“…This zone is over-aged under the action of welding heat, resulting in the dissolution of the precipitation phase and strengthening phase aggregation growth. The material hardness here drops significantly, forming the lowest hardness value of joints [23]. Figure 6 Microhardness of P-MIG joints and CMT joints.…”
Section: Resultsmentioning
confidence: 99%
“…HAZ is mainly the zone where the properties of the unmelted base material are different from the base material under the action of the welding heat cycle during the welding process. The main reason is related to the dissolution, precipitation, and grain coarsening of the second phase caused by welding heat input [23]. The composition of HAZ is mainly Al-Mg-Si alloy with the same composition as the base material.…”
Section: Haz Microstructure and Property Analysismentioning
This paper focuses on pulse metal inert gas welding (P-MIG) and cold metal transfer (CMT) of 6082-T6 aluminium alloy. The microstructure and properties of joints were analysed and the phase transformation of the welding zones (WZ) was calculated using JMatPro. The results showed that CMT joints are better than P-MIG joints in tensile strength and hardness. The main reason is that the average grain size and the second phase size of CMT joints are smaller than those of P-MIG joints. Moreover, the larger number of large-angle grain boundaries (LAGB), diffusely distributed Al3Mg2 and Al6Mn phases in CMT WZ, as well as a small amount of distributed Al3Zr, are beneficial to the joints properties too.
“…This zone is over-aged under the action of welding heat, resulting in the dissolution of the precipitation phase and strengthening phase aggregation growth. The material hardness here drops significantly, forming the lowest hardness value of joints [23]. Figure 6 Microhardness of P-MIG joints and CMT joints.…”
Section: Resultsmentioning
confidence: 99%
“…HAZ is mainly the zone where the properties of the unmelted base material are different from the base material under the action of the welding heat cycle during the welding process. The main reason is related to the dissolution, precipitation, and grain coarsening of the second phase caused by welding heat input [23]. The composition of HAZ is mainly Al-Mg-Si alloy with the same composition as the base material.…”
Section: Haz Microstructure and Property Analysismentioning
This paper focuses on pulse metal inert gas welding (P-MIG) and cold metal transfer (CMT) of 6082-T6 aluminium alloy. The microstructure and properties of joints were analysed and the phase transformation of the welding zones (WZ) was calculated using JMatPro. The results showed that CMT joints are better than P-MIG joints in tensile strength and hardness. The main reason is that the average grain size and the second phase size of CMT joints are smaller than those of P-MIG joints. Moreover, the larger number of large-angle grain boundaries (LAGB), diffusely distributed Al3Mg2 and Al6Mn phases in CMT WZ, as well as a small amount of distributed Al3Zr, are beneficial to the joints properties too.
“…ANOVA is used to evaluate the influence of the control factors on the experimental results. The following parameters of ANOVA are used for analyzing the experimental results (Ross, 1996; Montgomery, 2000; Kumar et al , 2008; Kumar et al , 2009):Sum total of all results (T): Equation 5 Correction factor (CF): the term reduces the variation of the process: Equation 6 Total sum of squares (SS T ): it is the difference between the sum of squares of all the trial run results and CF: Equation 7 Sum of squares due to a parameter: Equation 8 where N A1 , N A2 and N A3 are the numbers of trial with parameter at levels 1, 2 and 3, respectively. The sum of squares SS B and SS C are calculated in the similar way.Degree of freedom (DOF): Equation 9 Equation 10 The DOF f B , f C and f e are calculated in the similar way.Variance: the variance of each factor is determined by the sum of the squares of each trial sum of results involving the factor divided by the degrees of freedom of the factor: Equation 11 Variance ratio ( F ‐ratio): it is the ratio of variance of each factor to the error variance: Equation 12 The value of calculated F ‐ratio for a factor is then compared with the critical value of F which is tabulated at a chosen level of significance α.…”
PurposeThe purpose of this paper is to investigate experimentally the effect of volume of casting, pouring temperature of different materials and shell mould wall thickness on the surface roughness of the castings obtained by using ZCast direct metal casting process.Design/methodology/approachTaguchi's design of experiment approach was used for this investigation. An L9 orthogonal array (OA) of Taguchi design which involves nine experiments for three factors with three levels was used. Analysis of variance (ANOVA) was then performed on S/N (signal‐to‐noise) ratios to determine the statistical significance and contribution of each factor on the surface roughness of the castings. The castings were obtained using the shell moulds fabricated with the ZCast process and the surface roughness of castings was measured by using the surface roughness tester.FindingsTaguchi's analysis results showed that pouring temperature of materials was the most significant factor in deciding the surface roughness of the castings and the shell mould wall thickness was the next most significant factor, whereas volume of casting was found insignificant. Confirmation test was also carried out using the optimal values of factor levels to confirm the effectiveness of this approach. The predicted optimal value of surface roughness of castings produced by ZCast process was 6.47 microns.Originality/valueThe paper presents experimentally investigated data regarding the influence of various control factors on the surface roughness of castings produced by using ZCast process. The data may help to enhance the application of ZCast process in traditional foundry practice.
“…And the role of cleaning up [6] . Russian scholars such as ОрлапнМ [7] have shown that the double-arc surfacing metal has the characteristics of fine crystal structure and uniform distribution of strengthening phases. This is because in the double-arc surfacing process, the melting electrode arc can form a certain penetration depth, while the non-melting electrode arc can replenish the alloy for the surfacing layer.…”
A high-speed camera is used to observe the arc starting and arc stabilization process of the TIG-MIG hybrid welding system. Paschen’s law is used to analyze the path of TIG welding arc breakdown under the condition of the conductive channel provided by the MIG welding arc, and the arc starting process of the double arc hybrid welding is determined. The study found that when the electrode spacing is less than 8.5 mm, two molten pools can form a common molten pool after arc initiation of MIG welding; when the spacing is 10 mm, the two molten pools after arc initiation form a “8” shape; When the distance is 12 mm, there is a low temperature zone between the two arcs, which is separated.
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