WO2020143310A1 - Stainless steel composite plate for use in petroleum and natural gas delivery pipelines and preparation method therefor - Google Patents

Abstract

A stainless steel composite plate for use in petroleum and natural gas delivery pipelines, comprising a base material and a coating material, the coating material being metallurgically coated onto the base material, the coating material being austenitic stainless steel, and the chemical composition of the base material by weight percentage being: C: 0.03％-0.09％, Si: 0.2％-0.4％, Mn: 1.00％-1.70％, P≤0.02％, S≤0.01％, Alt: 0.015％-0.050％, Nb: 0.020％-0.090％, V≤0.05％, Ti: 0.006％-0.030％, Cr: 0.10％-0.30％, Ni≤0.30％, Mo≤0.10％, Cu≤0.30％, B≤0.001％, and the remainder being Fe and a small amount of unavoidable impurities; and a preparation method for the stainless steel composite plate for use in petroleum and natural gas delivery pipelines, the preparation method being simple and easy to implement and low cost; the prepared composite plate has good corrosion resistance and strong toughness, a straighter composite interface, more uniform coating thickness, and better surface quality, and can be directly used without needing annealing heat treatment.

Description

Stainless steel composite plate for oil and gas transmission pipeline and preparation method thereof Technical field

The invention belongs to the field of bimetallic composite board and its manufacturing technology, and in particular relates to a stainless steel composite board for oil and gas transportation pipes and a preparation method thereof.

Background technique

With the continuous progress of the oil and gas industry, the world's energy demand is increasing, and the easily exploitable oil and natural gas resources are decreasing. In order to meet the global industrialization demand for oil and gas, the exploration and development of oil and gas fields have gradually developed into regions with more severe environmental conditions. In recent years, oil and gas fields with high content of CO ₂ , high content of Cl ^-1 , high content of H ₂ S, high temperature, high pressure and elemental sulfur have emerged continuously. In harsh environments with high corrosiveness such as H ₂ S, Cl ^-1 and CO _{2, the} corrosion of oil and gas well casings and gathering and transportation pipelines made with conventional pipeline steel is extremely serious, especially under the combined action of temperature and pressure , It is easy to cause accidents such as perforation and cracking of gathering pipelines. The use of pure stainless steel pipes is expensive and costly, and the stainless steel pure material as the anti-corrosion part only accounts for one third, causing a huge waste of material. The stainless steel composite plate for pipelines has both the good corrosion resistance of multi-layer stainless steel and the high strength and high toughness of the base pipeline steel. The bimetallic composite pipe prepared from it can significantly improve the corrosion resistance of the pipeline and extend the service life of the pipeline At the same time, the material price is also suitable.

The main preparation technology of stainless steel composite plates for pipelines is mainly the explosive composite method and the vacuum rolling composite method. For example, Patent Application No. 201410424877.3 "Preparation of a stainless steel/pipeline steel composite plate for oil and gas transportation pipelines" discloses a production method for preparing stainless steel composite plates for oil and gas pipelines by an explosive composite method. Due to the problems of noise pollution and environmental pollution caused by the explosive compound method, the initiation point cannot be metallurgically combined and the long-term annealing after the explosion has a great impact on the corrosion resistance of stainless steel. It is a composite plate production method that will be gradually eliminated. The vacuum rolling compound method adopts a welding group billet, which is heated at a high temperature and then rolled to achieve a good metallurgical combination of the base material and the cladding material. It is a green and environmentally friendly method for producing composite boards. While the vacuum rolling composite method is used to produce composite panels, the existing traditional blank assembly process mainly seals the surroundings, and then drills and then evacuates the blanks, such as the patent publication number CN103639203A "Symmetrical Hot Rolling to Produce Stainless Steel Composite Panel Vacuum The "encapsulation method" discloses that this method is used to form the blank. Because this method requires sealing and welding before drilling and vacuuming, the process is cumbersome, and in the atmospheric environment, the edge of the composite welded composite blank is not easy to oxidize, which affects the bonding. . Another novel way of forming blanks is electron beam direct welding of the blanks in a vacuum environment, eliminating the need for drilling and vacuuming after sealing and welding, such as Patent Publication No. CN102069289A "Preparation of a stainless steel-carbon steel composite board" What is disclosed is the use of electron beams to weld stainless steel and carbon steel directly in a vacuum environment. However, due to the great difference in thermal expansion coefficient between stainless steel and carbon steel in this method, it is easy to crack the weld seam between stainless steel and carbon steel during the heating process due to the different expansion, and the rolling power is not too high. The stainless steel clad plates for oil and gas transmission pipelines have high requirements on the performance of substrates and cladding materials, and also have high requirements on the bonding performance. To obtain good comprehensive performance of the stainless steel clad plates for oil and gas transmission pipelines, the composition and rolling of the substrates There are strict requirements for the process.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art, and to provide a stainless steel composite plate for oil and gas transmission pipelines and a preparation method thereof. The preparation method is simple and easy, and the cost is low. The prepared composite plate has good Corrosion resistance, strength and toughness, the composite interface is flatter, the thickness of the cladding material is more uniform, the surface quality is better, and it can be used directly without annealing and heat treatment.

