US20060288854A1 - Superalloy mortar tube - Google Patents

Superalloy mortar tube Download PDF

Info

Publication number
US20060288854A1
US20060288854A1 US11/162,745 US16274505A US2006288854A1 US 20060288854 A1 US20060288854 A1 US 20060288854A1 US 16274505 A US16274505 A US 16274505A US 2006288854 A1 US2006288854 A1 US 2006288854A1
Authority
US
United States
Prior art keywords
mortar tube
tube
mortar
superalloy
forming
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US11/162,745
Inventor
Mark Witherell
Richard Becker
Jose Santiago
Steve Tauscher
Michael George
Ramon Espinosa
George Hathaway
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Department of Army
Original Assignee
US Department of Army
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Department of Army filed Critical US Department of Army
Priority to US11/162,745 priority Critical patent/US20060288854A1/en
Assigned to US GOVERNMENT AS REPRESENTED BY THE SECRETARY OF THE ARMY reassignment US GOVERNMENT AS REPRESENTED BY THE SECRETARY OF THE ARMY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ESPINOSA, RAMON A., GEORGE, MICHAEL C., SANITAGO, JOSE, BECKER, RICHARD F., HATHAWAY, GEORGE E., TAUSCHER, STEVEN G., WITHERELL, MARK D.
Publication of US20060288854A1 publication Critical patent/US20060288854A1/en
Priority to US12/099,948 priority patent/US7963202B1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41A—FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
    • F41A21/00—Barrels; Gun tubes; Muzzle attachments; Barrel mounting means
    • F41A21/20—Barrels or gun tubes characterised by the material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41A—FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
    • F41A21/00—Barrels; Gun tubes; Muzzle attachments; Barrel mounting means
    • F41A21/32—Muzzle attachments or glands
    • F41A21/34—Flash dampers

Definitions

  • the invention relates in general to mortar tubes, and in particular to mortar tubes without cooling fins and having reduced wall thicknesses.
  • Mortars tubes presently used by the United States armed forces are generally available in three sizes of nominal inside diameter, namely, 60 mm (millimeter), 81 mm and 120 mm.
  • the current 60 mm and 81 mm mortar tubes have cooling fins that function to reduce the tube temperature during firing.
  • the mortar tube cooling fins are expensive to manufacture and add additional weight to the mortar tube.
  • the 120 mm mortar tube does not have cooling fins because its required rate of fire is less than the 60 mm and 81 mm mortars.
  • the present invention provides reduced weight mortar tubes by eliminating the need for fins on the 60 mm and 81 mm tubes and by reducing the wall thickness of all three sizes of mortar tubes.
  • the present invention is a mortar tube made of a superalloy.
  • the superalloy may be, for example, one of cobalt based, iron based and nickel based. Because of the excellent heat strength of superalloys, the mortar tube may have an external surface that is free of cooling fins.
  • Another aspect of the invention is a method of making a mortar tube comprising providing a superalloy material and forming the mortar tube from the superalloy material.
  • FIG. 1A is a side view of a known mortar tube.
  • FIG. 1B is a sectional view taken along the line 1 B- 1 B of FIG. 1A .
  • FIG. 2A is a side view of a mortar tube according to the invention.
  • FIG. 2B is a sectional view taken along the line 2 B- 2 B of FIG. 2A .
