CN111455275A - Seamless steel tube for oil-gas well perforating gun and manufacturing method thereof - Google Patents

Abstract

The invention relates to a seamless steel tube for a perforating gun of an oil and gas well and a manufacturing method thereof, wherein the seamless steel tube comprises the following chemical components, by mass, 0.30-0.34% of C, 0.17-0.37% of Si, 0.60-0.75% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, 1.00-1.20% of Cr, 0.20-0.30% of Mo, 0.020-0.045% of Als, less than or equal to 0.30% of Ni, less than or equal to 0.20% of Cu, and the balance Fe and other inevitable elements.

Description

Seamless steel tube for oil-gas well perforating gun and manufacturing method thereof

Technical Field

The invention relates to the technical field of seamless steel tube manufacturing, in particular to a seamless steel tube for an oil-gas well perforating gun and a manufacturing method thereof.

Background

Perforating guns are important tools in oil and gas production and geological exploration and are used for well completion or cementing in oil fields. The high-efficiency energy-accumulating blasting principle is adopted, a perforating gun is conveyed to a part to be perforated of a sleeve by a cable, and an electric detonator detonates a perforating bullet. Influenced by service conditions, the perforating gun barrel is required to have good strength and toughness. Meanwhile, the requirement on the geometric dimension precision of the steel pipe is high.

Disclosure of Invention

The invention provides a seamless steel tube for a perforating gun of an oil-gas well and a manufacturing method thereof, which adopt the processes of 'rolling steel making by turns, L F refining, VD vacuum refining, rolling by a continuous rolling mill set and heat treatment', and have the advantages of reasonable steel making process, pure steel, less impurities, accurate component control, advanced tube making process, good geometric dimension of the steel tube and stable performance.

In order to achieve the purpose, the invention adopts the following technical scheme:

a seamless steel tube for a perforating gun of an oil and gas well comprises the following chemical components in percentage by mass: 0.30 to 0.34 percent of C, 0.17 to 0.37 percent of Si, 0.60 to 0.75 percent of Mn and less than or equal to 0.015 percent of P; less than or equal to 0.010 percent of S, 1.00 to 1.20 percent of Cr1, 0.20 to 0.30 percent of Mo, 0.020 to 0.045 percent of Als, less than or equal to 0.30 percent of Ni, and less than or equal to 0.20 percent of Cu; the balance of Fe and other inevitable elements.

A seamless steel tube for a perforating gun of an oil and gas well comprises the following chemical components in percentage by mass: 0.31 to 0.33 percent of C, 0.25 to 0.29 percent of Si, 0.65 to 0.70 percent of Mn and less than or equal to 0.012 percent of P; less than or equal to 0.008 percent of S, 1.05 to 1.15 percent of Cr1, 0.22 to 0.27 percent of Mo and 0.025 to 0.035 percent of Als; the balance of Fe and other inevitable elements.

A manufacturing method of the seamless steel tube for the oil and gas well perforating gun comprises the following manufacturing process routes of molten iron pretreatment → converter smelting → L F + VD external refining → continuous casting and continuous rolling → hot rolling → heat treatment → flaw detection, wherein the manufacturing process comprises the following steps:

the hot rolling process comprises the following steps: checking and accepting a tube blank, cutting, heating, perforating, resisting oxidation of the tube blank, continuously rolling MPM or PQF, removing the tube, sizing by a micro-tension reducing mill, cooling, sawing, straightening, blowing, checking and packaging the tube material; heating the tube blank at 1260-1300 ℃; descaling by adopting high-pressure water during sizing;

the heat treatment process comprises the following steps: quenching and tempering the steel pipe in an external spraying and internal spraying compression roller rotating quenching mode; the quenching temperature is 880 +/-20 ℃, the tempering temperature is 600 +/-10 ℃, and the heat preservation time is 40-60 min.

