Submerged arc welding wire deposited metal with hydrogen embrittlement resistance and using method

Abstract

The invention belongs to the technical field of pipeline welding, and particularly relates to submerged arc welding wire deposited metal with hydrogen embrittlement resistance and a using method. The invention discloses submerged arc welding wire deposited metal with hydrogen embrittlement resistance. The submerged arc welding wire deposited metal comprises the following chemical components in percentage by weight: 0.03-0.08% of C; 0.05 to 0.3 percent of Si; 0.3 to 0.8 percent of Mn; s < = 0.004%; less than or equal to 0.010% of P; 0.01 to 0.1 percent of Ni; 0.01 to 0.1 percent of Cr; 0.01 to 0.1 percent of Cu; 0.01% to 0.06% of Nb; 0.01 to 0.03 percent of V; 0.01 to 0.02 percent of Ti; b: 0.001 to 0.01% of the total weight of the raw materials; and the balance of Fe or inevitable impurities. The design of low C, Mn and low alloy elements is adopted for deposited metal of the submerged arc welding wire, the intake of S and P elements in a welding wire and a welding flux source is strictly controlled, the content of inclusions such as MnS and diffusible hydrogen is reduced, the matched fluorine-alkali type sintered low-hydrogen welding flux is good in arc protection, O and H in air can be effectively isolated, the deposited metal is dehydrogenated, desulfurized and deoxidized, and the service life of the submerged arc welding wire is prolonged. And it is ensured that deposited metal has excellent hydrogen embrittlement resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline welding, and particularly relates to a submerged arc welding wire deposited metal with hydrogen embrittlement resistance and a use method thereof. Background Art

[0002] As the lightest atom, a hydrogen atom has a very small atomic radius and is extremely easy to enter the interior of a metal material as an interstitial atom and diffuse within the crystal lattice. If there are defects (such as pores, inclusions, precipitates, non-metallic inclusions, etc.) inside the pipe and in the welded joint, due to the presence of a strain field around them, it can interact with the hydrogen strain field to attract hydrogen around itself to generate hydrogen pressure. Subsequently, under the coupled action of stress (applied stress, residual stress, internal stress, etc.) and hydrogen, when the internal pressure exceeds the strength of the pipe, brittle cracking will occur.

[0003] Currently, seamless pipes with low steel grades and medium and small diameters are mainly selected for long-distance hydrogen pipelines, and the application of submerged arc welded pipes is less. The main reason is that the thermal effect of submerged arc welding will lead to relatively serious non-uniformity of the microstructure in the welded joint. Compared with seamless pipes, the probability of defects occurring at the welded joint increases, and the performance deteriorates to a certain extent compared with the base material, which will exacerbate the risk of hydrogen-induced embrittlement failure. For existing conventional straight seam and spiral seam submerged arc welded pipes, the weld seam contains relatively high levels of elements such as C, Mn, S, P, and O. These elements, either due to high hydrogen embrittlement sensitivity, easy formation of segregation and inclusions, or easy aggregation of hydrogen at the tips, etc., make the welded joint prone to hydrogen embrittlement, affecting the performance of the pipe. Summary of the Invention

[0004] Aiming at the problem that existing conventional straight seam and spiral seam submerged arc welded pipes are prone to hydrogen embrittlement due to the relatively high levels of elements such as C, Mn, S, P, and O in the weld seam, the purpose of the present invention is to provide a submerged arc welding wire deposited metal with hydrogen embrittlement resistance and a use method thereof. The deposited metal of the present invention has excellent comprehensive properties, with a tensile strength ≥ 450 MPa, low P, low S, good HIC and SSCC resistance, excellent impact toughness and hydrogen embrittlement resistance, a diffusible hydrogen content ≤ 3 ml / 100 g, and a fracture toughness K IH ≥ 210 MPa·m 1 / 2 , and is particularly suitable for the production and manufacture of medium and low steel grade submerged arc welded pipes.

