KR20220123363A - Stainless steel wire for welding LNG tank made of 9%Ni steel - Google Patents

Abstract

The present invention relates to a stainless steel welding wire for manufacturing a liquefied natural gas (LNG) tank made of 9 % Ni steel and, more particularly, to a stainless steel welding wire for manufacturing an LNG tank made of 9 % Ni steel capable of obtaining a weld metal having excellent strength and cryogenic impact toughness by adjusting the contents of Ni, Mn, Cr, and Mo. The stainless steel welding wire for manufacturing an LNG tank made of 9 % Ni steel of the present invention can be applied to welding of 9 % nickel steel by adjusting the content relationship of Ni, Mn, Mo, and Cr, and a weld metal having excellent cryogenic toughness of the welded part can be obtained.

Description

{Stainless steel wire for welding LNG tank made of 9%Ni steel}

The present invention relates to a stainless steel welding wire for manufacturing a 9% Ni steel LNG tank, and more particularly, an LNG capable of obtaining weld metal having excellent strength and cryogenic impact toughness by adjusting the content of Ni, Mn, Cr, and Mo It relates to stainless steel welding wire for making tanks.

Liquefied gases such as LNG (Liquefied Natural Gas, boiling point: -164 ℃), liquid oxygen (Liquefied Oxygen, boiling point: -183 ℃), and liquid nitrogen (Liquefied Nitrogen, boiling point: -196 ℃) are used for cryogenic storage. in need. Therefore, in order to store these gases, a structure such as a pressure vessel made of a material having sufficient toughness and strength at cryogenic temperatures is required.

As a material that can be used at a low temperature in a liquefied gas atmosphere, a Cr-Ni-based stainless alloy, 9% Ni steel, and 5000-series aluminum alloy have been conventionally used. However, in the case of aluminum alloy, the alloy cost is high and the design thickness of the structure is increased due to low strength, and the use is limited due to poor weldability. Cr-Ni-based stainless steel and 9% Ni steel overcome the problem of low strength of aluminum, but have been a problem in application, such as an increase in manufacturing cost due to the inclusion of expensive nickel.

Also, as another technique for structural steel used in liquefied gas, so-called nickel-free high manganese steel completely excluding nickel has been used. However, these techniques have problems in that cost increases and heat treatment facility load occurs due to an increase in the number of heat treatment cycles. Accordingly, as in Korean Patent Registration No. 10-135843, a technology for securing cryogenic toughness by using austenite as the main structure instead of ferrite has been developed.

The conventional wire used to weld such structural steel has been developed to be selectively applicable to 9% Ni steel or stainless alloy or high manganese steel according to the physical properties of structural steel in order to satisfy the strength and impact value of the structure after welding. . However, if there is a restriction according to the material of the structural steel, confusion may be caused in the work process, and there is a disadvantage in terms of economy. Accordingly, there is a need to develop a welding material that can be welded without restriction of structural steel materials and has excellent cryogenic toughness of the welded part.

Republic of Korea Patent No. 10-1353843

An object of the present invention is to provide a stainless steel welding wire for manufacturing a 9% Ni steel LNG tank having physical properties usable for an LNG tank in order to solve the above problems.

In order to achieve the above object, the present invention

In the stainless steel welding wire for manufacturing an LNG tank, the total composition of the wire is % by weight,

Ni: 6.0 to 15.0 wt%, Cr: 13.0 to 25.0 wt%, Mn: 5.69 to 10.0 wt%, Mo: 1.73 to 1.94 wt%, W+Nb: 0.57 to 1.67 wt%, Si: 0.05 to 1.0 wt%, C: 0.5% by weight or less (except for 0% by weight), P+S: Limited to 0.1% by weight or less (except for 0% by weight),

the balance Fe and unavoidable impurities;

It satisfies the following [Relational Expression 1],

The base material of the LNG tank is 9% Ni steel,

Characterized in providing a deposited metal having a yield strength of 400 to 487 MPa, a tensile strength of 640 to 740 MPa and a Charpy impact toughness value of 33 to 45 J at -196°C,

We offer stainless steel welding wire for making 9%Ni steel LNG tanks:

[Relational Expression 1]

1 < {Cr+Mo+W+Nb}/{Ni+Mn+30(C+N)} < 1.5

The stainless steel welding wire includes flux cored arc welding (FCAW), submerged arc welding (SAW), gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), inert gas metal arc welding (MIG), and It is characterized in that it is a welding wire of any one of inert gas tungsten arc welding (TIG).

