JPS62124095A - Welding wire and welding method - Google Patents

Abstract

PURPOSE:To decrease blow holes and to improve the slag detachability by specifying the specific components of a welding wire to a specific content or below and specifying the above-mentioned specific components in a molten metal to a specific content or below according to the contents of Si and Mn of a base metal. CONSTITUTION:Gas shielded metal arc welding is executed by the welding wire contg. <=0.15wt% C, <=0.5-2.5wt% Si and 0.5-1.0wt% in total of 1 or >=2 kinds among Zr, Ti, and Al and consisting of the balance Fe and impurities or contg. 0.05-1.0wt% in total of 1 or >=2 kinds among Bi, Sb, and Nb. The content of Si in the weld metal is specified to 0.2-1.6, the content of Mn to <=0.8%, the total content of Zr, Ti, and Al to <=0.3%, and the total content of Bi, Sb, and Nb to <=0.1% according to the contents of Si and Mn in the base metal. The post treatment and paintability of the weld zone are improved if the slag which does not separate and contain unsatd. SiO2-FeO-MnO melt in solid soln. SiO2.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) This invention is gas shielded metal arc welding.

In particular, the present invention relates to improvements in welding wires suitable for use in carbon dioxide shielded metal arc welding, and more particularly to improvements in gas shielded metal arc welding methods using the welding wires.

(Prior art) Conventionally, when welding structures and mechanical parts (products) that are coated with anti-rust coating after welding, such as vehicle frames, the slag that adheres to the bead after welding is brushed off before painting. It was removed by peeling it off, hammering it, or washing it off with a water jet. The slag that adheres to the bead after welding is mainly 5i02-FeO-M
It is made of n-based metal oxide and is non-conductive, so it is especially suitable for electrodeposition coating (/rrL) as an anti-rust coating after welding.
Regarding painting, see, for example, New Automotive Engineering Handbook, Society of Automotive Engineers of Japan °° Edition, Volume 9w4, pages 1-76.
It is described on pages 1-77. ), the paint will not get on the areas covered by the slag. When this slag peels off later, rust occurs from that part, significantly deteriorating the durability of structures and mechanical parts (products). Moreover, the appearance is also inferior.

(Problems to be Solved by the Invention) When manufacturing structures or mechanical parts (products) that are coated with anti-rust coating after welding, it is possible that the slag attached to the bead after welding cannot be easily removed. Removal requires a lot of effort and increases the water pressure of the water jet. This not only leads to a decrease in productivity, but also increases energy consumption and is dangerous; therefore, it is desirable that the slag adhering to the weld zone be easily peeled off after welding.

This invention was made in view of the above-mentioned problems and demands of the conventional art, and has good peelability of the slag attached to the welded part after welding, making it possible to remove the slag extremely easily. The present invention aims to provide a welding wire and a welding method.

[Structure of the Invention] (Means for Solving the Problems) The welding wire with good slag removability according to the present invention has the following features:
C: 0.15% by weight or less, Si: 0.5 to 2.5% by weight
, Mn: 1.0% by weight or less, and a total of 0.05% of one or more selected from Zr, Ti, and Al.
~1.0% by weight, further Bi, Sb, N as necessary
A total of 0.b of one or two or more selected from b.
0.005 to 1.0% by weight, the balance being Fe and impurities.

In addition, the welding method according to the present invention with good slag releasability uses C: 0.15% by weight or less, Si: 0.5 to 2.5% by weight, Mn: 1.0% by weight or less, and Zr, Ti. ,A
A total of 0.1 or more selected from l.
05 to 1.0% by weight, and if necessary Bi, Sb,
A total of 0 types of one or more types selected from Nb
．． When performing gas-shielded metal arc welding using a welding wire consisting of 005-i, o weight%, balance Fe and impurities, the amount of Si in the weld metal may be 0 depending on the amount of Si and Mn in the base metal. .2 to 1.6% by weight, and the amount of Mn is not more than O, a weight%, and the total amount of Zr, Ti, and Al is not more than 0.3% by weight, and furthermore, Bi, Sb, and N.
When containing b, the amount of Si is within the above component range so that the total amount thereof is 0.1% by weight or less.

Mn amount and Zr, Ti, A vertical position, Bi, S
The method is characterized by using a welding wire having a composition with a selected amount of Nb and Nb. In addition, in this specification, "weld metal" means a metal made by melting a welding wire and a base metal.