In order to solve the above technical problems, the present invention provides a stainless steel composite plate for oil and gas pipelines, including a base material and a cladding material, and the cladding material is metallurgically bonded to the substrate;

The cladding material is austenitic stainless steel;

The chemical composition of the substrate by weight percentage is: C: 0.03%-0.09%, Si: 0.2%-0.4%, Mn: 1.00%-1.70%, P≤0.02%, S≤0.01%, Alt: 0.015%-0.050% , Nb: 0.020%-0.090%, V≤0.05%, Ti: 0.006%-0.030%, Cr: 0.10%-0.30%, Ni≤0.30%, Mo≤0.10%, Cu≤0.30%, B≤0.001%, The balance is Fe and a small amount of inevitable impurities.

The technical solutions further defined by the present invention are:

Further, in the aforementioned stainless steel composite plate for oil and gas transmission lines, the cladding material is S30403 (304L), S31008 (310S), S31603 (316L), S31703 (317L), or S32168 (321) austenitic stainless steel.

In the aforementioned stainless steel composite plate for oil and gas pipelines, the structure of the base material is bainite + a small amount of proeutectoid ferrite structure, or acicular ferrite + bainite structure; the structure of the coating material is austenite structure .

In the aforementioned stainless steel composite plate for oil and gas transmission lines, the yield strength of the base material: 415-635 MPa, the tensile strength: 520-760 MPa, the elongation ≥ 20%, and the Charpy impact energy at -20°C Akv ≥ 120J.

In the aforementioned stainless steel composite plate for oil and gas pipelines, the cladding material was tested for intergranular corrosion according to ASTM A262 Method E. The curved outer surface showed no intergranular cracking, and the intergranular corrosion resistance was good.

In the aforementioned stainless steel composite plate for oil and gas transmission lines, the shear strength of the stainless steel composite plate for oil and gas transmission lines is ≥350 MPa, and the composite interface does not crack after 180° internal bending and external bending.

The invention also designs a method for preparing stainless steel composite plates for oil and gas pipelines, which specifically includes the following steps:

(1) Preparation of blanks: According to the variety and specifications of the finished composite board, prepare the base material and the cover material blank, and polish the surface of the base material and the cover material blank to be composited, remove the rust layer and oxide layer on the surface of the blank, and make the surface complete Exposed fresh metal;

(2) Brushing of the release agent: apply the release agent to the non-composite surface of the covering material to ensure that the release agent is evenly painted on the surface of the covering material, and then dry the release agent;

(3) Preparation of composite billet: spot seal is fixed on the four peripheral parts of the surface of one of the base materials to be compounded, the height of the seal is the sum of the thickness of the two covering materials, and the width is 30-60mm; Stack and place in the groove surrounded by the seal, and then put the other substrate composite face down, cover the two cladding materials, ensure that the four sides of the upper and lower substrates are flush with the outer edge of the seal, forming a to be sealed Welded composite billet; vacuum electron beam is used to weld the gap between the composite billet seal and the substrate in a vacuum chamber, and the vacuum degree value during welding is less than 10×10 ^-2 Pa;

