有限元基础-失效分析kind-ation

1Die

Casting

Dies:Aspects

of

Die

Design,Heat

Treatment,

and

Application压铸模具设计,热处理及应用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模具设计基本原理热处理前留出至少20mm的余量,以保证最终尺寸.过渡面尽量保持平缓,不要太 .(对于铝,镁合金的模具至少大于1,5mm.,模芯和型腔面壁应该尽可能远离开口处(>50mm,避免进口处的腐蚀和抗热磨损).进口处的设计应保证熔炼液顺利进入型腔面的各个部分!剧烈的会引起模具的腐蚀和模具的

.安装冷却槽以保证模具型腔面的表面温度均匀.冷却胜于外部喷射冷却.避免毛糙表面和

的角落.型腔面和开口处的壁厚要充分,以避免应力增加.General

Guidelines

for

Die

Design模具设计基本原理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模具设计基本原理型腔面表面和外部的表面的距离应大于50mm.型腔表面到冷却口的距离应大于25mm,离核芯应大于50mm.型腔面深度和整个

的厚度的比例要小于

1

:

3!4General

Guidelines

for

Die

Design模具设计基本原理Avoid

uneven

mass

distribution!避免表面不平引起的变形5ple y

Removed

Forged

Surface锻面未彻底清除6Risk

due

to

Burrs毛边引起的裂缝7Risk

due

to

Burrs毛边引起的裂缝8Risk

due

to

Burrs

and

Bore

Holes毛边及开洞口引起的裂缝9Risk

due

to

Burrs毛边引起的裂缝10Risk

due

to

Burrs毛边引起的裂缝11Risk

due

to

Thin

Walls壁薄引起的裂缝12Risk

due

to

Bore

Holes

and

Thin

Walls开洞口和壁薄引起的裂缝13Risk

due

to

Bore

Holes开洞口引起的裂缝14Risk

due

to

Thin

Walls壁薄引起的裂缝15Risk

due

to

Thin

Walls壁薄引起的裂缝16Risk

due

to

Small

Radii半径小引起的裂缝17Risk

due

to

Small

Radii半径小引起的裂缝18Heat

Treatment

of

Die

Casting

Dies压铸模具热处理1920Heat

Treatment

-

General

Remarks热处理基本要点Heat

treatment

requires

certain

time

and

temperature

regimes,

itcannot

be

accelerated!热处理需要一定的时间和温度,不能够无原则的加快速度.Stress

relieve

the

dies

after

rough

machining!粗加工后需要应力

.Quench

as

fast

as

necessary

and

as

mild

as

possible!淬火尽可能要快,尽可能要柔和.Check

thermocouples

of

furnace

regularly!定期测量温度变化.Temper

immedia y

after

quenching

(min.

2x)!淬火后要立即回火.(至少两次)Do

not

reharden

the

tools

without

annealing

the

tools!重新淬火前必须进行退火.21Total

furnace

weight:ca.40

t

设备重量40Tpiece

weight:>250kg

bis

2500kg

单件重量250KG到2500KGCharge

Size:

1000x1000x500

mm

尺寸1000x1000x500mmRange

of

hardening

temperature:

860

-

1030

°C淬火温度范围860-1030

°CTemperature

uniformity:

+/-

5°C

from

200温度浮动范围:从200起+/-5°CProgrammer:

DEMIG

DEVR

+Prosys2

Process

leading

system控制系统Furnace

Technology

at

Kind

&

CoKIND

&

CO公司热处理技术22Technical

Data

of

Vacuum

Furnace真空炉技术参数Convective

heating

对流传热for

a

better

temperature

uniformity

during

heating为了保证加热过程中温度的平缓Quenching

pressure

up

to

13bar

abs.

nitrogen淬火压力高达13Bar时氮气冷却high

cooling

capacity

(with

separate

water

re-coolingsystem)

guarantees

a

great

quenching

potential.高冷却容量保证淬火能力(通过拥有独立的水重冷却系统)Cooling

Fan

冷却风扇Power

consumption

460

KW

or

625

HP

电耗量

460

KW

或

625HPSome

Typical

Charges典型的尺寸23Production

Charges生产尺寸24Procedure程序A

charge

with

2200

kg

Charge

weight

is

runningappr.

