有限元基礎(chǔ)-失效分析kind-ation

1Die

Casting

Dies:Aspects

of

Die

Design,Heat

Treatment,

and

Application壓鑄模具設(shè)計(jì),熱處理及應(yīng)用2Give

a

minimum

of

2,0

mm

allowance

on

each

side

before

heattreatment

in

order

to

assure

proper

finish

sizes

(distortion)!Prefer

smooth

changes

of

cross-sections

and

umpossible

radii

(for

Al

and

Mg

>

1,5

mm!)Inserts,

cores,

and walls

should

be

located

as

far

fromthe

gate

as

possible

(>

50

mm; avoiding

erosion

and

heatchecking

near

the

gate)!Design

gates

so

that

the

melt

flows

smoothly

and

freely

into

allparts

of

the !

Excessive

turbulences

of

the

melt

causeerosion

of

the

die

and

bad

castings!Locate

cooling

channels

so

that

the

entire

surface

of

the

diehas

a

uniform

temperature

profile!Prefer

internal

cooling

to

external

spray

cooling!Avoid

rough

surfaces

and

sharp

corners!Give

sufficient

wall

thickness

between and

holes

inorder

to

avoid

stress

accumulation!General

Guidelines

for

Die

Design模具設(shè)計(jì)基本原理熱處理前留出至少20mm的余量,以保證最終尺寸.過(guò)渡面盡量保持平緩,不要太 .(對(duì)于鋁,鎂合金的模具至少大于1,5mm.,模芯和型腔面壁應(yīng)該盡可能遠(yuǎn)離開(kāi)口處(>50mm,避免進(jìn)口處的腐蝕和抗熱磨損).進(jìn)口處的設(shè)計(jì)應(yīng)保證熔煉液順利進(jìn)入型腔面的各個(gè)部分!劇烈的會(huì)引起模具的腐蝕和模具的

.安裝冷卻槽以保證模具型腔面的表面溫度均勻.冷卻勝于外部噴射冷卻.避免毛糙表面和

的角落.型腔面和開(kāi)口處的壁厚要充分,以避免應(yīng)力增加.General

Guidelines

for

Die

Design模具設(shè)計(jì)基本原理3surface

and

the

outer

surfaceThe

distance

between

theshould

be

>

50

mm!The

distance

between

thesurface

to

cooling

channelsshould

be

>

25

mm,

near

corners

even

>

50

mm!The

ratio

of depth

/

total

thickness

of

the

insert

<

1

:

3!General

Guidelines

for

Die

Design模具設(shè)計(jì)基本原理型腔面表面和外部的表面的距離應(yīng)大于50mm.型腔表面到冷卻口的距離應(yīng)大于25mm,離核芯應(yīng)大于50mm.型腔面深度和整個(gè)

的厚度的比例要小于

1

:

