JPS6228098A - Granular material for welding - Google Patents

Abstract

PURPOSE:To effectively provide an effect of a fluoride by compounding an alkaline earth metal fluoride or fluoride of a lanthanide element coated with 1-30wt% water glass in terms of SiO2 with a flux. CONSTITUTION:The alkaline earth metal fluoride or fluoride of the lanthanide element coated with 1-30wt% water glass in terms of SiO2 is compounded with the flux in the stage of producing the granular material (flux) for welding. The water glass melts earlier than the fluoride and acts as an excellent heat conductive medium to increase the contact area between the fluorides in the stage of welding if the fluoride coated with the water glass in the above- mentioned manner is used. As a result, the effect of improving the arc stability and blow hole resistance intrinsic to the fluoride is effectively obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the improvement of granular welding materials used in flux-cored wires, etc., and more specifically, the present invention relates to the improvement of granular welding materials used in flux-cored wires, etc., and in particular, the improvement of alkaline earth metals blended in the granular welding materials. The present invention relates to a granular welding material that has succeeded in effectively exerting various functions of fluorides and lanthanide element fluorides during welding.

[Conventional technique ml Powder and granular welding material (hereinafter sometimes referred to as flux)
A variety of compositions have been proposed depending on the purpose and application, and one of them is one containing fluorides such as alkali total fluoride, alkaline earth metal fluoride, and lanthanide element fluoride. be able to.

By the way, when producing a powder-like welding material, the above-mentioned alkali metal fluoride, etc. is kneaded with other powder-like raw materials (hereinafter, the term "slack raw material" may be used as a concept that includes the above-mentioned alkali metal fluoride, etc.). Granulationφ
Although it is common to go through a process such as drying, the fact is that the mixing process is carried out by the common method of feeding each flux raw material into a kneading machine and mechanically stirring the flux raw materials. Therefore, when observing each flux raw material particle microscopically, it is found that the contact state between each flux raw material particle is not necessarily maintained sufficiently, and in some cases, the particles may It is even confirmed that fine holes are left in the separated state. This state of the flux raw material particles after stirring is not expected to change significantly even after the granulation and drying process, and of course, even after the core raw material is filled into the metal sheath, micropores will remain. The situation of taking things will not change.

If the contact state between the flux particles filled in the flux-cored wire is insufficient as described above, the heat conduction efficiency between the flux raw material particles during welding will not necessarily be maintained well, and this will result in poor welding. It is difficult to say that the thermal effect during welding necessarily affects all particles of the flux raw material, and accordingly, the effects during welding become insufficient.

The above-mentioned insufficiency also applies to the above-mentioned fluoride, which is a component of the flux, but the fluoride originally lowers the melting point of the filling flux and improves air stability, blowhole resistance, etc. It is formulated in order to However, if these are not sufficiently exposed to the heat action during welding due to poor contact between particles, the above-mentioned arc stabilizing effect and blowhole resistance due to melting point lowering action will be adversely affected. Become. Especially when using alkaline earth metal fluorides and lanthanide element fluorides, which are located on the high melting point side among fluorides.

The above M effect becomes even more pronounced (see Table 1).

(Left below) ゛, ';', (, +, :”=pl Therefore, when using alkaline earth metal fluorides or lanthanide element fluorides as the fluoride.

It is necessary to take some measures to alleviate as much as possible the negative effects associated with the above-mentioned contact condition not being sufficiently guaranteed.

[Problems to be Solved by the Invention] The present invention has been made with attention to these circumstances, and it is an object of the present invention to effectively exhibit the effects of alkaline earth gold-14 fluorides and lanthanide element fluorides during welding. The purpose is to provide a powder-like welding material that can be used.

[Means for Solving the Problems] The granular welding material according to the present invention comprises an alkaline earth metal fluoride or a lanthanide element fluoride coated with 1 to 30% by weight of water glass in terms of SiO2. The gist lies in the combination of ingredients.

[Effect and υ゛%' square color 9J] The granular welding material according to the present invention has the following features: (1) the alkaline earth metal fluoride or lanthanide element fluoride to be blended is coated with water glass; The greatest feature is that the degree of coverage with the water glass (in other words, the water glass content) is defined as 1 to 30% by weight relative to the fluoride in terms of SiO2. The explanation will focus on these points.

