JPS61132297A - Production of melt type flux for submerged arc welding - Google Patents

Abstract

PURPOSE:To incorporate a low melting point metal element stably with high yield without segregation by melting first the raw material removing a low melting point metal or the chemical compound and by adding the low melting point metal or the compound prior to the cooling solidification of this melted raw material. CONSTITUTION:A melting first started with other compound raw materials only excluding Pb or Bi raw material, which is added afterwards in the production of the melt type flux for submerged arc welding. Pb or Bi is thus contained stably with high yield without segregation in the flux for submerged arc welding and the production cost of the flux is reduced and the quality is elevated.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a manufacturing method for stably containing a low melting point metal element without segregation and at a high yield in a molten flux for submerged arc welding. .

(Prior Art) Conventionally, many melting type fluxes for submerged arc welding containing PB or Bi, which are low melting point metal elements, have been proposed. 1- There were various problems with the manufacturing method.

For example, Japanese Patent Publication No. 59-9275 proposes a molten flux for submerged arc welding, which is made by mechanically mixing a material containing lead oxide with a molten flux.

However, this flux has the drawback that the uniformity of its components, which is a major feature of molten flux, is impaired by mechanically mixing the PbO-containing raw materials, resulting in segregation. In addition, this proposal points out that the production method of molten flux, which involves adding lead glass, which is a compound of the low melting point metal Pb, to the flux raw material and incorporating 5 PB by melting has a poor yield. are doing.

Furthermore, JP-A-56-141992 proposes a melting type flux for submerged arc welding containing a trace amount (0.2wi% or less) of PB or Bi, and the manufacturing method thereof is shown as follows. .

That is, generally speaking, if all the raw materials are uniformly mixed and melted while being poured into a melting crucible little by little, the segregation of pbo and Bi2O5 in the flask is reduced.

However, even with this production method, the yield of Pb or Bi is low, and the amount of expensive Pb or Bi raw materials used is large relative to the content in the flux, resulting in a very high production cost. be. Furthermore, due to the poor yield, the content varies widely among produced fluxes, and it has been extremely difficult to stably produce fluxes containing trace amounts of such components.

That is, conventionally, pb or B, which is a low melting point metal element,
There has been no satisfactory method for stably containing i in flux without segregation and at a high yield.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems of the prior art, and its purpose is to stably contain low melting point metal elements without segregation and at a high yield. An object of the present invention is to provide a method for producing a molten flux for submerged arc welding.

(Another means to solve the problem) The gist of the present invention is that p, which is a low melting point metal element,
In a method for producing a molten flux for submerged arc welding containing one or more of B or Bi, the raw material excluding the low melting point metal or its compound is first melted, and before the molten raw material is cooled and solidified, the low melting point metal or The present invention provides a method for producing a molten flux for submerged arc welding, which comprises adding the compound to the molten raw material.

The present inventors investigated in detail whether Pb or Bi can be contained in flux without segregation and with good yield. As a result, in order to obtain a uniform composition without segregation, it is better to use a molten type, and in the case of adding a reducing agent during the manufacturing process, the Pb or Bi raw material is melted after the reaction of the reducing agent has progressed rapidly. If no reducing agent is added or a small amount is added, by shortening the melting time of the Pb or Bi raw material, it is possible to significantly improve the yield of Pb or Bi and to obtain a flux with a stable composition. This solves the problems of the conventional method.

(for production) The present invention will be explained in detail below along with its operation.

The feature of the present invention is that p is a low melting point metal element.
In the production of Rakunan type flux for submerged arc welding containing B or Bi, it is sometimes possible to start melting only with other blended raw materials excluding the Pb or Bi raw materials, and then add the Pb or Bi raw materials later. .

In the conventional production method in which PB or Bi raw materials are mixed with other raw materials and melted at the same time, PB or Bi is easily reduced and becomes metal particles that settle at the bottom of the furnace, or evaporates and becomes K contained in the flux. It gets harder. In particular, F e -M
When coexisting with a reducing agent such as n or graphite, this phenomenon is so pronounced that it may be hardly contained in the flux.

Therefore, the effect of the present invention is difficult to obtain unless the reaction proceeds before the PB or Bi raw material is melted, although the reducing agent differs depending on the degree of addition of the reducing agent.

In addition, PB or Bi is reduced and precipitated or evaporated by reaction with the carbon electrode or carbon lining of an electric melting furnace used in ordinary melting type flux production. In this case, the longer the time that the Pb or Bi raw material is melted, the lower the yield. Therefore, the most effective time to add the PB or Bi raw material is immediately before pouring it out of the melting furnace or ladle because the other raw materials are completely melted, the energization is finished, and the raw materials are cooled and solidified.