[0005] The technical solution of the present invention lies in: a submerged arc welding wire deposited metal with hydrogen embrittlement resistance. The chemical composition of the submerged arc welding wire deposited metal is by weight percentage: C: 0.03 - 0.08%; Si: 0.05 - 0.3%; Mn: 0.3 - 0.8%; S ≤ 0.004%; P ≤ 0.010%; Ni: 0.01 - 0.1%; Cr: 0.01 - 0.1%; Cu: 0.01 - 0.1%; Nb: 0.01 - 0.06%; V: 0.01 - 0.03%; Ti: 0.01 - 0.02%; B: 0.001 - 0.01%; the balance is Fe or inevitable impurities.

[0006] The carbon equivalent CE of the submerged arc welding wire deposited metal Pcm is in the range of 0.13 ≤ CE Pcm ≤ 0.16.

[0007] The diffusible hydrogen content of the submerged arc welding wire deposited metal ≤ 3 ml / 100g, and the fracture toughness K IH ≥ 210 MPa·m 1 / 2 .

[0008] The design principles of the chemical composition of the above-mentioned submerged arc welding wire deposited metal with hydrogen embrittlement resistance are as follows: Element C is an important element to ensure the strength of the deposited metal and is also the main solid solution strengthening element. The higher the content, the greater the hydrogen embrittlement sensitivity of the deposited metal, and at the same time, the cold cracking tendency increases. The content of element C is controlled between 0.03 - 0.08%.

[0009] Element Si can improve the hardness and strength of the deposited metal and is a good deoxidizer. However, when the content is too high, it is easy to form inclusions and segregation with element Mn, which has an adverse effect on the toughness of the deposited metal and increases the hydrogen embrittlement sensitivity at the same time. The content of element Si is controlled between 0.05 - 0.3%.

[0010] Element Mn is a good deoxidizer and desulfurizer, which can effectively reduce the impurity content and has an important strengthening effect on the deposited metal. However, when the content is too high, it is easy to form a low-temperature transformation microstructure zone that is more sensitive to hydrogen embrittlement. The content of element Mn is controlled between 0.3 - 0.8%.

[0011] Elements S and P are harmful elements in the deposited metal. Element S segregates severely in the deposited metal, seriously deteriorating the quality, and it is easy to cause hydrogen atoms infiltrating into the deposited metal to gather at the tip of sulfides, forming internal hydrogen pressure and inducing hydrogen-induced cracking; Element P can improve the atmospheric corrosion resistance of the deposited metal, but it will also significantly reduce the plasticity and toughness of the deposited metal. The contents of elements S and P are respectively controlled within ≤ 0.004% and ≤ 0.010%.

[0012] The Ni element can strengthen ferrite, refine pearlite, and improve strength. It has little effect on plasticity but is of great significance for improving the low-temperature toughness of the deposited metal. Excessive content will reduce the fluidity of the deposited metal, be unfavorable for the forming of the deposited metal, and increase costs. The Ni element is controlled between 0.01% and 0.1%.

[0013] The Cr element can reduce proeutectoid ferrite and has the effect of refining ferrite grains, improving the low-temperature toughness and corrosion resistance of the deposited metal. However, too high a Cr content will increase the brittle transition temperature. The Cr element is controlled between 0.01% and 0.1%. The Cu element can improve the atmospheric corrosion resistance of the deposited metal. Especially when used in combination with P, it can also improve the strength of the deposited metal. The effect of Cu against HIC is the most obvious. However, too high a content will increase the hot brittleness of the deposited metal. The Cu element is controlled between 0.01% and 0.1%.

[0014] The Nb element can refine grains, improve the impact toughness of the deposited metal and lower its brittle transition temperature. Add an appropriate amount of this element, and the Nb element is controlled between 0.01% and 0.06%.

[0015] The chemical composition of the wire used for the submerged arc welding of the submerged arc welding wire deposited metal is by weight percentage: C: 0.03 - 0.06%; Si: 0.01 - 0.1%; Mn: 0.3 - 0.6%; S ≤ 0.004%; P ≤ 0.008%; Ni: 0.01 - 0.06%; Cr: 0.01 - 0.04%; Cu: 0.01 - 0.08%; Mo: 0.05 - 0.1%; the balance is Fe.

