CN103003657A

CN103003657A - Contoured thickness blank for ammunition cartridges

Info

Publication number: CN103003657A
Application number: CN2011800343400A
Authority: CN
Inventors: D·K·舍尔; J·A·道瑟特
Original assignee: AK Steel Properties Inc
Current assignee: Cleveland Cliffs Steel Properties Inc
Priority date: 2010-07-14
Filing date: 2011-07-14
Publication date: 2013-03-27
Also published as: EP2593745A1; TW201211494A; BR112013000888A2; MX2013000489A; JP2013536391A; KR20130038363A; AU2011279126A1; ZA201300232B; CA2804519A1; WO2012009527A1

Abstract

An austenitic stainless steel ammunition cartridge (12) includes an outer region (16) and a base, wherein the outer region (16) is about 50% - 80% of the thickness of the base, which serves to minimize the sidewall ironing required to form the cartridge. The cartridge blank (10) can be formed by spin forming, compression forming, grinding, or a combination thereof. Tooling (76) to form the blank (10) can include at least a pair of blocks (80) and inserts (78), at least one insert defining a centrally positioned aperture (82).

Description

The blank that is used for the variable thickness of ammunition cylindrical shell

Denier K. She Er

Joseph A. Dao Sete

Priority

The application requires the U.S. Provisional Patent Application sequence number No.61/364 that is entitled as " CONTOURED THICKNESS BLANK FOR AMMUNITION CARTRIDGES " of submission on July 14th, 2010,263 priority, the disclosure of this provisional application are come combination here by reference.

Background technology

Ammunition comprises metal shell or the cylindrical shell of usually being made by brass, and it encapsulates bullet, gunpowder and the fire in a stove before fuel is added separately.The cylinder-shaped of filling becomes the percussion chamber that cooperates exactly firearms.

The manufacturing of this brass cylindrical shell usually is known as and comprises the cup shell annealing that makes weight-normality lattice brass, and the cup shell deep-draw is made the net shape of cylindrical shell through the multistage pressure device.The technique that is used for brass also is included in the ironed stretching tube body sidewall of process of drawing and secondary drawing process, so that wall tilts with respect to base portion, wherein carries out a plurality of intermediate annealings between deep-draw processes.

Brass with enough low work hardening rate and low-frictional force can be used for a plurality of annealing and the ironed drawing process of sidewall, and is applicable to comprise the deep-draw processes of the thin stretching of heavy side wall pressure.By contrast, steel has for example performance of high work hardening rate, high strength and high frictional force.These performances can cause wearing and tearing and cut problem, usually cause reduce die life, and are so that the thin stretching difficult of heavy side wall pressure, and usually infeasible in the process that repeats secondary drawing and annealing steps.Equally, although carbon steel has been used for forming cylindrical shell, this cylindrical shell comprises waxing or applying protective finish and gets rusty preventing.

Description of drawings

Although specification with particularly point out and clearly claimed claim of the present invention as end; believe that the present invention will understand better from the following description of some examples of providing by reference to the accompanying drawings; identical Reference numeral represents identical element in the accompanying drawing, in the accompanying drawing:

Fig. 1 shows according to the ammunition cylindrical shell blank of example of the present invention viewgraph of cross-section at the first state;

Fig. 2 shows the ammunition cylindrical shell blank of Fig. 1 at the viewgraph of cross-section of the second formed cylinder body state;

Fig. 3 shows the elevation view of exemplary rotational forming operation;

Fig. 4 shows the elevation view of another exemplary rotational forming operation;

Fig. 5 shows the elevation view of exemplary compression forming operation;

Fig. 6 shows the elevation view for the mould of Alternative exemplary compression forming operation;

Fig. 7 shows the elevation view of exemplary grinding operation;

Fig. 8 shows the elevation view of another exemplary rotational forming operation;

Fig. 9 shows exemplary plunger and the elevation view of the cylindrical tube that forms via plunger; And

Figure 10 shows the decomposition diagram of exemplary tool.

