A p110 externally thickened oil well pipe and its manufacturing method

Abstract

The invention discloses a P110 externally-thickened oil well tube and a manufacturing method thereof. The P110 externally-thickened oil well tube is prepared from 0.22%-0.32% of C, 0.15%-0.45% of Si, 1.00%-1.50% of Mn, not greater than 0.03% of P, not greater than 0.03% of S, and the balance of Fe and inevitable impurities. The manufacturing method of the P110 externally-thickened oil well tube comprises the following steps of performing converter smelting, performing external refining, performing billet continuous casting, performing round billet rolling, heating round billets in a ring-shaped furnace, performing tube penetrating in a fungoid type punching machine, rolling the tube in a continuous tube rolling machine, heading and externally thickening the tube end, and performing electric-induction quenching-and-tempering heat treatment. According to the P110 externally-thickened oil well tube and the manufacturing method thereof disclosed by the invention, low-cost C-Mn steel is adopted as a round billet raw material, and noble metals are not added, so that the alloy cost is low; moreover, the steel tube heating time is short, the efficiency is high, the energy is saved and, the consumption is reduced, and the manufacturing period is shortened.

Description

technical field [0001] The invention belongs to the technical field of low-alloy steel manufacture, and mainly relates to a P110 steel grade externally thickened oil well pipe and a manufacturing method thereof. Background technique [0002] Among the varieties of seamless pipes, oil wells are the largest special-purpose pipes, accounting for about 1 / 4 of my country's seamless pipe consumption (about 1 / 3 of the world), and its production technology level basically represents the overall level of seamless pipes . With the continuous exploitation of global oil, the drilling depth is gradually deepened, and higher strength requirements are put forward for the matching oil well pipes. Earlier, oil fields mainly used H40 oil well pipes with a tensile strength below 414MPa. Until a few years ago , J55 oil well pipes with a yield strength below 552MPa are commonly used in oil fields. Up to now, N80 oil well pipes with a yield strength of 552MPa or more have been widely used and gra...

AI Technical Summary

Problems solved by technology

[0003] At present, P110 seamless steel pipes for oil wells generally require off-line heat treatment of the hot-rolled steel pipes to meet the required strength requirements, that is, the yield strength is 758-965MPa and the tensile strength is above 862MPa. At the same time, the elongation, Charpy However, the off-line walking furnace quenching and tempering heat treatment process commonly used in the prior art can obtain satisfactory mechanical properties, but its disadvantage is that it requires a long heating and holding time and increases energy consumption. , the production cycle is longer and the cost is higher. Under the background of the oversupply of steel in the current and future long-term, the profit margin of the product is low and lacks competitive advantages.

The disadvantage of the above three patents CN200810032583.0, CN201110421067.9, and CN200910018524.2 is that there are welds in the invented products, which increases the risk of failure in use

The invention has two shortcomings: one is that due to the use of ERW welding process, the content of P and S is strictly controlled, and the requirements are not higher than 0.01% and 0.008% respectively, which is much higher than the API standard. The content of P and S in P110 oil well pipe is not high. The requirement of 0.03% increases the manufacturing cost; the second is the increase of the risk of use

The invention has three deficiencies: one is that the alloy formula contains precious metal Cr, which increases the cost of the alloy; The manufacturing cost is reduced; the third is the increase of the use risk, ibid.

The invention has three deficiencies: one is that the alloy formula contains precious metals Cr, V, Nb, and Ti, which increases the cost of the alloy; the other is that the P content is high, which affects the welding quality;

There are two deficiencies in this invention: one is that the alloy formula contains precious metal Cr, which increases the cost of the alloy; the other is that the manufacturing method of the steel pipe cannot be given

The disadvantages of this invention are twofold: one is that the alloy formula contains precious metals such as Cr, Mo, Ni, which increases the alloy cost; the other is that the heating time of the steel pipe is long, which increases energy consumption

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