Influence of the Degree of Cold Drawing on the Microstructure and Properties of Pipes Used for Dampers

Abstract

Dumpers are the main components of the suspension system with vertical oscillations role in the absorption of the automobile. The combination of suspension coil with dumper is forming the main body of the suspension system. Shock absorber pipe is mainly used for production of motorcycles, cars (sedan) car shock absorber, is the size of the relatively high precision seamless pipe products, its manufacturing costs and lower selling prices relatively seamless, with excellent cost performance, got the car and motorcycle manufacturing industry recognition, are gradually replacing the use of seamless pipes in the area. The cold work process of pipes drawing consists of reducing the cross-section of a pipe by pulling the pipe through series of conical dies. The metal pipe drawing technology has been widely used to manufacture fine pipes. The influence of the degree of cold drawing on the mechanical properties of the carbon steel material were studied using the tensile test and hardness test experiments in order to replicate the service condition of the pipes used for automotive dumpers. Microstructure analysis were perfomed using optical analysis on a LEICA 5000DMI microscope up to 1000X magnitude and SEM images with a dual beam QUANTA 200 3D FEI SEM scanning electron microscope. The purpose of the work is to observe the main effects of the degree of reduction at different gradations by analysing the microstructure and mechanical proprieties behavior. The study used the stress-strain relationship of the tensile test experiment to study the effect of the degree of cold-drawing deformation on the yield strength and tensile strength properties of the dumpers used in automotive industry. The toughness of the low carbon steel used for the dumper manufacture reduces as the degree of drawing deformation increases. The ductility of the material also reduces with increasing degree of rawing deformation. The yield strength of the material was observed to reduce with increasing degree of cold-drawing, an indication of reduction in the ductility and the tensile strength of the material reduced with increasing degree of cold-drawn deformation. After high degrees of cold deformation by drawing, the hardness proprieties are increasing highlighted by cold-straining.