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Plastic Mould Steels:>

Fletcher Easysteel Page 54



Increasing demands with regard to the tools in plastic moulding ask for the specific development of tool steels having certain service properties for different ranges of application. Tools for the processing of plastics are mainly stressed with regard to pressure and wear. According to the type of plastics, there may in addition exist a stressing by corrosion. The various types of plastics and different processing methods set requirements on the tool steel, as for instance:• Economic machinability or cold-hobbing ability• Smallest change in size upon heat treatment• Good polishability• Great compressive strength• High wear resistance• Sufficient corrosion-resisting quality The selection of a steel for a given tool is governed by these requirements. The current tool steels for plastic moulding are indicated in the list below. These steels meet nearly all requirements.

Steel Selection: Case hardening steels: Apart from a proper design and a heat treatment adapted to the respective steel grade the selection of a suitable steel is decisive for the efficiency of a tool. The case hardening steels offer excellent polishability and machinability. Therefore injection moulds as well as compression moulds are chiefly made from polishable case-hardening steels possessing high wear-resistance in the carburized case combined with good toughness in the core.

DIN Spec Aust. Stand. AISI/SAE Chemical Composition (Typical Analysis in %)

Case-hardening steels C Si Mn S Cr Mo Ni V Co Ti Al

1.2764 P 100 A ~ P 2 0.18 0.2 0.4 - 1.2 0.2 4.0 - - - -

Heat-treated steels

1.2311 P 20 A P 20 0.40 - 1.5 - 1.9 0.2 - - - - -

1.2312 P 20 A + S P 20 + S 0.40 - 1.5 0.05 1.9 0.2 - - - - -

1.2738 0.40 - 1.5 0.05 1.9 1.2 - - - - -

Corrosion-resistant steels

1.2083 420 420 0.42 - - - 13.0 - - - - - -

Through-hardening steels

1.2344 EFS H 13 A H 13 0.40 1.0 - - 5.3 1.4 - 1.0 - - -

1.2379 D 2 A D 2 1.55 - - - 12.0 0.7 - 1.0 - - -

1.2767 P 6 A - 0.45 - - - 1.4 0.3 4.0 - - - -

1.2510 01 01 0.95 - 1.1 - 0.6 - - - - - -

Nitriding steels

1.8550 - - 0.35 - - - 1.7 0.2 1.0 - - - 1.0

Maraging steels

1.2709 - 18 MAR 300

<0.03 - - - - 5.0 18.0 - 10.0 1.0 -



Heat-treated steels:Even with large sizes, sufficient core hardness can still be achieved. With the plastic parts becoming larger and larger, the use of case-hardening steels makes the heat treatment of the moulds a difficult problem because of the dimensional changes involved. Moreover, the number of articles to be made being frequently small, the production capacity of such moulds is not fully utilized. Hence, one proceeded to cut the impression into a previously heat-treated block by a machining operation. Even smaller sized moulds are now made by this method. A working strength of about 1100 N/mm2 has been found to give the best results. As heat-treated steels and grades 2311, 2312 and 2711 have been developed. 2311 and 2711 are preferably used in cases of high demand for polishability and for moulds with textured surfaces. 2312 is produced with increased S-content thus offering an excellent machinability combined with good polishability.

clamping plate

cavity platelead pinpressure padblankcavity plateejector pinejector plateejector base plateclamping plate

centering flangesprue bushingclamping plate

cavity plate

lead pinfinish-moulded article

cavity plateejector pinejector plateejector base plate

clamping plate

Schematic plan of acompression mouldingtool for plastics

Schematic plan of aninjection moulding



Nitriding steels: Nitriding steels are successfully used for screws and cylinders, since they have a tough core and a hard wear-resistant surface. The aluminium-alloyed-nitriding steel 1.8850 presents a very high surface hardness.

Corrosion-resistant steels: 1.2083, a corrosion-resistant 13% chromium steel, is used for processing chemically active plastic materials.

Through-hardening steels: Through-hardening steels are distinguished by high hardenability and compressive strength. Moreover, they are characterized by a superior close tolerance upon heat treatment. Due to their high compressive strength they are best suited for plastic moulds being subjected to high compressive forces. A significant advantage for these steels is given by the possibility of carrying out greater machining operations after the heat treatment. Contrary to the case hardening steels in this case there is no risk of wearing out a carburized surface zone resulting in a new heat treatment. The tool steel 1.2767 offers high toughness and is used for adequately stressed moulds. Moreover this steel offers a good polishability, ability for photo etching and eroding. Especially during heat treatment in vacuum furnaces it is distinguished by lowest size changes. 1.2344 EFS is especially suitable for moulds and screws as it can be nitrided and still have a high core strength after nitriding. Due to its high hot tensile strength also moulds and screws being subjected to a higher thermal load are successfully manufactured from this steel. The grades 1.2379 and 1.2842 listed among the group of through-hardening steels are predominantly used for pressure pads and smaller-sized plastic moulds when processing duroplastics of an abrasive nature.

