WO2018124591A1 - Solid wire having reduced slag - Google Patents

Abstract

One embodiment of the present invention provides a solid wire comprising 0.02-0.08 wt% of carbon (C), 0.2-1.0 wt% of silicon (Si), 0.9-1.5 wt% of manganese (Mn), 0.01-0.035 wt% of titanium (Ti), 0.02-0.025 wt% of aluminum (Al), and the balance of iron (Fe) and impurities, wherein X represented by the following formula is 16-200. <Formula> X=[Al]/[Ti]*100 In the formula, [Ti] and [Al] are respectively the amounts (wt%) of titanium and aluminum with respect to the total weight of the solid wire.

Description

Slag Reduced Solid Wire

The present invention relates to a slag-reduced solid wire, and more particularly to a solid wire that can be easily peeled off while the slag is reduced.

As a steel plate of the structural member of an automobile lower body, a galvanized steel plate, a zinc alloy plated steel plate, an unplated steel plate, etc. are used. In addition, gas shielded arc welding is often applied to the welding of the structural member of the vehicle lower body.

However, when arc welding a steel plate, a blowhole may generate | occur | produce in a weld joint part, ie, a weld metal. In particular, it is known that blow holes are likely to occur when arc-welding a galvanized steel sheet or a zinc alloy plated steel sheet.

In the blowhole, when carbon in the weld metal reacts with oxygen due to heat input during welding, bubbles are generated by gasification of CO ₂ gas or various adsorption components, and gasification by reaction of low temperature gasification reaction components, and the bubbles are welded. As a result of confinement in the weld metal with the solidification of the metal, it remains as a void. Particularly, in the zinc or zinc alloy plated steel sheet, blowholes are likely to occur because zinc or zinc alloy having a low melting point plated on the surface of the steel sheet evaporates during welding, and the zinc vapor becomes bubbles in the weld metal in the molten state. When a large number of such blowholes generate | occur | produce, the intensity | strength of a weld joint will fall, a problem will arise as a structural member, a coating defect will arise easily, and the appearance and shape of a weld bead will also become easy to produce.

On the other hand, steel sheets used for structural members of automobile lower bodies are generally coated by electrodeposition coating after welding. However, in the case of welding by the gas shield arc welding method, since CO ₂ or Ar + 5 to 20% CO ₂ is used as the shielding gas, deoxidation elements such as Si and Mn in the welding wire are used as oxygen in the shielding gas during the welding process. Reacts with the component to form an oxide. The oxide floats on the molten weld metal surface and becomes slag. Since the slag (oxide) is not conductive, electrodeposition coating is not performed on the slag on the surface of the weld bead, resulting in poor coating or coating defect, which may lower the corrosion resistance and aesthetics of the welded portion after coating.

Accordingly, in gas shielded arc welding of steel sheets used in structural members of automobiles, etc., in particular zinc or zinc alloy plated steel sheets, blowholes are prevented from occurring in the weld metal of the weld joint portion as much as possible. At the same time, it is very important to suppress the generation of slag on the weld metal surface.

Relatedly, Japanese Patent Application Laid-Open No. 07-080478 is a welding wire used for gas shielded arc welding of a zinc or zinc alloy plated steel sheet, which mainly suppresses the occurrence of blowholes and accompanying pits in gas shielded arc welding. Initiate a welding wire. The disclosed welding wire is, in weight percent, C; 0.03 to 0.15%, Si; 1.00-2.50%, Mn; 0.10 to 1.00%, provided that Mn / Si is in the range of 0.65% or less, and P; 0.013% or less, 0.005 to 0.200% in one or two of Al and Ti in total, and 0.0050 to 0.0500% in one or two of S and O in total, with the remainder containing Fe and unavoidable impurities will be.

In addition, JP-A-62-124095 discloses an invention for improving slag peelability. In other words, the slag generated after welding mainly contains SiO ₂ -FeO-MnO-based metal oxide, the properties of which are determined by the composition ratio of Si and Mn in the weld metal, and the amount of Si and Mn in the weld metal is high. It is to be that Mn.

The present invention is to solve the above-mentioned problems of the prior art, an object of the present invention is to significantly reduce the amount of slag generated between welding or during welding, and at the same time inevitably produced solid wire with improved peelability of slag To provide.

