haldenwanger ceramics for kilnscomponents having higher thermal shock resistance allowing increased...

Ceramics for KilnsHALDENWANGER

HALDENWANGER

CONTENTS

2

SIGNIFICANCE of ceramics for kiln construction and furniture

SUMMARY of our ceramic materials

INSULATION COMPOUNDS

REFRACTORY CEMENTS

Physical PROPERTIES

CERAMIC TUBES Selection from our production programme

TOLERANCES according to DIN 40680

EXAMPLES OF APPLICATIONS for ceramic materials

CERAMIC ROLLERS

EXAMPLES OF APPLICATIONS for ceramic components

SIZES of muffles, open both ends

TECHNICAL CERAMICS

Optimised utilisation of energy: The short thermal cycle of the roller hearth kiln.

3

4-5

6-7

8

9

10

11

12-13

14-15

16-17

18

19

Tem

per

atur

e °C

roller hearth kiln chamber kiln

I N T R O D U C T I O N

M A T E R I A L S

D E S I G N I N G

A P P L I C A T I O N

S O L U T I O N S

Heat treatment is an important processstep in research and industry. Heattreatment is also linked to energyconsumption. Energy is an essentialand valuable commodity and willalways continue to appreciate in value.For this reason, and also to support theneed for reducing energy consump-tion, furnace design and constructionhas undergone fundamental changesin recent years and these changes willcontinue. Success in achieving thesechanges has been mainly attributedto the use of structural ceramiccomponents and optimised ceramicmaterials which have replacedtraditional metal parts.

HALDENWANGER is the producer of high temperature, fine ceramics.

HALDENWANGER fine ceramics offer:Components with reduced wallthickness and therefore lower heatabsorptionComponents having higher thermalshock resistance allowing increased heating ratesLight, but mechanically strong and thermally stable kiln furniture,which is suitable for fast firingThin, self-supporting designs

HALDENWANGER

SIGNIFICANCE of ceramics for kiln construction and furniture

3

I N T R O D U C T I O N

Intermittent Kiln

firing time/h

tunnel kiln

M A T E R I A L S

HALDENWANGER

SUMMARY of our ceramic materials

4

IMPERVIOUS MATERIALS

Alsint 99,7

Best, high temperature, ceramicmaterial for kiln construction with99,7% Al2O3 (the difference is mainlyMgO and SiO2).

Type C 799 according to DIN VDE 0335Refractoriness up to 1700 °CGood thermal shock resistance dueto high thermal conductivityHigh mechanical strengthHigh electrical resistivity

Recommended applications:

High working temperature, chemical attack, e.g. hydrogenand other reducing gasesClean kiln atmosphere Thin-walled designs having highthermal shock resistance

Pythagoras 1800 Z

Impervious, mullite high performancematerial

Refractoriness up to 1600 °CVery high thermal shock resistanceHigh mechanical strengthHigh electrical insulation even athigh temperaturesEvaporation extremely low, therefore no contamination of kiln atmosphere; no reactionwith heating elementMost suitable material for radiant heating tubesKiln tubes made ofPythagoras 1800 Z can be very thin-walled

Pythagoras

Most economical, mullite material forkiln components

Type 610 according to DIN VDE 0335Application temperatures up to1400 °CVery good chemical resistanceagainst gases free of fluorineFor kiln working under normalconditions Pythagoras has a goodthermal shock resistance and goodmechanical strength.Pythagoras is a very economicalmaterial being used as imperviousprotection sheaths and insulatorsfor temperature measurement.

Halsic-I

Silicon infiltrated reaction bondedsilicon carbide (SiSiC)

Reaction bonded SiC matrix, free ofpores, with residual metallic siliconHigh temperature ceramics forhighest mechanical loadsExtremely good oxidation resistanceLarge sized components possibleApplication temperatures up to1350 °CCorrosion resistant against strongacids and alkaline solutionsHigh thermal conductivity

Halsic-S

Pressureless sintered silicon carbide(SSiC)

Dense sintered SiC matrix with verylow percentage of closed poresHigh temperature ceramics forextreme mechanical loadsExtremely good oxidation resistanceApplication temperatures up to1600 °CCorrosion resistant against strongacids and alkaline solutions

POROUS MATERIALS

Alsint porous

High purity, porous 99,5% Al2O3

Better thermal shock resistancethan Alsint 99,7Refractoriness is similar toAlsint 99,7Similar chemical resistanceto Alsint 99,7Reducing gases, even pure hydrogen, do not attackAlsint porous.Alsint porous is mainly used for themanufacture of ignition dishes andcrucibles, but also for porous outerprotection tubes for thermocouples.Isostatic pressing is possible, sothat large tubes can also bemanufactured. Muffle tubes

SKA 100 NG

High purity, porous 99,5% Al2O3

Refractoriness up to 1700 °CHigh thermal shock resistanceGood chemical resistanceSKA 100 NG can be used inprotection furnaces with reducingor even hydrogen atmospheres.

