US2133848A

US2133848A - Corrosion resistant tubular article

Info

Publication number: US2133848A
Application number: US223272A
Authority: US
Inventors: Donald K Crampton; Newell W Mitchell
Original assignee: Chase Brass and Copper Co Inc
Current assignee: Chase Brass and Copper Co Inc
Priority date: 1938-08-05
Filing date: 1938-08-05
Publication date: 1938-10-18
Anticipated expiration: 1955-10-18

Description

Patented Oct. 18, 1938 UNITED STATES CORROSION RESISTANT TUBULAR ARTICLE Donald K. Crampton,

Marion, and Newell W.

Mitchell, Waterbury, Conn, assignors to Chase Brass & Copper (30., Incorporated, Waterbury,

Conn., a corporation No Drawing. Application August 5, 1938,

Serial No. 223,272

Claims.

This invention relates to improvements in corrosion-resistant tubular articles, and more particularly, corrosion-resistant wrought-metal tubular articles formed of copper-base alloys containing phosphorus, zinc and tin, with or without other elements which do not seriously impair the properties of the alloy.

This application is a continuation-in-part of our application Serial No. 71,807, filed March 30, 1936.

We have found that Wrought-metal tubular articles, such, for example, as tubes, pipes, etc., made of copper-base alloys containing phosphorus from about to about 2%, zinc from about 1% to about 30%, tin from about to about 8%, and copper, the copper, phosphorus, zinc and tin constituting about 90% or more of the alloy, with or without one or more additional elements in such substantially-innocuous amounts as do not seriously impair the properties of the alloy, have valuable corrosion-resistant properties, especially when conveying or holding or otherwise contacting saline liquid or dilute acid. The additional elements may range up to a total of about depending on what elements are added, some being more innocuous than others.

While each of the elements iron and antimony should not be present much in excess of about 0.1%, silver, which is comparatively innocuous, may be present to as high as about 10% provided not too much of other elements is present. Nickel may be present to as high as about 5 and lead and silicon may each be present to as high as about 3%.

We have discovered that aresnic has a particularly harmful eifect on the corrosion resistance to saline liquid and dilute acid, of wroughtmetal tubular articles made of copper-base alloys herein set forth of copper, phosphorus, zinc and tin, even when the arsenic is present in very small amount. We have discovered it to be important that the tubular articles for use in contact with saline liquid or dilute acid and formed of these copper-base alloys of copper, phosphorus, zinc and tin should be substantially free from arsenic, that is, that arsenic, if present at all, should not be present in excess of 0.1%. We have found that arsenic has a very harmful action which brings about corrosion with consequent serious loss of tensile strength and ductility and ultimate destruction of the tubular article. Not only is this true when these articles are subjected to plain corrosion without stress in the presence of saline liquid or dilute acid, but also when they are subjected to mechanical stress in the presence of saline liquid or dilute acid. Under commercial conditions, the tubular articles are frequently used under mechanical stress while subjected to corrosion by saline liquid or dilute acid, the amount or rate of corrosion being accelerated by the mechanical stress. Failure by stress corrosion in actual service is a very serious problem. We have discovered that wrought-metal tubular articles formed from copper-base alloys herein set forth of copper, phosphorus, zinc and tin, when substantially free of arsenic, have exceptional corrosion resistance to saline liquid and dilute acid, both when subjected to these fluids under conditions of mechanical stress and free of stress.

Corrosion-resistant wrought-metal tubular articles in accordance with this invention are preferably formed of copper-base alloys of copper, phosphorus, zinc and tin without additional elements, although as previously explained, certain additional elements may be tolerated provided they are present only in such amounts as are substantially innocuous.

Although the phosphorus may range from about to about 2%, the zinc from about 1% to 30%, and the tin from about to about 8%, it is preferable to have the phosphorus from about to about 1 the zinc from about 3% to about 20%, and the tin from about 1 to about 5%. Within the ranges of the elements of this preferred alloy range, three separate alloy types may advantageously be made, all having phosphorus from to about 1 /2%, the first having zinc from about 3%. to about 7% with the tin from about 3% to about 5%, the second having zinc from about 7% to about 12% with the tin from about 2% to about 4%, and a third having zinc from about 12% to about 20% with the tin from about 1 to about 3%. And within the ranges of said three alloy types, three alloys may be advantageously made having nominal composition as follows: all three have about 1% phosphorus, the first having about 5% zinc with about 4% tin, the second having about 10% zinc with about 3% tin, and the third having about 15% zinc with about 2% tin.

In all the corrosion-resistant wrought-metal tubular articles made in accordance with this invention, as the zinc content is increased from about 1% to about 30%, it is preferable to decrease both the ratioof tin to phosphorus and thecombined amounts of tin plus phosphorus.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiment are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

We claim:

1. A wrought-metal tubular article for use in contact with saline liquid or dilute acid and characterized by good corrosion resistance to saline liquid and dilute acid and formed from an alloy substantially free of arsenic and consisting of: phosphorus from about 4% to about 2%; zinc from about 1% to about 30%; tin from about to about 8%; and the balance substantially of copper.

2. A wrought-metal tubular article for use in contact with saline liquid or dilute acid and characterized by good corrosion resistance to saline liqu d and dilute acid and formed from an alloy substantially free of arsenic and consisting of: phosphorus from about A to about 1 zinc from about 3% to about 20%; tin from about 1 to about 5%; and the balance substantially of copper.

3. A Wrought-metal tubular article for use in contact with saline liquid or dilute acid and characterized by good corrosion resistance to saline liquid and dilute acid and formed from an alloy substantially free of arsenic and consisting of: phosphorus from about J% to about 1 zinc from about 3% to about 1%; tin from about 3% to about 5%; and the balance substantially of copper.

4. A wrought-metal tubular article for use in contact with saline liquid or dilute acid and characterized by good corrosion resistance to saline liquid and dilute acid and formed from an alloy substantially free of arsenic and consisting of: phosphorus from about to about 1 zinc from about 7% to about 12%; tin from about 2% to about 4%; and the balance substantially of copper.

5. A wrought-metal tubular article for use in contact with saline liquid or dilute acid and characterized by good corrosion resistance to saline liquid and dilute acid and formed from an alloy substantially free of arsenic and consisting of: phosphorus from about to about 1 zinc from about 12% to about 20%; tin from about 1 5% to about 3%; and the balance substantially of copper.

DONALD K. CRAMPTON. N. W. MITCHELL.