Welding Test Number 170. Investigation of Welded Butts and Seams in S.T. S. Subjected to Ballistic Impact. Report of Tensile and Bend Tests

The tensile and bend tests reported herein are part of a test to investigate different types of butts and seams subjected to ballistic impact CR letter to Comdt. Philadelphia, JJ46-1-19TB 114 of October 13, 1938. There were fifteen 15 specimens tested, three 3 specimens each for base metal, double V butt weld machined flush, double V butt weld as deposited, welded scarph joint machined, and welded scarph joint as deposited. All specimens were 3 inch wide of 60 lb. STS plate. Two specimens of each group of three were used for the tensile tests. A section 18 inch long was cut from the middle of the third specimen for the bend test. The different specimens arranged in order of decreasing tensile strength are as follows base metal, as deposited scarph weld, machined scarph weld, as deposited butt weld, machined butt weld. Results were quite consistent. The base metal ultimate strength averaged 114,400 lbs. per sq. in. The welded specimens developed 75 per cent to 88 per cent of the strength of the plate. The base metal specimen was bent to an angle of 180 deg without failure. The failure of the butt weld specimens was gradual, the machined butt being a little more ductile than the as deposited . However, it is to be noted that the machined specimen failed through the weld while the as deposited failed in the bend. The scarph joints failed with a sharp fracture, the as deposited joint being considerably more ductile than the machined joint. Tables and photographs are included.