2767 EFS Supra: Where there is an extremely high requirement of polishability, ability for photo-etching and eroding, remelted tool steel is recommended. Therefore, the grade. 1.2767 EFS SUPRA has been developed for mirror-polished plastic moulds, for finest photo design and for texture-eroded surfaces. The dimensional stability during heat treatment was further improved compared with the standard grade.

Recommended Steel for Compression and Injection Moulds

Material Working strength or hardness (approx. values)

1.2162 surface hardness 60 HRC, core strength 1100 N/mm2

1.2311 1000 N/mm2

1.2312 1100 N/mm2

1.2083 56 HRC

1.2767 52 HRC

1.2344 EFS 50 HRC

1.2379 60 HRC

1.2842 60 HRC

1.2709 56 HRC (precipitation hardened)


Fletcher Easysteel 8

Recommended Steels for accessories

Tool Material Working strength or hardness (approx. values) Remarks

screw 1.8550 1000 N/mm2 nitrided

1.2344 EFS 1300 N/mm2 nitrided

1.2379 58 HRC

cylinder 1.2344 EFS 1000 N/mm2 nitrided

1300 N/mm2 nitrided

spruce bushing 1.2379 60 HRC

1.2842 60 HRC

centering flange, ejector plateclamping plate, mould frame

1.2312 1200 N/mm2

pressure pad 1.2379 60 HRC

1.2842 60 HRC

ejector pin 1.2344 EFS 1450 N/mm2 nitrided

lead pin 1.2842 60 HRC



PDS5Product Shortname: MLDF

Chemical Composition: PDS 5 Patent Pending

Colour Code: Red/Blue

Applications: General Purpose Plastic Mould Steel with excellent machinability

Selection of Plastic Mould Steels:

Rating for

DIADO BRAND

Usua

l Wor

king

Ha

rdne

ss

Mac

hina

bilit

y

Mirr

or S

urfa

ce

Phot

o-et

chin

g

Wel

dabi

lity

Wea

r Res

ista

nce

Toug

hnes

s

Stre

nght

Thermo Plastics General Life Long Uses

PDS 5 HRC 33 A B A A B B B

Hardenability:

Mechanical Properties:

PDS5 Hardness HRC Yield Strength kgf/mm2

Tensile Strength kgf/mm2

Reduction of Area % Elongation %

33.0 90 102 48 21


Plastic Mould Steels:>AISI P20 (DIN 1.2311)

Product Shortname: MOLD, MLDF

AISI P20 Supplied Heat Treated 950-1100MPa

DIN-Material Number: 1.2311

Specifications: 40 CrMnMo 7. AISI: P20.

Typical Analysis: C Mn Cr Mo 0.4% 1.5% 1.9% 0.2% Colour Code: Red

Steel Properties: Quenched and tempered plastic mould steel. Hardness in condition as supplied 280-325 HB. Good machinability, better polishability compared with 1.2312. Capable for texturing.

Characteristics: 1.2311 is supplied in the heat treated condition to a tensile strength of 950-1100MPa and by further heat treatment a hardness level of approximately 50 HRC can be achieved. Improved wear resistance can be achieved by flame/induction hardening to give a surface hardness of up to 54 HRC or by nitriding, to give a surface hardness of approximately 60 HRC whilst maintaining the high, as supplied core strength of 950-1100MPa. This grade offers excellent polishability and good surface finish when subjected to electrical discharge machining (EDM) or texturing.

Applications: Plastic mould, zinc die-casting tooling. High tensile application – heavy duty shafts, gears, axles, crusher rolls, bolts, etc. Plastic moulds, mould frames for plastic moulds and pressure casting dies, sleeves of recipients.

Size Range:

Rounds MOLD - Metric (mm)

16 25 32 45 50 65 80 90 100 110 140 355 443

Flats - Metric (mm)

25 35 50 70 75 100 150 250

Note: We will be pleased to cross-cut your requirements. Other grades available ex stock. 1.2312 free machining grade of P 20 used where heavy milling operations etc. are to be used. 1.2738 P 20 with the added advantage of Nickel to give higher core strength through very thick sections.



