Microstructure and Mechanical Properties of Cold Rolled AISI 1018 Low Carbon Steel

In this investigation, mechanical properties and microstructure of AISI 1018 low carbon steel in the form of strips with the dimensions about 50 × 25 × 4 mm subjected to cold rolling gradually by 20, 30, 40, and 50% were studied. The effect of the percentage of cold rolling on the mechanical properties of AISI 1018 low carbon steel was estimated by using tensile test, Brinell hardness test. The tensile test was done by using Universal Tensile Machine (UTM) to define yield strength and tensile strength as the percentage of increasing in the deformation, while the Brinell hardness number was obtained for each percentage of rolled deformation. Also, the microstructure of the specimens was analyzed by optical microscope. The results of this investigation show that the yield strength decreased with increasing the percentage of cold rolled as 300,233, 200, and 171 MPa, while the tensile strength decreased as 368, 297, 274 and 238 MPa respectively. While Brinell hardness number increased with increasing the percentage of rolling deformation as 145, 192.1,221 and 240.3 (HB) respectively. This is, in turn, show that increasing brittleness as a result of increasing rolling deformation. The photomicrographs of the specimens show that increasing in percentage of cold rolling leads to stretch the grains, which consist of fine ferrite grains with the pearlite grains.