US2668109A

US2668109A - Machinable titanium base tellurium alloy

Info

Publication number: US2668109A
Application number: US289005A
Authority: US
Inventors: Harry P Croft
Original assignee: Kennecott Copper Corp
Current assignee: Kennecott Corp
Priority date: 1952-05-20
Filing date: 1952-05-20
Publication date: 1954-02-02
Anticipated expiration: 1971-02-02

Description

Patented Feb. 2, 1954 Harry P. Croiit, Greens Fa Kennecott N. Y., a corporationof No Drawing, Application May 20', 1952," Serial No. 289.005

2 Claims.

This invention relates to titani m-base alloys and, more particularly, to titanium-base alloys characterized by good machining properties.

In the past, little has been known concerning the machinability of titanium metal and, consequently, there is practically no information relative to machinable alloys of titanium. Separate publications have compared the machinability of titanium to that of stainless steel, in one instance, and to that of free-machining stainless steel in another instance. since the machinability of stainless steel and free-machining stainless steel difier by a factor of about two, it will be apparent that the actual machinability of titanium metal is a somewhat controversial subject. In view of recent interest in titanium alloys and their applications, it has become increasingly desirable that information relative to the machinability of titanium alloys be obtained and that titanium alloys having good machining properties be developed.

It is, therefore, an object of this invention to provide alloys of titanium which are readily machinable.

It is a further object of this invention to provide free-machining alloys of titanium comprising titanium and an element having low solubility in titanium.

Yet another object of this invention is to provide free-machining alloys comprising titanium and tellurium.

Other objects and advantages of this invention will be apparent, in view of the following detailed description thereof:

In general, this invention relates to free-machining titanium-base alloys comprising titanium, and from about 0.02% to about 0.45% tellurium, particularly alloys containing from 0.05% to0.40% tellurium.

The introduction of tellurium as an alloying element in titanium presents substantial difiiculty because of the low boiling point and high vapor pressure of tellurium. For this reason, it is desirable to form a master alloy of titanium and tellurium to provide a relatively high-boiling point compound for subsequent addition to perature range of from 950 1 to 1000 F., the tellurium reacts exothermally with the tirms, Conn.,-assignorto Copper Corporation,

New York New York,

taniumproducing compounds having a metallic appearance. These compounds, or master alloys, may then be used in preparing titanium-lick luriumalloys of any desired composition.

'Ii-Te alloys of the present invention have been prepared and evaluated for machinability with results as tabulated in Table I below. Two common types of machining operations have been used in evaluating the machining properties of the present alloys. These two operations,

turning on a lathe and cutting with a saw, arebelieved to be representative machining operations and to afford a reasonable evaluation of relative machinability. Data I are reported on the basis of the machinability of unalloyed titanium as a reference. A value Avg. feed on alloy Index- 100X Av feed on standard Table I Oompositiom Percent Te i gg fi gg 1 Balance titanium.

Lathe tests reported above were made on a glnalloyed attendant loss of mechanical properties. Table II below shows that mechanical properditions of this invention:

Table II Ultimate 0.2Percent Elonge- Reduc- Vickers gggfi s'laensigiJ StYieldth tion, Pcralign of Hardreng reng cent in tea ness Percent Te p. s. i. p. s. i. l-inch Percent Number Unalloyed- 75, 400 54, 300 29 51 183 0.07 so, 600 66, 000 30 55 201 83, 200 64, 000 29 45 204 79, 200 60, 000 27 45 190 78, 600 54, 500 28 44 203 1 Balance essentially all titanium.

From Table II it is clear that the alloys of this invention possess increased tensile strength and yield strength, as compared with unalloyed titanium, and. retain excellent ductility properties without sacrifice of hardness.

It will be clear that useful alloys with increased properties of machinability and good machinability and good mechanical properties have been disclosed herein. It will be understood that the particular properties and descriptions are not intended to limit the scope of the invention but are presented for illustrative purposes only. The

titanium used in preparing the alloys of the present invention may be produced by either the magnesium-reduction method or by the iodide process, or in any other way, and may contain small amounts of impurities, such as carbon, iron, and nitrogen.

What is claimed is:

l. A titanium-base alloy consisting essentially of from .02% to .45% tellurium, balance titanium, characterized by an improved machinability of at least 104 as determined by a lathe test as compared with for an unalloyed titanium specimen.

2. A titanium-base alloy consisting essentially of from .05% to .40% tellurium, balance titanium, characterized by an improved machinability of at least 104 as determined by a lathe test as compared with 100 for an unalloyed titanium specimen. HARRY P. CROFT.

References Cited in the file of this patent Goldhofi, R. M., et a1.: TheInfluence of Insoluble Phases on Machinability of Titanium, published as ASM Preprint #30, 1952.

Claims

1. A TITANIUM-BASE ALLOY CONSISTING ESSENTIALLY OF FROM .02% TO .45% TELLURIUM, BALANCE TITANIUM, CHARACTERIZED BY AN IMPROVED MACHINABILITY OF AT LEAST 104 AS DETERMINED BY A LATHE TEST AS COMPARED WITH 100 FOR AN UNALLOYED TITANIUM SPECIMEN.