result

Tensile Test

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Journal 1:Enhanced mechanical properties of friction stir welded dissimilar AlCu joint by intermetallic compounds (May 2010)Bending Test

Conclusions: 1060 aluminum alloy and commercial pure copper were successfully friction stir welded. Reinforcing particles were mainly composed of Al2Cu, Al4Cu9, and few AlCu particles. UTS of the composite structure was as high as 210 MPa. The hardness increased substantially due to the strengthening effect of the AlCu IMC particles. Bending without fracture was generated at the AlCu interface.7-Jan-13 7

Journal 2:Dissimilar friction welding of induction surface-hardened steels and thermochemically treated steels (April 2012)Background: Friction welding is a highly productive process that relies on the conversion of mechanical energy into thermal energy. For friction joining of surface hardened steels, the distribution of the thermal gradient on the surfaces in contact during the process is affecting the hardness at the interface. This work is focused on the particularities of the conventional friction welding process of dissimilar steels for joints in which one component is induction-hardened, using high frequency currents, and the other one is subject to another heat or thermochemical treatment, such as carburization or nitriding.

Experiment: Hardness test (HVS 10A1 hardness tester on longitudinal section, polished and nital-etch join) Macroscopic (Olympus SZH-10 stereo microscope) Microstructure (Olympus BH-2 metallographic microscope) Bending test (Instron 250 kN universal testing machine) Torsion test (Schenk-Trebel torsion testing machine 1600Nm) Impact test (V-Notched, 300 J Charpy pendulum)

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Journal 2:Dissimilar friction welding of induction surface-hardened steels and thermochemically treated steels (April 2012)

MaterialsSteel C45 C55 16MnCr5 34CrNiMo6 C 0.48 0.56 0.17 0.36 Mn 0.63 0.61 1.14 0.61 Si 0.25 0.27 0.31 0.28 P 0.029 0.028 0.025 0.027 S 0.028 0.024 0.026 0.027 Cr 1.07 1.52 Mo 0.24 Ni 1.54

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Journal 2:Dissimilar friction welding of induction surface-hardened steels and thermochemically treated steels (April 2012)Treatments

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Fig. 1. Hardness gradient of the C55 steel after high frequency inductionhardening

Fig. 2. Macro and micrographic images of the dissimilar C55 inductionhardened with a C45 quench-hardened steel friction welded joint

Fig. 3. Hardness gradients for two values of the friction/upsetting pressure across the joining plane for the dissimilar C45 quench-hardened-C55 induction-hardened friction welded joint, measured in the marginal and central areas, respectively7-Jan-13 11

Fig. 4. Details about the microstructure and hardness gradients in pre-welding state for the 16MnCr5 (carburized) and 34CrNiMo6 (induction-hardened) steels used in the experiments.

Fig. 5. Macro and microscopic images of the friction welded joints of induction-hardened 34CrNiMo6 and 16MnCr5 carburized-quenched-tempered steels.

Fig. 6. Hardness gradients in axial direction across the joint plane for the induction-hardened 34CrNiMo6 steel with a 16MnCr5 carburizedquenched-tempered steel joint for two values of the friction/forging pressure.7-Jan-13 12

Fig. 7. Typical microstructure and hardness gradient observed for the C45 after the nitriding operation and the macroscopic image of the C55 inductionhardened and C45 nitrided steel joint.

Results and Discussions: A biconcave HAZ forms for high friction/forging pressures (300/400 N/mm2), if one of the components is thermomechanically treated. The decrease of the pressure did not affect the process, neither the extent of the softening area. The nitride layer contributes to the reduction of the relative friction between the components in the vicinity of the rotational axis. The experimental results show that a high quality joint can only be obtained if the nitride layer is fully expunged from the joint plane. If such nitride debris are still present, a quasi-cleavage fracture occurs due to the high cooling rate during the friction welding process, as also observed for other combinations with nitrided steels.

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Journal 2:Dissimilar friction welding of induction surface-hardened steels and thermochemically treated steels (April 2012)Conclusions: The friction pressure is limited to about 200 N/mm2, since higher values were observed to lead only to minor reduction of the hardness on the inductionhardened surface and can favor the presence of discontinuities in the center of the joint plane. Influenced by the presence hard layers in the join plane. By increasing the axial pressure, the thermochemically hardened layer can be expunged in the burr. The presence of the nitride layer contributes to the reduction of the friction in the vicinity of the rotational axis. Regardless of the friction/forging pressures used (200/300 or 300/400 N/mm2) the joints showed good mechanical properties, but the complete expulsion of the nitride layer was observed only for 6 mm upset length.

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Journal 3:Dissimilar friction stir welding between 5052 aluminum alloy and AZ31 magnesium alloy (January 2010)Background: Al alloy (combination between mass reduction and high strength); Mg alloy (low density and high specific strength). Joining Al alloy and Mg alloy will be difficult if we use conventional fusion welding because of large intermetallic compounds. FSW is a potential candidate for dissimilar welding because of lower processing temperature and can produced defect-free weld, i.e. joining Al 2024/Al 7075, Al/steel, Al/Cu, dan Al/Mg Experiment: 5052 Al alloy + AZ31 Mg alloy, plate thickness 6 mm. Surface of plate was grounded using grit paper to remove oxide layer then cleaned by ethanol. 5052 Al alloy (advancing side) and AZ31 Mg alloy (retreating side) from tool pin in FSW process. FSW machine using FSW-3LM-003, vrot = 600 r/min and vwelding = 40 mm/min. Butt join was resulted parallel to rolling path direction. Microstructure analysis at cross section of weld direction by OM (KEYENCE VHX-600) and SEM (Quata200) Etch solution: picric acid (4,2 g), acetic acid (8 ml), distilled water (10 ml), ethanol (70 ml). Hardness measurement by HVS-100 digit hardness tester, load ! N, dwell time 20 sec.

Materials

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Journal 3:Dissimilar friction stir welding between 5052 aluminum alloy and AZ31 magnesium alloy (January 2010)Defect-free using FSW (vrot = 600 r/min, vwelding = 40 mm/min).Interface Mg alloy + Al alloy

Fig. 1. Surface appearance of dissimilar weld prepared by FSW

Defect-free

Fig. 2. Optical approach of cross-s