16

h

before

cooling

starts.2200公斤重的材料在冷却开始前需要运行约6小时.The

following shows

the

structuretransformation

of

steel

in

time-lapse

photography以下的

演示了材料结构的变化25Electro-Discharge-Machining

(EDM)

General

Remarks电火花加工主要要点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电火花加工主要要点退火材料的电火花加工:常规机加工初步电火花加工,应力不要太大,避免产生电弧,过度损耗材料通过最终放火完成电火花加工(低电流,高频率)研磨或抛光电火花层表面,以减少热处理和机加工过程中出现裂缝变形的淬火材料的电火花加工:常规机加工淬火,回火初步电火花加工,应力不要太大,避免产生电弧,过度损耗材料通过最终放火完成电火花加工(低电流,高频率)研磨或抛光电火花层表面,以减少热处理和机加工过程中出现裂缝变形的再次回火,温度为最后一次回火温度减去15度27Electro-Discharge-Machining

(EDM)电火花加工RoughRa

7,5µm28FineRa

6,3

µmFineRa

4,0

µmFine

FineRa

3,0

µm Ra

2,0

µmFinishElectro-Discharge-Machining

(EDM)电火花加工Increasing

intensityof

the

EDM

process提高电火花的强度29Thermal

Fatigue

Test

热疲劳试验Test

temperature

600

°C

/

water 2000

Cycles试验温度为

600

°C

/

水

2000

次冷热变化V

=

10

:130Not

eroded

erodedElectro-Discharge-Machining

(EDM)电火花加工Element元元Atomic

radiusin

nm原原原原Atomic

weight原原原原Fe

铁Iron0,12855,85C

碳Carbon0,08612,001N

氮Nitrogen0,07414,00731Nitriding

of

Hot-work

Tool

Steels热作模具钢氮化处理Crystalline

Structure

of

Iron铁原子的晶体结构Iron-Atoms32Atoms

on

interstitial

lattice

sites

in

ironα-Ironγ-IronNitriding

Process氮氮过氮Nitriding

Agent氮氮剂Process

Temperature(°C)Process

Time(h)

时时Salt

bath

nitriding盐溶溶溶cyanide-containingsalt

melt

溶化5700,2

-

4,0Gas

nitriding气溶ammonia

gas

氨气500

-

54010

-

100Plasma

nitriding等等等溶溶Nitrogen-hydrogen-mixture

溶氮氮氮化400

-

6000,2

-

30Nitriding

Processes氮化过程3334Nitriding

-

N-Profile

in

an

Iron

Alloy铁合金元素氮化曲线135791

11

3'NinterstitiellMNyDistance

from

the

surface与表面的距离Nitrogen

concentration

液氮渗入000000050

HVKernhärteGrenzhärte

=

Kernhärte

+

50HVNitrierhärtetiefe

NhtNitriding

-

Hardness

Profile

Nitrided

Steel氮化材料硬度曲线Core

hardness

核芯硬度Distance

from

the

surface与表面的距离Hardness

in

HV

0,5Nitriding

depth

氮化深度Hardness

limit

=

Core

hardness

+

50

HV硬度范围内=模芯硬度+50

HV3550

µmgasnitrided

500

°C,15

h气氮500°C,15

小时36Nitrided

surface此氮化表面Precipitations

on

grain

boundaries边界沉淀20

µmNitriding

-Hot-work

Tool

Steel

Dominial

USN

(1.2343,

H11)热作钢

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氮化时间的影响Nitriding

duration:氮化时间Distance

from

the

surfaceHärte

in

HV0,5Hardness

in

HV

0,5Compound

layer复合层Diffusing

element扩散元素Outer

contour

after

nitriding氮化后外部形状Original

contour

原始形状Diffusiong

element

扩散元素Dimensional

change

due

toincreased

volume

afterdiffusion扩散后容量增加引起尺寸变化38Nitriding

-

Dimensional

Change氮化

-

尺寸变化Nitriding

of

Diecasting

Dies压铸模具氮化Nitrocarburization

540°C

3h

碳氮共渗

540°C

3

小时

Surface

hardness:

1260

HV

0,3

表面硬度Compound

layer:

~

6

µm

复合层Diffusion

layer:0,11-0,12mm

扩散层39Nitriding

of

Diecasting

Die压铸模具氮化Nitriding

„Programm

99“Surface

hardness: ~

1000

HV0,3Compound

layer:

0

µmDiffusion

layer:

0,11

mm40Pre-Heating

and

Cooling

of

Die

Casting

Dies压铸模具的预热和冷却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压铸模具的预热和冷却预热:预热是必要的,可以避免温度突变预热必须均匀.有 的模具预热要慢,保证和模架的温度和膨胀一致.铝,镁合金材料的预热温度建议为:200-300°C.冷却:用水,

