DE1508319C - Welding fluid - Google Patents

Description

The invention relates to a welding means, in particular for welding low-alloy, high-strength Steels, especially after the submerged arc welding process.

To produce a high-quality weld, the use of welding material is necessary in order to to create a protective layer over the base material at the welding point, which prevents the oxidation of the Base material and its undesired changes during welding are prevented. That on a case-by-case basis The case welding equipment used depends on the type of base material to be welded and the one used Welding process.

The welding means according to the invention is for welding steel, in particular low-alloy, high-strength steels provided. While there are a number of welding processes, for example the electro-slag welding process is satisfactory, it is particularly suitable for the submerged arc welding process. In the submerged arc welding process, a top layer of molten Welding agent applied to the end of the welding wire electrode with the arc and shield the molten base material from the atmosphere. The submerged arc welding process Applied welding agents are mixtures of granulated, fusible substances that make up the end the wire electrode and the base material in the melting zone. The submerged arc welding process is used a lot because, among other things, it is easily automated and at considerably higher speeds than most other known welding processes and allows welds of great thickness.

Welding means have already been proposed, but they do not belong to the state of the art (German patents 1,220,236 and 1,247,814), which are well suited for low-alloy, high-strength steels, as they welded joints of high impact strength and notable other mechanical Properties. However, these welding means are expensive to manufacture.

According to the invention there is provided a new and improved welding means which is essential is cheaper than the suggested one. The weld seams produced with the welding means according to the invention are in their mechanical properties those using the proposed welding means produced welds are generally superior or at least equivalent. Since the inventive Welding agent is inexpensive, it is also of practical use when welding less high quality Steels such as high-strength steels. The welding means according to the invention produce welded joints of particular high strength and high impact strength. In addition, is the welding means according to the invention Flows well in the molten state during the welding process and thus creates a smooth weld from which the slag can be easily removed.

The welding agent according to the invention consists of 5 to 16% aluminum oxide (Al ₂ O ₃ ), 3 to 15% manganese oxide (MnO), 0 to 40, preferably 20% calcium fluoride (CaF ₂ ), 15 to 40, preferably 15% sodium fluorosilicate (Na ₂ SiF ₆ ), the remainder silicon dioxide (SiO ₂ ) and calcium oxide (CaO). The last two components mentioned are in a weight ratio SiO ₂ : CaO of 2.03; 1 to 1: 1, and the sum of calcium fluoride and sodium fluorosilicate is not less than 20%. The percentages are percentages by weight.

Raw materials of a commercial degree of purity are preferably used to produce the welding means according to the invention, although impurities usually do not noticeably adversely affect the action of the welding means. Preferably, raw materials with a particle size of <0.297 mm are used. To produce the welding material, silica, lime, aluminum oxide, manganese oxide, fluorspar and sodium fluorosilicate are mixed evenly in the selected proportions in the dry state. You can use natural silicates with at least 90% SiO ₂ and a maximum of 5% aluminum (e.g. silica). Commercially available lime should contain at least 92% CaO after burning at 1093 ⁶ C and a maximum of 1.5% magnesium and 2% aluminum. Commercially available manganese oxide can also be used with a minimum of 45% manganese, a maximum of 8% iron, a maximum of 5% aluminum, a maximum of 1% zinc, arsenic and lead and a maximum of 2% barium. Using commercially available, calcined at 1093 ⁰ C alumina with an Al ₂ O ₃ content of 99%. The mineral fluorspar should contain at least 95% CaF ₂ .

The welding means according to the invention can be produced in the usual way from the raw materials mentioned, such as melting, sintering or using binders.

In the preferred melting process, the raw materials are mixed mechanically, the mixture in melted in a graphite crucible at 1316 to 1427 ° C, the melt at this temperature for 20 minutes held, then quenched to room temperature and then broken and ground.

When the welding means are produced by sintering, a mixture of the constituents is ^{heated in an oven to 900 °} C. for 1.5 hours. The mixture is then cooled, crushed and sieved to the desired fineness.

In the manufacture of welding means using binders, the components mixed with water glass in a ratio of 1 part water glass to 3 parts welding agent mixture, Heated for 3 hours to 482 ° C, crushed and sieved.

Table 1 gives examples of welding means according to the invention which are made by the melting process were manufactured. The analyzes were made on the blends of the ingredients prior to being melted together determined.

