DE1937313A1 - Durable lead alloys - Google Patents

Description

Patent attorney Dipl.-Ing. A. Spalthoff Essen, Pelmanstrasse 31

Telephone 772008

REDEMAT S.A., 3-5, Place Winston Churchill, Luxembourg, Grand Duchy of Luxembourg

Durable lead alloys

The present invention relates to lead alloys with improved mechanical properties, especially lead alloys with increased Fatigue strength.

Lead alloys with low creep strength have serious ■ Disadvantages in various areas of application to or limit theirs Use. . -, - "'■

For example, the low fatigue strength of solder alloy racks is often a problem Serious disadvantage, as normal solder alloys, for example, do not even transfer the stresses caused by the thermal expansion of several Meter-long zinc gutters that are soldered together are created. Farther are soldered connections in electrical engineering and in the packaging industry limited in their application if they have to endure a monotonous continuous load, e.g. even at elevated temperatures.

For lead alloys as a semifinished product, such as strips, sheets, _v tubes, wires, the lack of creep resistance is an especially strong protuberant disadvantage. ^;

When using lead alloys in accumulators, the Problems of creep rupture strength are not as much in the foreground as that electrochemical problems. The standard alloy for stronger batteries is the PbSb 6 alloy. The permissible load on this alloy is

00 98 8 5/1278

ORPfNAt

with a limitation of the creep resistance to 1 % per year between 3o and 70 kp / cm at room temperature (Hofmann, lead and lead alloys, Springer-Verlag, 2nd edition, p. 227). The tendency to reduce the Sb content (because of the Sb migration and the resulting "poisoning" of the cell) continues. In this respect, a lead alloy that has high fatigue strength and fatigue strength is also advantageous for the accumulator industry. By reducing the casting cross-section, we can save weight. ~ '■

Radiation protection and noise protection are modern areas of application for Lead or lead alloys for which an improved creep rupture strength is also important.

Information on the long-term strength of lead-tin alloys in Ab- f

There is hardly any dependence on the tin content in the literature. There are Creep rupture strength values for lead-tin alloys are available.

Hofmann (lead and lead alloys, 2nd edition, p. 451) specifies a tensile stress of 7o kp / cm as the long-term ■ stability for. 10 days service life for Sn contents between 32 and 100% PbSn 4o and PbSn 2o for 1% elongation per year at room temperature a fatigue strength of about Io kp / cm and 12 kp / cm, respectively

will. . ■ ■ - ₁ ~

The invention is based on the object of providing lead alloys with increased Indicate the creep strength, through which the above-mentioned disadvantages are eliminated and through which new areas of application are opened up will. I.

The object is achieved according to the invention in that the alloy o, ool-l, o wt.% Barium and at least one element of the group consisting made of silver, aluminum, boron, bismuth, cadmium, hydrogen, magnesium, oxygen, sulfur, antimony, selenium, silicon, tin, tellurium and zinc contains and that the barium is present with the element as a compound, which comes about in the liquid or also in the solid state of the alloy has come and which has a dispersion-enhancing effect and / or states of order and / or to order-like states (cluster formation) leads in the grid, which have a solidifying effect.

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The elements can preferably be in the following percentages by weight of the alloy, are present: '

Silver ο, οοΐ - Io %

Aluminum o, ooil - 2%

Boron ο, οοΐ - 1 %

Bismuth ο, οοΐ - 6 %

Cadmium ο, οοΐ - Io %

Magnesium ο, οοΐ - 6 %

• Oxygen ο, οοΐ - ο, 2% -

Hydrogen ο, οοΐ - ο, 2%

Sulfur. ο, οοΐ - 2%

. Antimony ο, οοΐ - 2 %

' , Selenium ο, οοΐ - 1 %

.'- ■■ silicon ο, οοΐ - 2%

Tin ο, οοΐ - 9ο % '■

Zinc 'ο, οοΐ - 1 %

Tellurium -ο, οοΓ - 1% ;

Preferred long-term stable lead alloys are alloys which are made of o, oil - l, o% by weight of barium and an element in the specified percent by weight of the above group, the remainder being lead or lead-tin.

A lead alloy Pb-Ba-O according to the invention, for example 0.07% by weight Containing barium and 0.06 wt.% Oxygen, was tested for long-term stability examined. From the determined crawl cu'rven (lo, ooo hours) Hess

- 2

With a load of 112 kp / cm, a value smaller than the permissible elongation of 1 % per year at room temperature can be determined. This showed that the creep strength was greater than 112 kp / cm ^.

Rolling tests were undertaken to test the usability of the alloys according to the invention. The alloy Pb-Ba-O could be rolled cold without any difficulty from a casting thickness of 5 mm to 1 mm, which corresponds to a degree of deformation of 8 % .

The hardness of the alloy Pb-Ba-O was in HV (kp / mm) compared to Fine lead:

Fine lead PbHBa-O

before rolling 4.15 7 »91

after rolling 3.18 lo, 9o.

009885/1278

Because a large part of the lead semi-finished product is consumed in the sulfuric acid industry the alloys according to the invention must be corrosion-resistant to dilute sulfuric acid. These corrosion attempts left a poorer corrosion behavior of the alloys according to the invention not recognize against fine lead. .

Tests on lead-tin-based alloys according to the invention have similar results Results achieved. On the basis of the creep curves it has been determined that the lead-tin-based alloys according to the invention versus lead-tin alloys have a lower elongation despite a higher load * The load capacity of the Pb-Sn-based alloys according to the invention at higher loads is at least twice as large and at low loads there is a stagnation ™ got up from crawling.

Soldering tests with these alloys have shown that the wetting of the Solders of brass and zinc are at least as good as in the case of conventional ones PbSn solder alloys.

009885/1278 owswal _{) NSPECTEQ}

Claims (4)

PATENT CLAIMS q ': ■ I J Ο / J I xj 1. Durable lead alloy, characterized in that it contains o, ool-l, o wt.% Barium and at least one element of the group consisting of silver, aluminum, boron, bismuth, cadmium, hydrogen, magnesium, oxygen, sulfur, antimony, Contains selenium, silicon, tin, tellurium and zinc and that the barium is present with the element as a compound which has come about in the liquid or also in the solid state of the alloy and which has a dispersion-enhancing effect and / or to states of order and / or states similar to order (cluster formation ) leads in the lattice, which have a solidifying effect. 2. lead alloy according to claim 1, characterized in that the Elements are present in the alloy in the following percentages by weight: · ".- ■ -. Silver ο, οοΐ - Io % ■ ■ Aluminum ο, οοΐ - 2 % Boron O ₅ OOl- 1 % Bismuth ο, οοΐ - 6 % "; Cadmium ο, οοΐ - Io % Magnesium ο, οοΐ - 6 % - - Oxygen ο, οοΐ - ο, 2% Hydrogen ο, ool - ο, 2% '■ - ■ "■ -. Sulfur ο, ool - 2 % Antimony ο, οοΓ - 2 % Selenium ο, οοΐ - 1 % Silicon ο, οοΐ - 2 % Tin o, pol- 9o % Tellurium ο, οοΐ - 1 % Zinc o, ool - 1 % 3. Lead alloy according to claims 1 and 2, characterized in that it consists of ο, οοί-ΐ, ο % barium, at least one element of the group as in claim 1, and in the parts by weight as in claim 2, remainder lead. , 4. lead alloy according to claims 1 and 2, characterized in that ^; that the lead alloy is a lead-tin ^ base alloy. ''- 00 98 85/1278 ^ qinäl m ^% ®