IL129887A - Composite stratified material and its use for coins - Google Patents

Abstract

A composite stratified material consisting of a core layer of a ferritic chromium steel, which is plated on both sides with a steel layer, the steel used for plating the core layer consisting of, in percentage by mass rest iron as well as impurities from the manufacturing process, and additionally containing one or more of the following elements in percentage by mass: for use as material for the manufacture of stamped coins, slugs or chips.

Description

Composite stratified material and its use for coins KRUPP VDM GmbH Coinage Material The invention relates to a readily coloured stainless steel for and fo related objects as and name or number plates with patterns or characters imprinted on in earlier it was important the value of the metal coins to be equal to their face this requirement the choice of and and alloys were the course of industrialization from the mid 19th century more and more of low intrinsic value came into the material of which was chosen low cost of cture on the one and visual appearance on the Often nickel and certain copper alloys were there has been more and more call for cheaper In the course of this various types of rustproof steel have also already been made into coins mainly ferritic steel X 6 Cr 17 Material and austenitic steel X 5 18 12 Material More widespread use of steel as a coinage material has hitherto prevented by the problems of imprinting Due to hardness numbers that practice are still about 140 to 160 or on average about 150 in the the imprinted images are relatively although they are very resistant to abrasion and the coins remain for a long as described in XVII Mint Conference Madrid Also the bluish particularly of rustproof makes them look less valuable than the coinage materials such as silver or nickel and alloys In contrast to mechanical used in the the electronic widely used nowadays will not only measure a diameter and thickness but will also measure its electric conductivity inductively at various at various distances from its outer This enables stratified composites to be recognized with particular and to be separated foreign coins and As a a further important criterion in the production of coinage materials is that the properties of the such as electric and magnetization behaviour must be adjusted to within a very narrow acceptance The objective of the invention is therefore to provide a coinage consisting of rustproof which is easier to imprint than and at the same looks white or and which be made into coins that can be distinguished certainty from other coins or counterfeit coins in automatic esters This objective is according to the with a coinage consisting of stainless steel with the following composition chromium to nickel to copper to with the remainder being iron and impurities one more of the following elements can be added to this manganese nitrogen sulfur phosphorus molybdenum niobium aluminium cobalt boron Preferably a composite material is used which has of a ferritic chromium plated on both sides with a layer of the steel according to the It is advantageous if the thickness of the layers is 10 to of the overall thickness of the stratified composite it has been found that a coinage material consisting of such a the state not only has the desired white or silvery but also is able to have its hardness kept distinctly below 140 and indeed generally even below 120 These hardness are on average about lower than those for the rustproof steel used for coin blanks in the state of the make it possible to achieve a very much deeper and very much more imprinted Despite the resistanc to abrasion of this new coinage as determined a on test is comparable to that of the steels X 6 Cr 17 and X 5 18 and is by a factor of approximately than that of conventional coinage materials such as The new coinage comparabilit to other steels was also in for resistance to tarnishing in an aggressive laboratory over a solution and with subjection to artificial the coinage is according to the as the two outer layers of a composite this will make it particularly certain that such coins can be distinguished from other coins or counterfeits in commonly used The invention will now be described in greater an example of its A stainless steel with following composition was chromium nickel copper manganese silicon carbon nitrogen sulfur phosphorus molybdenum titanium niobium aluminium boron the being iron and The steel was and then to produce a strip mm Coin blanks with a diameter of mm were then punched out of the cold rolled These blanks were of the desired After the diameter was Each disk weighed and had density of The disks able to be to a of 117 without g consequently they were easy to as was determined by striking In a drum these coins were compared with others made of the stainless steels X 6 Cr 17 and X 5 18 ccnnnonly used for and the loss of mass with all three materials was Coins made of the very commonly used copper material on the other wore three times as In a corrosion in an aggressive laboratory over a NaCl solution and with subjection to artificial the new coinage material had only insignificantly altered after three Strips of this were plated onto both sides of fsrritic chromium steel X 6 Cr The thickness of each such outer layer was of the overall with the consequence that the resultant coins be distinguished with certainty from coins and counterfeits in testers commonly used A excellent feature of the invention that should be mentioned is that the new coinage material can be recycled with no by means of technologies commonly and this is true not only when it is used as a sole component but also when it is used as a component of a composite material together with a ferritic insufficientOCRQuality

Claims (1)

6 129-S87/2 CLAIMS:

1. Use of a composite stratified material consisting of a core layer of a ferritic chromium steel, which is plated on both sides with a steel layer, the steel used for plating the core layer consisting of, in percentage by mass rest iron as well as impurities from the manufacturing process, and additionally containing one or more of the following elements in percentage by mass: as material for the manufacture of stamped coins, slugs or chips. Use according to claim 1 , characterized in that the thickness of the plated layers is 10 to 30% of the total thickness of the composite stratified material. Use according to claim 1 or 2, characterized in that the core layer consists of the material X6Crl7. For the Applicants REI NERS