  • FIG. 3 is a graph of tube temperature vs. axial position for two finless tubes.
  • the present invention eliminates conventional cooling fins and reduces the wall thickness of mortar tubes by constructing the mortar tubes using a high strength superalloy.
  • the superalloys are known and typically fall into one of three types, iron based, cobalt based and nickel based. In general, the superalloys have material strengths greater than 140 ksi at tube temperatures greater than 1000 degrees Fahrenheit. The use of a higher strength material permits a thinner wall thickness, as compared to conventional tubes.
  • FIG. 1A is a side view of a known 81 mm mortar tube 10 .
  • Tube 10 includes cooling fins 12 on the rear portion near the breech.
  • the cooling fins 12 reduce the temperature of the mortar tube 10 from about 1160° F. to 1022° F. at presently required maximum rates of fire, i.e., 30 rounds per minute for 2 minutes and 15 rounds per minute sustained. These rates of fire are based on mortar ammunition having maximum design pressures of 15,800 psi.
  • a separate blast attenuation device (BAD) 14 is attached at the muzzle end of the tube 10 .
  • BAD blast attenuation device
  • FIG. 1B is a sectional view of the tube 10 taken along the line 1 B- 1 B of FIG. 1A .
  • tube 10 has a wall thickness g.
  • the steel used to make tube 10 cannot withstand the design ammo pressure loads if the tube temperature increases above 1160° F., as it would if the tube 10 had no cooling fins 12 .
  • FIG. 2A is a side view of a mortar tube 20 according to the invention.
  • FIG. 2B is a sectional view of the tube 20 taken along the line 2 B- 2 B of FIG. 2A .
  • tube 20 has a wall thickness h.
  • Tube 20 does not have cooling fins, in particular, the rear portion 24 of tube 20 , where fins would normally be formed, is without fins.
  • a BAD 22 is formed integrally with the tube 20 .
  • Tube 20 may be formed by machining or a metal flow-forming process.
  • Tube 20 is made of a superalloy that is one of nickel based, iron based or cobalt based.
  • the rate of fire (ROF) in number of rounds per minute (rds/min) for ammunition dictates the temperatures that a mortar tube will experience, as a general matter.
  • the maximum ROF is 25 rds/min for 1 minute and 5 rds/min sustained.
  • the maximum ROF is 30 rds/min for 2 minutes and 15 rds/min sustained.
  • the conventional tube has a very low ROF and is unable to satisfy future requirements for operational use.
  • FIG. 3 graphically shows temperature profile vs. axial position in the tube for a conventional 81 mm tube (lower curve) and the inventive 81 mm tube (upper curve) at each tube's maximum permissible ROF.
  • the inventive tube's temperature is approximately 400° F. hotter, because of the ability to handle a larger ROF.
  • the conventional mortar tube cannot handle an increased ROF, as needed to meet future requirements, without adding cooling fins.
  • the mortar tubes made according to the invention weigh approximately thirty percent less than conventional mortar tubes. After much experimentation, analysis and testing, it was discovered that, for a 60 mm superalloy mortar tube, the preferred wall thickness is in the range of about 1.75 mm to about 2.5 mm. For an 81 mm superalloy mortar tube, the preferred wall thickness is in the range of about 2 mm to about 5 mm. For a 120 mm superalloy mortar tube, the preferred wall thickness is in the range of about 2 mm to about 6.75 mm.

