JPS6349396A - Coated electrode for hard facing - Google Patents

Abstract

PURPOSE:To improve coating crack and coating stickability and to improve working efficiency by using a filling core wire contg. carbonate and filled specifically with the balance alloy power and metallic powder and specifying the alloy powder and metallic powder in a coating material to be coated on the outside periphery of the core wire. CONSTITUTION:While C has high hardening power, the increase of the hardness is satd. and the toughness of a weld metal is deteriorated if the ratio thereof is excessive ly light. Cr has high wear resistance resistance as well, but the hardness decreases on the contrary and the wear resistance is deteriorated as well if the ratio thereof is excessively high. Therefore, the electrode having the compsn. consisting of 0.3-8.0wt.% C and 5-3.50wt.% Cr is used. After 0.15-3.0% carbonate and 10-15% alloy powder, etc., by the total weight of the filling core wire is filled into a mid steel wire pipe, the pipe is drawn. The coating material contg. 3.0-18.0% alloy powder, etc., by the total weight of the coating material is coated on the outside periphery of such core wire. The carbonate is used as the important raw material for slag forma tion and shielding effect in the ordinary coating material. The alloy powder, etc., in the coating material to be coated on the outside periphery is decreased to improve the coating crack and coating stickability.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a coated arc welding rod for hardfacing, and more specifically, to a coated arc welding rod for hardfacing, and more specifically, it relates to a coated arc welding rod for hardfacing. Curing that improves paintability and prevents coating material from peeling due to drying, minimizes coating material loss due to impact during transportation and storage, increases the amount of welding during welding, and reduces the occurrence of spatter. This invention relates to a coated arc welding rod for overlay.

(Prior art) A coated arc welding rod for hardfacing uses C, Mn, Cr, M, etc. to impart wear resistance, heat resistance, etc. to the bath-deposited metal.
Although it contains large amounts of alloying elements such as O, V, W, and B, the core wire used is generally made of mild steel because it is necessary to maintain good wire drawability. . Furthermore, even when an alloy core wire is used, C, which has a high hardenability, is suppressed as much as possible in consideration of wire drawability.

Therefore, many of the alloying elements and deoxidizing elements must be contained in large amounts in the coating material in the form of alloy powder or metal powder. When these alloy powders and metal powders are mixed in large amounts in coating materials,
Alloy powders and metal powders do not have water absorbency, so coatings made by adding a binder such as water glass and wet mixing have weak binding strength (and the lubricity of the coating required in the earthenware process is poor). is also inferior,
This is a cause of decreased productivity.

In addition, in the drying process, the bonding strength of the coating material is similarly weak, so if it is dried at high temperatures immediately after painting, it is likely that the coating material will bleed. This is followed by a complicated process of high-temperature drying, which greatly reduces productivity.

In addition, even if dry side drift does not occur, the adhesion of the coating material is weaker than that of general coated arc welding rods, so the coating material tends to fall off due to shocks during transportation, storage, and arc starting, which can lead to poor welding. This was one of the reasons why it was not possible.

In order to solve these problems, the present inventors proposed a method for improving the coating adhesion of a coated arc welding rod for hardfacing by limiting the composition of the coating material in Japanese Patent Application Laid-Open No. 56-151195. is disclosed.

In addition, JP-A-58-184096 discloses a method for improving coating smearing during drying by limiting the composition of the coating and at the same time using raw materials that have been surface-treated with some of the metal powder in the coating. Disclosed.

However, the effects obtained from these inventions cannot be said to be sufficient (.) It has been desired to develop a coated arc welding rod for hardfacing that has further productivity and welding workability.

Furthermore, in Japanese Patent Application Laid-Open No. 59-150694, metal carbonate 1
A filler containing 3 to 30% by weight of a carbon steel sheath type without an opening is added to the outer periphery of the core wire with a filling rack containing 3 to 30% by weight of a filler containing at least 1 carbonate, a metal fluoride, a metal oxide, and a metal. A low-hydrogen coated arc welding rod that greatly improves the cracking resistance, toughness, welding efficiency, bath welding workability, and X-ray performance of bath welding metal by applying a coating material with a specified amount of powder. is disclosed.

However, in this welding rod, only carbonate is added to the inside of the filled core wire, and although the melting rate during bath welding is certainly improved, the amount of deposited metal obtained by welding is Since all carbonates become slag, they do not increase the amount of welding.