Plastic Mould Steels:>AISI P20Physical Properties: Thermal Expansion

Thermal Conductivity

Hot Forming: Hot forming OC Cooling 1050-850 slow, e.g. in furnace

Heat Treatment: Soft annealing OC Cooling Hardness HB 710-740 furnace max. 235

Hardening Hardness after quenching from OC in HRC N/mm2

840-870 oil or 51 1730 hot bath 180-220OC

Tempering OC 100 200 300 400 500 600 700 HRC 51 50 48 46 42 36 28 N/mm2 1730 1670 1570 1480 1330 1140 920

10–6 x m 20-100 20-200 20-300 m x OC 11.1 12.9 13.4

20-400 20-500 20-600 20-700OC 13.8 14.2 14.6 14.9

J 20 350 700OC cm x s x OC 0.357 0.334 0.320

Time – Temperature – Transformation Diagram Tempering Diagram

1 10 102 103 104 105

1 10 100 1000 10 000

1200

1100

1000

900

800

700

600

500

400

300

200

100

0

SecondsTime

Tem

pera

ture

in O C

70

66

62

58

54

50

46

42

38

34

30 0 100 200 300 400 500 600 700 800 Tempering Temperature in OC

Hard

ness

in H

RC


Plastic Mould Steels:>AISI P20 (DIN 1.2738)

DIN-Material Number: 1.2738.

Specifications: 40 CrMnNiMo 8 6 4 AISI: P20 + Ni

Typical Analysis: C Mn S Cr Mo Ni Ca 0.40% 1.5% <0.005% 1.9% 0.2% 1.0% +

Colour Code: Red/Yellow

Steel Properties: Hardened and tempered plastic mould steel. Improved through-hardenability compared with 1.2311 due to the nickel content of 1.0 percent. Recommended for all plastic moulds of a thickness exceeding 400mm. Hardness in condition as-supplied 280 to 325 HB. 1.2738 is a micro-alloyed vacuum-degassed special steel combining excellent machinability due to the additional Ca-treatment, polishability and texturing properties.



10–6 x m 20-100 20-200 20-300 mK 11.1 12.9 13.4

20-400 20-500 20-600 20-700OC 13.8 14.2 14.6 14.9

W 20 350 700OC mK 34,5 33,5 32,0


AISI P20 Physical Properties: Thermal Expansion




Hardening in oil or Hardness or tensile strength after quenching from OC hot bath HRC N/mm2

840-870 180-220OC 51 1730 Tempering OC 100 200 300 400 500 600 700 HRC 51 50 48 46 42 36 28 N/mm2 1730 1670 1570 1480 1330 1140 920




AISI 420 (DIN 1.2083)Product Shortname: PQ, PQF

AISI 420 Supplied Annealed


Specifications: X 42 Cr 13. Corrosion-resistant, good polishability.

Typical Analysis: C Cr 0.42% 13.0%

Colour Code: Purple

Characteristics: 1.2083 is a vacuum arc degassed heat-treatable stainless steel ideally suited to those plastic mould applications requiring a high degree of corrosion and wear resistance.

Applications: Plastic moulding of corrosive vinyls and acetates, moulds used in humid conditions, cutlery, knife blades, needle valves, etc. Moulds for processing of corrosively acting plastics.

Size Range:

Rounds PQ - Metric (mm)

20 30 40 45.8 55.8 66 76 91.5 101.5 111.5

151.5 202 253

A selection of flats is also available ex stock. We will be pleased to cross-cut your requirements from stock sizes of Flats.

DIN 1.2316Product Shortname: PQF

Stainless mould steel, pre hardened

Typical Analysis: C Cr Mo 0.36% 16.0% 1.2%

Colour Code: Red/Purple

Characteristics: No further heat treatment required. Increased corrosion resistance in comparison with 2083, good polishability. Good machinability due to the additional calcium treatment.

*Available in a range of flats sizes ex stock, which we can cross cut to your requirements.



