Senior engineering specialist, Hercules Incorporated, Wilmington, Del.
Pages: 20 Published: Jan 1980
The 26Cr-1Mo alloys stabilized with titanium and the 29Cr-4Mo alloys have many potential applications in the chemical process industries. There is particular concern about the effect of interstitial content and the titanium addition on weldability, weld fracture toughness, and ductility.
This paper discusses the weldability of the new titanium-stabilized 26Cr-1Mo and 29Cr-4Mo (26-1 and 29-4) alloys in various commercially available thicknesses [3.276 to 3.81 mm] (0.129 to 0.150 in.), using matching and dissimilar filler metals, and compares the ductility and impact toughness of these materials with those of E-BRITE 26-1 (a high-purity ferritic stainless steel). Both the gas tungsten-arc and shielded metal-arc welding processes were used.
Welds were evaluated on the basis of tensile, bend, Charpy V-notch impact properties, and weld metal interstitial content (carbon, nitrogen, and oxygen).
Sound welds were made in titanium-stabilized 26Cr-1Mo and 29Cr-4Mo alloys. It was concluded that welding procedures that optimize gas shielding must be used. Routine gas tungsten-arc welding procedures are not adequate. Because of the high ductile-to-brittle transition temperature and low notch toughness observed in the gas tungsten-arc welds, this procedure is not recommended for fabrication of chemical process equipment from the stabilized ferritic stainless steels in the thicknesses studied. It was found that the welds made with high-purity filler metal were superior to those made with the titanium-stabilized filler metal.
The fracture behavior and notch toughness of the shielded metal-arc welds made with Hastelloy C-276, Hastelloy G, and Haynes 25 were satisfactory, and these procedures can be used for fabrication of chemical process equipment.
ferritic stainless steels, weldability, weld impact toughness, weld ductility, weld lateral expansion, titanium stabilization, dissimilar filler metals, interstitials (purity), ductile-to-brittle transition temperature, welding procedures, fracture toughness
Paper ID: STP38210S