Furthermore, since a large amount of carbonate is added to the filled core wire, it is not possible to reduce ivy, and furthermore, supplying the metal component from the coating only causes problems such as in the case of hardened puzzle welding. , it is impossible to add large amounts of metal or carbon components to the bath metal.

(Problems to be Solved by the Invention) The present invention prevents the dry coating material from coming off, which was a problem with conventional coated arc welding rods for hardfacing, and further improves the adhesion of the coating. It is an object of the present invention to provide a coated arc welding rod for hardfacing, which can improve work efficiency by increasing the amount of bath deposition during welding work, reducing spatter, etc.

(Means for Solving the Problems) As a result of various studies on the effect of raw materials on preventing coating material from running and improving adhesion, the present inventors found that the conventional method of modifying the coating material by adjusting the particle size of the coating material Although this measure was effective to some extent, it was found that the coating composition of the coated arc welding rod for hardfacing, which contains large amounts of alloy powder and metal powder, could not provide a fundamental solution.

Next, we investigated the application of filled core wire as a means to minimize the amount of alloy powder and metal powder in the coating material, which deteriorate the paintability and crack resistance of the coating.

As a result, it was discovered that it is effective to use a filled core wire in which alloy powder, metal powder, graphite, etc. are sealed inside the core wire, and the present invention was achieved based on this finding.

Furthermore, in addition to these measures, it has also been found that by sealing an appropriate amount of carbonate inside the core wire, it is possible to reduce spatter, improve the bath deposition speed, and improve work efficiency.

That is, the gist of the present invention is that the composition of the welding rod, which is composed of a core wire and a coating material, is C: 0.3 to 8.0% by weight, Cr: 5 to 35%.
．． Welding rod containing 0% by weight, and C: 0.5-2.
Welding rod containing 0% by weight, IVfn: 10-18.0% by weight, further C: 2.0-8.0% by weight, W: 40-
In a coated arc welding rod for hardfacing containing 55.0% by weight, carbonate is 0.15 to 38% based on the total amount of filled core wire.
0% by weight, one or two of alloy powder, metal powder, graphite
A coating applied to the outer periphery of the core using a drawn filled core after filling a mild steel pipe with a flux containing at least 10% by weight based on the total amount of the filled core. Alloy powder, metal powder and graphite account for 1
The species or two or more species have a content of 3.0 to 18% based on the total amount of the coating material.
A coated arc welding rod for hardfacing, characterized in that it is coated with a coating material containing 0% by weight.

The present invention will be explained in detail below.

(Function) The reason for specifying the flux to be filled in the filled core wire in the coated arc welding rod for hardfacing of the present invention will be described.

Carbonates are commonly used in coatings as important raw materials to improve slag formation, shielding effect and slag viscosity control.

In the present invention, in addition to the effect of the carbon salt from the coating material around the core wire, by adding carbonate to the inside of the filling, it was possible to significantly reduce spatter and improve work efficiency. It is something.

Figure 1 shows the carbon dioxide in the filling flux when 5 rtcml of filled core wires with various addition amounts of carbonate and fluoride in the filling flux were manufactured and bath-welded on a mild steel base material at a bath welding current of 210 A. It is a figure of the result of investigating the relationship between salt and fluoride contents, and welding speed.

As is clear from FIG. 1, it can be seen that adding an appropriate amount of carbonate to the packed core wire has a remarkable effect on improving the bath deposition rate.

That is, the carbonate added to the inside of the cord decomposes during bath contact, and carbon dioxide gas is generated from inside the cord. The carbon dioxide gas increased the arc partial pressure directly below the arc, strengthened the shielding effect, and enabled smooth transfer of the four drops, which had a remarkable effect on reducing spatter and increasing the amount of bath deposited.

However, 0.155% by weight based on the total amount of filled core wire
If the temperature is too high, the effect will not be fully demonstrated, and the occurrence of sumitta,
No increase in the amount of bath kimono was observed.

If the weight coefficient exceeds 3.0, the amount of carbon dioxide gas increases due to the decomposition of the carbonate, explosions occur directly under the arc, smooth transfer of m droplets is inhibited, and the amount of spatter generated increases, which is undesirable. Therefore, the carbonate content is 0.15 to 3.
It was defined as 0% by weight.

