A method for producing a nickel-based composite pipe line steel plate

Abstract

The application discloses a production method of a nickel-based composite pipeline steel plate, and the chemical component mass percentage of the base material is as follows: C=0.02%-0.04%, Si=0.05%-0.25%, Mn=1.6%-1.65%, P<=0.010%, S<=0.0015%, Alt=0.025%-0.050%, Nb=0.03%-0.060%, Ti=0.010%-0.020%, Cu=0.20%-0.25%, Cr=0.24%-27%, Ni=0.09%-0.13% and V=0.03-0.04%; and the chemical component mass percentage of the composite material is as follows: C<=0.05%, Si=0.25%-0.50%, Cr=19.5%-23.5%, Ni=38-46%, and Co=0.28-0.30%. The application adopts vacuum rolling composite+low-speed deformation technology+ultra-fast cooling process to obtain N08825+X70 composite pipeline steel with excellent strength, wherein the maximum wall thickness of the base material reaches 45mm, and the thickness of N08825 is 3mm.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgy and relates to a production method of a nickel-based composite pipe line steel plate. BACKGROUND

[0002] The main transportation mode of oil and natural gas is pipeline transportation. Since hydrogen sulfide, carbon dioxide and other substances in oil and gas can accelerate the corrosion of pipe line steel, accidents of failure and even rupture of oil pipeline due to corrosion and external environment occur from time to time, which brings not small threat to the safety of life and property of the state and people. If nickel-based alloy is used as pipe line steel, the problem of insufficient corrosion resistance can be solved, but the price is high and the comprehensive mechanical properties are not as good as those of pipe line steel, so the use of nickel-based composite plate becomes the first choice.

[0003] The nickel-based alloy composite plate is a bimetallic composite plate obtained by combining carbon steel as a base layer and nickel-based alloy as a composite layer through rolling or other ways. Therefore, the nickel-based alloy composite plate not only has good mechanical properties of the base layer, but also has good corrosion resistance and oxidation resistance of the nickel-based alloy, which not only greatly reduces the production cost and saves resources, but also meets the needs of customers and the market, so that the nickel-based alloy composite plate is widely used in the fields of nuclear power, bridge, water conservancy, aerospace and the like. Under this background, the research and production of the nickel-based alloy composite plate can not only ensure its corrosion resistance and excellent mechanical properties, but also greatly reduce the production cost. SUMMARY

[0004] The application aims to provide a production method of a nickel-based composite pipe line steel plate, which adopts vacuum rolling composite + low-speed deformation technology + ultra-fast cooling process to obtain N08825 + X70 composite pipe line steel with excellent strength, wherein the maximum wall thickness of the base material reaches 45 mm and the thickness of N08825 is 3 mm.

[0005] In order to realize the above-mentioned application, the application adopts the following technical scheme:

[0006] The application discloses a production method of a nickel-based composite pipeline steel plate, and the technological process comprises the following steps: surface treatment of a base material, encapsulation and assembly welding, one-time heating, one-time rolling, back to a pit for two-time heating, two-time rolling, cooling, heat treatment, plate opening and finishing, flaw detection and warehousing.The chemical component mass percentage of the base material is as follows: C=0.02%-0.04%, Si=0.05%-0.25%, Mn=1.6%-1.65%, P<=0.010%, S<=0.0015%, Alt=0.025%-0.050%, Nb=0.03%-0.060%, Ti=0.010%-0.020%, Cu=0.20%-0.25%, Cr=0.24%-27%, Ni=0.09%-0.13%, V=0.03-0.04%, and the rest is Fe and inevitable impurities; the chemical component mass percentage of the composite material is as follows: C<=0.05%, Si=0.25%-0.50%, Cr=19.5%-23.5%, Ni=38-46%, Co=0.28-0.30%, and the rest is Fe and inevitable impurities.The key process steps comprise the following steps:

[0007] (1) composite blank preparation: X70+N08825+N08825+X70 double-face symmetrical composite welding, isolation agent is added between the two composite materials, the thickness of the isolation agent is 0.2-0.3 mm, the thickness of the submerged arc welding around the isolation agent is 200-300 mm, the thickness of the composite blank is 500-600 mm, and vacuum is extracted after welding, and the vacuum degree is <=-1 Pa;