Accompanying drawing is not intended to limit by any way, and being susceptible to numerous embodiments of the present invention can multiple other modes implement, and comprises those that not necessarily describe out in the accompanying drawing.Be combined in the specification and as an illustration the accompanying drawing of a book part show many aspects of the present invention, and be used for illustrating principle of the present invention with specification, but understand the accurate configuration of the present invention shown in being not limited to.

The specific embodiment

The following description of following example of the present invention should not be used for limiting the scope of the invention.Those of ordinary skill in the art will understand other examples, feature, aspect, embodiment and advantage from following description.As will understanding, the present invention can have other different and obvious aspects, and these do not depart from the present invention.Therefore, drawing and description should be thought illustrative in itself, and do not have limitation.

Blank

Fig. 1 shows the exemplary cylindrical shell blank 10 of the first state, and Fig. 2 shows the exemplary cylindrical shell blank 10 of the second state, and wherein after first drew operation, cylindrical shell 12 was drawn into cylindrical shape.The exemplary molding thickness blank 10 that forms the first state that further describes below is shown in Figure 1 for has centre button section 14 and perimeter 16.Thicker centre button section 14 becomes the base portion of cylindrical tube at the second state.Perimeter 16 reduced at least button section 14 thickness 50%, thereby when cylindrical shell 12 is drawn into cylindrical form, allow the minimum ironed stretching of sidewall.As shown in Figure 2, and as following description, the blank 10 of Fig. 1 is further processed the cylindrical shell 12 that forms Fig. 2, so that button section 14 becomes the base portion 18 of cylindrical tube 12.

Blank 10 can be formed by the metal including, but not limited to austenitic stainless steel.Austenitic stainless steel is known for those of ordinary skill in the art.It is the alloy that comprises chromium and nickel, has the austenite as main phase.Compare with other steel, this alloy has high ductibility, low yield stress and high tensile.The component of austenitic stainless steel can comprise the N of the C that for example is not more than about 0.045% percentage by weight, the Si that is not more than about 0.60% percentage by weight, about 0.03%-0.06% percentage by weight ₂, approximately about 1.4% percentage by weight of 1.0%-Mn, approximately about 17.8% percentage by weight of 17.2%-Cr, approximately about 3.4% percentage by weight of 3.1%-Cu, approximately about 8.4% percentage by weight of 8.1%-Ni, be not more than the P of about 0.035% percentage by weight, the Mo that is not more than the S of about 0.002% percentage by weight and is not more than about 0.4% percentage by weight.Alternatively, the austenite stainless steel constituent can comprise for example C, the Si of about 0.45% percentage by weight, the N of about 0.045% percentage by weight of about 0.035% percentage by weight ₂, the Mn of about 1.2% percentage by weight, the Cr of about 17.5% percentage by weight, the Cu of about 3.25% percentage by weight, the Ni of about 8.25% percentage by weight, the P of low weight percentage and the Mo of S and about 0.2% percentage by weight.Shown in the described component form 1 below, M=maximum wherein.

The chemical constituent of form 1 austenitic stainless steel (measuring with percentage by weight)

?

C

Si

N ₂

Mn

Cr

Cu

Ni

P

S

Mo

Scope

0.045M

0.60M

0.03/0.06

1.0/1.4

17.2/17.8

3.1/3.4

8.1/8.4

0.035M

0.002M

0.4M

Target

0.035

0.45

0.045

1.2

17.5

3.25

8.25

Low

02

Under cold rolling and annealing conditions, this austenitic stainless steel can have following mechanical performance: 0.2% yield strength=31.5ksi; Final hot strength (UTS)=77.5ksi; Total elongation at break is (based on primary standard length 2 ")=52.5%; N value (10% to critical value)=0.404, and hardness is 68HRBW.This performance can obtain from the standard uniaxial tensile test that carries out according to ASTM E8 and A370.N value or strain hardening exponent obtain simultaneously, but the method for determining is covered by ASTM E646.The material of testing in the example that is described below and austenitic stainless steel described above for example can melt, hot rolling between about 2250 ℉-about 2320 ℉, strand-anneal(ing) between about 1950 ℉-about 2000 ℉, cold rolling, and at about 1950 ℉ final annealings.

