Abstract

Oil Country Tubular Goods (OCTG) steels are used in the form of tubes in the casing column of the oil well walls and exhibit martensitic structure after quenching and tempering. Due to the high cost of chromium, nickel and molybdenum, an alternative is the replacement of these elements by boron, which increases the hardenability. In order to maintain the efficiency of boron in solution it is necessary to add titanium to form Titanium Nitrides (TiN), which inhibit austenitic grain growth and avoid the formation of boron nitride. In the present study samples of a coil were quenched at 850 and 1050 °C. The microstructures, hardness, yield stress, tensile strength and elongation were obtained and Lepera reagent was used to visualize the martensite after quenching. The results show that the hardness, yield stress and tensile strength at the temperature of 850 °C are higher than 1050 °C and elongation is less.

Keywords: Bit speed; Intrusion theory; Bit speed equation; Practical application