The stainless steel welding wire for manufacturing a 9% Ni steel LNG tank of the present invention is applicable to welding of 9% nickel steel by controlling the content relationship of Ni, Mn, Mo, and Cr, and it is possible to obtain a weld metal with excellent cryogenic toughness in the weld zone. It works.

Hereinafter, the present invention will be described in more detail.

In this specification, when welding is performed, a weld metal and a molten base material are melted and solidified metal during welding.

As used herein, a deposited metal refers to a metal transferred from a filler metal (wire), which is a metal material added during welding, to a welding part.

According to one aspect of the present invention, in the stainless steel welding wire for manufacturing an LNG tank, the overall composition of the wire is wt%, Ni: 6.0 to 15.0 wt%, Cr: 13.0 to 25.0 wt%, Mn: 5.69 to 10.0 wt% , Mo: 1.73 to 1.94 wt%, W+Nb: 0.57 to 1.67 wt%, Si: 0.05 to 1.0 wt%, C: 0.5 wt% or less (except for 0 wt%), P+S: 0.1 wt% or less (Except for 0% by weight), contains the remainder Fe and unavoidable impurities, and satisfies the following [Relational Expression 1], the base material of the LNG tank is 9% Ni steel, yield strength 400 ~ 487 MPa, tensile strength It provides a stainless steel welding wire for manufacturing a 9% Ni steel LNG tank, characterized in that it provides a weld metal having a strength of 640 to 740 MPa and a Charpy impact toughness value of 33 to 45 J at -196°C. [Relational Expression 1] is 1 < {Cr+Mo+W+Nb}/{Ni+Mn+30(C+N)} < 1.5.

Ni: 6.0 to 15.0 wt%

Nickel (Ni) is a component added to stabilize the austenite structure, and when the content is less than 6.0 wt%, the austenite structure is unstable and undesirable, and when it exceeds 15.0 wt%, it is preferable to deteriorate the high-temperature cracking resistance can't Therefore, the content of Ni is preferably limited to 6.0 to 15.0 wt%.

Cr: 13.0 ~ 25.0 wt%

Chromium (Cr) is a component that improves the strength of the weld metal and stabilizes the austenite structure. When the content is less than 13.0 wt %, sufficient strength cannot be obtained, which is undesirable, and when it exceeds 25.0 wt %, the weld metal It is undesirable because the low-temperature impact toughness of Therefore, the content of Cr is preferably limited to 13.0 ~ 25.0% by weight.

Mn: 1.0 ~ 10.0 wt%

Manganese (Mn) is a component that stabilizes the austenite structure and improves the deoxidation action and weldability. When the content is less than 1.0 wt%, it is not preferable because sufficient deoxidation effect is not obtained, and when it exceeds 10.0 wt%, the weld metal final The solidification segregation to the solidification region is accelerated, and the melting point of the melt is lowered, which deteriorates the high-temperature cracking resistance, which is undesirable. Therefore, the content of Mn is preferably limited to 1.0 ~ 10.0% by weight.

Mo: 5.0 wt% or less (except for 0 wt%)

Molybdenum (Mo) has an effect of improving the strength of the weld metal. When the Mo content is small, sufficient strength is not obtained, which is not preferable, and when it exceeds 5.0 wt%, the toughness of the weld metal deteriorates, and the solidification and segregation of Mo is promoted, which is not preferable because the high-temperature cracking resistance deteriorates. Therefore, the content of Mo is preferably limited to 5.0% by weight or less.

Si: 0.05 to 1.0 wt%

Silicon (Si) is a component that improves the deoxidation action and weldability. When the content is less than 0.05 wt%, the deoxidation role is insufficient, and when it exceeds 1.0 wt%, the crack susceptibility increases due to the generation of the Laves phase, which is undesirable. . Therefore, it is preferable to limit the Si content to 0.05 to 1.0 wt% or less.

C: 0.5 wt% or less (except for 0 wt%)

Carbon (C) has an effect of improving the strength of the weld metal, but there is a problem of reducing toughness by forming carbides when added excessively. Therefore, the content of C is set to 0.5% or less based on the total weight of the wire. More preferably, it is preferably 0.1 wt% or less in order to prevent deterioration of the toughness of the weld metal.

P+S: 0.1 wt% or less (except for 0 wt%)

P (phosphorus) and S (sulfur) are one of the main elements influencing high-temperature cracking, and can cause high-temperature cracking by generating low-melting-point compounds. In the case of the present invention, the total content of P+S is preferably less than 0.1% by weight.