By the way, the slag formed in the welded part after welding is mainly 5i02-F e O as described above.
-M n Q-based metal oxide, and its properties are determined by the composition ratio of Si and Mn in the weld metal. That is, the relationship between the composition ratio of Si and Mn in the weld metal and the properties of the generated slag is shown in the explanatory diagram of FIG. That is, the region (■) shown in FIG.
-F e O-M n This is the range for separating the O melt.

Therefore, based on this figure 81, the present inventors found that if the composition ratio of Si and Mn in the weld metal is located within the region T in figure 1, the slag produced will generally be thin and fine. We predicted that it would be a practical product and would be easy to handle, and as a result of conducting experiments, we confirmed that this prediction was true. Furthermore, it was confirmed that better results were obtained in areas far from the boundary with area (2) than in areas close to the boundary with area (2). In other words, it was confirmed that it is good to set the Si content and Mn content in the weld metal to be high in Si and low in Mn.

Therefore, the composition ratio of Si and Mn in the weld metal is
By using a welding wire whose composition is within region 1 in the figure and at a certain distance from region 2, and depending on the Si and Mn contents in the base metal,
i,! :By performing welding using a welding wire containing Si and Mn whose composition ratio of Mn falls within the above preferred range, it becomes possible to generate a thin, fine slag that is easy to peel off. , it becomes possible to easily remove slag after welding.

Based on the results of these considerations, the composition of the welding wire with good slag releasability according to the present invention is as follows: C: 0.15% by weight or less, Si: 0.5 to 2.5% by weight, Mn: 1.0 % by weight or less, and Zr.

7i, one or more selected from Al in a total of 0.05-/L, 0% by weight, and if necessary, B
The total amount of one or more selected from i, Sb, and Nb was 0.005 to 1.0% by weight, and the balance was Fe and impurities.

In welding wires with such a composition, C is an effective element for increasing the strength of the weld zone, but if it is too large, the hardness of the weld metal increases and the toughness and ductility decreases, so it should not exceed 0.15% by weight. And so. Moreover, the amount of Si and Mn is
It was determined for the reason explained based on the figure, and the amount of Si was 0.5% by weight or more, and the amount of Mn was 1.0% by weight or less. However, if the amount of Si is too large, the hardness of the weld metal will increase and the toughness and ductility will decrease, so it is set to 2.5ii% or less. Furthermore, Zr, Ti, and Al have strong deoxidizing properties, which improve the cleanliness of the weld metal, refine the crystal grains, and suppress the occurrence of blowholes, improving the mechanical properties of the weld metal. Because it is an effective element to improve the
It was made to contain 1 or more cans. However, since a large amount of these elements would actually reduce the toughness of the weld metal, the total amount was set at 1.0% by weight or less. Furthermore, Bi, S
b and Nb are effective elements for improving the peelability of slag after welding and improving welding workability, so in order to obtain such effects, the total amount of these elements should be 0.005% by weight or more. It is also desirable to include it as necessary. However, if added in large amounts, the mechanical properties of the weld metal will deteriorate, so even if added, the total amount should be 1.0% by weight.
It is necessary to do the following.

Furthermore, in the welding method with good slab peelability according to the present invention, a welding wire having the above-mentioned composition, that is, C
: 0.15% by weight or less, Si: 0.5 to 2.5% by weight,
Mn: 1.0% by weight or less, and one or more selected from Zr, Ti, and Al in total from 0.05% to
1.0% by weight, and if necessary, one or more selected from Bi, Sb, and Nb for a total of 0.00%
When performing gas shield metal arc welding using a welding wire consisting of 5 to 1.0% by weight, the balance being Fe and impurities, the amount of Si in the weld metal may be 0 depending on the amount of Si and Mn in the base metal. .2-1.6% by weight and M n
l is 0.8% by weight or less, and the pot weight of Zr, Ti, and Al is 0.3% by weight or less, and Bi, Sb, and N
When containing b, the amount of Si is within the above component range so that the total amount thereof is 0.1% by weight or less.

Mn amount and Zr, Ti, A vertical, Bi, Sb
, a welding wire having a composition with a selected amount of Nb was used.

In this welding method, the amount of Si and Mn in the weld metal
The amount was determined for the reason explained based on the above-mentioned FIG. 1, and depends on the amount of Si and the amount of Mn in the base metal.
More preferably, the Si content is 0.2% by weight or more and the Mn content is 0.
．． The content was adjusted to 8% by weight or less. If the amount of Si in the weld metal is too large, the mechanical properties will deteriorate, so 1.
The content was adjusted to 6% by weight or less. Furthermore, c in the weld metal
y) Total amount of Zr, Ti, Al and Bi, Sb.