[0016] The welding flux used for the submerged arc welding of the submerged arc welding wire deposited metal is a fluorine-alkali type sintered low-hydrogen welding flux. The chemical composition of the fluorine-alkali type sintered low-hydrogen welding flux is by weight percentage: HJ401 welding powder: 35 - 45%; MgO: 15 - 20%; TiO 2 : 3 - 7%; BaCO 3 : 8 - 15%; CaF 2 : 20 - 25%; Al powder deoxidizer: 1 - 4%; Mn-Fe alloying agent: 8 - 12%; P < 0.01%; S < 0.015%.

[0017] The basicity range of the fluorine-alkali type sintered low-hydrogen welding flux is 1.8 - 2.5.

[0018] A method for using the submerged arc welding wire deposited metal with hydrogen embrittlement resistance as described above includes the following steps: S1: Before welding, preheat the test plate, and the preheating temperature is 150 - 200 °C; S2: Select the welding wire and flux that match the deposited metal of the submerged arc welding wire. Use automatic submerged arc welding with a welding current of 560 - 600 A, a voltage of 28 - 32 V, a welding speed of 40 cm / min, and an interpass temperature of 160 - 180 °C during welding. S3: After welding, the deposited metal of the submerged arc welding wire is heat-treated. The heat treatment process is to hold at 600 ± 20 °C for 60 - 90 min, and then air-cool to room temperature.

[0019] The technical effects of the present invention are as follows: 1. The deposited metal of the submerged arc welding wire of the present invention adopts a design with low C, Mn and low alloying elements, and strictly controls the intake of S and P elements at the source of the welding wire and flux, reducing inclusions such as MnS and the diffusible hydrogen content. The matching fluorine-alkali type sintered low-hydrogen flux provides good arc protection, can effectively isolate O and H in the air, and performs dehydrogenation, desulfurization, and deoxidation treatment on the deposited metal, ensuring that the deposited metal has excellent hydrogen embrittlement resistance and solving the problem of hydrogen embrittlement prone to occur in conventional straight seam and spiral seam submerged arc welded pipes due to the high content of elements such as C, Mn, S, P, and O at the weld. 2. After heat treatment, the deposited metal of the submerged arc welding wire of the present invention has excellent comprehensive properties, with a tensile strength ≥ 450 MPa, low P, low S, good HIC and SSCC resistance, excellent impact toughness and hydrogen embrittlement resistance, a diffusible hydrogen content ≤ 3 ml / 100 g, and a fracture toughness K IH ≥ 210 MPa·m 1 / 2 in a 6.3 MPa hydrogen environment, and is particularly suitable for the production and manufacturing of medium and low grade submerged arc welded pipes. Detailed Embodiments

[0020] Example 1 A deposited metal of a submerged arc welding wire with hydrogen embrittlement resistance. The chemical composition of the deposited metal of the submerged arc welding wire is by weight percentage: C: 0.03 - 0.08%; Si: 0.05 - 0.3%; Mn: 0.3 - 0.8%; S ≤ 0.004%; P ≤ 0.010%; Ni: 0.01 - 0.1%; Cr: 0.01 - 0.1%; Cu: 0.01 - 0.1%; Nb: 0.01 - 0.06%; V: 0.01 - 0.03%; Ti: 0.01 - 0.02%; B: 0.001 - 0.01%; the balance is Fe or unavoidable impurities.

[0021] The carbon equivalent CE Pcm of the deposited metal of the submerged arc welding wire ranges from 0.13 ≤ CE Pcm ≤ 0.16.

[0022] The diffusible hydrogen content of the deposited metal of the submerged arc welding wire ≤ 3 ml / 100 g, and the fracture toughness K IH ≥ 210 MPa·m 1 / 2 .