Blank can be by any method preparation known in the art.Fig. 3-7 shows preparation in the method for the blank 10 of its first state.Under its first state, blank can comprise the perimeter 16 around button section 14, so that perimeter 16 has the thickness of the scope between about 50%-80% of the thickness of centre button section 14.For example, sidewall 20 shown in Figure 2 can be in about 0.015-0.025 inch scope, and base portion 18 can have the thickness greater than sidewall thickness.This relatively large thickness need to be in molding process minimum ironed stretching, in order to perimeter 16 is positioned to the second state of Fig. 2 from the first state of Fig. 1, at the second state, perimeter 16 forms sidewalls 20.In another example, blank can comprise the perimeter 16 around button section 14, so that perimeter 16 has the thickness in the scope between about 50%-60% of the thickness of centre button section 14.

Blank can rotational forming shown in Fig. 3 or 4.With reference to figure 3, the arm 22 of rolling mill can comprise axle 24 and head 26, and rotates around the corresponding longitudinal axis A of axle 24.Each head 26 is trapezoidal shape normally, although other shapes also are apparent for those of ordinary skills.Head 26 comprises the blank contact surface 28 of the first approximate horizontal, relative second surface 30 and is arranged in therebetween the 32 and the 4th surface 34, the 3rd surface at the respective end place of first surface 28 and second surface 30.The 32 and the 4th surface 34, the 3rd surface is usually parallel to each other, and axis A is approximately perpendicular to the 32 and the 4th surface 34, the 3rd surface.

Blank 10 comprises machine contact surface 36 and relative downside surface 38.

Surface

36,38 is layout parallel to each other roughly.Blank 10 comprises the central axis B that is approximately perpendicular to head contact surface 36.Blank 10 rotates around central axis B, one or more arms 22 of rolling mill rotate around corresponding longitudinal axis A simultaneously, machine contact surface 36 work of blank 10 so that the blank contact surface 28 of the head 26 of cursor 22 reclines, in order to form button section 14 and perimeter 16, button section 14 has the thickness larger than perimeter 16.Alternatively, arm 22 can rotate when blank keeps fixing.

Alternatively, as shown in Figure 4, rolling mill can comprise the axle 42 with longitudinal axis C and the annular arm 44 that for example centers on the longitudinal axis C rotation of axle 42 in the direction shown in the arrow D.As mentioned above, in this exemplary form, along with blank 10 rotates around central axis B, the simultaneously various piece of cursor 44 machine contact surface 36 work of blank 10 that recline, blank 10 is formed has button section 14 and perimeter 16.Alternatively, arm 44 can rotate when blank 10 keeps fixing.

Blank can or forge under vertical compression contracting load and compress formation by cold forming, warm moulding, thermoforming.As shown in Figure 5, blank 10 can be placed on the upper surface 46 of bottom block 48 of press 50.The top block 52 of press 50 can comprise first 54, second portion 56 and third part 58, and wherein second portion 56 is arranged between first 54 and the third part 58.The shape of first 54 and third part 58 can be essentially rectangular or square, and other shapes also within the scope of the invention.First 54 and third part 58 can have the downside of substantial linear, in order to recline blank 10 compressions, thereby form perimeter 16 when the direction of arrow E is activated.Second portion 56 can comprise the

wall

60,62,64 that limits aperture 66, and it arranges size and blank 10 compressions that are configured to recline, thereby forms button section 14.The two half-unit of press reaches together with manner known in the art, thereby forms blank 10.