(Iv) Heating: The composite billet is sent to a heating furnace for heating, the heating temperature is 1120-1230°C, and the total heating time is controlled according to the thickness of the billet in the time of 1.0-2.0min/mm;

(5) Rolling and cooling: Rolling is carried out using the TMCP process large reduction method, the first pass reduction rate in the rough rolling stage is more than 10%, and the last pass reduction rate in the rough rolling is more than 25%; the intermediate billet thickness is rolled The total thickness is 2.0-3.0 times, the open rolling temperature in the finishing rolling stage is 830-950℃, and the final rolling temperature is controlled at 800-900℃; after rolling, the steel is cast at a high speed, and the composite plate directly enters the ultra-fast cooling device for 5-20℃/ Rapid cooling at s speed, the temperature of red return is controlled at 350-550℃;

㈥Cutting sub-board: plasma or flame cutting is used to cut the composite board. After cutting the head, tail and both sides, the upper and lower single-sided composite boards are separated, and then the single-sided composite board is straightened and the surface is polished. After that, get the stainless steel clad plate products of the required specifications.

The technical solutions further defined by the present invention are:

Further, in the aforementioned method for preparing a stainless steel composite plate for oil and gas transmission pipelines, the welding depth of the electron beam sealing and welding in step (iii) is 30-60 mm.

In the foregoing preparation method of the stainless steel composite plate for oil and gas transmission lines, the compression ratio in the rough rolling stage of the rolling process in step (v) is ≥2.0.

The beneficial effects of the invention are:

(1) The base material of the present invention adopts a low carbon + trace Nb, Ti composition design, which expands the non-recrystallization interval, can appropriately increase the final rolling temperature, and is beneficial to obtain excellent corrosion resistance of the cladding material, while the substrate is still not recrystallized Zone rolling, also has good strength and toughness;

⑵ The invention directly seals and welds the group billet in the vacuum chamber environment, reducing the drilling and vacuuming processes of the traditional process, and the vacuum degree is more guaranteed; at the same time, the compound billet is welded by the seal and the substrate to avoid stainless steel and carbon The problem of direct welding steel billet cracking due to inconsistent expansion during heating;

(3) Compared with explosive recombination, the present invention adopts a stainless steel composite plate for oil and gas transportation pipeline prepared by combining vacuum welding assembly billet and TMCP rolling process, the composite interface is flatter, the thickness of the cladding material is more uniform, and the surface quality is better, and It can be used directly without annealing and heat treatment.

BRIEF DESCRIPTION

FIG. 1 is a microstructure diagram of the interface of the composite board in Example 1 of the present invention, FIG.

FIG. 2 is a microstructure diagram of a composite board base material in Example 1 of the present invention.

detailed description

Examples 1-5

This embodiment provides a stainless steel composite plate for oil and gas transmission pipelines, which includes a base material and a cladding material, and the cladding material is metallurgically bonded to the substrate;

Table 2 lists the stainless steel grades of the stainless steel clad plate cladding materials used in the oil and gas pipelines of Examples 1-5;

Table 1 lists the chemical composition mass percentages of the stainless steel composite plate base material blanks used in the oil and gas transmission lines of Examples 1-5;

Table 1 Smelting composition of base steel grades

Examples	C	Si	Mn	P	S	Nb	V	Ti	Alt	Cr	Ni	Cu	Mo	B
Example 1	0.06	0.25	1.45	0.012	0.0025	0.040	0.001	0.009	0.032	0.18	0.01	0.02	0.011	0.0002
Example 2	0.06	0.20	1.55	0.012	0.0023	0.045	0.001	0.010	0.035	0.17	0.01	0.02	0.012	0.0001
Example 3	0.05	0.20	1.56	0.012	0.0021	0.045	0.001	0.011	0.034	0.16	0.01	0.02	0.011	0.0002
Example 4	0.06	0.30	1.63	0.012	0.0022	0.055	0.001	0.012	0.036	0.27	0.18	0.02	0.010	0.0002
Example 5	0.06	0.29	1.65	0.012	0.0018	0.065	0.001	0.015	0.032	0.26	0.25	0.15	0.011	0.0001