Abstract

A finless mortar tube is made of a superalloy. The superalloy is based on one of cobalt, iron and nickel. The finless mortar tube has an integrally formed blast attenuation device. The mortar tube may be 60, 81 or 120 mm. The mortar tube is capable of a substantial increase in the rate of fire compared to conventional mortar tubes.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This application claims the benefit under 35 USC 119(e) of U.S. provisional patent application 60/522,510 filed on Oct. 7, 2004 and 60/522,566 filed on Oct. 14, 2004, which applications are hereby incorporated by reference.
    • STATEMENT OF GOVERNMENT INTEREST
  • The inventions described herein may be manufactured, used and licensed by or for the U.S. Government for U.S. Government purposes.
    • BACKGROUND OF THE INVENTION
  • The invention relates in general to mortar tubes, and in particular to mortar tubes without cooling fins and having reduced wall thicknesses.
  • Mortars tubes presently used by the United States armed forces are generally available in three sizes of nominal inside diameter, namely, 60 mm (millimeter), 81 mm and 120 mm. The current 60 mm and 81 mm mortar tubes have cooling fins that function to reduce the tube temperature during firing. The mortar tube cooling fins are expensive to manufacture and add additional weight to the mortar tube. The 120 mm mortar tube does not have cooling fins because its required rate of fire is less than the 60 mm and 81 mm mortars.
  • Generally speaking, the soldier in the field benefits whenever anything he/she must handle is made to weigh less. The present invention provides reduced weight mortar tubes by eliminating the need for fins on the 60 mm and 81 mm tubes and by reducing the wall thickness of all three sizes of mortar tubes.
    • SUMMARY OF THE INVENTION
  • In broad terms, the present invention is a mortar tube made of a superalloy. The superalloy may be, for example, one of cobalt based, iron based and nickel based. Because of the excellent heat strength of superalloys, the mortar tube may have an external surface that is free of cooling fins.
  • Another aspect of the invention is a method of making a mortar tube comprising providing a superalloy material and forming the mortar tube from the superalloy material.
  • The invention will be better understood, and further objects, features, and advantages thereof will become more apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • In the drawings, which are not necessarily to scale, like or corresponding parts are denoted by like or corresponding reference numerals.
  • FIG. 1A is a side view of a known mortar tube.
  • FIG. 1B is a sectional view taken along the line 1B-1B of FIG. 1A.
  • FIG. 2A is a side view of a mortar tube according to the invention.
  • FIG. 2B is a sectional view taken along the line 2B-2B of FIG. 2A.
  • FIG. 3 is a graph of tube temperature vs. axial position for two finless tubes.
    • DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • The present invention eliminates conventional cooling fins and reduces the wall thickness of mortar tubes by constructing the mortar tubes using a high strength superalloy. The superalloys are known and typically fall into one of three types, iron based, cobalt based and nickel based. In general, the superalloys have material strengths greater than 140 ksi at tube temperatures greater than 1000 degrees Fahrenheit. The use of a higher strength material permits a thinner wall thickness, as compared to conventional tubes.
  • FIG. 1A is a side view of a known 81 mm mortar tube 10. Tube 10 includes cooling fins 12 on the rear portion near the breech. The cooling fins 12 reduce the temperature of the mortar tube 10 from about 1160° F. to 1022° F. at presently required maximum rates of fire, i.e., 30 rounds per minute for 2 minutes and 15 rounds per minute sustained. These rates of fire are based on mortar ammunition having maximum design pressures of 15,800 psi. A separate blast attenuation device (BAD) 14 is attached at the muzzle end of the tube 10.
  • FIG. 1B is a sectional view of the tube 10 taken along the line 1B-1B of FIG. 1A. As seen in FIG. 1B, tube 10 has a wall thickness g. The steel used to make tube 10 cannot withstand the design ammo pressure loads if the tube temperature increases above 1160° F., as it would if the tube 10 had no cooling fins 12.
  • FIG. 2A is a side view of a mortar tube 20 according to the invention. FIG. 2B is a sectional view of the tube 20 taken along the line 2B-2B of FIG. 2A. As seen in FIG. 2B, tube 20 has a wall thickness h. Tube 20 does not have cooling fins, in particular, the rear portion 24 of tube 20, where fins would normally be formed, is without fins. A BAD 22 is formed integrally with the tube 20. Tube 20 may be formed by machining or a metal flow-forming process. Tube 20 is made of a superalloy that is one of nickel based, iron based or cobalt based.
  • The rate of fire (ROF) in number of rounds per minute (rds/min) for ammunition dictates the temperatures that a mortar tube will experience, as a general matter. The higher the ROF number, the higher the temperatures the mortar tube will experience. For an 81 mm finless mortar tube of conventional construction, the maximum ROF is 25 rds/min for 1 minute and 5 rds/min sustained. For an 81 mm finless mortar tube made in accordance with the invention, the maximum ROF is 30 rds/min for 2 minutes and 15 rds/min sustained. Thus, the conventional tube has a very low ROF and is unable to satisfy future requirements for operational use.
  • FIG. 3 graphically shows temperature profile vs. axial position in the tube for a conventional 81 mm tube (lower curve) and the inventive 81 mm tube (upper curve) at each tube's maximum permissible ROF. The inventive tube's temperature is approximately 400° F. hotter, because of the ability to handle a larger ROF. The conventional mortar tube cannot handle an increased ROF, as needed to meet future requirements, without adding cooling fins.
  • The mortar tubes made according to the invention weigh approximately thirty percent less than conventional mortar tubes. After much experimentation, analysis and testing, it was discovered that, for a 60 mm superalloy mortar tube, the preferred wall thickness is in the range of about 1.75 mm to about 2.5 mm. For an 81 mm superalloy mortar tube, the preferred wall thickness is in the range of about 2 mm to about 5 mm. For a 120 mm superalloy mortar tube, the preferred wall thickness is in the range of about 2 mm to about 6.75 mm.
  • While the invention has been described with reference to certain preferred embodiments, numerous changes, alterations and modifications to the described embodiments are possible without departing from the spirit and scope of the invention as defined in the appended claims, and equivalents thereof.

Claims (16)