AISI 420Physical Properties: Thermal Expansion




Hardening in oil, air or Hardness after quenching from OC hot bath HRC 1020-1050 500-550OC 56 Tempering OC 100 200 300 400 500 600 HRC 56 55 52 51 52 40

10–6 x m 20-100 20-200 20-300 m x OC 10.5 11.0 11.0

20-400 20-500 20-600 20-700OC 11.5 – – –

J 20 350 700OC cm x s x OC 0.200 0.230 0.262

70

66

62

58

54

50

46

42

38

34

300 100 200 300 400 500 600 700 800 Tempering Temperature in OC

Hard

ness

in H

RC

Tempering Diagram




DIN 1.2767Product Shortname: MLDH, MHTF

Supplied Annealed


Specifications: X 45 NiCrMo 4. BS:EN30B

Typical Analysis: C Cr Mo Ni 0.45% 1.4% 0.3% 4.0%

Colour Code: Grey/Purple

Steel Properties: Steel for air- and oil-hardening, high hardenability, highest toughness. Good Polishability.

Characteristics: 1.2767 is supplied in the annealed condition but by further heat treatment can be hardened up to around 54 HRC. The chemical make-up of 1.2767 enables it to be ‘air’ hardened or vacuum hardened with minimum distortion. 1.2767 displays excellent polishability and toughness in the hardened condition making it suited to high pressure plastic moulding applications. It also possesses good thermal properties for plastic moulding applications.

Applications: Compression/injection moulds, cutlery dies, blanking dies, high tensile applications such as shafts, rollers, axles, etc. Cutlery dies, blanking dies for large sizes, billet shears, drawing jaws, massive embossing and bending tools, plastic moulds, reinforcements.

Size Range:

Rounds MLDH - Metric (mm)

16 25 30 40 45.8 50 65 75 100 111.5 131.5

Flats MLDF - Metric (mm)

20 25 40 50 60 80 110

Note: Can also be used for Cold Work and Shock Resisting applications. We will be pleased to cross-cut your requirements from stock sizes of Flats.

Also used as a Cold Work Steel 1.2767 can be heat treated to strengths in excess of 1500 MPa lending itself toapplications where extremely high stresses are involved.



DIN 1.2767Physical Properties: Thermal Expansion




Hardening in oil, air or Hardness after quenching from OC hot bath HRC 840-870 180-220OC 56 Tempering OC 100 200 300 400 500 600 HRC 56 54 50 46 42 38

10–6 x m 20-100 20-200 20-300 m x OC 11.8 12.5 12.8

20-400 20-500 20-600 20-700OC 13.1 13.4 13.8 13.6

J 20 350 700OC cm x s x OC 0.300 0.305 0.320

Time – Temperature – Transformation Diagram Tempering Diagram

1 10 102 103 104 105 106

1 10 100 1000 10 000

1000

900

800

700

600

500

400

300

200

100

0

SecondsTime

Tem

pera

ture

in O C

70

66

62

58

54

50

46

42

38

34

300 100 200 300 400 500 600 700 800

T

empe

ring

Tem

pera

ture

in O C

Hard

ness

in H

RC



Alumec 89/Alumec 79 Product Shortname: ATOL

Colour Code: Alumec 89 - Yellow, Alumec 79 - Blue

Steel Properties: Alumec 89 has higher strength and wear properties than Alumec 79 (see chart below).

Characteristics: Alumec is a high strength aluminium alloy having uniform through thickness properties. This high strength coupled with low density and enhanced machinability

makes Alumec ideally suited for many tooling applications. High metal removal rates are achieved by standard machining methods along with EDM and in addition, Alumec can be further surface hardened or plated.

Applications: Used in areas where high strength/weight ratios are required and where heavy machining is to be carried out, such as; injection moulding, blow moulding, rubber moulding, prototype tooling, jigs and fixtures, hydraulic manifold systems.

Size Range:

Stocked in 2000mm x 1000mm sheets/plates - Metric (mm)

12.7 16 20 25 40 50 75 100 150 200

Mechanical Properties:

Thickness Range (mm)

Tensile Strength (MPa)

0.2% Proof Stress (MPa)

Elongation (%)

HardnessBrinell Rockwell B

Alumec79 Alumec89 Alumec79 Alumec89 Alumec79 Alumec89 Alumec79 Alumec89 Alumec79 Alumec89

> 6.35 - 25 545 600 485 555 10 11.5 167 180 86 90

> 25 - 50 520 580 455 530 9.5 9.5 159 174 84 89

> 75 - 100 500 570 430 520 9 8 152 174 82 89

> 100-125 480 560 400 515 8.5 7 149 174 81 89

> 125 - 167 465 550 375 500 8 4.5 143 174 79 89

> 167 - 205 435 510 340 450 7.5 5 131 159 74 84

> 205 - 305 410 460 310 400 7.5 4 123 146 70 80

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