JPH1096184A - Soldering material for welding formed stainless steel material and paper-making stainless steel wire gauze welded with the soldering material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a soldering material for the welding of stainless steel, having small potential difference from the stainless steel and forming a weld part having high corrosion resistance and to provide a paper-making stainless steel wire gauze welded with the soldering material. SOLUTION: This soldering material for the welding of formed stainless steel is composed of 20-40wt.% of gold, 15-30wt.% of silver, 15-30wt.% of copper, 2-6wt.% of nickel and 0-4wt.% of chromium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brazing filler metal for welding a stainless steel molded article, and more particularly to a stainless steel mesh for papermaking welded using the brazing filler metal.

[0002]

2. Description of the Related Art Conventional brazing filler metal for welding stainless steel requires an increase in the gold content in order to improve the corrosion resistance and strength of the brazing material itself. Most of them were expensive. In an environment where brazing material is used, nickel has been included to improve corrosion resistance to chlorides, and chromium has been included to improve corrosion resistance to sulfides. Is 70% or more, and there is no change that gold is the main component. This is the so-called gold wax. Theoretically, a gold content of 18 carats (75
%) Or more, corrosion of the brazing material itself can be prevented. However, in order to increase the content of gold, there is a serious problem that the base material to be welded at the welded portion is more rapidly corroded due to a difference in ionization tendency. If the base material to be welded is corroded, the strength of the welded portion will eventually decrease, causing a problem that the welded portion is cut or dropped. Therefore, even if only the brazing material remains without being corroded, there is no point in welding for the purpose of joining objects. There is also the problem of cost. Silver brazing was also used in addition to gold brazing.However, in the environment where stainless steel products are used, silver brazing has the drawback that, contrary to gold brazing, there is a shortcoming that the brazing material is corroded immediately and has a practical problem. Was.

[0003] In the field of papermaking, stainless steel meshes endlessly welded to dandy rolls, meshes of circular cylinder cylinders and the like are often used. In the papermaking process, many chemicals are used to improve the quality of the paper, so some of the raw materials include chlorides and oxidizer residues for bleaching pulp,
Additives such as aluminum sulfate are present. In addition, paper mills are often constructed along the sea for convenient loading and unloading of raw materials and paper, and seawater is often mixed with groundwater used. As described above, the stainless steel wire mesh used in the paper mill is used in an environment where metals are highly corrosive, so the welded portion of the stainless steel wire is corroded, the welding strength is reduced, and there is a danger of breakage. Is big.
If the weld breaks, it naturally becomes unusable and the service life is extended. This is a major problem, and there has been a strong demand for the development of a brazing material that does not cause corrosion of the weld.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention relates to a brazing material having improved corrosion resistance of a welded portion and good performance such as workability. It is an object of the present invention to provide a stainless steel wire mesh for papermaking which is welded by the above method.

[0005]

SUMMARY OF THE INVENTION The present invention comprises: 1. 20 to 40% by weight of gold, 15 to 30% by weight of silver, 15 to 30% by weight of copper and 2 to 6% by weight of nickel. And a brazing material for stainless steel formed from 0 to 4% by weight of chromium 2. The brazing material for welding a formed stainless steel according to item 1, wherein the formed stainless steel is a stainless steel wire mesh for papermaking. After placing the brazing material described in the section between the butted ends of the stainless steel wire mesh for papermaking, heating it to dissolve the brazing material and welding the ends of the wire mesh to form an endless stainless steel for papermaking. Wire mesh. "

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present inventor has determined that a welded portion welded with a conventional brazing material has a large difference in ionization tendency between the brazing material and the base material to be welded. The present invention was completed by elucidating that the corrosion of the weld had progressed rapidly. That is, as in the conventional case, when the base material to be welded is stainless steel and the brazing material is gold brazing, the base material to be welded is an electrically base metal having a higher ionization tendency than the brazing material. Is a noble metal that is electrically noble and has a lower ionization tendency than stainless steel.
As a result, electrolytic corrosion occurred due to the potential difference, and corrosion of the base stainless steel had progressed. In particular, when chloride or seawater is mixed, naturally, the corrosion of the base material of the welded portion is significantly accelerated. Therefore, in order to achieve the above object, first, it was necessary to minimize the potential difference between the brazing material and stainless steel.

To reduce the potential difference between stainless steel and brazing material, it is necessary to lower the potential of the brazing material, and to lower the potential, it is necessary to reduce the gold content of the brazing material. As a result of intensive studies, the present inventor has found that in order to reduce the potential difference, the content of gold, which was conventionally 70% or more for preventing corrosion of the brazing material itself, is 20 to 20%.
It was clarified that it had to be 40%. If the content of gold is less than 20%, the corrosion resistance of the brazing material itself is not sufficient, and corrosion due to the environment of the brazing material occurs during use. If it is more than 40%, the decrease in potential is not sufficient because the base material is insufficient. Electrolytic corrosion occurs on stainless steel. Gold content 2
When it is set to 0 to 40%, the potential of the brazing material becomes substantially equal to that of stainless steel, and no electrolytic corrosion occurs. In addition, there is a secondary effect that the brazing material can be manufactured at a low price because the content of gold is low.