The remainder may be Fe and unavoidable impurities. In addition, copper (Cu) may be further included in an amount of 0.5 wt% or less (except for 0 wt%). Copper (Cu) is a precipitation hardening element and its content is preferably limited to 0.5 wt% or less. When it exceeds 0.5 wt %, hardenability increases and low-temperature impact toughness is softened, which is undesirable. In addition, nitrogen (N) may be further included in an amount of 0.2 wt% or less. As for nitrogen (N), N is a solid solution strengthening element, and it is preferable to limit the content to 0.2 wt% or less. When it exceeds 0.4 wt%, low-temperature impact toughness is deteriorated, and a complete austenite structure is generated, which is not preferable because high-temperature cracking resistance and porosity resistance are deteriorated.

The welding wire of the present invention can secure the properties of the welding part by controlling the content relationship of Mn, Cr, and Mo.

Mo, W, and Nb have an effect of improving the strength of the weld metal, and at least one may be selected and included. If at least one selected from the group consisting of Mo, W, and Nb is less than 0.1% by weight, sufficient strength is not obtained, which is not preferable, and when it exceeds 5.0% by weight, the toughness of the weld metal deteriorates, and high-temperature cracking resistance It is undesirable because the sex is deteriorated. Therefore, it is preferable to limit it to 0.1 to 5.0 wt%. In Relation 1, Q may be any one of Mo, [Mo+W], [Mo+Nb], [Mo+W+Nb], W, Nb, and [W+Nb]. Relation 1 may be more preferably 1.5>{Cr+Q}/{Ni+Mn+30(C+N)}>1. When the value according to Relation 1 is 1.5 or more or 1 or less, it is difficult to secure strength, cryogenic toughness, that is, an impact value, and thus the quality of the weld may be deteriorated.

Specifically, the stainless steel welding wire of the present invention may further include W in an amount of 2.0% by weight or less, or may be included in place of Mo. Tungsten (W) has the same effect as Mo to improve the strength of the weld metal. When the W content exceeds 2.0% by weight, the toughness of the weld metal may deteriorate. Therefore, the content of W is preferably limited to 2.0 wt% or less.

In addition, the stainless steel welding wire of the present invention may further include Nb in an amount of 1.5 wt % or less, or may be included in place of Mo. Niobium (Nb) can improve the strength of the weld metal in the same way as Mo. When the Nb content exceeds 1.5% by weight, the toughness of the weld metal may deteriorate. Therefore, the content of Nb is preferably limited to 1.5% by weight or less.

According to another aspect of the present invention, in the welding wire, the welding metal component obtained by the wire is, in weight %, Ni: 8.0 to 14.0 wt%, Cr: 15.0 to 23.0 wt%, Mn: 1.0 to 8.0 wt% , Mo: 4.0 wt% or less (excluding 0 wt%), Si: 0.05 to 1.0 wt%, C+N: 0.01 to 0.2 wt%, P+S: 0.1 wt% or less (0 wt% Except for cases), the remainder includes Fe and unavoidable impurities.

Depending on the alloy composition of the welding wire, the physical properties of the obtained weld metal, in particular, whether to secure physical properties for use in the manufacture of an LNG tank, are different, and the wire according to the present invention can obtain a weld metal having excellent strength, toughness, and impact value.

Nickel (Ni) is a component added to stabilize the austenite structure. When the content is less than 8.0 wt%, the austenite structure is unstable and it is difficult to secure strength, and when it exceeds 14.0 wt%, high-temperature cracking resistance This decrease is undesirable. Therefore, the content of Ni is preferably limited to 8.0 to 14.0% by weight.

Chromium (Cr) is a component that improves the strength of the weld metal and stabilizes the austenite structure. When the content is less than 15.0 wt %, sufficient strength cannot be obtained, which is undesirable, and when it exceeds 23.0 wt %, the weld metal It is undesirable because the low-temperature impact toughness of Therefore, the content of Cr is preferably limited to 15.0 ~ 23.0% by weight.

Manganese (Mn) is a component that stabilizes the austenite structure and improves the deoxidation action and weldability. When the content is less than 1.0 wt%, a sufficient deoxidation effect is not obtained, which is undesirable, and when it exceeds 8.0 wt%, the weld metal solidifies. As segregation is promoted, the high temperature cracking resistance deteriorates, which is not preferable. Therefore, the content of Mn is preferably limited to 1.0 ~ 8.0% by weight.