[0023] The chemical composition of the wire used for the submerged arc welding wire deposited metal during submerged arc welding is by weight percentage: C: 0.03 - 0.06%; Si: 0.01 - 0.1%; Mn: 0.3 - 0.6%; S ≤ 0.004%; P ≤ 0.008%; Ni: 0.01 - 0.06%; Cr: 0.01 - 0.04%; Cu: 0.01 - 0.08%; Mo: 0.05 - 0.1%; the balance is Fe.

[0024] The welding flux used for the submerged arc welding wire deposited metal during submerged arc welding is a fluorine - alkali type sintered low - hydrogen welding flux. The chemical composition of the fluorine - alkali type sintered low - hydrogen welding flux is by weight percentage: HJ401 welding powder: 35 - 45%; MgO: 15 - 20%; TiO 2 : 3 - 7%; BaCO 3 : 8 - 15%; CaF 2 : 20 - 25%; Al powder deoxidizer: 1 - 4%; Mn - Fe alloy agent: 8 - 12%; P < 0.01%; S < 0.015%.

[0025] The basicity range of the fluorine - alkali type sintered low - hydrogen welding flux is 1.8 - 2.5. The fluorine - alkali type sintered low - hydrogen welding flux of the present invention has a moderate basicity of 1.8 - 2.5. Excessive basicity will increase the viscosity of the weld metal, thereby reducing the fluidity of the weld, affecting the weld appearance, and prone to weld defects such as inclusions and pores.

[0026] The submerged arc welding wire deposited metal of the present invention adopts a design of low C, Mn and low alloying elements, strictly controls the intake of S and P elements at the source of the wire and the welding flux, reduces inclusions such as MnS and the content of diffusible hydrogen. The matched fluorine - alkali type sintered low - hydrogen welding flux provides good protection for the arc, can effectively isolate O and H in the air, performs dehydrogenation, desulfurization and deoxidation treatment on the deposited metal, ensures that the deposited metal has excellent hydrogen embrittlement resistance, and solves the problem that conventional straight - seam and spiral - seam submerged arc welded pipes are prone to hydrogen embrittlement due to the high content of elements such as C, Mn, S, P and O at the weld.

[0027] Example 2 A method for using a submerged arc welding wire deposited metal with hydrogen embrittlement resistance as described above, including the following steps: S1: Before welding, preheat the test plate, and the preheating temperature is 150 - 200 °C; S2: Select a wire and a welding flux that match the submerged arc welding wire deposited metal, adopt automatic submerged arc welding, the welding current is 560 - 600 A, the voltage is 28 - 32 V, the welding speed is 40 cm / min, and the inter - layer temperature during welding is 160 - 180 °C; S3: After the submerged arc welding wire deposited metal is welded, it is heat-treated. The heat treatment process is to keep the temperature at 600±20°C for 60 - 90 minutes, and then air-cooled to room temperature.

[0028] After heat treatment, the submerged arc welding wire deposited metal of the present invention has excellent comprehensive properties, with a tensile strength ≥450 MPa, low P and S, good HIC and SSCC resistance, excellent impact toughness and hydrogen embrittlement resistance, a diffusible hydrogen content ≤3 ml / 100 g, and a fracture toughness K IH ≥210 MPa·m 1 / 2 , and is particularly suitable for the production and manufacturing of submerged arc welded pipes with medium and low steel grades.

[0029] Example 3: According to a submerged arc welding wire deposited metal with hydrogen embrittlement resistance described in Example 1 above, using the usage method of a submerged arc welding wire deposited metal with hydrogen embrittlement resistance described in Example 2, submerged arc welded pipe welding is carried out. The specific situation is as described in Examples 3 - 8, and the comparative examples are Comparative Examples 1 - 2.

[0030] In Examples 3 - 8 and Comparative Examples 1 - 2, the chemical element compositions of the submerged arc welding wire deposited metal are shown in Table 3 by weight percentage.

