| Summary: | Cold headability is the ability of a cylindrical metallic specimen to be shaped at high strain rate into the head of a bolt, screw or other cold-formed part without cracking. This property is material dependent and can be influenced by many factors such as chemical composition, surface condition, and microstructure. This project focuses on the effect of microstructure upon the cold headability of a medium carbon steel (1036M). Six different microstructures were produced by various heat treatment conditions. Drop Weight Tower (DWT) tests, developed at McGill in 2000 by Dr. N. Nickoletopoulos, were used on samples of these materials. Visual inspection, metallographic and SEM analysis were performed to identify cracks on the surface of tested samples, and trace their cause. The axial and circumferential strains of tested samples were measured and the strains at which cracks first occurred were used to assess the cold headability. This research further indicates that DWT testing is a valid method for evaluating the cold headability of metallic materials and that the cold headability is particularly sensitive to the microstructure of a material.
|
|---|
