High-quality non-quenched and tempered seamless steel tube for drilling and manufacturing method thereof

Abstract

The invention discloses a high-quality non-quenched and tempered seamless steel tube for drilling and a manufacturing method thereof. The tube for drilling comprises, 0.36% to 0.38% of C, 0.25% to 0.35% of Si, 1.46% to 1.66% of Mn, 0.26% to 0.32% of Mo, 0.06% to 0.08% of V, 0.022% to 0.032% of Ti, 0.014% to 0.018% of Alt, 0 to 0.010% of P, 0 to 0.010% of S, 55 ppm to 75 ppm of N, 0 to 1.5 ppm of H, 0 to 25 ppm of O, 0 to 0.038% of As+Sn+Pb+Sb+Bi, the balance Fe and inevitable impurities. The metallographic structure is the uniform and fine granular bainite structure; according to the performance, the tensile strength Rm is larger than or equal to 1100 MPa, the yield strength Rp0.2 is larger than or equal to 960 MPa, the elongation percentage A is larger than or equal to 16%, and the longitudinal impact energy AKU2 is larger than or equal to 75J. The granular bainite structure formed by the unique ingredients of the non-quenched and tempered steel meets the design requirement for the tensile strength, the yield strength, the elongation percentage and the longitudinal impact energy, the same quality requirement is met compared with the quenching and tempering technology adopting quenching and high temperature tempering, one heating step is omitted, the production process is shortened, and the production efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of manufacturing seamless steel pipes for drilling, in particular to a high-quality non-quenched and tempered seamless steel pipe for drilling and a manufacturing method thereof. Background technique [0002] With the development of society, people's demand for materials is increasing, resulting in an increasing demand for mineral resources and energy. The shortage of mineral resources and energy is a common problem faced all over the world. Now, geological drilling for ore prospecting and oil prospecting has developed into mineral resources with more complex geological conditions and a depth of more than 1,500 meters. In this way, more stringent requirements are put forward for the comprehensive performance of drill pipes used for geological drilling: Not only is the material required to manufacture geological drill pipes to have a higher strength level, but also to have a certain degree of toughness and p...

AI Technical Summary

Problems solved by technology

It is far from meeting the requirements of deep drilling in the crust and seabed

[0004] The applicant retrieved the article "Development of XJY high-strength precision geological pipes" published in the journal "Prospecting Engineering (Geotechnical Drilling and Excavation Engineering)" Volume 36, Issue 6 (P28-30) in June 2009. The composition of the article is not disclosed. The geological pipes for drilling use special heat treatment, the matrix metallographic structure is ferrite + pearlite, the tensile strength is 940-1010MPa, the yield strength is 630-660MPa, and the elongation is 12.5-14%. Low, reflected in the drilling process is poor wear resistance, low reuse rate

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