3!4General

Guidelines

for

Die

Design模具設(shè)計(jì)基本原理Avoid

uneven

mass

distribution!避免表面不平引起的變形5ple y

Removed

Forged

Surface鍛面未徹底清除6Risk

due

to

Burrs毛邊引起的裂縫7Risk

due

to

Burrs毛邊引起的裂縫8Risk

due

to

Burrs

and

Bore

Holes毛邊及開(kāi)洞口引起的裂縫9Risk

due

to

Burrs毛邊引起的裂縫10Risk

due

to

Burrs毛邊引起的裂縫11Risk

due

to

Thin

Walls壁薄引起的裂縫12Risk

due

to

Bore

Holes

and

Thin

Walls開(kāi)洞口和壁薄引起的裂縫13Risk

due

to

Bore

Holes開(kāi)洞口引起的裂縫14Risk

due

to

Thin

Walls壁薄引起的裂縫15Risk

due

to

Thin

Walls壁薄引起的裂縫16Risk

due

to

Small

Radii半徑小引起的裂縫17Risk

due

to

Small

Radii半徑小引起的裂縫18Heat

Treatment

of

Die

Casting

Dies壓鑄模具熱處理1920Heat

Treatment

-

General

Remarks熱處理基本要點(diǎn)Heat

treatment

requires

certain

time

and

temperature

regimes,

itcannot

be

accelerated!熱處理需要一定的時(shí)間和溫度,不能夠無(wú)原則的加快速度.Stress

relieve

the

dies

after

rough

machining!粗加工后需要應(yīng)力

.Quench

as

fast

as

necessary

and

as

mild

as

possible!淬火盡可能要快,盡可能要柔和.Check

thermocouples

of

furnace

regularly!定期測(cè)量溫度變化.Temper

immedia y

after

quenching

(min.

2x)!淬火后要立即回火.(至少兩次)Do

not

reharden

the

tools

without

annealing

the

tools!重新淬火前必須進(jìn)行退火.21Total

furnace

weight:ca.40

t

設(shè)備重量40Tpiece

weight:>250kg

bis

2500kg

單件重量250KG到2500KGCharge

Size:

1000x1000x500

mm

尺寸1000x1000x500mmRange

of

hardening

temperature:

860

-

1030

°C淬火溫度范圍860-1030

°CTemperature

uniformity:

+/-

5°C

from

200溫度浮動(dòng)范圍:從200起+/-5°CProgrammer:

DEMIG

DEVR

+Prosys2

Process

leading

system控制系統(tǒng)Furnace

Technology

at

Kind

&

CoKIND

&

CO公司熱處理技術(shù)22Technical

Data

of

Vacuum

Furnace真空爐技術(shù)參數(shù)Convective

heating

對(duì)流傳熱for

a

better

temperature

uniformity

during

heating為了保證加熱過(guò)程中溫度的平緩Quenching

pressure

up

to

13bar

abs.

nitrogen淬火壓力高達(dá)13Bar時(shí)氮?dú)饫鋮shigh

cooling

capacity

(with

separate

water

re-coolingsystem)

guarantees

a

great

quenching

potential.高冷卻容量保證淬火能力(通過(guò)擁有獨(dú)立的水重冷卻系統(tǒng))Cooling

Fan

冷卻風(fēng)扇Power

consumption

460

KW

or

625

HP

電耗量

460

KW

或

625HPSome

Typical

Charges典型的尺寸23Production

Charges生產(chǎn)尺寸24Procedure程序A

charge

with

2200

kg

Charge

weight

is

runningappr.

16

h

before

cooling

starts.2200公斤重的材料在冷卻開(kāi)始前需要運(yùn)行約6小時(shí).The

following shows

the

structuretransformation

of

steel

in

time-lapse

photography以下的

演示了材料結(jié)構(gòu)的變化25Electro-Discharge-Machining

(EDM)

General

Remarks電火花加工主要要點(diǎn)EDM

of

annealed

material:26Conventional

machiningInitial

EDM,

avoiding

?arcing“

and

excessive

material

removal

ratesFinish

the

EDM

operation

by

fine

sparking

(low

current,

highfrequencyGrind

or

polish

EDM

surface

in

order

to

reduce

risks

of

crackformation

during

heat

treatment

and

operationEDM

of

hardened

material:Conventional

machiningHardening

and

tempering

processInitial

EDM,

avoiding

?arcing“

and

excessive

material

removal

ratesFinish

the

EDM

operation

by

fine

sparking

(low

current,

highfrequencyGrind

or

polish

EDM

surface

in

order

to

reduce

risks

of

crackformation

operationTemper

the

die

15

°C

below

the

last

tempering

temp

eratureElectro-Discharge-Machining

(EDM)