In addition, this process can relate to the design of use three mould tools of compression.The first and second moulds seem to be similar to shown in Figure 5, and just the lower surface of top press can tilt with respect to the upper surface of bottom presses, as shown in Figure 6.For example, Fig. 5 shows the flat parallel surfaces between top and the bottom presses.Fig. 6 shows the mould that has unparalleled surface between top and bottom presses.The first mould can comprise the flat upper surface 124 that for example is used for bottom presses 126, as shown in Figure 6.The first mould can comprise the lower surface 128 for the inclination of top press 130 in addition, and lower surface 128 tilts with angle N with respect to the flat upper surface 124 of bottom presses 126.Angle N can for example be 1 degree, so that the outer end of the lower surface of the inclination of top press removes about 0.018 from the upper surface of bottom press when two press compressions ".Alternatively, angle N can be in the scope of about 0.1 degree-about 5 degree.The inclination of adding two strict formative stages to via the first and second moulds for example helps blank material outwards to flow, because the lower surface that material can be by the top press is with respect to the described inclination of the upper surface of bottom presses and more gradually motion and outwards compressing.

Alternatively, exemplary grinding operation shown in Figure 7 can be used for forming blank 10.Blank 10 can remain to bottom block 68 by downward power F suction or vacuum.As shown in Figure 7, arm 70 comprises that axle 74 extends through central aperture 72 wherein.Axle 74 comprises the longitudinal axis G of approximate horizontal, and axle 74 rotates in the direction of arrow H around longitudinal axis G.This rotation for example can realize on the direction of the longitudinal axis G that is approximately perpendicular to axle 74 as shown by arrow I up and down vertical motion via pitch wheel mechanism (not shown).Alternatively, axle 74 can not move on the direction that is approximately perpendicular to axis G rotationally, to realize the similar motion of arm 70.Arm 70 moves to the position that the blank 10 that reclines grinds, thereby forms perimeter 16 along with blank 10 rotates in the direction of for example arrow J around central axis B.In addition and/or alternatively, arm 70 can realize to down stroke when the blank 10 that reclines grinds, and this can be rotatable or non-rotatable.

Alternatively, as shown in Figure 8, blank can directly form the cylindrical tube shape via the rotational forming operation.For example about 0.06 " thick flat blank (for example blank 100) can rotational forming be cylinder form on lower supporting part 102.Rotary machine 104 can comprise axle 106 and the arm 108 that extends from axle 106, and it forms axle and arm component 110 together.Axle and arm component 110 can rotate around the longitudinal axis K of axle and arm component 110, and blank 100 can keep fixing as shown in Figure 7, perhaps can be simultaneously rotate around the longitudinal axis of blank 100.Axle and arm component 110 can move downward in the direction of arrow L, in order to form the sidewall 112 of cylindrical tube 14, shown in Fig. 7 dotted line.For example, the perimeter 116 of blank 110 can form downwards on the direction of arrow M, to form sidewall 112.

Alternatively, as shown in Figure 9, have shaping plunger 118 less than the top width of bottom width and can be used to allow length 120 variable thickness along cylindrical tube 122, this is that final cylindrical shell shape is necessary.This process can be carried out in single operation, and the intermediate steps that does not need to add forms cylinder form, and this eliminates for example 3-4 intermediate steps.In addition, the flat blank that can eliminate by simple profile forms three required initial drawing operations of cylinder form, and is as described below.Randomly, centre button section can be in the circular flat section of about 0.04 " brazing of thickness place becomes about 0.020 ".

Alternatively, can use the instrument 76 that forms blank.This instrument comprises insert shown in Figure 10 78 and block 80.Insert 78 can for example be made by D-2 tool steel, and has the median plate that diameter is 2 " and thickness is 3/8 ", and has the hardness of 61HRC.Block 80 can for example be made by O-6 tool steel, and has the hardness of 59HRC.At least one insert 78 can comprise the central aperture 82 that extends through wherein.The diameter of central aperture 82 for example is 0.5 ".Block 80 can comprise the directing pin 84 in the blind hole 86 that is configured to be received in block 01, although directing pin 84 can be configured to be received in block 80 interior restrictions and pass in the aperture that block 80 extends.