Table 1
Analysis of the welding material in percent by weight

Sweat
medium SiO ₂ CaO Al ₂ O, MnO Na ₂ SiF ₆ CaF, ' A. 37 18.5 16.0 5.5 . 23 - B. 34.5 17.0 15.5 5.0 28 - C. 32 ' 16.0 14.0 5.0 33 - D. 37 19th 15th 4th 20th 5 E. 25th 15th 7th 3 20th 30th F. 25th 20th 15th 5 15th 20th

The welding equipment mentioned in Table 1 was used for welding ΗΥ-80 steel, that is a high-strength, low-alloy steel with a 0.2-size

ze from 56.2 to 70.3 kp / mm ² and the following composition:

Weight percent

Carbon <0.22

Manganese 0.1 to 0.4

Phosphorus <0.035

Sulfur <0.04

Silicon 0.15 to 0.35

Nickel 2 to 2.75

Chromium 0.9 to 1.4

Molybdenum 0.23 to 0.35

Iron rest

The full norm of ΗΥ-80 steel is in the “US. Government Specification MIL-S-16216D (NAVY) «.

A welding wire with a diameter of 4 mm and the following chemical composition was used for the welds applied:

Weight percent

Carbon 0.09

Sulfur; ... 0.004

Phosphorus .... 0.006

Silicon: 0.74

Manganese. ; 1.40

Chromium 0.04

Nickel 1.03

Weight percent

Copper 0.48

Molybdenum 0.28

Zirconium 0.076

Iron rest

Using welding means according to the invention, welded connections were made with the 4 mm thick welding wire on 25.4 mm thick ΗΥ-80 steel plates with a simple 45 ° bevel. Strength tests were then carried out, the results of which are shown in Table 2 are. During welding, heat of 17,520 joules / cm was generated by a direct current arc reverse polarity of 550 A amperage and 27 V arc voltage when the electrode is advanced at 50.8 cm / min. Another weld joint using welding means F. was produced in the same way, but heat of 21,260 joules / cm was passed through a DC arc of reverse polarity. Of 600 A current and 30 V arc voltage supplied, the test results of which are marked with * in Table 2. Welding wire electrodes were used made of bare metal, and the granulated welding material was in supplied in sufficient quantity.

Table 2
Strength properties of welded joints

tensile strenght 0.2 limit Elongation at break, JD TUCiI-
constriction Notched impact strength arpy-V-Pro ben), mkp -62.2 ° C Sweat
medium kp / mm ² kp / mm ² based
to 35.56 mm ° / o (Ch
space -17.8 ° C -51.1 ° C 2.46 75.0 68.9 % 57.2 temperature 5.89 3.84 3.42 A. 75.5 61.0 22.1 58.6 9.85 7.95 5.07 3.29 B. 77.0 62.0 22.8 57.8 10.82 6.58 4.12 2.19 C. 79.5 62.2 21.4- 57.0 9.86 6.98 4.38 2.47 D. 76.5 61.5 20.0 64.0 9.86 7.67 3.70 3.98 E. ^ 78.0 64.0 22.0 62.0 12.20 7.58 3.98 3.84 F. 74.5 60.2 22.8 64.2 12.61 6.58 4.25 F * 23.6 12.08

From Table 2 it can be seen that the welding means according to the invention have a weld seam with similar Strength properties like the base material results. The high notched impact strength is of particular interest of the weld seams obtained when using the welding means according to the invention. Out it can be seen from the data that the preferred weld composition is achieved by welding agent F is reproduced. In addition to the high impact strength of the welds when using the By means of welding agent F, the welding points are exceptionally bright, and the removal of slag is facilitated.

The welding means according to the invention can also be used for other welding processes, for example as a soul in soul electrodes. The addition of substances to the welding core that acts as a protective gas Act over the welding point is possible (R. A. W i 1-s ο η, "Welding Journal", Vol. 40, No. 1, January 1961). In addition, metal particles can be added to the welding means according to the invention, for example the have the same composition as the welding wire or the base material; such welding agent mixtures are known. The metal particles are at the electrode weld is magnetically attracted to the weld; you can also use it there where feeding of the welding material by gravity is not possible.

Claims (1)

Claim: Welding means, in particular for welding low-alloy, high-strength steels, especially according to the submerged arc welding process, consisting of 5 to 16 ° / ₀ aluminum oxide (Al ₂ O ₃ ), 3 to 15 ° / ₀ manganese oxide (MnO), 0 to 40%, preferably from 20 ° / "calcium fluoride (CaF ₂ ),
15 to 40%, preferably from 15 ° / ₀ Natriumfluor- silicate (Na ₂ SiF ₈ ), The remainder is silicon dioxide (SiO ₂ ) and calcium oxide (CaO) in a weight ratio of silicon dioxide to calcium oxide of 2.03: 1 to 1: 1, with the proviso that the total content of calcium fluoride and sodium fluorosilicate is at least 20 ° / _{0th ;}