General

Remarks電火花加工主要要點(diǎn)退火材料的電火花加工:常規(guī)機(jī)加工初步電火花加工,應(yīng)力不要太大,避免產(chǎn)生電弧,過(guò)度損耗材料通過(guò)最終放火完成電火花加工(低電流,高頻率)研磨或拋光電火花層表面,以減少熱處理和機(jī)加工過(guò)程中出現(xiàn)裂縫變形的淬火材料的電火花加工:常規(guī)機(jī)加工淬火,回火初步電火花加工,應(yīng)力不要太大,避免產(chǎn)生電弧,過(guò)度損耗材料通過(guò)最終放火完成電火花加工(低電流,高頻率)研磨或拋光電火花層表面,以減少熱處理和機(jī)加工過(guò)程中出現(xiàn)裂縫變形的再次回火,溫度為最后一次回火溫度減去15度27Electro-Discharge-Machining

(EDM)電火花加工RoughRa

7,5μm28FineRa

6,3

μmFineRa

4,0

μmFine

FineRa

3,0

μm Ra

2,0

μmFinishElectro-Discharge-Machining

(EDM)電火花加工Increasing

intensityof

the

EDM

process提高電火花的強(qiáng)度29Thermal

Fatigue

Test

熱疲勞試驗(yàn)Test

temperature

600

°C

/

water 2000

Cycles試驗(yàn)溫度為

600

°C

/

水

2000

次冷熱變化V

=

10

:130Not

eroded

erodedElectro-Discharge-Machining

(EDM)電火花加工Element元元Atomic

radiusin

nm原原原原Atomic

weight原原原原Fe

鐵Iron0,12855,85C

碳Carbon0,08612,001N

氮Nitrogen0,07414,00731Nitriding

of

Hot-work

Tool

Steels熱作模具鋼氮化處理Crystalline

Structure

of

Iron鐵原子的晶體結(jié)構(gòu)Iron-Atoms32Atoms

on

interstitial

lattice

sites

in

ironα-Ironγ-IronNitriding

Process氮氮過(guò)氮Nitriding

Agent氮氮?jiǎng)㏄rocess

Temperature(°C)Process

Time(h)

時(shí)時(shí)Salt

bath

nitriding鹽溶溶溶cyanide-containingsalt

melt

溶化5700,2

-

4,0Gas

nitriding氣溶ammonia

gas

氨氣500

-

54010

-

100Plasma

nitriding等等等溶溶Nitrogen-hydrogen-mixture

溶氮氮氮化400

-

6000,2

-

30Nitriding

Processes氮化過(guò)程3334Nitriding

-

N-Profile

in

an

Iron

Alloy鐵合金元素氮化曲線135791

11

3'NinterstitiellMNyDistance

from

the

surface與表面的距離Nitrogen

concentration

液氮滲入000000050

HVKernh?rteGrenzh?rte

=

Kernh?rte

+

50HVNitrierh?rtetiefe

NhtNitriding

-

Hardness

Profile

Nitrided

Steel氮化材料硬度曲線Core

hardness

核芯硬度Distance

from

the

surface與表面的距離Hardness

in

HV

0,5Nitriding

depth

氮化深度Hardness

limit

=

Core

hardness

+

50

HV硬度范圍內(nèi)=模芯硬度+50

HV3550

μmgasnitrided

500

°C,15

h氣氮500°C,15

小時(shí)36Nitrided

surface此氮化表面Precipitations

on

grain

boundaries邊界沉淀20

μmNitriding

-Hot-work

Tool

Steel

Dominial

USN

(1.2343,

H11)熱作鋼

Dominial

USN

(1.2343,

H11)氮化3720

μm8

h120

h1200100080060040020000,00

0,50

1,00

1,50Abstand

vom

Rand

in

mm8

h120

hNitriding

-

Influence

of

Nitriding

Time氮化時(shí)間的影響Nitriding

duration:氮化時(shí)間Distance

from

the

surfaceH?rte

in

HV0,5Hardness

in

HV

0,5Compound

layer復(fù)合層Diffusing

element擴(kuò)散元素Outer

contour

after

nitriding氮化后外部形狀Original

contour

原始形狀Diffusiong

element

擴(kuò)散元素Dimensional

change

due

toincreased

volume

afterdiffusion擴(kuò)散后容量增加引起尺寸變化38Nitriding

-

Dimensional

Change氮化

-

尺寸變化Nitriding

of

Diecasting

Dies壓鑄模具氮化Nitrocarburization

540°C

3h

碳氮共滲

540°C

3

小時(shí)