The exemplary tool that substitutes is by 2Meridian Blvd., Wyomissing, PA, the Carpenter883(model HI5 that the CARPENTER TECHNOLOGY CORPORATION of 19610-1339 makes) tool steel is made, and this tool steel is 5% chromium high temperature tool steel for the application of the very big rigidity of needs.For example, model H15 tool steel is known as and has in thermoforming and/or the ability of using in forging.Adopt this tool steel, moulding can at room temperature be carried out under static load.Selection with instrument of attempting heating mould and material can be provided.But model H15 tool steel is well operation with respect to cold forming, because instrument can be resisted the crackle and distortion (namely the surface keeps smooth and parallel) of carrier surface.

In view of the instruction here, those of ordinary skills will understand any shape that can use for this instrument.For example, this instrument can comprise cylindrical block, and it is sized to form the blank with appropriate size.The Alternative exemplary instrument can comprise S-7, and it is to have 0.55% carbon, 3.25% chromium and the air hardening level tool steel of 1.4% molybdenum.According to the factor of the Production Life of for example cost and hope, in view of the instruction here, those of ordinary skills will understand can use any tool steel.

Described instrument can be heat-treated.The method of heat treatment exemplary tool (for example described model H15 instrument) comprises instrument or cutter is sealed in the stainless steel bag.Bag so that in the annealing process procedure surface oxidation of instrument minimum.Instrument should be protected, and not oxidation in annealing process, namely physically via lid or for example protection keeper of stainless steel bag and not oxidation in annealing process, the perhaps chemically not oxidation via the control atmosphere.For example, in the control atmosphere, bag can be unnecessary.

The bag that holds tool steel is placed directly at 1400 ℉ and reaches 4 hours in the smelting furnace, with the increment of 50 ℉ per hour, is heated to 1850 ℉ from 1400 ℉, and remains on 1850 ℉ and reach 6 hours.Bag then removes from smelting furnace, and air is cooled to 650 ℉.At 650 ℉, bag is placed in the smelting furnace, and is cooled to 200 ℉ with the increment of 50 ℉ per hour, and then again air be cooled to 120 ℉.Reach 6 hours in the smelting furnace and follow the air cool to room temperature by at 1000 ℉ instrument being placed on, tempering occurs.At last, instrument is surperficial polished.

With respect to the instrument that comprises medium pore, the hardness of block can be in the scope of about 54HRC-63HRC, and when not having medium pore, hardness can be about 48-49.Usually, along with hardness increases, intensity also increases; But it is more crisp that material also becomes.Estimation yield strength based on hardness can be in the scope of about 200ksi-220ksi.

Provide although have being applied in the following example of instrument of intermediate annealing step, after blank beginning process operation without any the use of the annealing blank of further annealing steps also within the scope of the invention.

Blank is to the exemplary moulding of cylindrical shell

The blank 10 of Fig. 1 can form the second state of the cylindrical tube 12 that is depicted as Fig. 2, and forms final cylindrical form after the repeatedly pulling reduction, for example to obtain the final straight cylindrical size of wall.For example have processing that the austenitic stainless steel of aforesaid component (0.01 " thickness) carries out and for having 2 " blank of diameter, have following result at the order formative stage: (1) draws than being 1.7, diameter is 1.17 ", (2) draw than being 1.33, diameter is 0.88 ", (2) draw than being 1.33, diameter is 0.665 ", (4) draw than being 1.33, diameter is 0.500 ", and (5) draw than being 1.32, diameter is 0.378 ".The drawing economy of as above measuring equals initial diameter divided by the final diameter after each formative stage.For example, for the drawing of brass cylindrical shell, those of ordinary skills this five-stage of cicada sequentially reduce, and are that aforesaid specific austenitic stainless steel can not need intermediate annealing between formative stage.Although described five-stage technique, can use within the scope of the invention more positive quadravalence segment process, eliminated once reduction, this causes 2,1.4,1.4 and 1.33 drawing ratio after each stage.