The carbonate mentioned here is CaC0a, ? l/IgC
Os, NInCO3, BaCCh, Na2CO3, K
Say things like 2CO3.

Regarding the effect of the wall surface tested at the same time, as shown in Figure 1, a slight improvement in the welding speed was observed, but no effect was observed with carbonate, and there were problems with bath welding workability such as narrowing of the bead width. This is not desirable.

Next, the reason for specifying the 7 lux filling rate will be described. The flux filling rate in the present invention was determined by the following formula.

R1 W, : Pipe weight F, : Flux weight If the amount is less than 100% by weight based on the total amount of filled core wire, it will be difficult to satisfy the intended hardness and performance as a coated arc welding rod for hardfacing. In addition, when the weight exceeds 50, wire breakage occurs in the process of filling with flux and drawing, making it difficult to manufacture 4.0.5.0 core wire. The ratio was defined as 10 to 50% by weight based on the total amount of the filled core wire.

The use of mild steel pipe as the core wire material has good wire drawability, and since there are no joints, moisture absorption of the core wire can be prevented, and the straightness of the manufactured core wire is good, making it easy to apply when machine applied. By solving the buckling problem of mild steel) ξ
Eve was used as the cord material.

Next, we will discuss the reasons for specifying the alloy powder and metal powder for the coating material applied to the outer periphery of the core wire.

As mentioned above, there are problems when large amounts of alloy powder, metal powder, graphite, etc. are mixed in the coating material, and it is important to keep the amount of alloy powder, metal powder, and graphite in the coating material as low as possible. This has a significant effect on improving coating adhesion. However, Si used as a deoxidizer
, Mn, Ti, etc., are more efficient in deoxidizing when added from the coating material than from inside the core, and the purpose can be achieved by adding a small amount.

From these results, Si, kite, which is expected to have only a deoxidizing effect,
It is desirable to add Ti from the coating material. However, if the amount of one or more of alloy powder, metal powder, and graphite is less than 3.0% by weight based on the total amount of the coating material, the deoxidizing effect may not be sufficient (it may cause the generation of blowholes and hits). Undesirable.

In addition, if the weight exceeds 1000, the coating material may come off when the welding rod dries, and the fourth coating may be missing when starting the arc, so one or more of alloy powder, metal powder, and graphite should be added to the total amount of coating material. is defined in the range of 3.0 to 18.0% by weight.

Next, the reason for specifying the composition of the welding rod composed of the above-mentioned core wire and coating material will be described.

C has a high hardening ability and can significantly increase hardness by adding a small amount, and is an essential element for hardfacing materials. However, if it is less than 0.3% by weight, the effect will not be exhibited. In addition, when the weight coefficient sag is 8.0, the increase in hardness reaches a saturation point, and at the same time, the toughness of the weld metal deteriorates significantly.
Severe cracking also causes problems such as peeling of the welded metal, which is undesirable. Therefore, with respect to the total composition of the welding rod, C: 0.3
It was defined as ~8.0% by weight.

Like C, Cr has high hardening ability (improved wear resistance, excellent corrosion resistance and heat resistance, and is an important element for hardfacing materials. However, if Cr is less than 5.0% by weight, its effect is However, at this level of addition amount, there is no problem in using the same solid core wire as the conventional product and adding it through the coating.

Moreover, if the weight exceeds 35.0, no increase in hardness can be expected even if more is added, and on the contrary, the hardness tends to decrease, which is not preferable in terms of wear resistance. For these reasons, Cr: 5 to 350% by weight was specified with respect to the total composition of the welding rod.

Although C%Cr is specified as an essential component, other elements such as Si, Mn, Mo, V, W,
Nb.

By adding B and the like as necessary, it is possible to obtain a bath-deposited metal having the desired performance.

Next, the welding rod composition was C: 0.5 to 2.0% by weight, &In:
The reason for specifying the weight ratio of 10 to 18.0 will be explained below.

This type of welding rod is a coated arc welding rod used for welding high manganese steel, but if the C content is less than 0.5% by weight, the desired wear resistance cannot be obtained. Also c2. If the C content exceeds the OM content, the toughness of the bath-deposited metal will be extremely poor and cannot be used in practical use.