Surface

hardness:

1260

HV

0,3

表面硬度Compound

layer:

~

6

μm

復(fù)合層Diffusion

layer:0,11-0,12mm

擴(kuò)散層39Nitriding

of

Diecasting

Die壓鑄模具氮化Nitriding

?Programm

99“Surface

hardness: ~

1000

HV0,3Compound

layer:

0

μmDiffusion

layer:

0,11

mm40Pre-Heating

and

Cooling

of

Die

Casting

Dies壓鑄模具的預(yù)熱和冷卻Pre-heating:is

required

in

order

to

avoid

severe

thermal

shock

and

heat

checkingpre-heating

should

be

done

smooth

and

even.Dies

containing

inserts

should

be

pre-heated

slowly

so

that

the

insertsand

holders

can

keep

up

with

the

temperature

and

expand

smoothly.41?mended

pre-heated

temperature

for

Al

and

Mg:

200

-

300

°C.Cooling:pre-heating

the

cooling

medium

(water,

oil)

to

50

°C

reduces

the

risk

ofheat-checking.Cooling

liquid

colder

than

20

°C

is

not

mende

d.During

production

interruptions

the

cooling

should

be

adjusted

tokeep

the

die

pre-heated.Keep

external

spray-cooling

on

a

minimum

level.Pre-Heating

and

Cooling

of

Die

Casting

Dies壓鑄模具的預(yù)熱和冷卻預(yù)熱:預(yù)熱是必要的,可以避免溫度突變預(yù)熱必須均勻.有 的模具預(yù)熱要慢,保證和模架的溫度和膨脹一致.鋁,鎂合金材料的預(yù)熱溫度建議為:200-300°C.冷卻:用水,

油預(yù)熱冷卻劑至50°C,

減小熱突變引起的裂縫分險(xiǎn)低于20°C

的冷卻液不

使用.如果生產(chǎn)中斷,冷卻液要重新進(jìn)行預(yù)熱.盡量減少外部冷卻.4243Stress

relieving

of

Die

Casting

Dies壓鑄模具的應(yīng)力The

necessity

of

stress

relieving

of

die

casting

dies

depends

on

theconditions

duringoperation.

A

continuous

operation

without

any

interruption

is

the

best

prerequisite

fora

good

performance.In

case

the

inserts

were

manufactured

by

erosion

wemend

a

stress

relievingbefore

the shot!

In

case

they

were

manufactured

without

erosion

we mend

astress

relieving

after

sampling.

Additional

cycles

for

a

stress

relieving

process

can

beafter

5.000;

10.000

and

20.000

shots.As

soon

as

an

insert

shows

cracks,

a

stress

reliving

does

not

have

any

advantagebecause

the

cracks

have

already

relieved

the

stresses.

After

each

welding

process

astress

relieving

is

required

.We mend

the

following

temperatures:540

–

560°C

(1004

–

1040°F)For

this

range

of

temperature

a

furnace

with

inert

atmosphere

is

required.

The

soakingtime

on

this

temperature

should

be

approx.

6

h

followed

a

cooling

in

the

furnace

toapprox.

300°C

(572°F).

Afterwards

the

cooling

can

b

e

done

at

calm

air.Stress

relieving

of

Die

Casting

Dies壓鑄模具的應(yīng)力壓鑄模具應(yīng)力退火的必要性是無(wú)法用是或否來(lái)回答的.操作狀態(tài).連續(xù)操作,沒(méi)有任何間斷是提供模具最長(zhǎng)它取決于模具制造過(guò)程中的的最佳前提.一旦

發(fā)現(xiàn)侵蝕,建議在第一次壓鑄前進(jìn)行應(yīng)力退火.若在制造過(guò)程中沒(méi)有發(fā)現(xiàn)侵蝕,建議在抽樣檢查后進(jìn)行應(yīng)力退火.進(jìn)一步的應(yīng)力退火可在大約5000次壓鑄后,和10.000-20.000次壓鑄后進(jìn)行.一旦 出現(xiàn)裂縫擴(kuò)張趨勢(shì),