Molybdenum (Mo) has an effect of improving the strength of the weld metal. If the Mo content is small, it is not preferable because sufficient strength is not obtained, and when it exceeds 4.0 wt%, the toughness of the weld metal is deteriorated, solidification segregation is promoted, and high temperature cracking resistance is reduced, which is not preferable. Therefore, the content of Mo is preferably limited to 4.0 wt% or less.

If the content of silicon (Si) is less than 0.05% by weight, the deoxidation power is insufficient, and when it exceeds 1.0% by weight, the crack susceptibility increases according to the generation of the Laves phase, which is undesirable. Therefore, it is preferable to limit the Si content to 0.05 to 1.0 wt%.

Carbon (C) has an effect of improving the strength of the weld metal, but there is a problem in that when it is added excessively, carbide is generated and toughness is lowered. Nitrogen (N) is undesirable because N is a solid solution strengthening element, and when it is added excessively, low-temperature impact toughness is deteriorated, and a complete austenite structure is generated to deteriorate high-temperature cracking resistance and porosity resistance. Therefore, the total content of C + N is preferably limited to 0.01 to 0.5% by weight.

P (phosphorus) and S (sulfur) are one of the main elements influencing high-temperature cracking, and can cause high-temperature cracking by generating low-melting-point compounds. In the case of the present invention, the total content of P+S is preferably less than 0.1% by weight.

The remainder may be Fe and unavoidable impurities. In addition, copper (Cu) may be further included in an amount of 0.5 wt% or less (except for 0 wt%). Copper (Cu) is a precipitation hardening element and its content is preferably limited to 0.5 wt% or less. When it exceeds 0.5 wt %, hardenability increases and low-temperature impact toughness is softened, which is undesirable. In addition, nitrogen (N) may be further included in an amount of 0.2 wt% or less. As for nitrogen (N), N is a solid solution strengthening element, and it is preferable to limit the content to 0.2 wt% or less. When it exceeds 0.4 wt%, low-temperature impact toughness is deteriorated, and a complete austenite structure is generated, which is not preferable because high-temperature cracking resistance and porosity resistance are deteriorated.

On the other hand, when the stainless steel welding wire of the present invention or the welding metal obtained using the same satisfies {Cr+Mo}/{Ni+Mn+30(C+N)} > 1, the welding metal obtained by the welding wire is 400 MPa It has a yield point of more than 640 MPa, a tensile strength of 640 MPa or more, an elongation of 30% or more, and may have an impact value of 27J or more in the -196 ℃ Charpy impact test.

In addition, in the welding wire, the welding metal component obtained by the wire is, by weight, Ni: 8.0 to 14.0 wt%, Cr: 15.0 to 23.0 wt%, Mn: 1.0 to 8.0 wt%, Si: 0.05 to 1.0 wt% %, C+N: 0.01 to 0.2 wt%, P+S: 0.1 wt% or less (except for 0 wt%), at least one selected from the group consisting of Mo, W, and Nb (Q) contains 0.1 to 4.0% by weight, and the balance is Fe and unavoidable impurities, and provides a stainless steel welding wire for manufacturing an LNG tank that satisfies the following [Relational Expression 1]. [Relational Expression 1] is {Cr+Q}/{Ni+Mn+30(C+N)} > 1.

The content range of the specific composition is as described above.

When W or Nb is further included or Mo is substituted, it is preferable that the stainless steel welding wire of the present invention or the welding metal deposited using the same satisfies the following relational expression (2). In Relation 2, Q may be any one of Mo, [Mo+W], [Mo+Nb], [Mo+W+Nb], W, Nb, and [W+Nb]. Relation 1 may be more preferably 1.5>{Cr+Q}/{Ni+Mn+30(C+N)}>1. When the value according to Relation 1 is 1.5 or more or 1 or less, it is difficult to secure strength, cryogenic toughness, that is, an impact value, and thus the quality of the weld may be deteriorated.

Specifically, the weld metal welded using the stainless steel welding wire of the present invention may further include W in an amount of 2.0 wt % or less or replace Mo. Tungsten (W) has the same effect as Mo to improve the strength of the weld metal. When the W content exceeds 2.0% by weight, the toughness of the weld metal may deteriorate. Therefore, the content of W is preferably limited to 2.0 wt% or less.