SKA 100 NG as well as Alsint:

Does not react with the heatingelements, no contamination ofthe kiln atmosphere due toevaporation.Is most suitable for the porous,outer protection tube forthermocouples that mustwithstand very strong chemicalattacks.

M A T E R I A L S

HALDENWANGER 5

Sillimantin 60 NG

A specially developed material for usein kiln manufacture having an Al2O3

content between 73 – 75%.

Low porosityGood thermal shock resistanceNo reactions with the heating elementsWorking temperatures of up to1650 °CSpecial shapes possible forbridging long distancesbetween supportsExcellent chemical resistance.No contamination of the kilnatmosphere through evaporation.Suitable for kilns with a hightemperature gradientSillimantin 60 NG can be usedunder severe conditions as the outer protective tube intemperature monitoring devices.Rollers for roller kilns

Sillimantin 60

Most frequently used ceramic material in kiln designs

Type C530 according to DIN VDE 0335Application temperatures up to 1400 °CRefractoriness up to 1300 °C(subject to loading for rollerapplications)No reactions with heating elementsThis material can be formed usingmost moulding methods.Numerous special designs arepossible as well as a wide rangeof standard tubesThis material is used successfullyin laboratory and industrial kilns.

Sillimantin 65

A specially developed material for useas rollers having an Al2O3 contentbetween 78 – 80%

Refractoriness up to 1350 °C(subject to operational loading)Negligible reaction with glazesbecause of fine porosityRoller materials are detailedon page 14

Sillimantin KS

Most economical for support tubes

Refractoriness up to 1300 °CGood mechanical strengthLarge scale production with emphasis on the most commonlyused diameters permitting economical manufacture.A stock list of standard sizesis given on page 10.

SiC

Conventional, clay-bonded siliconcarbide

Excellent thermal conductivity allows the manufacture of thick-walled components having highmechanical strength.Furnace tubes with high thermalshock resistanceCan be used in oxidisingatmospheres up to 1400 °CHigh mechanical strength becauseof a large wall thicknessSighting tubes for opticaltemperature measurementOuter protection tubes fortemperature measurement up to 1200 °C in light and heavy metal smelts

Fused Silica

99,8% SiO2

Very low thermal expansionExcellent thermal shock resistanceCan be used continuously attemperatures up to 1000 °C

This material is used for:

Rollers in glass tempering furnacesCrucibles in high-frequency meltingRiser tubes for continuous castingCrucibles withstanding highthermal shock

Halsic-R

Recrystallised silicon carbide (RSiC)

Compact SiC matrix with open porosityClassic ceramic for hightemperature applicationsLarge sized components possibleReliable bonding of coatingsApplication temperatures: 1600 °C(oxidising) and approx. 2000 °C(under protective atmosphere)Resistant against strong acidsand alkaline solutions

Halsic-RX

Chemically doped recrystallisedsilicon carbide (RSiCdoped).

Compact SiC matrix with open porosityVery good oxidation resistanceMultiple increased life timecompared to Halsic-RIdeal material for porcelain fast firingLarge sized components possibleReliable bonding of coatingsApplication temperatures up to1650 °C (oxidising)

Insulation compounds are used forembedding or fixing electric heatingelements on ceramic parts. Anexception is the compound SKA 90(see right column).

Insulation compounds are used forfilling gaps and cracks as well as forkiln repair. Firing supports can also bemanufactured from these compounds.The compounds are prepared byadding water to the powder and set by heating. Final strength is achievedby heating to the required temperatureindicated in the table on page 7.

Shrinkage is minimal using thisprocess. HALDENWANGER insulationcompounds are free from electrolytesto ensure good electrical insulationeven at extremely high temperatures.

Preparation instructions anduse of insulation compounds

The powder is mixed thoroughly withwater which is free from electrolytes.For good processability the pasteshould not stick to the back of one’shand. After embedding, the insulationmaterial should be left for about 24 hours to dry at approx. 50 °C. Thematerial can then be shaped, filed or drilled.

Final strength of the insulation materialis achieved by heating it to the requiredtemperature. It is recommended tosurround the kiln tube with a layer ofinsulation during this heat treatment.