One aspect of the present invention is carbon (C) 0.02-0.08% by weight, silicon (Si) 0.2-1.0% by weight, manganese (Mn) 0.9-1.5% by weight, titanium (Ti) 0.01-0.035% by weight, aluminum (Al) Provided is a solid wire containing 0.02 to 0.025% by weight, residual amount of iron (Fe), and impurities, wherein X represented by the following formula is 16 to 200.

<Expression>

X = [Al] / [Ti] * 100

Wherein [Ti] and [Al] are the contents (% by weight) of the titanium and the aluminum, respectively, relative to the total weight of the solid wire.

In one embodiment, X may be 50 to 95.

In one embodiment, X may be 120 to 200.

In one embodiment, the solid wire may further comprise less than 0.02% by weight of phosphorus (P).

In one embodiment, the solid wire may further comprise 0.025 to 0.035% by weight of sulfur (S).

In one embodiment, the solid wire may further comprise less than 0.3% by weight of copper (Cu).

In one embodiment, the solid wire may further comprise 0.025 ~ 0.05% by weight of chromium (Cr).

In one embodiment, the solid wire may further comprise vanadium (V) of less than 0.002% by weight.

In one embodiment, the solid wire may further comprise molybdenum (Mo) of 0.01% by weight or less.

In some embodiments, the impurities may include one or more of 0.005 to 0.02 wt% of nickel (Ni) and 0.001 to 0.01 wt% of zirconium.

According to one aspect of the present invention, by adjusting the composition of the solid wire to a certain range it is possible to significantly reduce the amount of slag generated between or during welding.

In addition, the solid wire is to adjust the surface tension and heat shrinkage characteristics of the welding slag so that the slag inevitably generated can be easily peeled off.

It is to be understood that the effects of the present invention are not limited to the above effects, and include all effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a graph showing the composition of a solid wire according to the preparation and comparative examples of the present invention.

2 is a graph showing the surface tension according to the composition of the molten slag.

3 shows the volume change accompanying solidification of molten slag.

4 shows the composition of molten slag produced from solid wires according to Examples and Comparative Examples of the present invention.

5 is a photograph of a weld bead formed from a solid wire according to the preparation and comparative example of the present invention.

Hereinafter, with reference to the accompanying drawings will be described the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Throughout the specification, when a part is said to "include" a certain component, it means that it may further include other components, without excluding the other components unless otherwise stated.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

One aspect of the present invention is carbon (C) 0.02-0.08% by weight, silicon (Si) 0.2-1.0% by weight, manganese (Mn) 0.9-1.5% by weight, titanium (Ti) 0.01-0.035% by weight, aluminum (Al) Provided is a solid wire containing 0.02 to 0.025% by weight, residual amount of iron (Fe), and impurities, wherein X represented by the following formula is 16 to 200.

<Expression>

X = [Al] / [Ti] * 100

Wherein [Ti] and [Al] are the contents (% by weight) of the titanium and the aluminum, respectively, relative to the total weight of the solid wire.

Carbon (C): 0.02 ~ 0.08% by weight

Carbon has a deoxidizing action and improves the strength of the weld metal. Since thin-walled welding is rarely performed in multiple layers, it is not necessary to consider the reduction in strength due to reheating. You can get it.

However, when the content of carbon is lowered to less than 0.02% by weight, the strength can be applied only to mild steel, thereby decreasing the versatility. In addition, when the content of carbon is more than 0.08% by weight, the crack resistance is significantly lowered. In addition, the amount of spatter and fume generated, the deoxidation is excessive, the oxygen of the molten pool is reduced, the viscosity and surface tension of the molten paper increases. As a result, the barrier action to alleviate the arc force can be lowered, and the anti-lacing resistance and the undercut resistance can be lowered.

Silicon (Si): 0.2 ~ 1.0 wt%

Silicon can increase the electrical resistance while securing the strength of the solid wire. In 0.2 weight% or less, strength falls and there exists a problem which is difficult to apply other than mild steel. In addition, since the electrical resistance of the solid wire becomes excessively low, the current value per feeding amount increases. As a result, heat input becomes high, and a fall resistance and an undercut resistance may fall. Therefore, it is necessary to contain 0.2 weight% or more of silicon.

On the other hand, if the silicon content is more than 1.0% by weight, excessive deoxidation is made, and the oxygen of the molten oil decreases, thereby increasing the viscosity and surface tension of the molten paper. For this reason, the barrier action to alleviate the arc force may be lowered, and the anti-lacing resistance and the undercut resistance may be reduced.