In addition, the weld metal welded using the stainless steel welding wire of the present invention may further include Nb in an amount of 1.5 wt % or less, or may be included in place of Mo. Niobium (Nb) can improve the strength of the weld metal in the same way as Mo. When the Nb content exceeds 1.5% by weight, the toughness of the weld metal may deteriorate. Therefore, the content of Nb is preferably limited to 1.5% by weight or less.

In the stainless steel welding wire according to the present invention, the stainless steel welding wire is flux cored arc welding (FCAW), submerged arc welding (SAW), gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), inert It can be applied to any one welding of gas metal arc welding (MIG) and inert gas tungsten arc welding (TIG), and there is no limitation in the welding method. More preferably, it may be for submerged arc welding.

In relation to the stainless steel welding wire according to the present invention, the physical properties of the weld according to the content relationship of Cr, Mo, and Mn will be described in detail below with reference to Examples and Comparative Examples related to submerged arc welding, but the rights of the present invention The scope is not limited by the following examples.

A stainless steel submerged arc welding wire having the components shown in Table 1 was prepared.

Ni Cr Mn Mo Si C N P+S W Nb W+Nb Expression 1 One 8.61 16.47 5.69 1.95 0.43 0.015 0 0.03 0 0 0 1.25 2 8.6 16.57 8.14 1.93 0.41 0.015 0 0.03 0 0 0 1.08 3 8.95 16.07 6.75 1.25 0.5 0.015 0 0.03 0 0 0 1.07 4 8.04 16.14 6.79 1.05 0.49 0.015 0 0.03 0 0 0 1.13 5 8.61 16.47 5.69 1.73 0.53 0.015 0 0.03 0.57 0 0.57 1.27 6 8.72 16.24 6.07 0 0.49 0.015 0 0.03 1.95 0 1.95 1.19 7 7.88 16.02 5.76 0 0.55 0.015 0 0.03 0 1.07 1.07 1.21 8 8.62 15.93 6.23 0 0.46 0.015 0 0.03 1.37 0.54 1.91 1.17 9 7.66 16.57 5.58 0 0.53 0.015 0 0.03 2.23 0 2.23 1.37 10 7.59 16.51 5.67 1.94 0.53 0.015 0 0.03 0 1.67 1.67 1.47 11 7.69 16.69 5.71 0 0.53 0.015 0 0.03 0 1.93 1.93 1.34 12 7.29 11.68 6.67 1.25 0.39 0.015 0 0.03 0 0 0 0.90 13 9.61 16.17 6.19 7 0.5 0.015 0 0.04 0 0 0 1.43 14 15.37 15.97 6.93 1.25 0.49 0.015 0 0.03 0 0 0 0.76 15 9.61 16.19 6.94 1.25 0.47 0.015 0.26 0.03 0 0 0 0.70 16 6.17 18.19 5.95 3.91 0.44 0.015 0 0.03 0 0 0 1.76 17 7.94 16.21 9.08 1.13 0.55 0.015 0 0.03 0 0 0 0.99 18 7.67 16 10.75 5.17 0.49 0.015 0 0.03 0 0 0 1.12 19 7.11 12.19 6.75 6.64 0.5 0.015 0 0.03 0 0 0 1.32 20 7.86 25.73 10.61 1.25 0.43 0.015 0 0.03 0 0 0 1.43 21 9.19 16.92 10.18 1.37 0.39 0.015 0 0.03 2.19 0 2.19 1.03 22 7.59 16.37 10.09 0 0.4 0.015 0 0.03 2.86 0 2.86 1.06 23 7.64 16.97 10.91 1.94 0.51 0.015 0 0.03 0 1.56 1.56 1.08 24 9.51 17.54 10.05 0 0.51 0.015 0 0.03 0 1.97 1.97 0.98 25 9.95 15.57 7.63 0 0.51 0.015 0 0.03 0.15 0 0.15 0.87 26 7.59 15.95 6.05 5.07 0.43 0.015 0 0.03 2.13 0 2.13 1.64 27 7.95 16.17 5.89 5.14 0.51 0.015 0 0.03 0 1.67 1.67 1.61 28 9.62 15.81 5.91 5.08 0.51 0.015 0 0.03 2.07 1.59 3.66 1.54

Submerged Arc Welding (SAW) was performed for each welding material. In the case of SAW, welding was performed with a heat input of 10.0 to 18.0 KJ/cm. A wire diameter of 2.4 mm for SAW was used. A slope was formed on the improved surface of a 9% Ni steel plate, which is one of the base materials for manufacturing an LNG tank with a plate thickness of 20 mm, so that the angle of improvement was 30°. Thereafter, the base metals were arranged so that the root gap was 3 mm, and the same type of FCAW welding material was used on the side (the root part) where the improvement was narrowed by 1Pass welding to manufacture a weld joint.