Heating for the first time should bedone with care. Initial blackening of the compounds 1000 and 1000 Fduring heating is due to carbonisationof the organic binder and will disappearafter soaking temperature is reached.

If too much powder is mixed, the remainder can be dried and usedagain. Contamination may, however,render the insulation compounds unusable.

Information about kiln design

The electric heating coils must beevenly spaced and checked by meansof a gauge prior to embedding.

For kilns heated with nickel-chrome elements, i.e. for temperaturesexceeding 1000 °C, grid voltage is notrecommended.

The heating coils will last longer if the voltage is 110 V or less. If possible,the insulation compound should be prepared using water free ofelectrolytes.

Because of its ion content, normal tapwater reduces the electrical resistivityof the insulation substances. Thisshould be taken into consideration iffurnaces for high temperatures areinvolved.

If the powders are mixed frequently,water totally free of electrolytes mustbe used.

Insulation Compound 150

Our compound 150 is used forembedding heating wires havingdiameters of approximately 1 – 3 mm.

Due to its composition the compoundcan be used up to a temperature of approx. 1350 °C. The settingtemperature is 1000 °C. Please refer to “Insulation Compounds” for morepreparation details.

Insulation Compounds 60 – 1000 F

For fixing heating wires having adiameter of 1 mm or more, werecommend the use of compound 60at temperatures not exceeding 1350 °Cand compound 1000 for temperaturesup to 1800 °C. Heating wires with adiameter of less than 1 mm should beembedded with compound 250 attemperatures up to 1350 °C and withcompound 1000 F for temperatures up to 1800 °C.

Insulation Compound SKA 90

This substance was tailored to withstand slag attack. It is used for crucible linings in which precious metals are melted. Without such liningscontamination of molten metals mayoccur. Besides excellent corrosion resistance this compound also has an extremely good thermal shock resistance.

HALDENWANGER

INSULATION COMPOUNDS

6

M A T E R I A L S

1

2

M A T E R I A L S

HALDENWANGER 7

Isolationsmix no.

60coarse

grain structure

150medium

grain structure

250fine

grain structure

1000coarse

grain structure

1000 Ffine

grain structure

SKA 90

Refractoriness

SK 38 = 1825 °C

SK 38 = 1825 °C

SK 38 = 1825 °C

SK 42 = 2000 °C

SK 42 = 2000 °C

SK 38 = 1825 °C

Settingtemperature

1000 °C

1000 °C

1000 °C

1300 °C

1300 °C

Guide analysis

Al2O3 90,50 %SiO2 9,00 %

Al2O3 90,50 %SiO2 9,00 %

Al2O3 90,50 %SiO2 9,00 %

Al2O3 99,70 %SiO2 0,01 %

Al2O3 99,70 %SiO2 0,01 %

Al2O3 95,00 %SiO2 4,75 %

Grain size distr.

µm %

> 355 4,80> 200 78,60> 100 92,70> 90 94,10< 90 5,90

> 355 7,30> 200 11,80> 100 49,40> 90 63,50< 90 36,50

> 355 6,50> 200 10,00> 100 15,00> 90 23,20< 90 76,80

> 355 37,50> 200 71,00> 100 87,60> 90 92,70< 90 7,30

> 355 0,25> 200 2,25> 100 36,55> 90 54,15< 90 45,85

> 355 40,10> 200 81,20> 100 93,40> 90 94,50< 90 5,50

Max. temperature

1350 °C

1350 °C

1350 °C

1800 °C

1800 °C

1750 °C

Seeger cone small

at 150 °C/h

heatingrate

Available Insulation Compounds

M A T E R I A L S

WH Refractory Cement 1500

Directions for useWH refractory cement is an inorganicadhesive which is resistant totemperatures of more than 1500 °C.The surfaces to be joined togethermust be carefully cleaned of dirt, grease and oil. Remove all traces of thechemicals used for cleaning (petrol,acetone, soap powder) before applyingthe WH refractory cement. The facesmust be completely dry.Depending on the consistency re-quired, the cement should be mixedhomogeneously using 2 – 4 parts powder to one part liquid.

Apply a layer on each of the surfaces to be stuck together. The cement setsby chemical reaction and should be used within approx. 1 hour. Goodmechanical strength of the refractorycement is obtained after about 24 to36 hours at room temperature. Dryingat higher temperatures will acceleratethe hardening process and improve the mechanical strength.The mechanical strength of the WHrefractory cement as a function ofdrying temperature was verified intests. Square-sectioned rods of Sillimantin60 were cemented together at definedfaces and heated to a temperature of approx. 1500 °C. The cementedareas of the two pieces were thenstressed at room temperature until fracture occurred. The relationbetween mechanical strength and firing temperature proved to be linear.