The balance is Fe and a small amount of inevitable impurities;

Table 2 Grades of stainless steel with cladding materials according to examples of the invention

Examples	Example 1	Example 2	Example 3	Example 4	Example 5
Covering grade	S30403	S31008	S31603	S31703	S32168

The preparation method of the stainless steel composite plate for the oil and gas transmission pipeline of Example 1-5, the specific process parameters of each example are shown in Table 3, and specifically include the following steps:

(1) Preparation of blanks: According to the variety and specifications of the finished composite board, prepare the base material and the cover material blank, and polish the surface of the base material and the cover material blank to be composited, remove the rust layer and oxide layer on the surface of the blank, and make the surface complete Exposed fresh metal;

(2) Brushing of the release agent: apply the release agent to the non-composite surface of the covering material to ensure that the release agent is evenly painted on the surface of the covering material, and then dry the release agent;

(3) Preparation of composite billet: spot seal is fixed on the four peripheral parts of the surface of one of the base materials to be compounded, the height of the seal is the sum of the thickness of the two covering materials, and the width is 30-60mm; Stack and place in the groove surrounded by the seal, and then put the other substrate composite face down, cover the two cladding materials, ensure that the four sides of the upper and lower substrates are flush with the outer edge of the seal, forming a to be sealed Welded composite billet; vacuum electron beam is used to weld the gap between the composite billet seal and the substrate in a vacuum chamber, and the vacuum degree value during welding is less than 10×10 ^-2 Pa;

(Iv) Heating: The composite billet is sent to a heating furnace for heating, the heating temperature is 1120-1230°C, and the total heating time is controlled according to the thickness of the billet in the time of 1.0-2.0min/mm;

(5) Rolling and cooling: Rolling is carried out using the TMCP process large reduction method, the first pass reduction rate in the rough rolling stage is more than 10%, and the last pass reduction rate in the rough rolling is more than 25%; the intermediate billet thickness is rolled The total thickness is 2.0-3.0 times, the open rolling temperature in the finishing rolling stage is 830-950℃, and the final rolling temperature is controlled at 800-900℃; after rolling, the steel is cast at a high speed, and the composite plate directly enters the ultra-fast cooling device for 5-20℃/ Rapid cooling at s speed, the temperature of red return is controlled at 350-550℃;

㈥Cutting sub-board: plasma or flame cutting is used to cut the composite board. After cutting the head, tail and both sides, the upper and lower single-sided composite boards are separated, and then the single-sided composite board is straightened and the surface is polished. After that, get the stainless steel clad plate products of the required specifications.

Table 3 Specific process parameters of embodiments of the present invention

In this example, the cladding material was tested for intergranular corrosion in accordance with ASTM A262 Method E. The intergranular corrosion resistance is excellent. The weld depth of the electron beam seal welding in step (iii) is 30-60 mm; the rolling process in step (v) is rough The compression ratio at the rolling stage is ≥2.0.

Table 4 Various organizational performance of the embodiment of the present invention

The specific performance parameters of the composite board of Example 1-5 are shown in Table 4. The composite board has excellent tensile, impact, bending, shear strength and intergranular corrosion resistance. Figures 1 and 2 are Example 1 The photo of the microstructure of the composite interface of the composite plate and the microstructure of the substrate shows that the composite plate achieves good metallurgical bonding, and the substrate structure is bainite + proeutectoid ferrite.

