JPS60124493A - Flux cored wire for arc welding - Google Patents

Abstract

PURPOSE:To increase a deposition rate and to improve welding efficiency by specifying the chemical components of a steel material constituting a sleeve material. CONSTITUTION:A steel material consisting of <=0.05% (wt%, hereafter the same) C, 0.02-1.00% Si, 0.45-1.50% Mn, 0.01-0.20% Ti, 0.01-0.20% Al, and the balance Fe and inevitable impurities is used as a sleeve material to constitute an Fx wire. The deposition rate of a high level is obtd. while good welding operability and deposited metal characteristic are assured by the above-mentioned wire.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flux-cored wire for arc welding (hereinafter referred to as Fx
(abbreviated as wire), and in particular relates to Fx wire, which has further improved welding efficiency.

Fx wire has good welding workability and welding efficiency,
In particular, it has the advantages of good arc stability and low spatter (giving an excellent bead appearance), so its usage tends to increase more and more. Among these advantages, welding efficiency is extremely large. However, as welding technology advances, the demand for improving welding efficiency has become even stronger. Conventional measures to improve welding efficiency mainly focused on aspects of welding conditions, such as increasing welding current and increasing wire protrusion length. Countermeasures have been taken since then, but there are still many areas that have not been investigated regarding techniques for improving wire composition.

Under these circumstances, Akira Honshu and others have been conducting various studies to see if there is any room to further improve the welding efficiency of FX wire by devising the constituent materials of FX wire. As a result, they discovered that if the chemical composition of the steel material constituting the sheath material is properly adjusted, the welding speed can be increased and welding efficiency can be significantly improved, and the present invention has been completed.

That is, the structure of the Fx wire according to the present invention is such that the sheath material contains C: 0.05% (weight 962 or less) or less and Si: 0.05% or less.
02 to 1.00% Mn + 0.45 to 1.5096 Ti: 0.01 to 0.204 Al: 0.01 to 0.20% The remainder consists of Fe and inevitable impurities. It is something that you have.

First, the present inventors confirmed through preliminary experiments that the welding speed varies considerably depending on the chemical composition of the steel sheath, and based on this, we aimed to clarify the influence of the steel sheath components on the welding speed. We conducted basic experiments. That is, CXMnX5 IN is used as the main alloy component from the mild steel that is the material of the sheath material.
Taking up TL and A1, how the welding rate is affected by the abundance of each element was investigated by the following method.

The welding speed was measured in accordance with JIS 2 8182.

[Test wire and welding conditions]

Wire sheath Material: Mild steel Filling Flux: Lime-based flux Flux rate: 15% Cross-sectional shape: See Figure 4 below Wire diameter: 1.6 bait φ Welding conditions Welding current: 800A Welding voltage: 82V Welding speed: 80m/min Shield gas :C02%201/min Wire protrusion length: 20fl Base material: 12wt Welding method: Bead-on-plate method The results are as shown in Figure 1, and the welding speed increases as cii decreases, and S1% Mns As the Ti and Al contents increase, they increase, and in particular, S
The welding speed increases significantly as the amount of i increases.

This phenomenon corresponds to the electrical resistance of the Fx wire, and it is thought that the increase in electrical resistance increases the Joule heat generation during welding and increases the melting rate of the wire. By the way, Figure 2 is a graph showing the relationship between the electrical resistance and welding speed of FX wire, and from the perspective of the alloy composition of the steel sheath, the decrease in the amount of C and the increase in the amount of S i % Mn z71 % A l make the sheath material It is thought that the electrical resistance of the welding layer increased, which increased the welding speed. Note that the higher the flux rate (relatively speaking, the smaller the cross-sectional area of the sheath material), the higher the electrical resistance, and in the case of CU-plated wire, the electrical resistance is higher for wires with less Cu plating, and the welding speed increases. ing. The flux component itself has little effect on electrical resistance and has little effect on welding speed.

In the present invention, based on the above-mentioned basic experiment results, the content of each constituent element is strictly determined while taking into account the properties originally required for a steel sheath material. In addition, general F
The chemical composition of the mild steel that makes up the sheath material used in x wires is C: 0.05% or more, Si
: 0.0296 or less, Mn: 0.40% or less, Ti: 0
．． 0.01% or less, and -Al: 0.01% or less, and there is no example of reviewing the content of each element at least from the viewpoint of improving the welding speed.

The reason for setting the content range of the constituent elements of the sheath material in the present invention will be explained in detail below.

C: 0.05% or less It has the effect of increasing the concentration of the arc and strengthening the arc force, but as explained in FIG. 1, as the CR increases, the welding speed clearly decreases. Moreover, if the amount of C is too large, the toughness and cracking resistance of the welded metal will decrease, and the drawability during wire processing will also deteriorate, so the upper limit should be set at 0.05%, at which these inhibiting effects will not be a substantial problem. Established.

