A PROCESS FOR THE PRODUCTION OF 1.27MM THICK HIGH STRENGTH MEDIUM C-Mn STRAPPING QUALITY STEEL THROUGH MODIFIED AUSTEMPERING PRACTICE FOR PACKAGING APPLICATION

摘要

There is proposed a method for the production of 1.27 mm thick high strength C-Mn strapping quality steel through modified austempering practice comprising the following steps: a. Preparing steel in a basic oxygen furnace to provide the alloy chemistry was as follows: Chemistry: %C: 0.38-0.45 %Mn: 1.35-1.45 %P: 0.025 (max.) %S: 0.015 (max.) %Si: 0.2-0.3 %AI: 0.01-0.03 b. Subjecting the steel to a step of ladle furnace treatment for purpose of controlling the sulpher content, c. Subjecting the products of step (b) to a step of continuous casting to produce defect free slabs, d. Re-heating the slabs formed in step (c) by soaking about 1250° C, e. Subjecting the re-heated slabs to a step of hot strip rolling to obtain 2.8 mm strip, f. Subjecting the hard rolled strips to a step of pickling in HCL acid, g. Followed by cold rolling the pickled strips to obtain coils of 1.27 mm thick, h. Where after the cold rolled coils are subjected to slitting to obtain necessary narrow straps of 31.75 mm thickness, i. Subjecting the straps so produced to a step of austenitisation at temperatures in the ranges of 950-970° C, followed by j. Subjecting the austenitised straps to a step of slow and controlled cooling and thereafter subjecting the cooled straps to austempering in a lead bath at a temperature of around 450° C, so as to form about 15% ferrite.