1. A mortar tube made of a superalloy.
2. The mortar tube of claim 1 wherein the superalloy is one of cobalt based, iron based and nickel based.
3. The mortar tube of claim 1 wherein an external surface of the mortar tube is free of cooling fins.
4. The mortar tube of claim 1 further comprising an integral blast attenuation device.
5. The mortar tube of claim 1 having an inside diameter of about 60 mm.
6. The mortar tube of claim 5 having a wall thickness in a range of about 1.75 mm to about 2.5 mm.
7. The mortar tube of claim 1 having an inside diameter of about 81 mm.
8. The mortar tube of claim 7 having a wall thickness in a range of about 2 mm to about 5 mm.
9. The mortar tube of claim 1 having an inside diameter of about 120 mm.
10. The mortar tube of claim 9 having a wall thickness in a range of about 2 mm to about 6.75 mm.
11. A method of making a mortar tube, comprising:
providing a superalloy material; and
forming the mortar tube from the superalloy material.
12. The method of claim 111 wherein the forming step includes forming a finless mortar tube.
13. The method of claim 11 wherein the forming step includes forming a blast attenuation device integral with the mortar tube.
14. The method of claim 11 wherein the forming step includes machining the mortar tube from the superalloy material.
15. The method of claim 11 wherein the forming step includes forming the mortar tube from the superalloy material using a metal flow-forming process.
16. The method of claim 11 wherein the providing step includes providing a superalloy material selected from the group consisting of cobalt based, iron based and nickel based.
US11/162,745 2004-10-07 2005-09-21 Superalloy mortar tube Abandoned US20060288854A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US11/162,745 US20060288854A1 (en) 2004-10-07 2005-09-21 Superalloy mortar tube
US12/099,948 US7963202B1 (en) 2005-09-21 2008-04-09 Superalloy mortar tube

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US52251004P 2004-10-07 2004-10-07
US52256604P 2004-10-14 2004-10-14
US11/162,745 US20060288854A1 (en) 2004-10-07 2005-09-21 Superalloy mortar tube

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US12/099,948 Continuation-In-Part US7963202B1 (en) 2005-09-21 2008-04-09 Superalloy mortar tube

Publications (1)

Publication Number Publication Date
US20060288854A1 true US20060288854A1 (en) 2006-12-28

Family

ID=37565729

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/162,745 Abandoned US20060288854A1 (en) 2004-10-07 2005-09-21 Superalloy mortar tube

Country Status (1)

Country Link
US (1) US20060288854A1 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100236122A1 (en) * 2006-07-26 2010-09-23 Fonte Matthew V Flowforming Gun Barrels and Similar Tubular Devices
US20110011253A1 (en) * 2009-05-26 2011-01-20 Dynamic Flowform Corp. Stress Induced Crystallographic Phase Transformation and Texturing in Tubular Products Made of Cobalt and Cobalt Alloys
US7963202B1 (en) * 2005-09-21 2011-06-21 The United States Of America As Represented By The Secretary Of The Army Superalloy mortar tube
US8910409B1 (en) 2010-02-09 2014-12-16 Ati Properties, Inc. System and method of producing autofrettage in tubular components using a flowforming process
US9217619B2 (en) 2011-03-02 2015-12-22 Ati Properties, Inc. Composite gun barrel with outer sleeve made from shape memory alloy to dampen firing vibrations
US9662740B2 (en) 2004-08-02 2017-05-30 Ati Properties Llc Method for making corrosion resistant fluid conducting parts
GB2555579A (en) * 2016-10-28 2018-05-09 Bae Systems Plc Noise attenuation device
US10118259B1 (en) 2012-12-11 2018-11-06 Ati Properties Llc Corrosion resistant bimetallic tube manufactured by a two-step process
US20190264997A1 (en) * 2016-10-28 2019-08-29 Bae Systems Plc Noise attenuation device
USD889581S1 (en) * 2018-06-27 2020-07-07 The United States Of America As Represented By The Secretary Of The Army Mortar training aid
US11609060B1 (en) * 2020-08-20 2023-03-21 The United States Of America As Represented By The Secretary Of The Army Attenuating blast cone

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2990342A (en) * 1952-02-19 1961-06-27 George C Sullivan Method of making a gun barrel
US4146077A (en) * 1977-10-25 1979-03-27 Cabot Corporation Methods and apparatus for making cast hollows
US4756677A (en) * 1982-12-23 1988-07-12 Vereinigte Edelstahlwerke Aktiengesellshaft Method of manufacturing a weapon barrel
US5341719A (en) * 1992-12-14 1994-08-30 General Electric Company Multi-layer composite gun barrel
US6059573A (en) * 1998-03-20 2000-05-09 Fats, Inc. Mortar training device with functional simulated propelling charges
US20070221051A1 (en) * 2006-03-21 2007-09-27 Burkholder Daniel E Mortar blast attenuator diffuser

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2990342A (en) * 1952-02-19 1961-06-27 George C Sullivan Method of making a gun barrel
US4146077A (en) * 1977-10-25 1979-03-27 Cabot Corporation Methods and apparatus for making cast hollows
US4756677A (en) * 1982-12-23 1988-07-12 Vereinigte Edelstahlwerke Aktiengesellshaft Method of manufacturing a weapon barrel
US5341719A (en) * 1992-12-14 1994-08-30 General Electric Company Multi-layer composite gun barrel
US6059573A (en) * 1998-03-20 2000-05-09 Fats, Inc. Mortar training device with functional simulated propelling charges
US20070221051A1 (en) * 2006-03-21 2007-09-27 Burkholder Daniel E Mortar blast attenuator diffuser