Manganese (Mn): 0.9 to 1.5 wt%

Manganese can increase the electrical resistance while securing the strength of the solid wire. In 0.9 weight% or less, strength falls and there exists a problem which is difficult to apply other than mild steel. In addition, since the electrical resistance of the solid wire becomes excessively low, the current value per feeding amount increases. As a result, heat input becomes high, and a fall resistance and an undercut resistance may fall. Therefore, it is necessary to contain 0.2 weight% or more of manganese.

On the other hand, if the content of manganese is more than 1.0% by weight excessively deoxidation is made, the oxygen of the molten oil is reduced to increase the viscosity and surface tension of the molten paper. For this reason, the barrier action to alleviate the arc force may be lowered, and the anti-lacing resistance and the undercut resistance may be reduced. In addition, excessive slag may be generated to reduce paintability.

Titanium (Ti): 0.01 ~ 0.035 wt%

Titanium can improve arc stability in high current regions. In addition, since titanium is a deoxidation element, generation of a blowhole can be suppressed. If the content of titanium is less than 0.01% by weight it is difficult to fully implement this effect, if it is more than 0.035% by weight excess slag may occur. Therefore, the content of titanium may be adjusted to 0.01 to 0.035% by weight, preferably 0.025 to 0.035% by weight in consideration of the balance between suppression of blowholes and slag generation.

Aluminum (Al): 0.02 ~ 0.025 wt%

Aluminum is a strong deoxidation element and promotes deoxidation of molten metal during arc welding, but can increase the amount of slag generated. When the content of aluminum in the solid wire is less than 0.02% by weight, it is difficult to fully realize such an effect, and when it is more than 0.025% by weight, the slag formation reaction may be promoted.

In addition, in the solid wire, X represented by the following formula may be 16 ~ 200.

<Expression>

X = [Al] / [Ti] * 100

Wherein [Ti] and [Al] are the contents (% by weight) of the titanium and the aluminum, respectively, relative to the total weight of the solid wire.

In particular, referring to FIG. 1, when the solid wire satisfies the condition that X is 16 to 200 and the Al content is 0.02% by weight or more, the slag generation amount is reduced and the peeling property of the produced slag is significantly improved. You can.

2 is a graph showing the surface tension according to the composition of the molten slag. Referring to FIG. 2, the surface tension decreases as the content of SiO ₂ and TiO ₂ increases in the molten slag, while the surface tension increases as the content of Al ₂ O ₃ and MnO increases. That is, the solid wire includes a certain amount of Si and Mn in consideration of the basic physical properties of the solid wire, such as strength, crack resistance, and electrical resistance, but increases the content of Ti and Al in comparison with the conventional solid wire. The surface tension of the molten slag produced therefrom can be increased, so that the solidified slag can be easily peeled off. At this time, the surface tension of the molten slag may be 580mN / m or more, preferably 600mN / m or more, more preferably 600 ~ 650mN / m. If the surface tension of the molten slag is more than 650 mN / m, the barrier action to alleviate the arc force is lowered, the solvent resistance and undercut resistance may be lowered. X for adjusting the surface tension of the molten slag in the above range may be 120 ~ 200, preferably 180 ~ 200.

3 shows the volume change accompanying solidification of molten slag. Referring to FIG. 3, Al ₂ O ₃ , Al ₂ SiO ₅ , and Mn ₃ Al ₂ Si ₃ O ₁₂ contained in a molten slag generated from a solid wire including a predetermined amount of Al are iron (Fe). , steel) is a large difference in the volume change accompanying the solidification, and thus the solidified slag can be easily peeled off. At this time, the volume change amount associated with the solidification of the molten slag may be 2.00 * E-04 cm ³ or more, preferably, 2.00 * E-04 ~ 5.00 * E-04 cm ³ . The X for adjusting the volume change amount in the above range may be 50 to 95, preferably 60 to 95.

On the other hand, the solid wire may further include the following components.

Phosphorus (P): 0.02 wt% or less

The solid wire may further include 0.02% by weight or less of phosphorus (P). Phosphorus is an unavoidable impurity present in steel, and is generally included as an impurity in solid wire for arc welding. At this time, phosphorus is one of the main elements causing high temperature cracking of the weld metal, and it is preferable to suppress it as much as possible. If the content of phosphorus is more than 0.02% by weight, hot cracking of the weld metal becomes remarkable. Therefore, the content of phosphorus in the solid wire may be 0.02% by weight or less, preferably, 0.001 to 0.02% by weight in consideration of cost and productivity.