Required additional forming operation comprises following operation: (1) forms the operation reduce recess diameter, and (2) form the operation at cylindrical shell edge, and (3) form the operation in the zone that is configured to for example to receive primer cup in this edge.In view of the instruction here, those of ordinary skill in the art will understand employed forming operation.

Example

The blank of describing in the following example is pre-annealing.Initial blank is by shrinkage subtracts, is that dead annealed material forms subsequently through 50%-60%.

Example 1

For example attempt this moulding process at the mild steel that has the intensity lower than high-carbon steel, low work hardening and have the easy moulding of about 0.05-0.15C.For example, the test machine of 600KipTinius Olsen university and block of hardness body and function are tested at mild steel, and initial blank has 2.06 " diameter and 0.04 " thickness.Begin with 100Kip, blank loads with the 50Kip increment, so that final blank is 2.22 at the diameter of middle body ", and thickness is 0.031 ", and tapers to gradually " the edge of thickness that has 0.021.Then test has 1.53, and " the less blank of diameter obtains higher compression stress with the power for formed objects.The final diameter of less blank is 1.70 ", and final central thickness is 0.0307 ", and the final edge thickness is 0.016 ".

Example 2

Form ASTM specification T301 stainless steel blank.T301 stainless steel blank has the mechanical performance near aforesaid austenite stainless steel constituent, although T301 stainless steel blank has higher work hardening rate.T301 stainless steel blank has 1.53 original depth of " initial diameter and 0.0472 ".Increment with 100Kip arrives 300Kip, and obtaining final diameter is 1.625 ", final central thickness is 0.045 ", and final 1/4th edge thickness are 0.039 ".The block of hardness body and function is made tool of compression, and therefore not by moulding, and for example be generally flat.Use the hardness block, because imagine them in being best suited for the hardness range of this application.Employed hardness block is 42HRC, and slightly is being out of shape after the moulding fully.These blocks replace by 62HRC.Repeat this technique, be loaded into 350Kip, and unload at 400Kip.Final diameter is 1.64 ", hardness is 85-100HRB.When 1825 ℉ anneal, lower hardness is to 53-58HRB.After finally being loaded into 400Kip, final diameter is 1.76 ", last central thickness is 0.043 ", last total edge thickness is 0.030 ", final hardness is 90-93HRB.The hardness block of 62HRC forms crackle gradually, and is susceptible to thicker block and can prevents this crackle.Other instruments that form and produce up to 2.4 hundred ten thousand lbs by S-7 tool steel are used subsequently, not crackle.

Example 3

Form ASTM specification T305 stainless steel blank.The hardness block replaces by compressive plate, and it comprises a flat board and the one " plate of diameter medium pore that has 0.5.Plate has available D-2 tool steel processing.

Instrument is followed processed comprising the central opening of making button section 14, and has been designed removable compression insert.Base portion is made by O-6 tool steel, and insert made by D-2 tool steel, and base portion and insert are all in high 50HRC hardness range.

T305 stainless steel blank is loaded into 250Kip by the increment with 50Kip and forms, wherein complete discharge between the increment.At three position detect thickness: central authorities (" T1 "), leave button section 1/8 and " locate (" T2 "), leave outward flange 1/8 " and locate (" T3 ").Final measured value is as follows: diameter=1.61 ", T1=0.048 ", T2=0.0414 ", and T3=0.039 ".Material then is loaded into 300Kip, 350Kip and 400Kip, forms following final measured value: diameter=1.63 ", T1=0.048 ", T2=0.040 ", and T3=0.039 ".The hardness of position T2 is about 59.3HRA (96.5HRB), and the hardness of position T3 is about 61.3HRA (22HRC).This test causes the instrument crackle, centre button section lacuna.Lacuna is material is forced into open area in compression process result.The thickening of therefore wishing is accompanied by undesirable gauffer, and causing needs to realize having the height that harder instrument is controlled opening.For example, bar is inserted in the interior initial trial perforate of instrument insert, with formation button section, and allows suitable gap.Distance piece is used for control tool with respect to the height of blank in the vertical direction, to prevent the material gauffer.For example, highly can be fix or can regulate via distance piece.