Compared with the prior art, the invention has the beneficial effects that:

1) the invention adopts the processes of 'rolling steel making, L F refining, VD vacuum refining, continuous rolling mill rolling and heat treatment', the steel making process is reasonable, the steel is pure, the inclusion is less, the composition is controlled accurately, the pipe making process is advanced, the steel pipe has good geometric dimension and stable performance;

2) the seamless steel tube for the high-strength oil-gas well perforating gun with strong thermal matching is obtained by optimizing chemical components and perfecting process parameters;

3) the manufacturing process is easy to realize, and the product performance is uniform and stable.

Drawings

FIG. 1 is a first microstructure photograph of a seamless steel tube for use in a perforating gun for oil and gas wells according to the present invention.

FIG. 2 is a second microstructure photograph of a seamless steel tube for use in a perforating gun of an oil and gas well according to the present invention.

Detailed Description

The invention relates to a seamless steel tube for a perforating gun of an oil and gas well, which is characterized by comprising the following chemical components in percentage by mass: 0.30 to 0.34 percent of C, 0.17 to 0.37 percent of Si, 0.60 to 0.75 percent of Mn and less than or equal to 0.015 percent of P; less than or equal to 0.010 percent of S, 1.00 to 1.20 percent of Cr, 0.20 to 0.30 percent of Mo, 0.020 to 0.045 percent of Als, less than or equal to 0.30 percent of Ni and less than or equal to 0.20 percent of Cu; the balance of Fe and other inevitable elements.

Preferably, the seamless steel tube for the perforating gun of the oil and gas well comprises the following chemical components in percentage by mass: 0.31 to 0.33 percent of C, 0.25 to 0.29 percent of Si, 0.65 to 0.70 percent of Mn and less than or equal to 0.012 percent of P; less than or equal to 0.008 percent of S, 1.05 to 1.15 percent of Cr, 0.22 to 0.27 percent of Mo and 0.025 to 0.035 percent of Als; the balance of Fe and other inevitable elements.

The invention relates to a manufacturing method of a seamless steel tube for an oil and gas well perforating gun, which comprises the following manufacturing process routes of molten iron pretreatment → converter smelting → L F + VD external furnace refining → continuous casting and continuous rolling → hot rolling → heat treatment → flaw detection, wherein the manufacturing process comprises the following steps:

the molten iron pretreatment process comprises the following steps: the method comprises the steps of (1) entering blast furnace molten iron, spraying powder for desulfurization, slagging off, measuring temperature and sampling;

the converter smelting process comprises the following steps: adding molten iron and scrap steel, blowing oxygen, adding primary slag, discharging slag, adding secondary slag, blowing oxygen, pouring to measure temperature, sampling, tapping and alloying;

the external refining process comprises slagging in an L F furnace, heating, desulfurizing, alloying, soft blowing, degassing in a VD vacuum furnace, wire feeding and soft blowing;

the continuous casting and rolling process comprises the following steps: pouring with a tundish, pouring with a crystallizer, continuously casting, continuously rolling, inspecting and warehousing finished products;

the hot rolling process comprises the following steps: checking and accepting a tube blank, cutting, heating, perforating, resisting oxidation of the tube blank, continuously rolling MPM or PQF, removing the tube, sizing by a micro-tension reducing mill, cooling, sawing, straightening, blowing, checking and packaging the tube material; heating the tube blank at 1260-1300 ℃; descaling by adopting high-pressure water during sizing;

the heat treatment process comprises the following steps: quenching and tempering the steel pipe in an external spraying and internal spraying compression roller rotating quenching mode; the quenching temperature is 880 +/-20 ℃, the tempering temperature is 600 +/-10 ℃, and the heat preservation time is 40-60 min.

The invention starts from the aspects of screening and proportioning of alloy elements, steel cleanliness control, process optimization and parameter selection, structure optimization and the like, and finally determines the proportioning of the alloy elements and the manufacturing process which can meet the aim of the invention through a large amount of systematic experimental researches. Because of the bad operation conditions, the seamless steel pipe for the oil-gas well perforating gun adopts Cr-Mo series steel to ensure the strength and toughness of the steel, and simultaneously utilizes the mechanisms of solid solution strengthening, precipitation strengthening, fine grain strengthening and the like to obtain higher strength.