If the total amount of Nb is too large, the mechanical properties of the weld metal will deteriorate, so Zr and Ti are more preferably used.

The total amount of A, Bi, and Sb is 0.3% by weight or less.

The composition of the welding wire was selected so that the total amount of Nb was 0.1% or less.

(Example) In this example, a welding wire having a composition shown in Table 1 was used, and the base metal was low in Mn and low in Si (Mn: 0.
18 wt%, Si: 0.03 wt%) cold rolled steel plate (
Lap fillet welding was performed using a 2000 spcc) under the conditions shown in Table 2.

Table 2 Next, the number of blowholes generated in the weld metal formed after welding (number per 300 mm of weld bead) was investigated, and the results are shown in Table 3. Also,
High pressure (100 kgf) is applied to the slag attached to the weld metal.
/cmz) was used to examine the releasability of the slag, and the results are shown in Table 3. In Table 3, ■ indicates that the slag releasability was particularly good, O indicates that the slag releasability was good, and Δ indicates that the slag releasability was somewhat difficult. .

Table 3 As shown in Table 3, when the composition of the welding wire is in the range of high Si and low Mn included in the region (■) in FIG. Welding wire with a large Mn ratio (for example, positive, 5) is roughly Bi,
Welding wire containing one or more of Sb and Nb (for example, Nb)
It was confirmed that the slag removability was particularly good when using 0.0, 9.10).

On the other hand, welding wires that do not have a high Si, low Mn composition (for example, No. 1, No. 8).

When using No. 13), it cannot be said that the slag peelability is good, and Zr, Ti,
When a welding wire with a small amount of AM (for example, positive, 2) was used, a large number of blowholes were generated.

Next, to investigate the mechanical properties of the weld metal.

For some samples, test pieces with dimensions of 2.5XIOX55mm were prepared and Charpy impact test (0°O; n=
3) was performed. The results are shown in Table 4.

Table 4 As shown in Table 4, the amount of Si and Mn in the welding wire
Although the difference in toughness depending on the amount is relatively small, it was confirmed that when there is too much Sil (for example, No. 12), the toughness decreases.

Next, the base metal was replaced with the above-mentioned cold rolled steel plate (SPCC), and a combination of 5APH45 material and HT55 material, which are hot rolled steel plates for automobile structures, was used, and a welding wire of the above composition was used to produce a second Lap fillet welding was performed under the same conditions as shown in the table. After welding, we tried removing the slag using a high-pressure water jet.
The peelability of the slag was not very good. As a result of analyzing the composition of the weld metal, it was found that although it was within the range of area (3) in FIG. 1, it was close to the boundary line with area (2). That is, the amount of Si in the weld metal was slightly lower than the amount of Si and Mn in the welding wire, and the amount of Mn was significantly increased. The reason for this is that the Mn content in the base metal is high (0.9 to 1.0% by weight) and the Si content is low.

Therefore, in order to improve the removability of slag, as mentioned above, it is necessary to move the Si and Mn contents in the weld metal to a position away from the boundary line with area ■ in the area shown in Figure 1. It is necessary to Therefore, in order to realize this, welding wires having the compositions shown in Table 5, which do not substantially contain Mn, were manufactured.

And hot-rolled steel sheets for automobile structures (Mn: 0.95~
1.0% by weight) as the base metal, lap fillet welding was performed under the conditions shown in Table 6 using welding wires having the compositions shown in Table 5.

Table 6 shows the amount of Si and Mn in the weld metal after welding.
As a result of analyzing the amount, Si is 0.7% by weight and Mn is 0.4% by weight.
It was 5% by weight. Furthermore, the peelability of slag adhering to the weld metal surface was good.

Furthermore, when welding was performed using the welding wire shown in Table 5 and a cold rolled steel plate (SPCC) as the base metal, the amount of Si in the weld metal was 0.7% by weight, and the amount of Mn was The amount was 0.1% by weight, and the peelability of the adhered slag was extremely good. As a result of many experiments, we found that the slag releasability is improved when the amount of Si in the weld metal is between 0.2 and 1.
It was confirmed that it is desirable to determine the amount of Si and M n i in the welding wire so that the amount of Si in the welding wire is within the range of 6% by weight and the amount of Mn is 0.8% by weight or less. Regarding the mechanical properties of weld metal, Zr, Ti, and Al in weld metal
The amounts of Zr, Ti, Al, and Bi, Sb, and Nbi in the welding wire are determined so that the total amount of Bi, Sb, and Nb is 0.3% by weight or less, and the total amount of Bi, Sb, and Nb is 0.1% by weight or less. was confirmed to be desirable.