Example 4

" plate of central openings or insert are used for top and the bottom of instrument, to solve the lacuna problem to have 0.5.The insert of control height only is used for a side.Have 1.5 " another blank of diameter is loaded into 250Kip with the increment of 50Kip, causes following final measured value: diameter=1.6 ", T1=0.050 ", T2=0.0424 ", and T3=0.090 ".The not serious lacuna of centre button section, but heave, so that top surface does not keep fully smooth.Additional pad adds the top surface of the bar in the central openings of insertion tool to, reducing the height of insert, and regulates the gap downwards.

Example 5

Application standard level T305 stainless steel button section blank.The at room temperature shrinkage of button section subtracts four times, wherein after each compression cycle in 1850 ℉ intermediate annealings.Blank is approximately 205ksi in the first CYCLIC LOADING to the stress on the 400Kip(surface area), the stress that then is loaded on the 300Kip(surface area is 151ksi), the stress that then is loaded on the 350Kip(surface area is 148ksi), the stress that then is loaded on the 375Kip(surface area is 155ksi).After the 4th circulation, average attenuation is measured as 39.7%.For each annealing process, annealing temperature is 1825 ℉ and is thirty minutes long.

With respect to the first process operation, initial diameter is 1.5 ", original depth T1, T2 and T3 equal respectively 0.047 ".Final measured value after the first process operation is as follows: diameter 1.63 ", T1=0.048 ", T2=0.414 ", and T3=0.039 ".The hardness at T2 place was measured as 97HRB before annealing, and was 54HRB after the annealing under 1825 ℉.

With respect to the second process operation, initial measured value is identical with the final measured value of above the first process operation that provides.The final measured value of the second process operation is as follows: diameter=1.7 ", T1=0.0486 ", T2=0.0367 " and, T3=0.0332 ".Hardness measurement after the annealing of T2 place is 62.5HRB.

With respect to the 3rd process operation, initial measured value is identical with the final measured value of above the second process operation that provides.The final measured value of the 3rd process operation is as follows: diameter=1.78 ", T1=0.0494 ", T2=0.033 " and, T3=0.0295 ".The hardness measurement at T2 place is 88HRB before the annealing, and is 76HRB. after the annealing under 1825 ℉

With respect to the 4th process operation, initial measured value is identical with the final measured value of above the 3rd process operation that provides.The final measured value of the 4th process operation is as follows: diameter=1.86 ", T1=0.049 ", T2=0.0302 " and, T3=0.0265 ".

The insert of instrument began to occur the crack in moulding process before crackle appears in base portion.Employed power is up to 400,000lbs.Button section blank is from about 1.5 " being expanded to about 1.9 ", and realizes about 40% attenuation by two intermediate annealings.

Example 5

As mentioned above, the austenite stainless steel constituent formation blank that has low work hardening feature.For another group test, austenitic stainless steel is reduced to 0.060 " thickness, and anneal.Material is processed to 1.5, and " blank of diameter, in the first compression cycle, it reduces about 20% thickness.The heat treatment of tool using in each described illustrative methods, and the blank reception intermediate annealing of button section, and repeatedly reduce thickness, as described below.

Employed order is as follows: be loaded into the 350Kip compression stress, and then make anneal of material under 1950 ℉, then be loaded into 425Kip, and under 1950 ℉, anneal, be loaded into subsequently 475Kip, and under 1950 ℉, annealing, be loaded at last 500Kip, and under 1950 ℉, anneal.After each reduction, the initial hardness of 44.7HRA is increased to the amount in the scope between the about 63.5HRA of 54.2HRA-, and is reduced to the amount in the scope between the 40.6HRA-44.1HRA after each annealing, as shown in Table 2.Grainiess checks after the 4th annealing, and discovery is consistent with the grainiess of original material.