Regarding kites, as a high-altitude welding rod, if 10 to 18% by weight is added to the welding rod composition, depending on the AW hardness, the toughness of the weld metal, the degree of work hardening, etc., it is a common high-altitude welding rod (JIS -DFMA-B, JIS -DFMB-B
), it was specified in the above range because there was no problem in terms of quality.

Other elements, namely Si, Mo, V, W,
By adding Nb, B, etc. as necessary, it is possible to obtain a deposited metal having the desired performance.

Linear C: 2.0-8.0% by weight, W: 40--weight%
The reasons for the stipulation are explained below.

This type of welding rod has excellent wear resistance as a W-C type welding rod, and the W-C compound and tungsten carbide are precipitated in the weld metal, and in this precipitated state, the wear resistance is improved. Good or bad is decided.

C: If it is less than 20% by weight, the amount of tungsten carbide precipitated will be small and good m-wear properties cannot be expected.

Moreover, when the C8.0 weight coefficient is exceeded, the amount of tungsten carbide precipitated becomes excessive, and cracks in the bath-deposited metal increase, the toughness is poor, and peeling of the weld metal is observed, which is undesirable. Therefore, C: was specified as 2.0 to 8.0% by weight.

Next is the amount of W, which, like the amount of C, is an important element that affects the wear resistance of this type of welding rod, but at a sag of less than 40 weight, the wear resistance is not fully demonstrated. Further, a weight exceeding 55% by weight results in an excessive amount of precipitation, which is unfavorable in terms of cracking, toughness, and peeling of the weld metal from the base metal. So W: 4
It was defined as 0 to 55% by weight.

Also, other elements, namely Si, Mn, Cr, Mo, D,
By adding B and the like as necessary, a bath-deposited metal having the desired performance can be obtained.

Next, regarding the coating material, the present invention applies to a coated arc welding rod for hardfacing that contains a large amount of alloy components.

The aim is to improve productivity and bath contact work efficiency by adding as much alloying ingredients as possible to the filled core wire, and the coating material applied to the outer periphery of the filled core wire is mainly lime, wall surface, rutile, etc. It has a normal slag composition and is fully applicable.

(Example) Table 1 shows the pipes used in producing the filled core wires and the normal core wires used as comparative examples.

Table 2 shows the chemical components of the filled core wire manufactured using this ξ-ib. We also investigated products manufactured using filled core wires and mild steel solid core wires other than those of the present invention.

Table 3 shows the coating flux composition of the filled core wire and the Norirad core wire.

Table 4 summarizes the test results for the manufactured welding rods.

All welding rods were dried at 400°C for 60 minutes.

For chemical composition and hardness tests of bath welded metals, welding current 2
The composition and hardness are when 3 layers are stacked at 10A, and the core wire dimensions are all unified to 5.0 recess φ.

Coating material leakage evaluation was performed at 60°C for 15 minutes, 90°C for 15 minutes, and 120°C with 10 welding rods each touched after coating.
This is the result of continuously drying for 15 minutes and observing cracks in the coating with the naked eye.

Evaluation of coating adhesion was carried out using continuously dried welding rods,
After firing at 00°C for 60 minutes, the coated arc welding rod was inserted into a rotating tester and rotated for 3 minutes.

The dropout rate was calculated using the following formula.

Wo: Weight of the coated arc welding rod E: Weight of the core wire W: Weight of the coated arc welding rod after the dropout test Evaluation of spatter generation amount and fouling amount is l 6 tX80WX350w
Weigh the base metal of 3M41B of Z in advance, weld it on the base metal with a welding current of 210A, and check the melting amount of the welding rod at that time and the increase in the base metal after removing the slag on the base metal. This is the result measured as the amount of wear.

Covered arc welding rod A-1-A-17-1 which is an example of the present invention
Glazes No. 7 exhibited good results, with no coating material peeling due to drying and firing, and a drop-off rate of less than a factor of 10, which is very low for a coated arc welding rod for hardfacing.

In addition, the target hardness of the weld metal was obtained, and at the same time, the welding workability, especially the amount of spatter, was reduced, and both the melting rate and the welding rate were increased by 10 to 20%. On the other hand, welding rods A-18 to A-25 shown as comparative examples did not yield similar results when compared with the inventive examples.