For 1 to 11 according to the embodiment of the present invention, the arc stability of the weld joint that can be confirmed during the welding process, the slag peelability, the crack resistance of the weld joint, and the porosity of the bead appearance were visually compared to ◎ (excellent), ○ ( Good), Δ (poor), and × (poor) were evaluated in 4 stages, and the results are shown in Table 2 below.

crack resistance Arc Stability bead appearance Slag Removability Crack rate (%) One ◎ ◎ ◎ ◎ 0 2 ◎ ○ ○ ◎ 0 3 ◎ ◎ ◎ ◎ 0 4 ◎ ◎ ◎ ◎ 0 5 ○ ◎ ◎ ◎ 4 6 ◎ ◎ ◎ ◎ 0 7 ◎ ◎ ◎ ◎ 0 8 ◎ ◎ ◎ ◎ 0 9 ◎ ◎ ◎ ◎ 0 10 ○ ◎ ◎ ◎ 9 11 ◎ ◎ ◎ ◎ 0

The results of measuring the yield strength (YS), tensile strength (TS), elongation (EL), and Charpy impact energy at -196°C of the weld joint thus obtained are shown in Table 3 below.

YS(MPa) TS(MPa) elongation
(%) CVM Impact (J@-196℃) One 452 707 40 39 2 426 701 39 38 3 435 651 40 45 4 427 647 40 44 5 468 729 38 37 6 451 697 38 37 7 439 689 39 38 8 437 702 39 37 9 449 703 39 37 10 471 738 35 33 11 457 699 40 38 12 370 530 43 45 13 549 767 30 24 14 364 614 41 44 15 394 637 43 43 16 504 727 37 29 17 405 626 40 43 18 461 694 31 23 19 394 627 34 26 20 483 741 29 22 21 461 709 34 27 22 428 667 36 31 23 459 710 35 29 24 419 671 36 32 25 479 747 32 24 26 484 759 30 25 27 481 755 31 26 28 493 763 29 22

Referring to Table 3, in the case of 1 to 11 corresponding to the composition range of the present invention, a yield strength of 400 MPa or more, a tensile strength of 640 MPa or more, an elongation of 38% or more, and an impact value of 35 J or more were secured.

The stainless steel submerged arc welding wire according to the present invention is characterized in that it is possible to obtain a weld metal having excellent strength and cryogenic impact toughness by controlling the content of Mo and Cr while containing manganese in an amount of 10% by weight or less. Applicable to welding of 9% nickel steel base material, it has an advantageous effect in that it is possible to obtain a weld metal having excellent cryogenic toughness of the weld zone.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the following claims may be better understood. Those of ordinary skill in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the claims and their equivalents should be construed as being included in the scope of the present invention.

Claims (2)

In the stainless steel welding wire for manufacturing an LNG tank, the total composition of the wire is in wt%,
Ni: 6.0 to 15.0 wt%, Cr: 13.0 to 25.0 wt%, Mn: 5.69 to 10.0 wt%, Mo: 1.73 to 1.94 wt%, W+Nb: 0.57 to 1.67 wt%, Si: 0.05 to 1.0 wt%, C: 0.5% by weight or less (except for 0% by weight), P+S: Limited to 0.1% by weight or less (except for 0% by weight),
the balance Fe and unavoidable impurities;
It satisfies the following [Relational Expression 1],
The base material of the LNG tank is 9% Ni steel,
Characterized in providing a deposited metal having a yield strength of 400 to 487 MPa, a tensile strength of 640 to 740 MPa and a Charpy impact toughness value of 33 to 45 J at -196°C,
Stainless steel welding wire for making 9%Ni steel LNG tanks:
[Relational Expression 1]
1 < {Cr+Mo+W+Nb}/{Ni+Mn+30(C+N)} < 1.5 The method of claim 1,
The stainless steel welding wire includes flux cored arc welding (FCAW), submerged arc welding (SAW), gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), inert gas metal arc welding (MIG) and inert Gas tungsten arc welding (TIG) characterized in that any one of the welding wire, stainless steel welding wire for 9% Ni steel LNG tank production.