Form 2 shows the measured value of the hardness after each reduction and the annealing.The different button of four of coding representative test section sample, so that 8 the first button sections that refer to test of encoding, coding 16 refers to the second button section of test, coding 35 refers to the 3rd button section of test, and 46 the 4th button sections that refer to test of encoding.

Form 2: hardness measurement value

Refer back to testing sequence, after the first reduction, central thickness is measured as 0.0629 ", and the attenuation percentage of perimeter is measured as 19.79%, and diameter measurement is 1.64 ".After the second reduction, central thickness is measured as 0.0653 ", the attenuation percentage of perimeter is measured as 32%, and diameter measurement is 1.75 ".After the 3rd reduction, central thickness is measured as 0.0681 ", the attenuation percentage of perimeter is measured as 41.24%, and diameter measurement is 1.87 ".After the 4th reduction, central thickness is measured as 0.0695 ", the attenuation percentage of perimeter is measured as 46.50%, and diameter measurement is 1.95 ".

In addition, some orders finally are loaded into 600Kip, and this higher power causes approximately 5% other attenuation, perhaps overall attenuation more than 50%.For example, button section blank subtracts four times by the intermediate annealing shrinkage after each formative stage, and at the stress level of each stage compression to about 180ksi.The total reduction level that realizes is just more than 50% attenuation, and final diameter is about 2.1 ".

Illustrated and described numerous embodiments of the present invention, the further modification of method and system described herein can suitably be adjusted by those of ordinary skills and realize, and does not depart from scope of the present invention.Multiple possible like this modification is referred, and other modification also is apparent for those of ordinary skills.For example, example described above, embodiment, geometry, material, size, ratio, step etc. are exemplary.Therefore, scope of the present invention should be considered with regard to following claim, and is interpreted as the structure that is not limited to shown in specification and the accompanying drawing and describes and the details of operation.

Claims

1. ammunition cylindrical shell comprises:

(a) base portion, described base portion has the first thickness; And

(b) perimeter, described perimeter has the second thickness, the percentage of described the second thickness of described the first Thickness Ratio large at least 50%;

Wherein said ammunition cylindrical shell comprises austenitic stainless steel; And

Wherein said base portion and described perimeter comprise the single-piece austenitic stainless steel of one.

2. ammunition cylindrical shell according to claim 1, wherein, the little about 50%-80% of described the first thickness of described the second Thickness Ratio.

3. ammunition cylindrical shell according to claim 1, wherein, the little about 50%-60% of described the first thickness of described the second Thickness Ratio.

4. ammunition cylindrical shell according to claim 1, wherein, described austenitic stainless steel comprises the Cr of about 17.8 percentage by weights of about 17.2-, approximately Cu and the about Ni of about 8.4 percentage by weights of 8.1-of about 3.4 percentage by weights of 3.1-.

5. method that forms the ammunition cylindrical shell may further comprise the steps:

(a) form the blank with button section and perimeter and central axis, circumferentially around described button section, the perimeter of described blank and button part do not have the downside of the substantial linear that is approximately perpendicular to described central axis in described perimeter;

(b) form described perimeter towards the downward downside of described central axis, until described perimeter is roughly parallel to described central axis.

6. method according to claim 5, wherein, the formation method that is used for described blank comprises at least a of rotational forming or compression forming.

7. method according to claim 5, wherein, the formation method that is used for described blank comprises grinding.

8. method according to claim 5, wherein, described blank is by pre-annealing.

9. method according to claim 5, wherein, the formation method that is used for described blank comprises the compression forming of employing instrument, and described instrument has a pair of block and a pair of insert, and each block can receive corresponding insert.

10. method according to claim 9 wherein, comprises central aperture at least one insert.