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9662740B2 (en) 2004-08-02 2017-05-30 Ati Properties Llc Method for making corrosion resistant fluid conducting parts
US7963202B1 (en) * 2005-09-21 2011-06-21 The United States Of America As Represented By The Secretary Of The Army Superalloy mortar tube
US20100236122A1 (en) * 2006-07-26 2010-09-23 Fonte Matthew V Flowforming Gun Barrels and Similar Tubular Devices
US20110011253A1 (en) * 2009-05-26 2011-01-20 Dynamic Flowform Corp. Stress Induced Crystallographic Phase Transformation and Texturing in Tubular Products Made of Cobalt and Cobalt Alloys
US8302341B2 (en) * 2009-05-26 2012-11-06 Dynamic Flowform Corp. Stress induced crystallographic phase transformation and texturing in tubular products made of cobalt and cobalt alloys
US8671609B2 (en) 2009-05-26 2014-03-18 Dynamic Flowform Corp. Stress induced crystallographic phase transformation and texturing in tubular products made of cobalt and cobalt alloys
US8910409B1 (en) 2010-02-09 2014-12-16 Ati Properties, Inc. System and method of producing autofrettage in tubular components using a flowforming process
US9217619B2 (en) 2011-03-02 2015-12-22 Ati Properties, Inc. Composite gun barrel with outer sleeve made from shape memory alloy to dampen firing vibrations
US10118259B1 (en) 2012-12-11 2018-11-06 Ati Properties Llc Corrosion resistant bimetallic tube manufactured by a two-step process
GB2555579A (en) * 2016-10-28 2018-05-09 Bae Systems Plc Noise attenuation device
US20190264997A1 (en) * 2016-10-28 2019-08-29 Bae Systems Plc Noise attenuation device
US10670363B2 (en) * 2016-10-28 2020-06-02 Bae Systems Plc Noise attenuation device
GB2555579B (en) * 2016-10-28 2021-08-25 Bae Systems Plc Noise attenuation device
USD889581S1 (en) * 2018-06-27 2020-07-07 The United States Of America As Represented By The Secretary Of The Army Mortar training aid
US11609060B1 (en) * 2020-08-20 2023-03-21 The United States Of America As Represented By The Secretary Of The Army Attenuating blast cone

Similar Documents

Publication Publication Date Title
US20060288854A1 (en) Superalloy mortar tube
US7963202B1 (en) Superalloy mortar tube
US11215430B2 (en) One piece polymer ammunition cartridge having a primer insert and methods of making the same
US20200009632A1 (en) Flowforming Gun Barrels and Similar Tubular Devices
US8020333B2 (en) Cylinder with polycrystalline diamond interior
US5928799A (en) High temperature, high pressure, erosion and corrosion resistant composite structure
US8028626B2 (en) Frangible, ceramic-metal composite objects and methods of making the same
US5160802A (en) Prestressed composite gun tube
US7942090B1 (en) Enhanced operating life blank fire attachment for gas-operated weapons
US5341719A (en) Multi-layer composite gun barrel
US10323919B2 (en) Frangible, ceramic-metal composite objects and methods of making the same
US6482248B1 (en) Aluminum composite for gun barrels
US10718586B2 (en) Metal-metal-matrix composite barrels
US10866072B2 (en) Multi-piece cartridge casing and method of making
US4426248A (en) Process for coating rifle tubes
US6564689B1 (en) Blank for gun barrel, method for producing said gun barrel and gun barrel
CN116235020A (en) Boron steel high-pressure cartridge case
USH82H (en) Composite gun barrels
Polášek et al. Contact Fatigue Resistance of Gun Barrel Steels
JP2000080444A (en) Alloy steel for gun barrel
KR102645384B1 (en) --BMB omitted
Montgomery et al. Large caliber gun tube materials systems design
EP3754033B1 (en) Method of forming rimfire ammunition cartridge
DEMİR et al. Materials and Manufacture Processes of Assault Rifle Barrels
Dębski et al. Dilatometry of Steel for the Production of 5.56 mm Calibre Rifle Barrels

Legal Events

Date Code Title Description
AS Assignment

Owner name: US GOVERNMENT AS REPRESENTED BY THE SECRETARY OF T

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:WITHERELL, MARK D.;BECKER, RICHARD F.;SANITAGO, JOSE;AND OTHERS;REEL/FRAME:016567/0359;SIGNING DATES FROM 20050907 TO 20050920

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION