As there are various demands on steel butt-welding pipe fitting according to intended applications, the relevant JIS B 2312 and B 2313 incorporate special quality requirements, which shall be applied in case request is placed in advance by the order. These requirements include a tensile test to be performed on a specimen sampled form an actual product of pipe fittings-called hereafter the production test of tension. Because a pipe fittings is in three-dimensional form, sampling a tensile test specimen from pipe fitting requires a flattening process of the sampled specimen prior to its machining, and this flattening process may drop the yield strength because of Bauschinger effect.
This paper is to put the standardization of this production test of tension on pipe fittings in practice in view of preventing Bauschinger effect likely in the flattening process of sampled specimen.