However, if a dissolution time of about 90 minutes is required, depending on whether or not a reducing agent is added, as well as the amount of dissolution, dissolution current, dissolution voltage, etc., the Pb or Bi raw material may be If it is added to the melted raw material first, the effects of the present invention will not be impaired. Therefore, the term "before cooling and solidification," which is a component of the timing of adding the low-melting point metal or its compound to the molten raw material of the present invention, refers to the period from 30 minutes before to just before cooling and solidification.

In addition, when using fine-grained PB or Bi raw materials, in order to prevent a decrease in yield due to dissipation as dust, the PB or Bi raw materials may be mixed with a small amount of other raw materials or already manufactured flux, or mixed with water or By absorbing moisture or granulating it with water glass etc. and adding it to the molten raw material,
The effects of the present invention are even more apparent.

(Example) The present invention will be explained in more detail below using examples.

Using the two types of blended raw materials indicated by symbol F1 and symbol F2 in Table 1, the Pb or Bi contained in the flux produced by the Pb or Bi raw material addition method according to the present invention and the conventional method is The necessary amount of PB or Bi raw materials to be added was investigated in order to set the content to 0.05 wt%, which is effective in improving welding workability.

Here, in symbol F1, no reducing agent was added, and in symbol F2, 2 wt% of the reducing agent (graphite) was added to the blended raw materials.

As shown in Table 2, the method of adding the Pb or Bi raw material is the production method according to the present invention, indicated by P1 and P2. Only other raw materials except PB or B raw materials,
First, the Pb or Bi raw materials are mixed uniformly and melted, and the Pb or Bi raw materials are added one minute before cooling and solidifying in symbol P1, and in symbol P2, they are mixed with the already produced molten flux of the same composition as the one to be produced. , 15 minutes before cooling and solidifying.
Each was placed on top of the molten raw material in the furnace. Symbol P
No. 6 is a conventional method in which all raw materials including Pb or Bi raw materials are uniformly mixed and melted.

The dissolution time was 8 minutes, and the cooling and solidification method was a water pulverization method in which the molten flux was poured into running water.

PB or B of each flux produced in this way
Table 6 shows a quantitative analysis of the i content and a comparison with the amount blended as raw materials. According to this result, in the case of the flux according to the present invention with the symbol F1 composition, the amount of Pb or Bi raw material used can be reduced to 1/20 compared to the conventional method. In addition, since a reducing agent is added to the F2 composition, the present invention also uses slightly more (PB or Bi) raw material than the F1 composition flag, but the conventional method uses 25 times more flux than the flux according to the present invention. Even if raw materials are used, the target content in the flux is 0.05 wt%.
less than 30% of

Therefore, the flux produced by the production method of the present invention has a very high yield of PB or Bi, which are components of expensive raw materials, and can be provided at a lower cost than flux produced by the conventional production method, making it possible to significantly reduce raw material costs. . Furthermore, since it is a molten type, there is no problem with the polarization of Pb or Bi.

In the examples, the PB raw material was lead glass (41
Bismuth oxide (89 wt% in terms of Bi) was used as the Bi raw material, but in addition to oxides, single metals,
In both fluoride and fine compounds, the production method according to the present invention had an effect of 5%.

Table 1 (wt, %) Tatami reducing agent (graphite) is mixed and dissolved at 2 wt% of the blended raw materials Table 2 Table 3 (Effects of the invention) The present invention adds PB or Bi
It is possible to stably contain flux at a high yield and without segregation, and it has a great effect on reducing manufacturing costs and improving quality of flux, and its industrial value is extremely high.

Procedural amendment (voluntary) January 17, 1985 Mr. Manabu Shiga, Commissioner of the Patent Office■, Indication of case Patent Application No. 251697 λ of 1985
Title of the invention Process for producing molten flux for submerged arc welding 3 Person making the amendment Relationship to the case Patent applicant Place
2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (66)
5) Representative Takeshi of Nippon Steel Corporation 1) Toyota 4th generation Osamu Address 3-3-3-3 Nihonbashi, Chuo-ku, Tokyo Date of amendment order Showa year Month/day (shipment date) 6. Inventions increased by amendment Number of Claims A method for producing a melting type flux for submerged arc welding containing one or more of the low melting point metal elements I and Bi, in which a raw material excluding the low melting point metal or its compound is melted to %. A method for producing a molten flux for submerged arc welding, which comprises adding a low melting point metal or a compound thereof to the molten raw material before cooling and solidifying the molten raw material.

that's all

Claims (1)

[Claims] In a method for producing a melting type flux for submerged arc welding containing one or more of the low melting point metal elements PB and Bi, a raw material excluding the low melting point metal or its compound is melted, and before this molten raw material is cooled and solidified. , a method for producing a melting type flux for submerged arc welding, characterized by adding a low melting point metal or a compound thereof.