This cement is mainly used for joiningpieces operating at high temperaturesof at least 1700 °C.It is supplied as a single-componentsystem ready to use and after dryingfor approx. 24 hours at 100 °C thecement has a certain strength. Thestrength is reduced as the temperatureincreases up to approx. 800 °C. Above 800 °C the strength increasescontinuously and reaches its highestvalue at 1800 °C.Refractory cement 1800 should bekept closed at all times. A thin film ofhardened cement may have to beremoved before use.

WH Refractory Cement 1300/1800

This cement is also supplied ready foruse. It can be applied in the same fieldsas refractory cement 1800. However,its strength increases continuouslywith rising temperature. There is no reduction in strength up to 800 °C asdescribed for refractory cement 1800.It must be pointed out that this cementis hygroscopic. Furthermore, it canhave a corrosive effect on metals.Therefore, it is not suitable forembedding metal parts or heatingelements.


This cement is supplied as a single-component system. It must beprepared to a pulpy consistency by adding water and is then ready for application. The cement should be used within approx. 1 hour beforesetting starts. Compared to refractorycement 1500, this cement has the advantage of being suitable fortemperatures up to 1700 °C. Shrinkageduring firing is very low (approx. 2%).

Under certain conditions refractorycement 98 can be used as an electricalinsulator.

WH refractory compound WH 98.

HALDENWANGER

REFRACTORY CEMENTS

8

Important:Cements are not insulatingcompoundsCements are not suitable for fixing any kind of heating wireCements are not to be used in furnace construction.

M A T E R I A L S

HALDENWANGER

Physical

PROPERTIES

9

Unit

Alsi

nt 9

9,7

Pyth

agor

as 1

800

Z

Pyth

agor

as

Hals

ic-I

Hals

ic-S

Alsi

nt p

orou

s

Silli

man

tin 6

0 NG

Silli

man

tin 6

0

Silli

man

tin 6

5

Silli

man

tin K

S

SiC

(cla

y bo

nded

) 1)

Quar

zgut

Hals

ic-R

Hals

ic-R

X

Impervious Materials Porous Materials

Al2O3 content

Alkali content

SiC content

Si content (free)

Type acc. to DIN VDE 0335

Water absorption

Leakage rate at 20 °C

Density

Flexural strength 20 °C (3-point)

Flexural strength 1300 °C (3-point)

Young’s modulus

Hardness (Mohs scale)

Thermal expansion 20 - 700 °C

Thermal expansion 20 - 1000 °C

Thermal conductivity 20 - 100 °C

Max. working temperature 4)

Permissible continuous temperature for protection sheaths acc. to DIN 43724Permissible continuous temperature for insulating rodssheaths acc. to DIN 43724

Dielectric strength acc. to IEC 672-2

Volume resistivity at D.C. 20°C

Thermal shock resistance

Pore size (average)

Specific heat capacity 20 - 100 °C

%

%

%

%

–

%

hPa · dm3 · s-1

g · cm-3

MPa

MPa

GPa

–

10-6 · K-1

10-6 · K-1

W · m-1

· K-1

°C

°C

°C

kV · mm-1

Ω · cm

–

µm

J kg-1

· K-1

99,7

–

–

–

799

≤ 0,2

10-10

3,75-3,94

300

–

300-380

9

7,8

8,6

25

1700

1600

1800

26

1014

good

–

900

76

0,5

–

–

–

≤ 0,2

–

3,0

150

–

150

8

5,6

6,0

6

1600

–

–

26

1013

good

–

900

60

3,0

–

–

610

≤ 0,2

10-10

2,6

120

–

100

8

5,4

6,0

2

1400

1500

1500

26

1013

good

–

900

–

–

88-92

8-12

–

≤ 0,1

–

3,1

240-280 2)

250-300

370

–

3,7

4,3

100

1350 5)

–

–

–

–

very good

–

900

–

–

≥ 99

≤ 0,1

–

≤ 0,1

–

3,1

350-400 2)

370-420 2)

420

–

4,5

5,0

124

1600 5)

–

–

–

–

verygood

–

1000

99,5

–

–

–

–

2-7

–

< 3,6

70-110 2)