就沒(méi)有必要進(jìn)行應(yīng)力退火,

因?yàn)?已通過(guò)裂縫

了應(yīng)力.每次焊接過(guò)程后必須進(jìn)行應(yīng)力退火.建議以下操作溫度:540

– 560°C

(1004

–

1040°F)在這個(gè)溫度范圍內(nèi)熔爐必須具備惰性氣體.在此溫度中熔煉大約6小時(shí),爐內(nèi)冷卻至少至300°C.這之后才能在空氣中繼續(xù)冷卻.44Welding

of

Die

Casting

Dies

-

I壓鑄模具焊接指南

-

I對(duì)于腐蝕層也同如果

已經(jīng)過(guò)氮化處理,

氮化表面必須在焊接前去除.樣處理,

特別是石墨電極侵蝕, 也就是表面滲氮.預(yù)熱

預(yù)熱是焊接過(guò)程中的一個(gè)重點(diǎn).

預(yù)熱溫度必須在350

–450°C(662

–

842°F)

之間.

在焊接面上

必須用保護(hù)膜或鋁膜覆蓋.

這不僅能防止焊接過(guò)程中的過(guò)熱輻射,

還能起到保溫作用.

當(dāng)

冷卻到250°C(482°F)

時(shí)必須進(jìn)行再加熱.

同時(shí)必須注意溫度控制.焊接焊條的選擇,最佳的電極等取決于焊條的供貨商,(同一位置,焊點(diǎn)小).45Welding

of

Die

Casting

Dies

-

II壓鑄模具焊接指南

-

II焊接:焊條可選用與模具同等的材料(如W.-No.1.2343/1.2344);另外馬氏體時(shí)效處理焊條W.-No.1.2709

也適用.這種等級(jí)的材料能吸收焊接過(guò)程中產(chǎn)生的應(yīng)力.焊接后焊接區(qū)域的硬度如下:焊接后46W.-No.

1.2709W.-No.

1.2344W.-No.

1.2567approx.

40

HRC52

–

55HRCapprox.

45

HRC在480°C(896°F)下應(yīng)力退火后W.-No.

1.2709W.-No.

1.2344W.-No.

1.2567approx.

55

HRC52

–

55HRC48

–

52HRC在540–560°C(1004–1040°F)溫度下惰性氣體回火后W.-No.

1.2709W.-No.

1.2344W.-No.

1.2567approx.

48

HRC50

–

52HRC45

–

50HRCWelding

of

Die

Casting

Dies

-

III壓鑄模具焊接指南

-IIIIf

the

weld

consists

of

more

than

3

plies

a

"buffer

welding"

is

required.

For

thisoperation

we mend

a

grade(e.g.

CAPILLA

64

KBs)C

o

%0,10

2,40

2,40 leading

to

a

strength

approx.

1250

N/mm2.On

various

occasions

we

realised

that

austenitic

welding

rods

were

used

(can

bechecked

with

a

magnet

–

austenitic

grades

are

non-magnetic).

This

grade

achieves

astrength

of

only

600

–

800

N/mm2.

During

the

casting

process

this

leads

to

an

earlystart

of

thermal

fatigue

cracks

in

the

welded

zones.The

austenitic

steel

is

not

suitable

as

a

buffer

electrode

as

its

coefficient

of

thermalexpansion

is

twice

as

high

as

that

of

steels

such

as

W.-Nr.