Si: 0.02-1.00% In addition to acting as a deoxidizing agent and increasing the porosity resistance of the weld metal, it is also an extremely important element in increasing the welding speed as explained in Fig. 1. It must be contained at least .02%. However, if it is too large, the toughness of the weld metal will be poor, so it must be kept at 1.0% or less.

Mn: 0.45 to 1.50% Mn is an effective element for stabilizing the arc, improving welding workability, and increasing the welding speed, and must be contained in an amount of 0.45% or more. However, if it is too high, the raw material cost will increase and the sheath material will become hard and the drawability will be poor, so 1.5
It should be kept below 0%.

Ti: 0.01-0.20% As is clear from Figure 1, as the amount of T and i in the wire increases, the welding speed increases, but the effect is 0.01%.
It is effectively exhibited by containing the above amount. However, if it is too large, the arc tends to become unstable and the toughness of the weld metal tends to decrease, so it must be kept at 0.20% or less.

Al: 0.01-0.20% As is clear from FIG. 1, Al has the effect of increasing the welding speed, and also functions as a deoxidizing agent to improve the blowhole resistance of the weld metal. These effects can be effectively exhibited by containing 0.01% or more, but too much moxibustion causes poor toughness of the weld metal, so the content should be suppressed to 0.2096 or less.

The main elements contained in the steel material constituting the sheath material are as described above, but in addition to these elements, it is also effective to contain small amounts of elements that increase electrical resistance, such as rare earth elements and Zr.

The chemical composition of the steel sheath used in the present invention is as described above, and basically, if a steel sheath that meets these requirements is used, it will be possible to achieve a high level of welding while ensuring good welding work and weld metal properties. Although the welding rate can be obtained, other factors that affect the welding rate will also be briefly discussed.

First, the influence of flux components on welding speed.
The effect is small compared to steel scabbards. In other words, in Fx wire, most of the welding current flows through the sheath material, so even if the flux component changes slightly, it has almost no effect on the electrical resistance of the entire wire (see Figure 2), and the difference in welding speed. This is thought to be because it does not appear as . However, if the type of the main flux component changes, the welding efficiency will fluctuate in response to a large change in the droplet transfer phenomenon, so the welding speed will also slightly increase or decrease with this fluctuation. In this sense, a titania-based flux with good droplet transfer properties can achieve a higher welding rate than lime-titania-based or lime-based fluxes (including CaF2-based fluxes) with slightly poor droplet transfer properties. . The electrical resistance of the wire will increase if the flux component is treated with water glass (flux is kneaded and granulated with water glass, and the granulation is adjusted after drying) or the inner surface of the steel sheath is insulated (oxidation treatment, etc.). Therefore, some effect on improving the welding speed is recognized. In addition, the type of lubricant used for wire drawing has almost no effect on electrical resistance, so all conventionally known lubricants [such as higher fatty acid esters (N a % K
% Ca % M g), MO8Z series, Teflon series, graphite series, etc.] can be used. However, if the Cal content in the lubricant is reduced, the amount of spatter will be reduced and the welding speed can be slightly increased, so MoS2-based lubricants that can easily be reduced in C are optimal.

-Next, the flux filling rate is preferably 10 to 80%; if it is less than 10%, it will not be possible to contain a sufficient amount of metal powder or slag forming agent, making it difficult to adjust the composition of the weld metal, and causing slag coating. The enveloping properties are also poor, and welding workability is reduced. However, if it exceeds 80%, the sheath material must be made thinner, which makes the product wire softer, lowers the feedability, deteriorates the arc stability, and makes undercuts more likely to occur. Furthermore, there is a tendency that large heat input welding becomes difficult. Note that as the flux rate increases, the steel sheath becomes thinner, the electrical resistance increases accordingly, and the welding speed increases. By the way, Figure 8 shows an FX wire whose mild steel sheath is filled with titania-based flux.
It is a graph of experimental results examining the relationship between flux rate and welding speed. As is clear from this graph, the welding speed can be further effectively increased by increasing the flux rate to 20% or more.

Next, regarding the cross-sectional shape of the FX wire, there are no restrictions on the cross-sectional shape, and any shape shown in FIG. 4, (B), (C), or the like can be used, for example. However, the fourth
Figure (L7) with a complicated cross-sectional shape as shown in Q generally allows the sheath material to be made thinner, thereby increasing the electrical resistance. In so-called seamless wires as shown in Figure 4 (6), the surface is often plated with A1 or Cu to improve conductivity and prevent rust. Since plating reduces the electrical resistance, it has a negative effect from the purpose of increasing the welding speed.By the way, Figure 5 shows the Cu on the surface of the FX wire.
It is a graph of experimental results showing the relationship between plating amount and welding speed. However, as for the experimental conditions, a 1 or 2 Mφ F made by filling a titania-based flux into a seamless mild steel sheath material was used.
A predetermined amount of Cu plating is applied to the x wire, and shielding gas: Co2 (201/min), 270 (A) x 80 (
V)X80 (C1)m), JIS
The adhesion speed was examined according to Z8182. As is clear from Figure 5, the amount of plating (weight 96 relative to the total weight of the wire)
) is preferably 0.2096 or less; if it exceeds 0.20%, the electrical resistance of the sheath material becomes too small, making it impossible to sufficiently increase the welding speed. Moreover, the time required for the plating process becomes longer, which reduces productivity, and the toughness of the welded metal also tends to decrease.