The seamless steel tube for the oil-gas well perforating gun disclosed by the invention comprises the following main chemical components in parts by weight:

c is a carbide forming element, which can improve the strength of steel, and the lower limit of the content of C is 0.30% in order to ensure the necessary strength.

Si is an effective deoxidizing element, the deoxidizing effect is lacked when the content is too low, and the toughness of the steel is reduced when the content is too high, so that 0.2-0.4% of Si is selected as the alloy content range of the Si.

Mn is an austenite forming element and is used for improving the strength of steel and making up the yield strength lost due to the reduction of carbon content, and can improve the toughness of the steel and reduce the ductile-brittle transition temperature while improving the strength; the invention limits the content range of Mn to be 0.60-0.75%.

Cr is an element for expanding hardenability and is also an element for forming carbide, the effective matching of Cr and Mo improves the hardenability of steel, and the steel grade can be ensured to have good comprehensive mechanical properties under higher strength in the states of quenching and high-temperature tempering; the invention limits the content range of Cr to 1.00-1.20%.

Mo is similar to Cr and is an element for expanding hardenability, has strong affinity with C, is a carbide forming element and reduces the content of solid-dissolved C. In the quenched and tempered steel tempered at high temperature, Mo and C form alloy carbide particles which are separated out to play a role of secondary hardening, and the tempering at the temperature of over 600 ℃ is ensured to have higher strength and toughness. The effective matching of Cr-Mo can ensure that the steel grade has good comprehensive mechanical properties under higher strength in the states of quenching and high-temperature tempering. The content range of Mo is limited to 0.20-0.30%.

P is an impurity element, promotes center segregation, remarkably reduces the low-temperature impact toughness of steel, improves the ductile-brittle transition temperature of the steel, and also deteriorates the welding performance of the steel, and the content of the P is required to be reduced as much as possible, wherein the content of the P is required to be not more than 0.015 percent.

S is an impurity element, can segregate at a crystal boundary, is easy to form sulfide, and reduces the toughness of steel, and the content of S is required to be not more than 0.008 percent.

The following examples are carried out on the premise of the technical scheme of the invention, and detailed embodiments and specific operation processes are given, but the scope of the invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[ examples ] A method for producing a compound

In this example, the chemical composition of the seamless steel tube for the perforating gun of the oil and gas well is shown in table 1.

In this embodiment, the process for manufacturing the seamless steel tube for the perforating gun of the oil and gas well comprises the following steps:

the general process route is molten iron pretreatment → converter smelting → external refining (L F + VD) → continuous casting and rolling → hot rolling → heat treatment → flaw detection.

1. A steel-making process;

pretreating molten iron: molten iron of the blast furnace enters the station → powder injection desulfurization, slag skimming, temperature measurement sampling → the converter.

Converter smelting, namely adding molten iron and waste steel → blowing oxygen → adding slag charge → discharging slag → adding slag charge → blowing oxygen → inverting the furnace for temperature measurement and sampling → tapping, alloying → L F furnace;

external refining, namely L F furnace slagging → heating → desulfuration → alloying → soft blowing → VD vacuum furnace degassing, wire feeding, soft blowing → continuous casting;

continuous casting and rolling, namely, a steel ladle → a tundish protection pouring → a crystallizer protection pouring → 280mm × 380mm continuous casting → continuous rolling → inspection → finished product warehousing.

The operation key points are as follows: the molten iron desulphurization and slagging-off must be clean, so as to prevent the molten iron from resulfurizing and influencing the converter desulphurization. The double-slag operation time node of the converter is optimized, the desulfurization rate is increased, and simultaneously the decarburization of the converter is controlled to prevent the molten steel from being over oxidized. The alloying time node of the steel is reasonably tapped, so that the alloy is rapidly and effectively melted, and the yield is improved. The alloy is finely adjusted by refining to achieve an accurate target, and ferrotitanium must be added 5-8 minutes before the refining is finished. Meanwhile, the alloy has high requirement on steel quality due to large addition amount, the soft blowing time is controlled, the steel quality is uniform, and the purity is improved. The continuous casting ensures constant speed and secondary cooling water strength, and prevents the casting blank from cracking. And the hole patterns are adjusted by continuous rolling, so that creases are avoided.

