Strain distribution analysis of hot forged seamless pipe fittings

Abstract

A strain distribution analysis was carried out on hot forged seamless pipe fittings produced at a factory. The studies were conducted on pipe preforms, cut from a seamless pipe, which had a grid inscribed on the outside surface. The dimensions of the individual cells were measured before processing of the preforms and, once the parts had cooled down to room temperature, the dimensions of the distorted grids were recorded. The different components of strain were evaluated from both sets of measurements. Thermal evolution during forging was recorded by inserting a series of type K thermocouples into the preforms and logging the data into a computer system. Two preforms were loaded together in a single trial, whereas a third one was deformed by itself to evaluate the consistency of the process. Results from the analysis compare favourably with measurements of the change in wall thickness obtained by ultrasonic means in one of the pieces.