φ Also, the wire diameter is 1.2M, 1.6m+',
φ2, 0mm, 2.4tytznφ, 8.2Mφ
The diameter can be arbitrarily selected from among the above, but from the viewpoint of improving welding efficiency, a smaller diameter is more advantageous. Furthermore, welding using the FX wire of the present invention is generally performed using a shielding gas such as CO□ or Ar, but it can also be applied to self-shielded arc welding that does not use a shielding gas. Steel types include mild steel, high tensile steel,
Although it is mainly used for low-alloy steel, it can be applied to other steel types as well by adjusting the amount of alloying elements in the filling flux.

The present invention is constructed as described above, but the key point is that the chemical composition of the steel sheath is strictly specified, and the welding speed is increased by increasing the electric resistance of the Fx wire and increasing the Joule heating value. This can significantly contribute to improving welding efficiency.

Next, a field example will be given to clarify the effects of the present invention.

Experimental Example 1 Using a mild steel sheath material having the chemical composition shown in Table 1 and a filling flux having the chemical composition shown in Table 2, an FX wire with a diameter of 1.6 mm was manufactured according to a conventional method. As a lubricant for wire drawing, M
oS2 was used. The flux rate and wire cross-sectional shape are as shown in Table 2. The welding speed was measured in the same manner as described above (JIS Z8182).

[Welding conditions]

Welding current: 800A, DC (to) Welding voltage = 82v Welding speed: 80tM/min - Shielding gas: CO2,201/denominator Material: 0.12%C, 0.29%Sill, 44%
Mn, 0.020% P, 0100896S1 remaining iron tip-to-base metal distance: 20 mm The results are shown in Table 8.

Table 8 Experimental results The following is understood from the above experimental results.

No. 1-7. 9. 11. In No. 18, a sufficient welding speed could not be obtained because the outer skin metal component did not meet the requirements defined by the present invention. Further, from Nos. 1 to 8, it is recognized that a TiO□-based flux component is desirable. In addition, No. 8. 10゜12.14 gave good results in terms of efficiency, but No. 8
There is a problem with the wire drawability, No, 10.12.1
4 has a problem with welding performance (in terms of suction energy, JIS
Z 8818 YFW24 becomes difficult to satisfy), so it is not preferable. And, No. 15 to 24 satisfy the requirements of the present invention, but No. 15 to 18
As shown in Figure 2, adjusting the metal components of the outer skin is effective in improving efficiency. N□, 19 (compared with No. 1) is C
It is shown that even with aF2-based flux, the welding speed increases if the outer metal component is within the specified range of the present invention.

No. 15.20.21 indicates that the increase in flux rate is N
No. 22 (compared with No. 1) indicates that increasing the complexity of the wire cross-sectional diagnosis is effective in increasing the welding speed. In No. 28.24, the outer surface of the sheath material was plated with Cu, but it can be seen that the smaller the amount of plating, the better.

As described above, the efficiency of flux-cored wires can be significantly improved by applying the present invention.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the amount of each element in the steel sheath and the welding rate (Si and Mn are shown in units of the upper horizontal axis, and other elements are shown in units of the lower horizontal axis). FIG. 5 is a schematic diagram illustrating the relationship between the electric resistance and the welding speed of the FX wire, and FIG. 5 is a graph showing the relationship between the amount of Cu plating and the welding speed in the seamless FX wire. Applicant Kobe Steel, Ltd. Procedural Amendment (Hojo) 1. Display of the case Patent Application No. 231027 of 1982 2, Name of the invention Flux-cored wire for arc welding 3, Person making the amendment Relationship to the case Patent applicant No. 3-18 (119) Wakihama-cho-chome, Chuo-ku, Kobe City Kobe Steel, Ltd. Representative: Fuyuhiko Maki 4, Agent: Shinko Building, 2-3-7 Dojima, Kita-ku, Osaka 530 February 28, 1981 (Shipping date) 6. Subject of amendment Figure 4 (D )

Claims (1)

[Scope of Claim] A flux-cored wire for arc welding in which a steel sheath is filled with granular flux, wherein the chemical composition of the steel sheath is C: 0.05% or less (weight %: the same applies hereinafter). Si:0.0
2-1.00% Mn: 0.45-1.50% Ti: 0.01-0.2 (I A1: 0.01-0.20% Balance: Fe and inevitable impurities Flux-cored wire for arc welding.