Sulfur (S): 0.025 ~ 0.035 wt%

The solid wire may further include 0.025 to 0.035% by weight of sulfur (S). Sulfur is an unavoidable impurity present in steel, and it is generally included as an impurity in the solid wire for arc welding. At this time, sulfur reduces the surface tension of the weld bead so that the slag is wet to the spherical shape of the weld bead can improve the peelability of the slag. However, when the content of sulfur is more than 0.035% by weight, crack resistance of the weld metal may be lowered. Therefore, the content of sulfur in the solid wire may be 0.035% by weight or less, preferably, in consideration of cost and productivity may be 0.025 ~ 0.035% by weight.

Copper (Cu): 0.3 wt% or less

The solid wire may further include 0.3 wt% or less copper (Cu). Copper is an element derived from the copper plating performed on the wire surface as needed. Copper plating is a surface treatment method capable of stabilizing the power supply and electrical conductivity of the wire, when copper plating, a certain amount of copper may be included in the solid wire. If the copper content is more than 0.3% by weight, cracking susceptibility may be increased. Therefore, the content of copper in the solid wire may be 0.3% by weight or less, and preferably, 0.05 to 0.3% by weight in consideration of the supplyability and conductance of the wire.

Chromium (Cr): 0.025 ~ 0.05 wt%

The solid wire may further include 0.025 to 0.05 wt% of chromium (Cr). In general, chromium improves the strength of the weld metal. If the content of chromium is less than 0.025% by weight, it is difficult to sufficiently improve the strength of the weld metal, and if the content of chromium is more than 0.05% by weight, the toughness of the weld metal may decrease.

Vanadium (V): 0.002 wt% or less

The solid wire may further include vanadium (V) of 0.002 wt% or less. Vanadium can also improve the strength of the weld metal and can further improve the strength of the wire when included in the solid wire together with the chromium. If the content of vanadium is more than 0.002% by weight, the toughness of the weld metal may be lowered. Therefore, the content of vanadium in the solid wire may be 0.002% by weight or less, preferably, 0.0001 to 0.02% by weight in consideration of the strength of the weld metal.

Molybdenum (Mo): 0.01 wt% or less

The solid wire may further include molybdenum (Mo) of 0.01% by weight or less. Molybdenum can improve the strength of the weld metal. The lower limit of the effect can be 0.001% by weight, but is not limited thereto. On the other hand, when the content of molybdenum is more than 0.01% by weight, the sun resistance and undercut resistance may be lowered and a large amount of spatter may occur.

impurities

The impurity may include at least one of 0.005 to 0.02 wt% of nickel (Ni) and 0.001 to 0.01 wt% of zirconium. When the content of nickel and zirconium is out of the above range, the sun resistance and the undercut resistance may decrease, and a large amount of spatter may occur.

Hereinafter, embodiments of the present invention will be described in detail.

Example

In order to evaluate the peelability of slag inevitably generated after welding using the solid wire, the surface tension and the volume change accompanying the slag solidification of the molten slag derived from the solid wire having the composition according to Table 1 were measured, and the results were measured. It is shown together in Table 1 below.

ingredient	Example 1	Example 2	Example 3	Example 4	Comparative Example 1	Comparative Example 2	Comparative Example 3	Comparative Example 4
Si	0.2	0.2	0.5	0.5	0.2	0.2	0.5	0.5
Mn	One	One	One	One	One	One	One	One
Ti	0.01	0.03	0.01	0.03	0.01	0.03	0.01	0.03
Al	0.02	0.02	0.02	0.02	0.01	0.01	0.01	0.01
Fe	Remaining amount	Remaining amount	Remaining amount	Remaining amount	Remaining amount	Remaining amount	Remaining amount	Remaining amount
Slag Al 2 O 3 included	include	include	include	include	Without	Without	Without	Without
X ([Al] / [Ti] * 100)	200	66.7	200	66.7	100	33.3	100	33.3
Surface tension (mN / m)	645	584	623	591	589	575	557	561
ΔV (cm 3 )	2.38E-04	4.43E-04	2.18E-04	3.94E-04	-	5.46E-05	-	1.51E-04

(Unit: weight%)

Referring to Table 1, since the molten slag of Examples 1 to 4 includes the solid Al ₂ O ₃ derived from Al contained in the solid wire, the slag peelability due to surface tension and volume change will be excellent. It is expected.