2. Hot rolling process;

tube blank acceptance → cutting → heating → perforation → antioxidation → PQF continuous rolling → tube removal → micro-tensioning → cooling → sawing → straightening → blowing → inspection → tube material packaging;

the operation key points are as follows: the puncher ensures that the wall thickness of the steel pipe is uniform, and the capillary pipe cannot enter water; continuous rolling is carried out by using a core rod with a flawless surface for rolling and well lubricated by graphite; and descaling by high-pressure water during sizing.

3. A heat treatment process;

and (3) quenching and tempering the steel pipe in an external spraying and internal spraying compression roller rotating quenching mode. The transformation temperature Ac1 and Ac3 of the seamless steel tube for the oil-gas well perforating gun are respectively 740-750 ℃ and 810-820 ℃. In order to determine the heat treatment process of the steel pipe, a heat treatment process test was performed on the steel pipe of this grade.

The operation key points are as follows: the quenching furnace reaches the set temperature, and the steel pipe is fully austenitized; water quenching ensures that the central line of the rotating wheel of the steel pipe is horizontal; the temperature of the heat treatment furnace is accurately controlled, the temperature of the quenching furnace is controlled according to +/-20 ℃, and the temperature of the tempering furnace is controlled according to +/-10 ℃.

In this example, the main process parameters for process control are shown in table 2:

item	Example 1	Example 2	Example 3	Example 4	Example 5
						Pipe blank heating temperature (. degree. C.)	1270	1280	1290	1280	1275
Quenching temperature (. degree. C.)	890	865	890	870	880
						Tempering temperature (. degree.C.)	590	590	600	610	610
Incubation time (min)	40	45	55	50	60

In the embodiment, the microstructure of the seamless steel tube for the oil-gas well perforating gun after heat treatment is tempered sorbite, and the grains are fine, as shown in fig. 1 and 2.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (3)

1. The seamless steel tube for the perforating gun of the oil and gas well is characterized by comprising the following chemical components in percentage by mass: 0.30 to 0.34 percent of C, 0.17 to 0.37 percent of Si, 0.60 to 0.75 percent of Mn and less than or equal to 0.015 percent of P; less than or equal to 0.010 percent of S, 1.00 to 1.20 percent of Cr, 0.20 to 0.30 percent of Mo, 0.020 to 0.045 percent of Als, less than or equal to 0.30 percent of Ni and less than or equal to 0.20 percent of Cu; the balance of Fe and other inevitable elements.

2. The seamless steel tube for oil and gas well perforating guns as claimed in claim 1, characterized in that, the chemical composition of the seamless steel tube by mass percent is: 0.31 to 0.33 percent of C, 0.25 to 0.29 percent of Si, 0.65 to 0.70 percent of Mn and less than or equal to 0.012 percent of P; less than or equal to 0.008 percent of S, 1.05 to 1.15 percent of Cr, 0.22 to 0.27 percent of Mo and 0.025 to 0.035 percent of Als; the balance of Fe and other inevitable elements.

3. The method for manufacturing a seamless steel tube for a perforating gun of an oil and gas well according to claim 1 or 2, wherein the manufacturing process route is molten iron pretreatment → converter smelting → L F + VD external refining → continuous casting and rolling → hot rolling → heat treatment → flaw detection, wherein:

the hot rolling process comprises the following steps: checking and accepting a tube blank, cutting, heating, perforating, resisting oxidation of the tube blank, continuously rolling MPM or PQF, removing the tube, sizing by a micro-tension reducing mill, cooling, sawing, straightening, blowing, checking and packaging the tube material; heating the tube blank at 1260-1300 ℃; descaling by adopting high-pressure water during sizing;

the heat treatment process comprises the following steps: quenching and tempering the steel pipe in an external spraying and internal spraying compression roller rotating quenching mode; the quenching temperature is 880 +/-20 ℃, the tempering temperature is 600 +/-10 ℃, and the heat preservation time is 40-60 min.

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