[0008] (2) one-time heating: adopting a soaking pit for heating, the core temperature of the molten steel is 1150-1160 DEG C, the total heating time is 18-24 h, and the temperature difference between the core and the surface of the billet is <=15 DEG C;

[0009] (3) one-time rolling: rough rolling to 350-380 mm, three passes of 45-50 mm exist, the finish rolling temperature is >=1100 DEG C, and the cooling to room temperature is performed after the billet is discharged;

[0010] (4) two-time heating: adopting a walking beam type heating furnace for heating, the core temperature of the molten steel is 1130-1150 DEG C, the total heating time is 5-6 h, and the temperature difference between the core and the surface of the billet is <=20 DEG C;

[0011] (5) two-time rolling: the intermediate billet is set to 150-180 mm, the two-stage open rolling temperature is 840-860 DEG C, the single-pass rolling speed is 2-3 m / s, the last two passes are controlled to be rolled in a two-phase zone, and the finish rolling temperature is 690-730 DEG C;

[0012] (6) cooling: adopting an ultrafast cooling swing cooling mode, the swing cooling time is 60-120 s, and the final cooling temperature is 320-360 DEG C.

[0013] Invention principle: in the component design, the component design of ultra-low carbon, no Mo+ appropriate Cr+ Ni+ Cu micro-alloy Nb+ Ti can not only refine the grain, but also move the Ar3 line, which is very beneficial to the control of two-phase zone rolling. Regarding step (2), the heating process ensures that the alloy is fully solid-solved, the grain is fully austenitized, and the phenomenon of coarse growth does not occur, the casting blank absorbs heat fully, and the temperature is uniform, which can not only improve the low-temperature fracture toughness of the material, but also be beneficial to improve the shear strength of the joint surface. Regarding step (3), high temperature and large reduction of finish rolling, the original austenite grain size is refined, and the casting blank is cooled to room temperature after rolling, which further refines the grain size of the casting blank. Regarding steps (5) and (6), the method of reducing the rolling speed of finish rolling, the low rolling speed further refines the grain size, and the bonding degree of the base material and the composite material is greatly improved; two passes of two-phase zone rolling promote the deformation and flattening of polygonal ferrite, further improve the low-temperature toughness of the core of the material, and cooperate with the super-fast cooling swing cooling mode, so that the strength and toughness of the material are well matched.

[0014] The beneficial effects of the present application: solve the problem of low shear strength and low-temperature toughness of the current high-grade nickel-based composite pipe line steel, and solve the problem of thickness bounce of nickel-based and base material rolling. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The metallographic structure diagram of the steel plate produced in example 1. DETAILED DESCRIPTION

[0016] The content of the present application will be further illustrated below in combination with examples.

[0017] Example 1: production method of 42+3mm X70+N08825 nickel-based composite pipe line steel plate

[0018] The chemical composition of the composite plate base material is C=0.03%, Si=0.15, Mn=1.62%, P=0.008%, S=0.0012%, Alt=0.028%, Nb=0.045%, Ti=0.01%, Cu=0.22%, Cr=0.26%, Ni=0.09%-0.13%, V=0.036%, and the balance is Fe and inevitable impurities; the chemical composition of the composite material is C=0.04%, Si=0.45%, Cr=22.8%, Ni=42%, Co=0.29%, and the balance is Fe and inevitable impurities. The key process steps include:

[0019] (1) composite blank preparation: "X70+N08825+N08825+X70" double-sided symmetric composite welding, isolation agent is added between the two composite materials, the thickness of the isolation agent is 0.28mm, the four-arc welding is 240mm thick, and the composite blank is 560mm thick,

[0020] Vacuumizing after welding, vacuum degree≤-1 Pa.

[0021] (2) First heating: using soaking pit heating, the core temperature of the molten steel is 1156℃, the total heating time is 20.6h, and the temperature difference between the core and the surface of the billet is 14℃.

[0022] (3) First rolling: rough rolling to 365mm, there are three passes of 42mm reduction, the finish rolling temperature is 1116℃, and the cooling to room temperature.

[0023] (4) Second heating: using walking beam furnace heating, the core temperature of the molten steel is 1142℃, the total heating time is 5.6h, and the temperature difference between the core and the surface of the billet is 16℃.

[0024] (5) Second rolling: the intermediate billet is set to 162mm, the two-stage opening rolling temperature is 858℃, the single pass rolling speed is 2.8m / s, the last two passes are controlled in the two-phase region, and the finish rolling temperature is 700~720℃.