[0008] By the way, since the content of gold has been reduced, other materials must be blended into the brazing material instead of gold. In the present invention, silver is 15 to 30% by weight and copper is 15% by weight. -30% by weight. Other metals, such as palladium and indium, are not inconceivable only for lowering the potential, but cannot be adopted because of problems such as segregation and difficulty in alloying.
Since silver has a low melting point, if the content of silver is increased, the brazing filler metal is easily melted, the flow is good, and the workability is improved.
However, if the amount is too large, the flowability becomes too large and flows down without stopping at the welded portion, thereby deteriorating workability. Therefore, copper having a melting point higher than that of silver is contained to control the flowability of the brazing filler metal. Copper 30%
If the amount is more than the above, the flowability deteriorates because of too much, and the workability deteriorates. If it is less than 15%, the flowability is too large. Silver one
Workability is improved when the content is 5 to 30% by weight and the content of copper is 15 to 30% by weight.

Further, in the present invention, nickel is used in an amount of 2 to 6 in order to improve the corrosion resistance of the brazing material itself to chlorides.
% To improve the corrosion resistance to sulfides. 2% nickel content
If it is smaller than this, nickel segregation at the interface between the solder and the stainless steel at the welded portion is small, but the strength and corrosion resistance are not sufficient. If it is larger than 6%, the melting point becomes high and workability is deteriorated. Chromium does not necessarily have to be contained, but when it is contained, there is an advantage that corrosion resistance to sulfides is improved.
However, when the content is more than 4%, the melting point becomes high and workability deteriorates.

As described above, since the corrosion resistance to chlorides and sulfides is improved, the stainless steel for papermaking used in a situation where chlorides and sulfides are present in the papermaking raw material and the metal is very easily corroded. It is particularly suitable for welding wire mesh. Further, the stainless steel wire mesh for papermaking must be formed so that there is no difference between the welded portion and the ordinary portion in order not to generate the mark of the welded portion on the paper. For this purpose, the weft lines along both ends of the stainless steel wire mesh for papermaking are cut to about half of the diameter and butted, and a narrow plate-shaped brazing material is sandwiched and arranged between the butted parts. It is desirable to melt and weld the material. This is because, when welding is performed in this manner, the welded portion is formed in almost the same state as the normal portion, and the welded portion becomes one latitude line.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments. Example 1 35% gold, 40% silver, 21% copper, 4% nickel
To obtain an alloy. Example 2 35% gold, 40% silver, 17% copper, 5% nickel
% And chromium were melted at a rate of 3% to form an alloy. In both examples, the alloys were manufactured based on an alloy of gold, silver and copper and containing nickel and chromium. This has the advantage of preventing electrolytic corrosion and improving welding workability.

Comparative Example An alloy was melted at a ratio of 82% gold and 18% nickel. Comparative test The test was made by welding the ends of a 45 mesh stainless steel wire mesh plain-woven using a 0.254 mm diameter stainless steel meridian and a 0.254 mm diameter parallel wire with the brazing material of the example and the comparative example. Was placed in a 1: 1 mixed acid of 0.1% by weight of hydrochloric acid and 0.05% by weight of sulfuric acid prepared for the test, and the time until the welded portion was broken was compared.

FIG. 1 is a sectional view of a welded portion for explaining a welding method. The ends 4 of the stainless steel mesh woven by the meridians 2 and the wefts 3 abut against each other, and a plate-shaped brazing material 1
Is arranged. The weft line 5 along the end 4 at both ends is cut to about half the wire diameter. When the plate-shaped brazing material 1 is melted and welded by arranging in this manner, the weft lines 5 along the ends 4 at both ends are integrated into one line, and are formed almost in the same manner as the ordinary portion. Therefore, no mark is generated on the paper. Of course, there is no problem even if the meridians and the latitudes are reversed. The test results were 27 days for the example, 30 days for the example 2, and 5 days for the comparative example. As is clear from the comparative test, the welded portion welded by using the brazing material of the present invention has improved corrosion resistance in each step as compared with the conventional case. Therefore, the life of the stainless steel wire mesh is extended.

[0014]

As described above, since the brazing material of the present invention has a low gold content and a small potential difference from stainless steel, the corrosion resistance of the welded portion is good, and the brazing material can be manufactured at low cost. Cost reduction. Further, the content of nickel as well as gold is small, and the content of silver lowers the melting point, the flowability of the brazing material is good, the workability is good, and the welding work time is shortened. In addition, since the melting point is low, welding can be performed at a lower temperature than before, so that a low-temperature flux that does not vitrify due to heat can be used, but vitrification due to high heat can be prevented, and after welding Can be performed with hot water instead of hot water, which also has the effect of improving cleanability and safety.

[Brief description of the drawings]

FIG. 1 is a sectional view of a welded portion for explaining a welding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plate-shaped brazing material 2 Meridian 3 Latitudinal line 4 End part 5 Latitudinal line along end part

Claims (3)

[Claims] 1. It comprises 20 to 40% by weight of gold, 15 to 30% by weight of silver, 15 to 30% by weight of copper, 2 to 6% by weight of nickel and 0 to 4% by weight of chromium. , Stainless steel brazing filler metal. 2. The brazing material for welding stainless molded articles according to claim 1, wherein the stainless molded article is a stainless steel wire mesh for papermaking. 3. A brazing material according to claim 1, which is sandwiched between butted ends of a stainless steel wire mesh for papermaking, and then heated to melt the brazing material and welded to the end portion of the wire mesh. Stainless steel wire mesh for papermaking.