–

–

–

7,8

8,6

–

1700

–

–

–

–

good

1-3

–

72-74

≤ 1

–

–

–

6

–

2,65

60

–

85

–

5,2

5,7

–

1650

–

–

–

–

good

8,5

900

72-74

≤ 1

–

–

530

9

–

2,35

45

–

60

–

5,3

5,7

1,4

1350

1600

–

–

–

very good

2

800

78-80

≤ 1

–

–

–

11

–

2,45

55

–

75

–

5,3

6,3

1,4

1400

–

–

–

–

very good

1,5

900

70

≤ 1

–

–

–

9

–

2,35

45

–

60

–

5,3

5,7

1,4

1350

–

–

–

–

very good

2

–

–

–

70-90

–

–

8-13

–

2,2-2,5

30

–

–

–

5

5

–

1300

–

–

–

–

very good

3

–

–

–

–

–

4-6

–

1,92-2,00

30-40

45-60 3)

30-40

–

–

0,5-0,9

–

1000

–

–

–

–

very good

≤ 0,2

–

–

–

> 99

≤ 0,1

–

5

–

2,7

80-100 2)

90-110

280

–

3,9

4,5

35

1600 5)

2000 6)

–

–

–

–

very good

24

–

–

–

> 99

≤ 0,1

–

5

–

2,7

80-100 2)

90-110

280

–

3,9

4,5

35

1650 5)

2000 6)

–

–

–

–

very good

24

–

The physical properties stated above result from test pieces. These values can only be used as a reference to other forms and dimensions depending on manufacturing process, geometry, surface finish and machining. In practice, e.g. Alsint 99,7 components have a flexural strength of between 160 and 340 MPa. 1) properties for general information only due to different qualities,2) 4-point bending strength, 3) at 700°C, 4) depending on load, 5) in oxidising atmosphere, 6) in inert atmosphere.

D E S I G N I N G

HALDENWANGER10

Po

rous

Mat

eria

ls

Alsint 99,7

Type C799 (DIN VDE 0335)Al2O3 content 99,7%

Pythagoras

Type C610 (DIN VDE 0335)Al2O3 content approx. 60%

Alkali content 3%

Pythagoras 1800 Z

Al2O3 content approx. 76%

Alkali content 0,33%

CERAMIC TUBESSelection of our production programme

0,8 x 0,31,3 x 0,71,6 x 1,01,8 x 1,22,0 x 1,02,7 x 1,73,0 x 2,04,0 x 2,05,0 x 3,06,0 x 4,08,0 x 5,09,0 x 6,09,6 x 6,4

10,0 x 6,012,0 x 8,012,7 x 8,914,0 x 10,015,0 x 10,017,0 x 12,017,5 x 11,120,0 x 15,024,0 x 18,0

26 x 2028 x 2230 x 2335 x 2738 x 3042 x 3446 x 3850 x 4055 x 4560 x 5065 x 5670 x 6072 x 6275 x 6580 x 7085 x 7590 x 8095 x 85

100 x 85105 x 90110 x 95115 x 100

120 x 100120 x 105130 x 110140 x 120140 x 125150 x 130155 x 135160 x 140170 x 150175 x 155180 x 160185 x 165190 x 170200 x 175220 x 200240 x 220260 x 240270 x 250300 x 280320 x 300420 x 380450 x 430

Outer x inner Ø mm

0,8 x 0,31,3 x 0,71,6 x 1,01,8 x 1,22,0 x 1,02,7 x 1,73,0 x 2,04,0 x 2,05,0 x 3,06,0 x 4,08,0 x 5,09,0 x 6,09,6 x 6,4

10,0 x 6,012,0 x 8,012,7 x 8,914,0 x 10,015,0 x 10,015,0 x 11,017,0 x 12,017,0 x 13,017,5 x 11,1


80 x 7085 x 7590 x 7590 x 8095 x 85

100 x 85105 x 90110 x 95115 x 100120 x 100125 x 105130 x 110140 x 120140 x 125150 x 130160 x 140170 x 150180 x 160190 x 170200 x 180240 x 220300 x 280

Outer x inner Ø mm

48 x 4053 x 4360 x 5263 x 5370 x 6073 x 6375 x 6580 x 7082 x 7285 x 7486 x 7687 x 7788 x 7893 x 8395 x 85

100 x 90105 x 90115 x 105120 x 110

Outer x inner Ø mm

Sillimantin 60 NG

medium fine structureAl2O3 content

approx. 73–75%

20 x 1522 x 1724 x 1926 x 1828 x 2230 x 2335 x 2740 x 3250 x 4060 x 5070 x 6080 x 7090 x 75

100 x 85110 x 95120 x 100130 x 110140 x 120160 x 140200 x 175250 x 230330 x 310

20 x 1522 x 1724 x 1926 x 1828 x 2230 x 2335 x 2740 x 3250 x 4060 x 5070 x 6080 x 7090 x 75