(1) The combined alkaline earth metal fluoride or lanthanide element fluoride is coated with water glass = The alkaline earth metal fluoride or lanthanide element fluoride is used during welding of wires etc. to be inserted into flags as mentioned above. It is used for the purpose of improving arc stability and blowhole resistance, but in order to fully achieve this purpose, the above-mentioned alkaline earth metal fluorides, etc. quickly and easily melt and gasify during welding to provide sufficient shielding. There is a need to create an atmosphere.

As a result of repeated empirical research from various viewpoints, the present inventors have found that if the alkaline earth metal fluorides and lanthanide element fluorides blended into flux are coated with water glass, the above needs will be met and at the same time I learned that the above objectives can be fully achieved. The detailed data will be described later, and the reasons will be explained here in bulleted form.

(a) Compared to (a) alkaline earth metal fluorides and lanthanide element fluorides (hereinafter sometimes referred to as high melting point fluorides in the sense that they have a higher melting point than alkali metal fluorides), It has a low melting point (below 1000°C), and (b) has a low surface tension when melted at a high temperature.

(b) Since water glass has the property mentioned in (a) above that it has a low melting point, when radiant heat from the arc and heat conduction from the droplets act during welding, the water glass (as described above) fluoride) melts more quickly and easily than fluoride.

(c) Since the surface tension of molten water glass is low as shown in (b) above, the molten water glass not only easily wets the entire surface of the high melting point side fluoride but also wets other flux raw materials (e.g. Iron powder, other metals, intermetallic compounds, etc.) are also wetted, and as a result, the contact area between the wire molten water glass, the fluoride, and other flux raw materials increases, resulting in a closer contact relationship between them. be able to.

(d) The increased contact area as described in (c) above means that the heat transfer efficiency from the flux raw material of the above ability to the high melting point side fluoride increases, so the high melting point side fluoride is used in large amounts. The amount of heat is easily absorbed through the water glass, and its melting and melting is promoted.

In this way, molten water glass acts as an excellent thermal conductive medium for the high melting point side fluoride, smoothing the melting of the high melting point side fluoride, thereby improving arc stability and blowhole resistance during welding. Fluoride's original effect of improving performance can be effectively exhibited. If all of these materials, including not only the fluoride but also other flux raw materials, are coated with water glass, the amount of coated water glass will be too excessive, which will inhibit the conduction of arc heat to the fluoride. Dissolution remains in the fluoride, etc. in the metal box (flux columns may appear), and weldability deteriorates on the contrary.

Furthermore, although the above-mentioned fluoride is said to have poor syntronic properties, when the fluoride is coated with water glass as mentioned above, another effect is that it can prevent segregation of the fluoride within the metal sheath. It is also possible to enjoy

(2) The extent of the water glass coating is defined as 1 to 30 ton u% of the high melting point side fluoride in terms of SiO2: If the water glass addition rate is less than 1% by weight, the fluoride The coating becomes incomplete, and the action of water glass, that is, the action as a heat transfer medium, is weakened, and for this reason, the fluoride during welding cannot be sufficiently melted. It was not always possible to fully demonstrate its effects. On the other hand, when it exceeds 30% by weight, it has been found that the blending ratio of each flux raw material is adversely affected and it becomes impossible to blend the necessary flux raw materials. Furthermore, since the amount of water glass blended was excessive, the physical properties of the molten slag changed, resulting in deterioration of welding workability.

The present invention will be specifically explained below by giving examples.

Example 1 CaF2 and CaF3 powders were kneaded with water glass and coated with water glass through granulation, drying, and particle size adjustment steps.
2. CaF3 powder (hereinafter referred to as water glass coated 1caF2.Water glass coated IQceF3 powder) was obtained. Next, using the water glass coated mcaF2 powder etc. obtained above, the flux shown in Table 2 below was obtained, and this was mixed into 1. Composite wires were obtained by filling two sets of mild steel sheath materials.

The amount of water glass covered (converted to Si02) is:

The content was 25'if1 i, t% for CaF2, 11% by weight for CeF3, and the flux filling rate was 15% by weight. On the other hand, as a metal sheath, C: 0.03%
.

Mn: 0.30%, Si: 0.01%, P:
0.010%.

Mild steel with S: 0.014% (each weight %) and the balance Fe was used.

For comparison, all of the above flux raw materials were coated with water glass.
A wire obtained using a Q-type material and a composite wire using CaF2 and CeF3 coated with Al2O3 were simultaneously fabricated and examined. Using each of the composite wires obtained, welding workability was investigated under the following conditions, and the results shown in Table 3 were obtained.

Welding conditions Test base material: 5M41B Bevel shape: bead on plate Shield gas: Ar80%, CO220%.

