Mechanical Behaviour of Dual Phase Steel Tubes and Its Application in Automotive Industries

In the present investigation dual phase steel tubes are produced through induction heating and quench system with varied martensite and ferrite content. Thereby, spectrum of tensile properties are obtained for the given steel grade. Five most popular auto steel grade DP tubes are selected and examined for work hardening characteristics of the material. Further, Strain hardening exponent (n) is calculated for the all the grades of steel tubes used for the investigation to understand the metal forming behaviour of the DP tubular components. It is found that as the intercritical temperature increases, the strain hardening exponent decreases. Effect of cold drawing on the tensile properties of DP steel tubes are studied with various cold drawn reduction percentages. It is inferred that maximum cold reduction possible for DP tubes and strips are limited to about 10% in order to retain the dual phase steel characteristics. A correlation between strain hardening component and the micro constituents such as martensite and ferrite volume fraction is proposed. The prospective DP steel auto tubular components are discussed in this paper.