Specifically, in Examples 1 and 3 where X is in the range of 180 to 200, since the surface tension of the molten slag is large, the generated slag can be easily peeled off. On the other hand, in Examples 2 and 4 where X is in the range of 50 to 70, since the volume change between solidification of the molten slag is large, the peelability of the produced slag can be significantly improved accordingly.

Production Example

The composition of the solid wires according to Preparation Examples 1 to 4 and Comparative Preparation Examples 1 to 3 is shown in Table 2 below.

ingredient	Preparation Example 1	Preparation Example 2	Preparation Example 3	Preparation Example 4	Comparative Production Example 1	Comparative Production Example 2	Comparative Production Example 3
C	0.045	0.055	0.072	0.073	0.07	0.072	0.081
Si	0.631	0.79	0.543	0.487	0.65	0.524	0.458
Mn	1.192	1.47	1.214	1.21	1.18	1.25	1.199
P	0.01	0.017	0.01	0.01	0.012	0.01	0.01
S	0.026	0.03	0.032	0.035	0.0089	0.004	0.06
Ni	0.014	-	0.014	0.014	0.01	0.014	0.014
Cr	0.031	-	0.031	0.031	0.02	0.031	0.031
Mo	0.003	-	0.003	0.003	0.01	0.003	0.003
Cu	0.213	0.01	0.213	0.213	0.201	0.213	0.213
V	0.001	-	0.001	0.001	-	0.001	0.001
Ti	0.01	0.03	0.027	0.033	0.001	0.013	-
Zr	0.001	0.002	0.001	0.001	-	-	-
Al	0.02	0.025	0.025	0.02	-	0.002	-
Ca	-	0.0001	-		-	-	-
Fe	Remaining amount	Remaining amount	Remaining amount	Remaining amount	Remaining amount	Remaining amount	Remaining amount
X ([Al] / [Ti] * 100)	200	83.3	92.6	60.6	0.0	15.38	-

(Unit: weight%)

Experimental Example: Evaluation of Weld Bead Appearance

5 is a photograph of a weld bead generated after welding using a solid wire according to the manufacturing and comparative examples. Referring to FIG. 5, in Comparative Production Examples 1 to 3, a large amount of slag was observed in the center and side portions of the welding beads, while in the welding beads of Preparation Examples 1, 3 and 4, the amount of slag generation was reduced, in particular. In the weld bead of Production Example 1, slag hardly occurred.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the invention is indicated by the following claims, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the invention.

Claims (10)

1. 0.02 to 0.08 weight% of carbon (C), 0.2 to 1.0 weight% of silicon (Si), 0.9 to 1.5 weight% of manganese (Mn), 0.01 to 0.035 weight% of titanium (Ti), 0.02 to 0.025 weight% of aluminum (Al), Contains residual amounts of iron (Fe) and impurities,

   Solid wire, with X of 16-200 represented by the formula:

   <Expression>

   X = [Al] / [Ti] * 100

   Wherein [Ti] and [Al] are the contents (% by weight) of the titanium and the aluminum, respectively, relative to the total weight of the solid wire.
2. The method of claim 1,

   Solid wire, wherein X is 50-95.
3. The method of claim 1,

   Solid wire, wherein X is 120-200.
4. The method of claim 1,

   Wherein the solid wire further comprises 0.02% by weight or less of phosphorus (P).
5. The method of claim 1,

   Solid wire, the solid wire further comprises 0.025 to 0.035% by weight of sulfur (S).
6. The method of claim 1,

   Wherein the solid wire further comprises 0.3 wt.% Or less copper (Cu).
7. The method of claim 1,

   The solid wire, the solid wire further comprises 0.025 to 0.05% by weight of chromium (Cr).
8. The method of claim 1,

   And the solid wire further comprises no more than 0.002% by weight of vanadium (V).
9. The method of claim 1,

   Wherein the solid wire further comprises up to 0.01 wt.% Molybdenum (Mo).
10. The method of claim 1,

    And wherein said impurities comprise at least one of from 0.005 to 0.02 weight percent nickel and from 0.001 to 0.01 weight percent zirconium.

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