100 x 85110 x 95120 x 100130 x 110140 x 120160 x 140200 x 175250 x 230330 x 310

15 x 720 x 1220 x 1525 x 1525 x 1830 x 2035 x 2540 x 3045 x 3550 x 4055 x 4560 x 48

26 x 1828 x 2230 x 2335 x 2640 x 3250 x 4055 x 4560 x 4965 x 5470 x 5875 x 6280 x 6685 x 7190 x 7495 x 79

100 x 84105 x 89110 x 94115 x 99120 x 104125 x 109130 x 114


20253035404550556065707580859095100

We can grindintermediate sizes asper your requirement.

Outer x inner Ø mm

Sillimantin 60

Type 530 (DIN VDE 0335)medium fine structure

Al2O3 content approx. 73–75%

Outer x inner Ø mm

Sillimantin KS

medium fine structureAl2O3 content approx. 70%

Outer x inner Ø mm

SKA 100 NG

medium fine structureAl2O3 content approx. 99,5%

Outer x inner Ø mm

Siliciumcarbid

fine and coarse structureSiC content

70%

Outer x inner Ø mm

Quarzgut

especially for flatglass tempering

Ø mm

max. length on inquiry, max. diameter on inquiry

Imp

ervi

ous

Mat

eria

ls

fa

l

fa

l

D E S I G N I N G

HALDENWANGER 11

TOLERANCESaccording to DIN 40680

Accuracy

DIN VDE 0335, Type

Manufacturing method:

Cast

Turned

Non metered pressed

Metered semi wet pressed

Metered dry pressed

Machined in the green state

Extruded:Ø 30 mm and above

Extruded:up to Ø 30 mm

± 0,15± 0,20± 0,25± 0,30± 0,35± 0,40± 0,45± 0,50± 0,55± 0,60± 0,65± 0,70± 0,80± 0,90± 1,00± 1,20± 1,40± 1,60± 1,80± 2,00± 2,20± 2,50± 2,80± 3,00± 3,40± 3,80± 4,20± 4,60± 5,00± 5,50± 6,10± 6,80± 7,60± 8,30± 9,00± 9,50± 10,00± 0,01 · d

± 0,4± 0,6± 0,7± 0,8± 1,0± 1,2± 1,2± 1,5± 1,5± 2,0± 2,0± 2,0± 2,5± 2,5± 2,5± 3,0± 3,5± 4,0± 4,5± 5,0± 5,5± 6,0± 6,5± 7,0± 7,5± 8,0± 9,0± 10,0± 11,0± 12,0± 13,0± 14,0± 15,0± 16,0± 17,5± 19,0± 20,0± 0,02 · d

468

101316202530354045505560708090

100110125140155170185200250300350400450500600700800900

1000

above above above above above above above above above above above above above above above above above above above above above above above above above above

30405060708090

100110125140155170185200250300350400450500600700800900

1000

medium530/610 799

0,150,200,250,300,350,400,450,500,550,650,700,800,850,901,001,251,501,752,002,252,503,003,504,004,505,000,5% · I

1,71,81,92,02,12,12,22,32,42,52,62,72,93,03,13,53,94,34,75,15,56,37,17,98,79,51,5

We request your inquiry for closer tolerances.

Manufacturing method

Cast, turned, extruded for parts Ø 30 mm and above

Extruded for parts up to Ø 30 mm, non metered pressed, metered semi wet pressed metered dry pressed, machined in the green state

Degree of accuracycoarse medium

Deflection of a cylindrical body

applicationcustomary

applicationcustomary

coarse

• ••

The values determined for the degree of accuracy "coarse" do not apply forfirst manufacture. Special agreements apply here.• Customary manufacturing method

above above above above above above above above above above above above above above above above above above above above above above above above above above above above above above above above above above above above above

up to4 up to6 up to8 up to

10 up to13 up to16 up to20 up to25 up to30 up to35 up to40 up to45 up to50 up to55 up to60 up to70 up to80 up to90 up to

100 up to110 up to125 up to140 up to155 up to170 up to185 up to200 up to250 up to300 up to350 up to400 up to450 up to500 up to600 up to700 up to800 up to900 up to

1000

up to30 up to40 up to50 up to60 up to70 up to80 up to90 up to

100 up to110 up to125 up to140 up to155 up to170 up to185 up to200 up to250 up to300 up to350 up to400 up to450 up to500 up to600 up to700 up to800 up to900 up to

