Specifications | Matsushita supplement Zaida |
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Specifications | Matsushita supplement Zaida |
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Specifications | Matsushita supplement Zaida |
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Content | 7.5% K3AlF6and 10% K3AlF6wires. If the amount of K3AlF6in the flux is increased, the diffusible hydrogen content is ex- pected to decrease. However, further re- duction of the diffusible hydrogen was not observed simply with increasing the addition of K3AlF6beyond 5%. The dif- fusible hydrogen contents measured in welds prepared with 7.5% addition were between those given by the base wire and the 5% K3AlF6wire at any hydrogen ad- dition in the shielding gas. Also, the hy- drogen content measured in welds pre- pared with 10% addition of K3AlF6is as low as that with 5% addition at each hy- drogen content in the shielding gas. Moreover, this observation indicates the reduction of the diffusible hydrogen by the addition of an effective fluoride such as K3AlF6probably reached a plateau when the addition exceeded an optimal amount, which was determined to be 5% in this research. Figure 5 illustrates the same experimental results as those in Fig. 4 plotted as a function of the fluoride ad- dition. The three curves show hydrogen additions in the shielding gas resulted in increased weld metal diffusible hydrogen content. The drop of the diffusible hydro- gen is clearly observed from 0 to 5% of the fluoride addition and no further re- duction resulted from additions of more than 5%. According to the series of the dif- fusible hydrogen measurements with the K3AlF6wires, the optimum addition of the effective flu- oride was deter- mined to be 5% in the flux so that it was applied to the addition of other fluorides such as KF and MnF3. Effectiveness of KF According to the thermody- namic calcula- tions demon- strated earlier, the addition of KF is predicted to be more effective than the addition of K3AlF6. As seen in Fig. 1, the addi- tion of KF exhibits the greatest reduc- tion of hydrogen so that the hydro- gen level is very close to zero at even 0.04 atmos- phere of partial pressure of hydrogen, which is high com- pared to normal welding atmospheres. The diffusible hydrogen experiments were conducted with 5% KF addition wire to verify the effectiveness of KF as predicted by the calculation. The results are illustrated in Fig. 6. At 0% hydrogen in the shielding gas, the diffusible hydro- gen content in the weld metal deposited with the 5% KF addition wire is as low as in the weld metal deposited with the 5% K3AlF6addition wire. However, with a higher hydrogen content in the shielding gas, the weld metal diffusible hydrogen levels of 5% KF addition wire tend to be lower than those of base and 5% K3AlF6addition wires. Compared with the 5% K3AlF6addition wire, the reductions of the diffusible hydrogen with the 5% KF addition wire were 13.1 and 21.8% at 1 and 4% of hydrogen in the shielding gas, respectively. Consequently, it can be concluded the addition of KF can further reduce diffusible hydrogen. This fact matches the result of the thermodynamic calculation. Effectiveness of MnF3 The thermodynamic calculation demonstrated earlier also indicated the effectiveness of MnF3. As seen in Fig. 1, the reduction of the hydrogen shown by the addition of MnF3is close to that shown by the addition of KF. The results of the diffusible hydrogen measurements with 5% MnF3addition wire were illustrated in Fig. 7. The hydro- gen levels shown in this figure are much higher than those shown in the previous figures because the temperature and rela- tive humidity at the time when these dif- fusible hydrogen measurements were per- formed (27.5°C, 38–53% RH) were higher than those when the other measurements were conducted (23.3°C, 30% RH). Since the partial pressure of hydrogen becomes higher when both temperature and hu- midity increase, the diffusible hydrogen level will be higher in an environment with higher temperature and humidity. This fact makes it impossible to simply compare the values of the diffusible hy- drogen levels conducted under different environmental conditions. Therefore, the effectiveness of the addition of MnF3needed to be evaluated by calculating the reductions of the diffusible hydrogen lev- els for the experimental wires containing K3AlF6, KF and MnF3with respect to those of the base electrode. The reductions were also normalized according to the follow- ing equation: (27) where [H]D(base) is the weld metal dif- fusible hydrogen level of the base wire and [H]D(experimental) is that of the other ex- perimental wires containing K3AlF6, KF and MnF3. Figure 8 illustrates the reduc- tion given by the three fluoride-added electrodes with 5% K3AlF6, 5% KF and 5% MnF3, respectively. On average, the addi- tion of KF shows the largest reductions of 24.7, 36.7 and 39.0% at 0, 1 and 4% of hydrogen content in shielding gas, re- spectively. The reductions given by the ad- dition of MnF3are 34.7, 24.4 and 20.7% at 0, 1 and 4% of hydrogen content in shielding gas, respectively. These reduc- tions are approximately as large as those given by the addition of K3AlF6, whose re- ductions are 30.5, 27.2 and 22.1% at 0, 1 and 4% of hydrogen content in shielding gas, respectively. Consequently, it is obvi- ous the addition of MnF3is as effective as or more effective than K3AlF6in decreas- ing the diffusible hydrogen. The thermodynamic calculation has indicated the effectiveness of the addi- tions of KF and MnF3would be much greater than that of K3AlF6. Moreover, KF would be slightly more effective than MnF3according to the calculations. Therefore, the reduction of the hydrogen should be greater with KF, MnF3and K3AlF6, in that order. The experimental results followed this trend. Although the HDbaseHDerimental HDbase reduction []()−[]() []() ×=() exp %100 302-s| OCTOBER 2000 RESEARCH/DEVELOPMENT/RESEARCH/DEVELOPMENT/RESEARCH/DEVELOPMENT/RESEARCH/DEVELOPMENT Fig. 8 — Reduction of diffusible hydrogen from the levels given by base electrode established with 5% K3AlF6, 5% KF and 5% MnF3wires. |
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Following Datasheets | 10-2000-MOON-s (8 pages) 10-2000-NELSON-s (11 pages) 10-2002-HUANG-s (12 pages) 10-2002-VIANCO-s (10 pages) 10-2002-XIE-s (8 pages) 10-2003-COLLINS-s (8 pages) 10-2003-GOULD-s (5 pages) 10-2003-MENDEZ-s (11 pages) 10-2003-SOLOMON-s-1 (10 pages) 10-2003-VIANCO-s (10 pages) |
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