[0031] Table 3 Chemical element compositions of the submerged arc welding wire deposited metal in Examples 3 - 8 and Comparative Examples 1 - 2 by weight percentage (wt%) C Si Mn S P Ni Cr Cu Nb V Ti B <![CDATA[CE Pcm > Example 3 0.06 0.25 0.68 0.002 0.008 0.08 0.09 0.05 0.03 0.01 0.01 0.003 0.13 Example 4 0.06 0.24 0.70 0.003 0.008 0.08 0.08 0.09 0.03 0.01 0.02 0.004 0.13 Example 5 0.07 0.28 0.74 0.003 0.009 0.10 0.08 0.07 0.05 0.02 0.01 0.003 0.14 Example 6 0.07 0.29 0.74 0.003 0.008 0.10 0.07 0.10 0.05 0.02 0.02 0.004 0.15 Example 7 0.08 0.28 0.80 0.003 0.010 0.10 0.09 0.08 0.06 0.03 0.01 0.003 0.16 Example 8 0.08 0.28 0.80 0.003 0.009 0.09 0.09 0.10 0.06 0.03 0.02 0.004 0.16 Comparative Example 1 0.16 0.28 1.35 0.010 0.021 0.09 0.08 0.10 0.03 0.02 0.01 0.005 0.274 Comparative Example 2 0.02 0.28 0.20 0.003 0.007 0.09 0.07 0.10 0.04 0.02 0.01 0.005 0.076 After welding is completed, in accordance with the standard requirements, physical and chemical properties, HIC, SSCC, CTOD, diffusible hydrogen, and fracture toughness in a 6.3 MPa hydrogen environment of the submerged arc welding wire deposited metal in each example and comparative example are tested. The test results are shown in Table 4.

[0032] Table 4 Properties of the submerged arc welding wire deposited metal in Examples 3 - 8 and Comparative Examples 1 - 2 Yield strength Rt0.5 (MPa) Tensile strength Rm (MPa) Elongation A (%) Average impact energy at -20°C KV2 / J Diffused hydrogen (ml / 100g) <![CDATA[Fracture toughness (MPa·m 1 / 2 )]]> HIC (CSR; CLR; CTR) SSCC (-10°C) CTOD (mm) Experimental results Example 3 378 456 20.8 110 2.7 215 0;0;0 No cracks 1.083 Qualified Example 4 374 468 21.2 98 2.6 223 0;0;0 No cracks 1.108 Qualified Example 5 382 462 19.9 115 2.8 219 0;0;0 No cracks 1.095 Qualified Example 6 390 473 21.0 120 2.6 221 0;0;0 No cracks 1.118 Qualified Example 7 392 486 20.5 116 3.0 232 0;0;0 No cracks 0.982 Qualified Example 8 386 478 21.3 128 3.0 221 0;0;0 No cracks 1.008 Qualified Comparative Example 1 420 500 22.5 90 4.0 45 1;10;3 No cracks 0.213 Unqualified Comparative Example 2 300 360 21.2 87 2.0 36 0;0;0 No cracks 0.225 Unqualified Technical specification requirements / / / ≥94 / ≥55 0;0;0 No cracks ≥0.254 / It can be seen from Table 3 that the weight percentages of elements such as C, Mn, S, and P in Comparative Examples 1 and 2 exceed or are lower than the composition range specified in the technical solution of the present invention. For example, in Comparative Example 1, the contents of elements such as C, Mn, S, and P are increased; in Comparative Example 2, the contents of elements such as C and Mn are reduced. It can be seen from Table 4 that some values ​​of various performance indicators of the submerged arc welding wire deposited metal in Comparative Examples 1 and 2 cannot meet the requirements of the technical specifications. For example, the fracture toughness value, CTOD value, and impact toughness in Comparative Example 1 are lower than the requirements of the technical specifications, and the crack sensitivity rate (CSR), crack length rate (CLR), and crack thickness rate (CTR) in the HIC test results are higher than the requirements of the technical specifications; the fracture toughness value, CTOD value, and impact toughness test results in Comparative Example 2 are lower than the requirements of the technical specifications. Therefore, the hydrogen embrittlement resistance of the deposited metal in Comparative Examples 1 and 2 cannot meet the requirements.