[0025] (6) Cooling: using ultra-fast cooling swing cooling mode, the swing cooling time is 88s, and the final cooling temperature is 350℃.

[0026] Example 2: Production method of 54+3mm X70+N08825 nickel-based composite pipeline steel plate

[0027] The chemical composition of the composite plate base material is C=0.02%, Si=00.22%, Mn=1.62%, P=0.006%, S=0.0008%, Alt=0.028%, Nb=0.045%, Ti=0.015%, Cu=0.23%, Cr=0.26%, Ni=0.10%, V=0.038%, and the balance is Fe and inevitable impurities; the chemical composition of the composite material is C=0.03%, Si=0.45%, Cr=21.8%, Ni=45%, Co=0.29%, and the balance is Fe and inevitable impurities. Key process steps include:

[0028] (1) Composite billet preparation: “X70+N08825+N08825+X70” double-sided symmetric composite welding, isolation agent is added between the two composites, the thickness of the isolation agent is 0.28mm, the four-arc welding overlay thickness is 289mm, and the composite billet thickness is 580mm,

[0029] Vacuumizing after welding, vacuum degree≤-1 Pa.

[0030] (2) First heating: using soaking pit heating, the core temperature of the molten steel is 1156℃, the total heating time is 22h, and the temperature difference between the core and the surface of the billet is 14℃.

[0031] (3) First rolling: rough rolling to 370 mm, three passes of 48 mm reduction, finishing temperature 1122°C, and cooling to room temperature.

[0032] (4) Second heating: heating in a walking beam furnace, core temperature of the molten steel 1138°C, total heating time 5.8 h, and core and surface temperature difference of the billet 16°C.

[0033] (5) Second rolling: set intermediate billet to 178 mm, two-stage roughing temperature 845°C, single pass rolling speed 2.5 m / s, last two passes controlled in two-phase region, and finishing temperature 695-715°C.

[0034] Table 1 Mechanical property test results of the composite pipe produced in the example

[0035] .

Claims

1. A production method of a nickel-based composite pipeline steel plate, a process flow of which is substrate surface treatment - encapsulation and assembly welding - one-time heating - one-time rolling - back to pit for two-time heating - two-time rolling - cooling - heat treatment - opening plate finishing - flaw detection - warehousing, characterized in that: The chemical composition of the base material is C=0.02%-0.04%, Si=0.05%-0.25%, Mn=1.6%-1.65%, P≤0.010%, S≤0.0015%, Alt=0.025%-0.050%, Nb=0.03%-0.060%, Ti=0.010%-0.020%, Cu=0.20%-0.25%, Cr=0.24%-27%, Ni=0.09%-0.13%, V=0.03-0.04%, and the balance is Fe and inevitable impurities; the chemical composition of the composite material is C≤0.05%, Si=0.25%-0.50%, Cr=19.5%-23.5%, Ni=38-46%, Co=0.28-0.30%, and the balance is Fe and inevitable impurities; The key process steps include: (1) composite blank preparation: "X70+N08825+N08825+X70" double-sided symmetric composite welding, adding a separating agent between the two composite materials, the thickness of the separating agent is 0.2-0.3mm, the four-arc welding is 200-300mm thick, the composite blank is 500-600mm thick, and the vacuum degree after welding is ≤-1Pa; (2) first heating: using a soaking pit to heat, the core temperature of the molten steel is 1150-1160℃, the total heating time is 18-24h, and the temperature difference between the core and the surface of the billet is ≤15℃; (3) first rolling: rough rolling to 350-380mm, three passes of 45-50mm, the finish rolling temperature is ≥1100℃, and the cooling to room temperature after the line is cooled; (4) second heating: using a walking beam furnace to heat, the core temperature of the molten steel is 1130-1150℃, the total heating time is 5-6h, and the temperature difference between the core and the surface of the billet is ≤20℃; (5) second rolling: the intermediate billet is set to 150-180mm, the two-stage opening rolling temperature is 840-860℃, the single-pass rolling speed is 2-3m / s, the last two passes are controlled in the two-phase zone, and the finish rolling temperature is 690-730℃; (6) cooling: using a super-fast cooling swing cooling mode, the swing cooling time is 60-120s, and the final cooling temperature is 320-360℃.

Images