25 u/sin Welding position: downward Welding current: 280A, 30V, 30CP! .

Polarity: DCRP ・61′ Wood 1) High-speed video was used to evaluate the variation in arc length.

×: The variation in arc length is greater than the wire diameter O: Arc length fluctuation is less than the wire diameter Wood 2) The welded bead was examined by X-ray transmission.

X Number of nib blow holes: 3 / IOc+w or more O Number of nib blow holes: 3 @ / Less than 10 cm 0 3) The amount of water glass used for granulation is 20% of the total weight of flux in terms of SiO2 amount.
Met.

These results are summarized in bulleted form as follows.

As is clear from Table 3, 1caF of water glass of the present invention
2, Test No. consisting of CeF3, 2.3°4.5
, 6.7, good results were obtained in both arc stability and blowhole resistance.

In test No. 1, CaF2 and CeF3 were not covered with water glass, so CaF2 and CeF3 were not covered with water glass.
It is not easy to melt F2 and CeF3, and therefore poor results are obtained in both arc stability and blowhole resistance.

Test No. 8 is an example in which the entire flux was coated with water glass. In this example, since the entire flux was coated, the heat conduction to the inside of the granulated flux particles was rather poor, and as a result, the fluoride As a result, melting was inhibited, and both arc stability and blowhole resistance were deteriorated.

Test No. 9 is an example in which CaF2 is coated with Al2O3, and test No. 1O is an example in which CeF3 is coated with Al2O3. In these examples, since the melting point of Al2O3 is higher than that of SiO2, 1caF2
．． The good arc stability and blowhole resistance seen in CeF3 could not be obtained.

Example 2 BaF2 and LiBaF3 powders were kneaded with water glass,
After granulation, drying and particle size adjustment process, water glass coated rnBa
F2 and LiBaF3 were obtained. Next, using the wood glass-coated BaF2 powder obtained above, etc., a flux having a compounding ratio shown in Table 4 below was obtained, and this was filled into a 3.2 m-long mild steel sheath to form a composite. Got the wire.

(Left below), ;"The hydraulic lath coverage (Si02 equivalent) is 20% by weight for BaF2 and 12% by weight for LiBaF3,
The Fuller 7x filling rate was 1.8% by weight. In addition, the metal phase includes C: 0.08%, Mn: 0.40%,
Si: 0.05%, P: 0.014%, S
It was a mild steel containing 20.008% (each % by weight) and the balance Fe.

As in Example 1, all of the above flux raw materials were covered with ice glass for comparison. Such composite wire and Al
At the same time, a composite wire using BaF2°LiBaF3 powder coated with 2O3 was fabricated.

Using the obtained composite wire, welding workability was investigated under the following conditions, and the results shown in Table 5 were obtained.

Welding conditions Test base material: 5M50A Bevel shape: bead on plate Welding position 2 facing downward Welding current: 40OA, 27V, 30cps.

Polarity: DC3P self-shield The results are summarized in itemized form as follows.

As is clear from Table 5, test No. 2.3°4.5.
No. 6 is an example in which all the conditions of the present invention were satisfied, and good arc stability and blowhole resistance were obtained.

Test No. 1 is a conventional example in which the fluoride is not covered with water glass, so the fluoride is not easily melted during welding, resulting in poor arc stability.

1. The result was that both blowhole resistance properties were deteriorated. Test No. 17 is an example in which the entire flux was entirely covered with water glass. If the entire flux was covered with water glass, the heat conduction necessary for melting would be reduced, making it difficult to melt the flux as a whole, and for this reason, the arc stability and blowhole resistance would become insufficient.

Test Nos. 8 and 9 are examples in which Bap2 and LiBaF3 were coated with Al2O3. As in Example 1, in the composite wire to which Al2O3-covered mBaF2゜゛ LiBaFi is applied, the melting point of Al2O3 is equal to that of Si.
Since it is higher than O2, BaF2, LiBaFa (7)
Melting became difficult compared to composite wires using SiO2, BaF2, and LiBaF3, and as a result, both arc stability and blowhole resistance deteriorated.

[Effects of the Invention] Since the present invention is configured as described above, it provides a granular welding material that can effectively exhibit the effects of alkaline earth metal fluorides and lanthanide element fluorides during welding. We were able to.

Claims (1)

[Claims] A granular welding material comprising an alkaline earth metal fluoride or a lanthanide element fluoride coated with water glass in an amount of 1 to 30% by weight in terms of SiO_2.