[0033] It can also be seen from Table 4 that compared with Comparative Examples 1-2, the diffused hydrogen content of the deposited metal of the submerged arc welding wire in Examples 3-8 is ≤3 ml / 100 g, and the fracture toughness K in a 6.3 MPa hydrogen environment is IH ≥210MPa·m 1 / 2 , -10℃ CTOD≥0.98mm, the crack sensitivity rate (CSR), crack length rate (CLR) and crack thickness rate (CTR) in the HIC test are all zero, and the SSCC test results show no cracks. The deposited metal has high strength, high toughness and excellent hydrogen embrittlement resistance, and is suitable for hydrogen transportation.

[0034] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. Submerged arc welding wire deposited metal with hydrogen embrittlement resistance, characterized in that: The chemical composition of the submerged arc welding wire deposited metal is by weight percentage: C: 0.03 - 0.08%; Si: 0.05 - 0.3%; Mn: 0.3 - 0.8%; S ≤ 0.004%; P ≤ 0.010%; Ni: 0.01 - 0.1%; Cr：0.01~0.1%； Cu: 0.01 - 0.1%; Nb: 0.01 - 0.06%; V：0.01~0.03%； Ti: 0.01 - 0.02%; B: 0.001 - 0.01%; the balance is Fe or unavoidable impurities.

2. The submerged arc welding wire deposited metal with hydrogen embrittlement resistance according to claim 1, characterized in that: The carbon equivalent CE of the submerged arc welding wire deposited metal Pcm is in the range of 0.13 ≤ CE Pcm ≤ 0.

16.

3. The submerged arc welding wire deposited metal with hydrogen embrittlement resistance according to claim 1, characterized in that: The diffusible hydrogen content of the submerged arc welding wire deposited metal ≤ 3 ml / 100 g, and the fracture toughness K IH ≥ 210 MPa·m 1 / 2 .

4. The submerged arc welding wire deposited metal with hydrogen embrittlement resistance according to claim 1, characterized in that: The chemical composition of the welding wire used for the submerged arc welding wire deposited metal during submerged arc welding is by weight percentage: C: 0.03 - 0.06%; Si: 0.01 - 0.1%; Mn: 0.3 - 0.6%; S ≤ 0.004%; P ≤ 0.008%; Ni: 0.01 - 0.06%; Cr: 0.01 - 0.04%; Cu: 0.01 - 0.08%; Mo: 0.05 - 0.1%; the balance is Fe.

5. The submerged arc welding wire deposited metal with hydrogen embrittlement resistance according to claim 1, characterized in that: The welding flux used for the submerged arc welding wire deposited metal during submerged arc welding is a fluorine-alkali type sintered low-hydrogen welding flux. The chemical composition of the fluorine-alkali type sintered low-hydrogen welding flux is by weight percentage: HJ401 welding powder: 35 - 45%; MgO: 15 - 20%; TiO 2 : 3 - 7%; BaCO 3 : 8 - 15%; CaF 2 : 20 - 25%; Al powder deoxidizer: 1 - 4%; Mn-Fe alloy agent: 8 - 12%; P < 0.01%; S < 0.015%.

6. The submerged arc welding wire deposited metal with hydrogen embrittlement resistance according to claim 5, characterized in that: The basicity range of the fluorine - alkali type sintered low - hydrogen welding flux is 1.8 - 2.

5.

7. A method for using the submerged arc welding wire deposited metal with hydrogen embrittlement resistance as claimed in claim 1, characterized in that: comprises the following steps: S1: Before welding, preheat the test plate, and the preheating temperature is 150 - 200 °C; S2: Select a welding wire and a welding flux that match the submerged arc welding wire deposited metal, and use automatic submerged arc welding. The welding current is 560 - 600 A, the voltage is 28 - 32 V, the welding speed is 40 cm / min, and the interlayer temperature during welding is 160 - 180 °C; S3: After welding, perform heat treatment on the submerged arc welding wire deposited metal. The heat treatment process is to keep warm at 600 ± 20 °C for 60 - 90 min, and then air - cool to room temperature.