First, A-18, A-19, A21, and A-22 are examples in which the amount of carbonate in the filled flux is below the specified lower limit or without a solubilizer, and in all cases, the amount of spatter generated is large and the amount of bath melt is Both the amount of welding and the amount of welding showed lower values than the examples of the present invention.

In addition, A-18 has a low content of 2.5% by weight of one or more of alloy powder, metal powder, and graphite in the coating material. The transfer of the middle bath droplets is not smooth, and large spatters are observed, which is not preferable.

In Comparative Example A-20, on the contrary, the amount of carbonate in the packed flux exceeded the upper limit, and the values of bath melting amount and bath deposition amount were at the same level as the present invention example, but spatter The result was that the amount generated was inferior.

A-23, A-24, and A-25 are conventional coated arc welding rods that use solid core wire and add alloy components rather than coating materials, and have a high coverage rate of 45 to 50% and Both the coating agent release rate and the shedding rate are significantly inferior to those of the examples of the present invention. It is also found that both the bath melting rate and the fusing rate are inferior when compared with the examples of the present invention.

*I JISMCR (Cr: 99.8%)*
2 JISF Cr HO (C near, 1%, Cr
: 67.6%) *3 HC, metallic chromium (C
:9.1%, Cr:88.5%) *4 Chrome carbide (C:20%, Cr:80%) *5 JIS
FMOL (Mo: 62.0%) *6
JISFV2 (V: 52.3%) *7 Ferroboron (B: 20%) *8 Metallic nickel (Ni: 99.0%) *9 JIS
MMnE (Mn: 99.9%) *10
Metal W (W: 99.0%) *11 Graphite (C2 99.9%) (Effect of the invention) As explained in detail above, the present invention contains carbonate,
By using a filled core wire filled with remaining alloy powder and metal powder, and keeping the amount of alloy powder and metal powder in the coating material applied to the outer periphery of the core wire as low as possible, coating agent runout and coating adhesion are improved, and spatter is reduced. Significant improvements have been achieved in reducing energy consumption and improving work efficiency, and its industrial value is significant.

[Brief explanation of the drawing]

Figure 1 is a chart showing the relationship between calcium carbonate in the filled core wire, wall surface content (wt%) and welding speed.Representative: Patent Attorney Tatsuo Chanoki (tJ Near)

Claims (1)

[Claims] 1. The welding rod composition composed of a filled core wire and a coating material is C
Cr: 0.3 to 8.0% by weight and Cr: 5 to 35.0% by weight in a coated arc welding rod for hardfacing, carbonate 0.15 to 3.0% by weight based on the total amount of the filled core wire. , alloy powder,
After filling a mild steel pipe with flux containing one or more of metal powder and graphite in a range of 10 to 50% by weight based on the total amount of the filled core wire, using a filled core wire drawn, A coating material is applied on the outer periphery of the core wire in which one or more of alloy powder, metal powder, and graphite account for 3.0 to 18.0% by weight based on the total amount of the coating material. A coated arc welding rod for hardfacing. 2 The welding rod composition consisting of the filled core wire and coating material is C
:0.5-2.0% by weight, Mn: 10-18.0% by weight
A flux containing 0.15 to 3.0% by weight of carbonate, one or more of alloy powder, metal powder, and graphite, based on the total amount of the filled core wire. After filling a mild steel pipe in a range of 10 to 50.0% by weight based on the total amount of the filled core wire, the alloy powder that accounts for the coating material applied to the outer periphery of the core wire is used. , coated arc welding for hardfacing, characterized in that the coating material is coated with one or more of metal powder and graphite in an amount of 3.0 to 18.0% by weight based on the total amount of the coating material. rod. 3 The welding rod composition consisting of a filled core wire and coating material is C
: 2.0 to 8.0% by weight and W: 40 to 55.0% by weight in a coated arc welding rod for hardfacing, carbonate 0.15 to 3.0% by weight based on the total amount of filled core wire. , alloy powder,
After filling a mild steel pipe with a flux containing one or more of metal powder and graphite in a range of 10 to 50.0% by weight based on the total amount of the filled core wire, the filled core wire is drawn. A coating material in which one or more of alloy powder, metal powder, and graphite accounts for 3.0 to 18.0% by weight based on the total amount of the coating material is applied to the outer periphery of the core wire. A coated arc welding rod for hardfacing.