In addition, in this welding experiment, the welding current was 180 to 240A, and the welding voltage was 23 to 26V, considering the slag releasability.
From the viewpoint of arc stability, it was confirmed that it is more desirable to set the welding voltage to 24 to 27V.

In addition, when lap fillet welding and butt welding were performed on a wide variety of base metals using welding wires with the compositions shown in Table 5, the peelability of the adhered slag was good, and the tensile strength of the welded portion was The results of measurements of hardness, Charpy impact value, and hardness were also extremely good.

[Effects of the Invention] As explained above, the welding wire according to the present invention contains C: O, 15% by weight or less, Si: 0.5 to 2.5% by weight, Mn: 1.0% by weight or less, and Zr, Ti, Af
A total of one or two or more types selected from 0.
05 to 1.0% by weight, and if necessary Bi, Sb,
A total of 0 types of one or more types selected from Nb
．． 0.005 to 1.0% by weight, the balance being Fe and impurities, and in the welding method according to the present invention, when performing gas shield metal arc welding using a welding wire having the above composition, the base metal Depending on the amount of Si and Mn in the weld metal, the amount of Si in the weld metal is 0.2 to 1.
．． 6% by weight and the amount of Mn is 0.8% by weight or less, and further Z
r.

The total amount of Tf and Al is 0.3% by weight or less, and when Bi, Sb, and Nb are included, the total amount of these is 0.1% by weight or less.
Within the above component range, Si
amount, M n amount, and Zr.

Since the welding wire uses a welding wire with a selected composition of Ti, A, and Bi, Sb, and Nb,
The slag adhering to the weld metal surface after welding has good peelability, making it possible to remove the slag extremely easily, further improving welding workability, and removing the slag from the weld metal. The occurrence of 10-holes is also extremely small, and very excellent effects such as significantly improving the mechanical properties of the weld metal are brought about.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the relationship between the amount of Si and Mn in the weld metal and the properties of the slab. Patent applicant: Nissan Motor Co., Ltd. Applicant: Daido Steel Co., Ltd. Representative patent attorney: Figure 1

Claims (4)

[Claims] (1) C: 0.15% by weight or less, Si: 0.5 to 2.5
weight%, Mn: 1.0% by weight or less, and Zr, Ti,
A total of 0 types of one or more types selected from Al
．． A welding wire characterized in that the welding wire comprises 0.05 to 1.0% by weight, the balance being Fe and impurities. (2) C: 0.15% by weight or less, Si: 0.5 to 2.5
weight%, Mn: 1.0% by weight or less, and Zr, Ti,
A total of 0 types of one or more types selected from Al
．． 05 to 1.0% by weight, and a total of 0.005 to 1.0% by weight of one or more selected from Bi, Sb, and Nb.
A welding wire comprising 1.0% by weight, the balance being Fe and impurities. (3) C: 0.15% by weight or less, Si: 0.5 to 2.5
weight%, Mn: 1.0% by weight or less, and Zr, Ti,
A total of 0 types of one or more types selected from Al
．． When performing gas-shielded metal arc welding using a welding wire consisting of 05 to 1.0% by weight, the balance being Fe and impurities, the amount of Si in the weld metal may be 0 or 0, depending on the amount of Si and Mn in the base metal. .2-1.6% by weight and M
The amount of Si, the amount of Mn, and the amount of Zr, Ti, and Al are within the above component range so that the amount of n is 0.8% by weight or less, and the total amount of Zr, Ti, and Al is 0.3% by weight or less. A welding method characterized by using a welding wire having a composition selected from the following. (4) C: 0.15% by weight or less, Si: 0.5 to 2.5
weight%, Mn: 1.0% by weight or less, and Zr, Ti,
A total of 0 types of one or more types selected from Al
．． 05 to 1.0% by weight, and a total of 0.005 to 1.0% by weight of one or more selected from Bi, Sb, and Nb.
When performing gas-shielded metal arc welding using a welding wire consisting of 1.0% by weight, the balance being Fe and impurities, the amount of Si in the weld metal is 0.2% depending on the amount of Si and Mn in the base metal. ~1.6% by weight and Mn amount is 0
．． 8% by weight or less, and the total amount of Zr, Ti, and Al is 0.
．． The amount of Si, the amount of Mn, the amount of Zr, Ti, Al, and the amount of Bi, Sb, Nb are within the above component range so that the total amount of Bi, Sb, and Nb is 3% by weight or less and the total amount of Bi, Sb, and Nb is 0.1% by weight or less.
A welding method characterized by using a welding wire of a selected composition.