Claims:
What is claimed is
1. A metal alloy having the composition:
2. A wire cloth for papermaking machines, comprising warp wires of the alloy of the formula of claim 1.
3. A wire cloth for papermaking machines comprising warp wires of a metal alloy having the composition tin 4-12 percent, phosphorus 0.1-0.7 percent, manganese 0.1-2.0 percent, nickel 1-15 percent, 0.2-0.8 percent silicon and the balance copper.
Description:
BACKGROUND OF THE INVENTION
This invention relates to metal wires for use on papermaking machines, and it more specifically relates to warp wires composed of a particular alloy.
Various types of papermaking machines rely upon the use of continuous foraminous metallic belts or "wires" as the surface for deposition of fibers in the water-laying process. Fourdrinier machines, cylinder machines, inver-form machines, verti-form machines, and others make use of such belts of woven wire or perforated sheets. The metals most commonly used for such belts are Phosphor Bronze, bronze, brass, stainless steel and others. In the Fourdrinier machine, deposition of the fibers onto the screen is accomplished by depositing a suspension of paper fibers from a head box onto the rapidly moving wire belt. The open spaces in the wire permit the moisture from the fibers to drain through the interstices, leaving a web of paper on the wire to be delivered to a pressing section of the machine. Drainage and formation of the web are accelerated by table rolls and suction boxes over which the wire slides, so that the dryest possible paper web is formed before arriving at the pressing part of the machine. Paper of good quality can be efficiently produced only if the wire belt is smooth and uniform, and provides maximum drainage through the interstices.
The wire belts in modern papermaking machines are subject to severe deteriorating forces. There is rapid flexing of the wire, leading to fatigue failures, as well as a considerable amount of abrasion on the wire, and chemical attack by the more or less corrosive solutions which are used in the papermaking. Failure of the wire in such belts is therefore common, and a great many attempts have been made to improve the wire by forming it of different types of alloys, or by adding a protective coating of some sort to the wire.
The most common warp wire used in papermaking belts for many years has been a Grade C Phosphor Bronze with the following nominal composition:
Copper 92.5% Tin 7.5% Phosphorus 0.30%.
However, other alloys have been proposed, such as cobalt-chrome-nickel and various types of stainless steels. Additionally, it has been proposed to chromeplate the wires, and to coat them with various synthetic resins. However, none of these proposed wires has been entirely satisfactory.
An object of this invention is to provide a new alloy which has special utility in the formation of warp wires for papermaking machines.
Another object is to provide a new wire cloth for use in papermaking machines.
Still another object is to provide an alloy of good flexibility and abrasion resistance which is resistant to corrosion by the chemicals found in the papermaking process.
STATEMENT OF THE INVENTION
According to the invention, an improved alloy for use in wires of papermaking machines is formed of an alloy of copper, tin, phosphorus, nickel, either manganese or iron or both and, optionally, a small proportion of silicon.
PREFERRED EMBODIMENTS OF THE INVENTION
The alloy most preferred in the practice of my invention has the following composition:
Tin 4 to 12% Phosphorus 0.1 to 0.7% Manganese 0.1 to 2.0% Nickel 1 to 25% Copper Remainder.
Also suitable is a composition containing 0.1 to 1.0 percent of iron. This alloy has the formula:
Tin 4 to 12% Phosphorus 0.1 to 0.7% Iron 0.1 to 1.0% Nickel 1 to 25% Copper Remainder.
Although, as indicated above, iron or manganese can either be present in the alloy, it is also possible for both to be present in the formula at the same time. Such an alloy has the formulation:
Tin 4 to 12% Phosphorus 0.1 to 0.7% Manganese 0.1 to 2.0% Iron 0.1 to 1.0% Nickel 1 to 25% Copper Remainder.
The properties of all of the above alloys are even further improved if they contain additionally 0.2 to 0.8 percent silicon, provided a suitable heat treatment is provided after formation of the wires.
In the preferred embodiment of my invention, the alloys above are used for the formation of the warp wires of the cloth only. The weft or "shute" wires, which run across the belt, are not subjected to the same degree to the harmful influences exerted on the warp wires, and it is therefore not necessary that they have the same degree of resistance as the warp wires. The weft wires can therefore be of any desired alloy known to the prior art. Copper-zinc alloys having a minimum of 75 percent copper, and optionally tin or other similar materials in quantities of under 1.0 percent, have proven themselves well.
I contemplate the use of the warp wires formed of alloys of my invention in all types of belts for papermaking machinery, regardless of the type of machine, the type of weave, or the shape of the wire. It is to be understood that the warp wires may be used in a regular weave wire cloth, or in such other known weaves as semitwill, full-twill, or any other weave of wire cloth. Likewise, the wires can be round, flat, elliptical, or of any other shape which is usable for the production of a water laid fibrous web.
By way of example only, the warp wires in a screen may vary from 0.005 inch to 0.020 inch, and the weft wires from 0.006 inch to 0.020 inch. Wires in this size range have been used in various combinations of warp and weft wire sizes from 100 mesh to 24 mesh. A typical construction would be a cloth having 70 warp wires per inch of 0.0078 inch diameter and 56 weft wires per inch of 0.0085 inch diameter. Many combinations of warp and weft giving both square and rectangular mesh openings can be used.