In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims (9)

1. A stainless steel composite plate for oil and natural gas pipelines, characterized in that it includes a base material and a covering material, and the covering material is metallurgically bonded to the base material;

   The cladding material is austenitic stainless steel;

   The chemical composition of the base material is: C: 0.03%-0.09%, Si: 0.2%-0.4%, Mn: 1.00%-1.70%, P≤0.02%, S≤0.01%, Alt: 0.015%- 0.050%, Nb: 0.020%-0.090%, V≤0.05%, Ti: 0.006%-0.030%, Cr: 0.10%-0.30%, Ni≤0.30%, Mo≤0.10%, Cu≤0.30%, B≤0.001 %, the balance is Fe and a small amount of inevitable impurities.
2. The stainless steel composite plate for oil and gas pipelines according to claim 1, characterized in that the covering material is S30403 (304L), S31008 (310S), S31603 (316L), S31703 (317L) or S32168 (321) Austria Austenitic stainless steel.
3. The stainless steel composite plate for oil and gas pipelines according to claim 1, wherein the structure of the substrate is bainite + a small amount of proeutectoid ferrite structure, or acicular ferrite + bainite Structure; the structure of the covering material is an austenite structure.
4. The stainless steel composite plate for oil and gas pipelines according to claim 1, characterized in that: the yield strength of the base material: 415-635MPa, the tensile strength: 520-760MPa, the elongation ≥ 20%, -20 ℃ summer Specific impact energy Akv≥120J.
5. The stainless steel composite plate for oil and gas pipelines according to claim 1, characterized in that the cladding material is tested for intergranular corrosion according to ASTM E262 method E, and the curved outer surface does not exhibit intergranular cracking, and is resistant to intergranular corrosion Good performance.
6. The stainless steel composite plate for oil and gas pipelines according to claim 1, characterized in that the shear strength of the stainless steel composite plate for oil and gas pipelines is ≥350MPa, and the composite interface does not crack after 180° internal bending and external bending .
7. The method for preparing a stainless steel composite plate for oil and gas transmission lines according to claim 1, characterized in that it specifically includes the following steps:

   (1) Preparation of blanks: According to the variety and specifications of the finished composite board, prepare the base material and the cover material blank, and polish the surface of the base material and the cover material blank to be composited, remove the rust layer and oxide layer on the surface of the blank, and make the surface complete Exposed fresh metal;

   (2) Brushing of the release agent: apply the release agent to the non-composite surface of the covering material to ensure that the release agent is evenly painted on the surface of the covering material, and then dry the release agent;

   (3) Preparation of composite billet: spot seal is fixed on the four peripheral parts of the surface of one of the base materials to be compounded, the height of the seal is the sum of the thickness of the two covering materials, and the width is 30-60mm; Stack and place in the groove surrounded by the seal, and then put the other substrate composite face down, cover the two cladding materials, ensure that the four sides of the upper and lower substrates are flush with the outer edge of the seal, forming a to be sealed Welded composite billet; vacuum electron beam is used to weld the gap between the composite billet seal and the substrate in a vacuum chamber, and the vacuum degree value during welding is less than 10×10 ^-2 Pa;

   (Iv) Heating: The composite billet is sent to a heating furnace for heating, the heating temperature is 1120-1230°C, and the total heating time is controlled according to the thickness of the billet in the time of 1.0-2.0min/mm;

   (5) Rolling and cooling: Rolling is carried out using the TMCP process large reduction method, the first pass reduction rate in the rough rolling stage is more than 10%, and the last pass reduction rate in the rough rolling is more than 25%; the intermediate billet thickness is rolled The total thickness is 2.0-3.0 times, the open rolling temperature in the finishing rolling stage is 830-950℃, and the final rolling temperature is controlled at 800-900℃; after rolling, the steel is cast at a high speed, and the composite plate directly enters the ultra-fast cooling device for 5-20℃/ Rapid cooling at s speed, the temperature of red return is controlled at 350-550℃;

   ㈥Cutting sub-board: plasma or flame cutting is used to cut the composite board. After cutting the head, tail and both sides, the upper and lower single-sided composite boards are separated, and then the single-sided composite board is straightened and the surface is polished. After that, get the stainless steel clad plate products of the required specifications.
8. The method for preparing a stainless steel clad plate for oil and gas pipelines according to claim 7, characterized in that the welding depth of the electron beam sealing and welding in the step (iii) is 30-60 mm.
9. The method for preparing a stainless steel clad plate for oil and gas pipelines according to claim 7, wherein the compression ratio in the rough rolling stage of the rolling process in the step (v) is ≥2.0.

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