| 摘要 |
PURPOSE:To provide a good-quality penetration bead having good blow hole resistance by forming a backing strip for one-side welding of SiO2, Al2O3 and MgO which are made at least partly cordierite and are compounded at specific ratios and incorporating >=1 kinds of alkaline metallic oxides and moisture at specific ratios therein. CONSTITUTION:The backing strip for one-side welding is formed of the compo nents consisting of 4.5-6.0wt% SiO2, 28-38wt% Al2O3 and 3-15wt% MgO which are made at least partly cordierite. Further 0.3-3.2wt% 1 kinds of alkali metal oxides and 0.01-0.25wt% moisture are incorporated as essential components therein. Such backing strip widens the application range of welding current such as gas shielded arc welding and forms the good-quality penetration bead having the good blow hole resistance by the good fire resistance thereof.
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