DE650114C - Tough-hard tungsten alloys for gold nib tips - Google Patents

Description

Tough and hard tungsten alloys for gold nib tips It is known that alloys for gold nibs made of tungsten to a considerable extent and otherwise consist of platinum metals. On the other hand, are platinum metal alloys ungen known that up to i o o, lo tungsten and a low nickelo. like addition ,exhibit. Finally, technology knows alloys of iron, copper or nickel metals with a small addition of two platinum metals and tungsten. Alloys of these There are a large number of species. They are hard and sufficiently acid-resistant that they neither write off quickly nor be attacked by the writing ink. In the Machining: however, due to the brittleness of such alloys, the Need to tip with a very thin, fast rotating copper washer to split, which is wetted with emery pulp. This is an inconvenient treatment, which one strives to avoid.

Now we have succeeded in the composition of the alloys of the latter Kind of to change my mind in such a way that they. remain just as hard and acid-resistant as that well-known, but have an unusual toughness. This tenacity is so large that springs, the tips of which are made of the new alloys, in a simple Way can be split with a knife or scissors.

It has been found that the composition of the alloys that are processed in the new way, must meet very specific conditions. The alloys consist of about 65 to 80% tungsten with a content of about 5 to 20% iron, nickel or cobalt. What is new about such alloys, however, is that Their share of precious metals is largely made up of platinum or the equally soft Palladium consists and to a lesser extent of osmium or other hard platinum metals, which in this context primarily includes ruthenium, as well as rhodium and Iridium. A content of 8 to 20% platinum or palladium and of is recommended 2 to 10% osmium, ruthenium or iridium. So far, it has been avoided to use feather tips the soft platinum metals, platinum and palladium, to be added in larger quantities, because this made the alloys too soft. Surprisingly, however, it has found that if you consider platinum and a small amount of osmium with tungsten Main component with the addition of a metal such as iron, nickel or cobalt, Alloyed, substances are created that relate to the hardness of the alloys with correspond to a main content of the hard platinum metals mentioned, which, but at the same time an incomparably great -: ,, have greater toughness than those who so that they can be cut.

The following experiment serves as an example for determining the toughness: `` A grain of about i, 3 1111n-e '' is clamped and loaded between two steel jaws. - When a certain pressure is reached, it will burst. This pressure depends only on the toughness, not on the hardness of the grain; with brittle alloys it is only a few kilograms ram, for tough alloys 50 kg and honest For .the commercially available alloys n was under the specified conditions ,.,. @@ en. a breaking load at 1.3 mm -0 "from 5 to y.5-kg determined. The following examples may serve for the composition and the toughness or compressive strength of the new alloys: . Breaking load at i> 5 'mm 0 x. 65% W, = o% Ru, 15% Pt ' 100/0 Co 48.4 kg 2. 65 ° / o W, 10/0 Os, I50 / 0 Pt, 10% Co 56.3 kg 3. 65% W, 5% Os, 20% Pt, 10% Co over 70 kg 4. 8o0 / "WI 8 ° i0 Pt # 20/0 Os = 1o0 / 0 Co 50.9 kg 5. 80 ° / 0 W, 8% Pt, 2% Ir, = 0% Co 63.0 kg The examples show that to achieve the toughness, the presence of a predominant content of tungsten, furthermore a precious metal content which can exceed 25%, but mainly consists of soft platinum metals, and a further base metal content of at most 20% is necessary. It also shows that the addition of cobalt has a particularly favorable effect, which is known in this context, and that maximum values are achieved within the favorable alloy with osmium as an additive to platinum (Example 3). Platinum with the addition of ruthenium or rhodium, which are similarly hard platinum metals as osmium, results in alloys that are less tough and also softer, but nevertheless significantly exceed the compressive strength of conventional alloys.

The following values were given for previously known alloys: Breaking load at 1.3 mm 0 6. 70/0 W, 5% Os, 25% Co 23.7 kg 7. 65% W, 15% Os, 10% Rh, 10 0/6 Co 17.6 kg 8. 65% W, 15% Os, 100/0 Ru, 10% Co 5.8 kg 9. 65% W, = 5% Os, xoo / o Ptr xoo% Co 29.3 kg A comparison of the last example with example 2 shows that, with the rest of the composition, the reversal of the proportion of soft and hard platinum metals can almost double the compressive strength.

The use of a Köbält additive for the new alloys offers in processing the further advantage that all alloys can be welded on well while, as is well known, pure tungsten, as well as many alloys of tungsten, Molybdenum and the platinum metals are not suitable for direct welding onto gold nib tips suitable.

In the new alloys, this can always be at least 65% present Up to 20% of tungsten can be replaced by molybdenum or tantalum. Instead of the cobalt addition nickel or iron can occur, albeit with somewhat less effect.

The well-known arc melting method can be used for uniform melting use,. but also other melting processes, such as. the high frequency induction furnace, preferably with a crucible insert.

Claims (1)

PATCNTAN-sPRÜ-GHr,:. i. Tough and hard tungsten alloys for gold nib tips, characterized by a content of about 5 to 20% nickel, cobalt or iron, about 8 to 20% platinum or palladium and about 2 to 100% osmium, ruthepium or Iridium, remainder, namely about 65 to 80%, tungsten, with the proviso that the content on platinum or palladium must be greater than that on osmium, ruthenium or iridium. , 2. Alloys according to claim i, characterized in that the tungsten is up to 20% has been replaced by molybdenum or tantalum: 3. Process for manufacturing gold nib tips from the alloys according to claims i and 2, characterized by shear Cutting into the spring gap.