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Rare-earth-containing wet-H2S-corrosion-resistant T95 steel-grade oil well pipe and production method thereof

A production method, the technology of T95, is applied to the improvement of process efficiency and the manufacture of converters, etc. It can solve the problems of fluctuations in the mechanical properties of oil well pipes, poor toughness and corrosion resistance of oil well pipes, and poor operability.

Inactive Publication Date: 2013-10-23
INNER MONGOLIA BAOTOU STEEL UNION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1. Due to its relatively high content of C element (weight% ≥ 0.24%), this will make the toughness and corrosion resistance of the oil well pipe worse;
[0005] 2. The heat treatment temperature range is too wide (the tempering temperature is above 500°C), which will cause large fluctuations in the mechanical properties of the oil well pipe, and the operability is not strong

Method used

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  • Rare-earth-containing wet-H2S-corrosion-resistant T95 steel-grade oil well pipe and production method thereof
  • Rare-earth-containing wet-H2S-corrosion-resistant T95 steel-grade oil well pipe and production method thereof
  • Rare-earth-containing wet-H2S-corrosion-resistant T95 steel-grade oil well pipe and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Raw materials by weight percentage are: 90% of blast furnace molten iron and 10% of high-quality steel scrap.

[0044] The sequence of the production process is: molten iron pretreatment→top-bottom combined blowing converter smelting→LF furnace refining→VD vacuum treatment→round billet continuous casting→cutting→tube billet heating→piercing→continuous rolling→sizing→cooling→sawing→heat treatment → Straightening → Flaw detection → Thread processing.

[0045] The specific production process is briefly described as follows:

[0046] 90 tons of blast furnace molten iron is pretreated with "metal magnesium powder" for desulfurization and deoxidation, so that the S content in the molten iron is reduced to (weight percent) below 0.010%;

[0047] Mix the 90 tons of pretreated molten iron into a 100-ton top-bottom combined blowing converter, add 10 tons of high-quality steel scrap, and then use the single slag process to smelt. The final slag basicity is controlled at 3.0, and ...

Embodiment 2

[0068] The ratio of raw materials, production process, etc. and other process indicators of Example 2 are the same as those of Example 1, the difference is the chemical composition content, heat treatment system and steel pipe specification of the tube blank (the specification is ф194.46mm×16.00mm) , chemical composition detection result (weight %) sees Table 4:

[0069] The chemical composition testing result (weight %) of table 4 tube blank

[0070]

[0071] The heat treatment system is: 890±10°C for 45 minutes, then take out the furnace for water quenching, and 660±20°C for 75 minutes, then take out the furnace for air cooling. The straightening temperature of the steel pipe is 525°C, and the residual stress of the steel pipe measured by ring cutting method is 23MPa.

[0072] The test results of mechanical properties of seamless steel pipes are shown in Table 5, and the test results of SSC properties, HIC properties, microstructure and grain size are shown in Table 6. ...

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Abstract

The invention relates to a rare-earth-containing wet-H2S-corrosion-resistant T95 steel-grade oil well pipe and a production method thereof, belonging to the technical fields of metallurgy and molding. The oil well pipe is prepared from the following raw materials in percentage by weight: 90% of blast furnace molten iron and 10% of high-quality scrap steel. The pipe blank comprises the following chemical components in percentage by weight: 0.15-0.20% of C, 0.10-0.30% of Si, 0.80-1.10% of Mn, at most 0.015% of P, at most 0.005% of S, 0.90-1.20% of Cr, 0.30-0.50% of Mo, 0.05-0.10% of V, 0.01-0.03% of Ti, 0.01-0.04% of Al, 0.0005-0.0100% of RE, less than 0.10% of Cu, and the balance of Fe and non-detectable microelements. The technical process comprises the following steps: molten iron pretreatment, top-bottom composite-blown converter smelting, LF (ladle furnace) refinement, VD (vacuum degasser) vacuum treatment, circular blank continuous casting, cutting, pipe blank heating, perforating, continuous rolling, sizing, cooling, sawing, heat treatment, straightening, flaw detection and thread processing. The mechanical properties are as follows: the yield strength is 680-750 MPa, the tensile strength is 800-890 MPa, the yield ratio at most 0.90, the elongation percentage is at least 21%, the transverse impact value is at least 100 J / cm<2> (0 DEG C), the shear ratio is 100%, the grain fineness is at least Grade 8.0, the hardness is at most 23.0 HRC, the hardness difference is at most 3.0 HRC, and the residual stress is at most MPa. The product provided by the invention has the characteristics of high strength-toughness compatibility, fine crystal grains and favorable wet H2S corrosion resistance.

Description

1. Technical field: [0001] The invention belongs to the field of ferrous metal smelting and metal pressure processing, and relates to a rare earth-containing moisture-resistant H 2 S corroded T95 steel grade oil well pipe and its production method. 2. Background technology: [0002] Some of my country's oil and gas resources exist in water and H 2 S gas, which brings serious corrosion problems to oil and gas pipelines, and is difficult to predict. Wet hydrogen sulfide corrosion mainly has two damage types: stress corrosion corrosion (SSC) and hydrogen induced cracking (HIC). These two types of damage have produced serious accidents in the oil and gas extraction industry, and the moisture-resistant H 2 S corrosion is contradictory to high steel grades. For this reason, the anti-humidity H 2 S-corroded high-grade steel oil well pipes, the application of these oil well pipes can effectively reduce or prevent the damage caused by wet hydrogen sulfide corrosion. [0003] Af...

Claims

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Application Information

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IPC IPC(8): C22C38/28C21D8/10C21D1/25C21C5/35
CPCY02P10/20
Inventor 丰小冬贺景春乔爱云王秀石晓霞马爱清
Owner INNER MONGOLIA BAOTOU STEEL UNION