1000

mediumPermissible

deviation in mm

coarsePermissible

deviation in mm

mediumPermissible

deviation in mm

Degree ofaccuracy

Degree ofaccuracyNominal dimensional

range for length

coarsePermissible

deviation in mm

530/610 799

•

•

••

•

•• •

+ 0,8% · I

Deflection of a noncylindrical body

Nominal dimensionalrange for diameter

or length in mm

Diameter tolerances – deflectional tolerances without grinding to DIN 40680, issue 1983


HALDENWANGER

EXAMPLES OF APPLICATIONfor ceramic materials

12


HALDENWANGER 13

Roller hearth kilns for fast firing of walland floor tiles have been used fornearly 25 years. In this type of kiln theproducts to be fired are transportedthrough the kiln by means of rotatingceramic rollers. Since the beginningHALDENWANGER has supplied thevarious manufacturers and users ofkilns with oxide and non-oxide ceramicrollers. In the past, the diameter ofrollers was up to 55 mm with a lengthof approx. 2000 mm. Because ofincreased capacity demands, the walland floor tile industry asked for moreefficient kilns. That is the reason whykilns became wider and therefore therollers became longer. Today there areroller diameters of 30, 33.7, 40, 42, 45and 50 mm for maximum roller lengthof approx. 3700 mm. This correspondsto a useable kiln width of approx.2500 mm.

Roller tolerances have also becomemuch tighter. Today, diameter tole-rances of +/- 0,2 to +/- 0,3 mm are typical and roller bending is as small as 1,0 to 1,5 mm which corresponds to a TIR of 2-3 mm. Additionally, theoverall length taper specification of no more than 1mm is today a standardrequirement.

Production capacity allows us to pro-duce nearly all standard dimensions.The rollers must have good refractoryproperties to guarantee a perfectoperation for a given temperature andload. Furthermore, there is the need to

HALDENWANGER

CERAMIC ROLLERS

14


Worldwide, HALDENWANGER isthe only manufacturer of rollers forkilns and furnaces able to supplythe complete programme of rollermaterials. With our know-how ofproducing different mullite and SiC-based materials we offer custom-made solutions.

change rollers during kiln operation. Insuch cases, the high thermal gradientswhich rollers have to withstand meansthat a material must be selected havingsufficient thermal shock resistance.

Oxide ceramic rollers, these are ourmaterials Sillimantin 60, Sillimantin 65,Sillimantin 60 NG, are used in rollerhearth kilns for firing wall and floortiles. Non-oxide ceramic rollers,these are our materials Halsic-R(RSiC) and Halsic-I (SiSiC), areused in roller hearth kilns for firing sanitary ware andporcelain. These materialsare used because of thebetter creep resistancecompared to the oxideceramic rollers.

Before installing the rollers in the kiln they must be completely dry. This is very important if the rollers arechanged during operation. Drying isusually done by storing the rollers on or above the furnaces (utilisation of waste heat).

Heat losses in the kiln arise from theopen ends of the roller. By usingceramic fibre plugs the rollers aresealed at both ends. The plugs usuallyhave a maximum length of 100 mm to 200 mm.

The oxide ceramic rollers mustcontinue to rotate whilst they areheated up or cooled down. This is veryimportant, for example, if a roller hearthkiln is to be shut down for maintenanceor technical reasons.

Stationary oxide ceramic rollers, even for a short time, results in rollerbending. The drive to the rollers shouldnever be switched off even at kilntemperatures of 500 °C to 600 °C, asfrequently occurs. Stationary rollerssubjected to the above-mentionedtemperature will be damaged! When

the kiln is re-started, considerablebreakage is to be expected. The rollersmust also be kept rotating even overshort breakdown periods.

HALDENWANGER ceramic rollers areused for the firing of:

wall and floor tiles up to 1300 °C

tableware porcelain up to 1420 °C

sanitary porcelain up to 1300 °C

ferrites up to 1300 °C on supporting setters

heat treatments of metals up to 1200 °C.

Ceramic Supporting Rollers forGlass Tempering Furnaces

In glass tempering furnaces the glass is transported on rollers through thefurnace. Product is run directly on therollers, i.e. without supports.

The tempering time can be regulatedvia the rotational speed of the rollers

as well as by applying different heatingsystems.

All large sized glass plates are subjectto this secondary thermal treatmentbecause of new regulations. (singlepane safety glass)

The aim of this process is to cause pre-stressing the glass through heat,so that there are no sharp splinters ifthe glass breaks. Like safety glass, the pane must break into many harmlessparticles.