油预热冷却剂至50°C,

减小热突变引起的裂缝分险低于20°C

的冷却液不

使用.如果生产中断,冷却液要重新进行预热.尽量减少外部冷却.4243Stress

relieving

of

Die

Casting

Dies压铸模具的应力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压铸模具的应力压铸模具应力退火的必要性是无法用是或否来回答的.操作状态.连续操作,没有任何间断是提供模具最长它取决于模具制造过程中的的最佳前提.一旦

发现侵蚀,建议在第一次压铸前进行应力退火.若在制造过程中没有发现侵蚀,建议在抽样检查后进行应力退火.进一步的应力退火可在大约5000次压铸后,和10.000-20.000次压铸后进行.一旦 出现裂缝扩张趋势,

就没有必要进行应力退火,

因为 已通过裂缝

了应力.每次焊接过程后必须进行应力退火.建议以下操作温度:540

– 560°C

(1004

–

1040°F)在这个温度范围内熔炉必须具备惰性气体.在此温度中熔炼大约6小时,炉内冷却至少至300°C.这之后才能在空气中继续冷却.44Welding

of

Die

Casting

Dies

-

I压铸模具焊接指南

-

I对于腐蚀层也同如果

已经过氮化处理,

氮化表面必须在焊接前去除.样处理,

特别是石墨电极侵蚀, 也就是表面渗氮.预热

预热是焊接过程中的一个重点.

预热温度必须在350

–450°C(662

–

842°F)

之间.

在焊接面上

必须用保护膜或铝膜覆盖.

这不仅能防止焊接过程中的过热辐射,

还能起到保温作用.

当

冷却到250°C(482°F)

时必须进行再加热.

同时必须注意温度控制.焊接焊条的选择,最佳的电极等取决于焊条的供货商,(同一位置,焊点小).45Welding

of

Die

Casting

Dies

-

II压铸模具焊接指南

-

II焊接:焊条可选用与模具同等的材料(如W.-No.1.2343/1.2344);另外马氏体时效处理焊条W.-No.1.2709

也适用.这种等级的材料能吸收焊接过程中产生的应力.焊接后焊接区域的硬度如下:焊接后46W.-No.

1.2709W.-No.

1.2344W.-No.

1.2567approx.

40

HRC52

–

55HRCapprox.

45

HRC在480°C(896°F)下应力退火后W.-No.

1.2709W.-No.

1.2344W.-No.

1.2567approx.

55

HRC52

–

55HRC48

–

52HRC在540–560°C(1004–1040°F)温度下惰性气体回火后W.-No.

1.2709W.-No.

1.2344W.-No.

1.2567approx.

48

HRC50

–

52HRC45

–

50HRCWelding

of

Die

Casting

Dies

-

III压铸模具焊接指南

-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压铸模具焊接指南

-III建议使用以下等级的材料(譬如如果焊接超过3层,必须进行缓冲焊接,对于缓冲焊接,CAPILLA

64

KBs

)C0,10

2,40o

%2,40

强度可达将近1250N/mm².奥氏体焊条在许多场合也被普遍使用.(因为奥氏体材质无磁性,可以通过磁铁检查).这个等级的材质强度只能达到600–800

N/mm².在压铸过程中会由于热疲劳性差过早在焊接区域出现裂缝..奥氏体材料不适合作为缓冲焊条,因为它的热膨胀系数分别为W.-Nr.1.2343,1.2344

or

1.2367

的两倍.48Welding

of

Die

Casting

Dies

-

IV压铸模具焊接指南

-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压铸模具焊接指南

-IV焊接过程后的热处理是对于经过焊接的模具的性能有相当重要的影响.焊接后模具应在空气中冷却至80–100°C(176–212°F).一旦经过硬化和回火的模具冷却到80–100°C(176-212°F),必须在低于最后回火温度状态下再次进行回火至大约.30-50°C(最好30°C).回火时间大约为6小时.对于热作模具钢,如W.-

Nr.1.2343,1.2344

and

1.2367,如果焊接温度超过500°C,必须在惰性气体炉中进行热处理.如果没有惰性气体炉,模具必须在480–500°C(896–923°F)状态下进行应力退火.持续时间为6–8

小时.焊接区域和过渡区域将保持它们的硬度.50Welding

of

Die

Casting

Dies

-

V压铸模具焊接指南

-

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