1.2343,

1.2344

or

1.2367respectively.47Welding

of

Die

Casting

Dies

-

III壓鑄模具焊接指南

-III建議使用以下等級(jí)的材料(譬如如果焊接超過(guò)3層,必須進(jìn)行緩沖焊接,對(duì)于緩沖焊接,CAPILLA

64

KBs

)C0,10

2,40o

%2,40

強(qiáng)度可達(dá)將近1250N/mm2.奧氏體焊條在許多場(chǎng)合也被普遍使用.(因?yàn)閵W氏體材質(zhì)無(wú)磁性,可以通過(guò)磁鐵檢查).這個(gè)等級(jí)的材質(zhì)強(qiáng)度只能達(dá)到600–800

N/mm2.在壓鑄過(guò)程中會(huì)由于熱疲勞性差過(guò)早在焊接區(qū)域出現(xiàn)裂縫..奧氏體材料不適合作為緩沖焊條,因?yàn)樗臒崤蛎浵禂?shù)分別為W.-Nr.1.2343,1.2344

or

1.2367

的兩倍.48Welding

of

Die

Casting

Dies

-

IV壓鑄模具焊接指南

-IVThe

heat

treatment

after

the

welding

process

is

an

important

factor

in

respect

of

theperformance

of

the

welded

mould.After

welding

the

die

should

cool

down

on

calm

air

down

to

80

–

100°C

(176–

212°F).As

soon

as

hardened

and

tempered

tools

have

cooled

down

to

80

–

100°C

(176

-

212°F)they

have

to

be

tempered

at

a

temperature

approx.

30

-

50

°C

(ideally

30

°C)

lower

thanits

final

tempering

temperature

(refer

to

the

die′s

journal).

The

time

of

temperatureshall

be

approx.

6

hours.

An

inert

gas

atmosphere

is

required

as

hot-work

tool

steelssuch

as

W.-Nr.

1.2343,

1.2344

and

1.2367

start

to

scale

at

temperatures

above

500

°C

ina

normal

atmosphere.If

an

inert

gas

furnace

is

not

available

a

stress

relieving

annealing

is

required

at

480

–500°C

(896

–

923°F).Holding

time

6

–

8

hThe

welded

area

and

transition

zone

will

keep

their

hardness49Welding

of

Die

Casting

Dies

-

IV壓鑄模具焊接指南

-IV焊接過(guò)程后的熱處理是對(duì)于經(jīng)過(guò)焊接的模具的性能有相當(dāng)重要的影響.焊接后模具應(yīng)在空氣中冷卻至80–100°C(176–212°F).一旦經(jīng)過(guò)硬化和回火的模具冷卻到80–100°C(176-212°F),必須在低于最后回火溫度狀態(tài)下再次進(jìn)行回火至大約.30-50°C(最好30°C).回火時(shí)間大約為6小時(shí).對(duì)于熱作模具鋼,如W.-

Nr.1.2343,1.2344

and

1.2367,如果焊接溫度超過(guò)500°C,必須在惰性氣體爐中進(jìn)行熱處理.如果沒(méi)有惰性氣體爐,模具必須在480–500°C(896–923°F)狀態(tài)下進(jìn)行應(yīng)力退火.持續(xù)時(shí)間為6–8

小時(shí).焊接區(qū)域和過(guò)渡區(qū)域?qū)⒈３炙鼈兊挠捕?50Welding

of

Die

Casting

Dies

-

V壓鑄模具焊接指南

-

VAs

soon

as

annealed

dies

have

cooled

down

to

80

-

100

°C

(176

-

212

°F)

they

must

besoft

annealed

immedia y

at

820

-

840

°C

(1508

-

1

544

°F).

The

time

on

temperatureshall

be

4

-

6

hours

followed

by

a

slow

cooling

in

the

furnace.

In

the

weld

as

well

as

inthe

transition

zone

this

leads

to

an

annealed

microstructure

and

a

correspondingstrength.A

concluding

comment:Annealed

dies,

which

were

welded,

bear

the

great

risk

that

cracks

start

in

the

weldedzone

during

hardening

(caused

e.g.

by

pores

in

the

weld

or

by

capillary

cracks

in

theweld

or

transition

zone).

Therefore

it

must

be

guaranteed

that

the

welded

area

isabsoluIt

is

oury

free

of

cracks.mendation

to

start

with

the

pre