Because of the sensitivity of the glasssurface, the ceramic rollers used mustbe very smooth and free of the smallestundulation. The bending and theconcentricity are very importantfactors, too.

Furthermore, the ceramic materialmust have good thermal shockresistance properties in order towithstand changes of temperatureoccurring in the process.

The material used for these rollers isour Fused Silica. In use today are solidas well as hollow fused silica rollerswhich can be supplied with mountedmetal end caps.

HALDENWANGER 15



HALDENWANGER

EXAMPLES OF APPLICATIONSfor ceramic components

16

By means of selected examples youwill recognize how we are handling and solving problems. It is shown, how we co-operate with our customers to achieve optimal results. The follow-ing pages explain the practical applic-ations of our ceramics in furnace construction.

Annealing Boxes + Melting Crucibles

Annealing boxes and melting cruciblesmade from ceramic material arerequired in almost every industrialsector. The type of HALDENWANGERmaterial used depends on the chemicalor thermal stress the material has to withstand. The various sizes andgeometries are determined by ourcustomers. We are able to providehelpful advice influencing productquality and costs through our widerange of design possibilities. Suchwork requires a joint effort in selectingthe materials and determining theproduct geometry.

Fused Silica

Working temperatures are possible up to 1000 °C. The low linear thermalexpansion and therefore good thermalshock resistance permits short heat-up times.

Alsint Porous

Alsint porous is the right material fortemperatures exceeding 1300 °C, evenin a reducing atmosphere. The maincharacteristic of this material is itschemical resistance. Heat-up ratesmust be adapted to this material. It isalso possible to influence the requiredthermal shock resistance by geometryand wall thickness.

Support Tubes

Support tubes are required for theconstruction of furnaces with exposedheating coils. Our material SillimantinKS has proved itself over the years andis used by many renowned companiesbuilding kilns. All commonly used sizesof support tubes can be deliveredex stock. Special dimensions of Sillimantin 60 are manufactured (seetable on page 10).If the usual material, Sillimantin KS,does not meet the requirements of your special application, there are thefollowing additional possibilities:

Alsint 99,7 with its higher supporting capacity, greater supporting distance (without bending), gastightness and chemical inertness.

Pythagoras as an imperviousmaterial has a better refractorinessthan Sillimantin KS.

Sillimantin 60 NG combines thegood refractory properties of Alsint with good resistance to thermal shock.

Firing Supports

In the ceramic and electrical industryfiring supports or kiln furniture arerequired for kiln car structures.Normally in the ceramic industry tube sections, for example of the size 55 x 45 x 200 up to 300 mm, areused in order to keep the firing settersat the right distance. In the productionof ferrites rectangular solid shapes ofdifferent sizes are used for the samepurpose. These supports also carry the setter plates with the ferrites onthem. The high mechanical strength of ceramics enables you to use small firing supports. The result is animprovement of the relation betweenkiln furniture and products to be fired.

Kiln Furniture Structures

Please refer to our leaflets “Halsic-R/Halsic-RX, Halsic-I/Halsic-S” for ouradditional manufacturing programme.

HALDENWANGER 17



8r 2r

4656

46 56

100110

80 90

WS: 6.5

95105

95 105

WS: 6.8

160170

43 53WS: 5.5

155170

65 81

WS: 9.5

135150

185

200

WS: 10.0

10r 5r

7483

63 74

101122

84 103

WS: 11.0

180195

89 105

WS: 8.5

175195

127

145

20r 10r

164

86 102

175

180

265280

130

145

WS: 9.5

95105

5412

0

75

50

118133

82 97

17r9r

5967

140160

110

1358778

145170

115

140

WS: 13.8

227255

177

200

5r

HALDENWANGER

SIZESof muffles, open both ends

18

Dimensions stated here for a wide range of muffles are for Sillimantin 60 only. For Sillimantin 60 NG muffles, please use a correction factor of –5%.

The objective of this brochure is todemonstrate how we are helpingour customers to solve problemsencountered in kiln design. However,HALDENWANGER’s capabilities donot stop here. Numerous design pro-grammes involving technical ceramicsvery often mean ‘difficult problems’for the manufacturers and in suchcircumstances HALDENWANGER isthe company to provide the solutions.

Technical ceramics have been used for many years in various productionprocesses. Many new fields are beingadded to the already existing broadrange of applications ranging from space exploration and mechanical engineering to chemistry and most sophisticated electronics.

Additional application areas forHALDENWANGER technical ceramics are:

Mechanical applications, from shafts to cylinder liners

Refractory applications, from saggers to heat-exchangers

Chemical applications, from evaporating dishes to combustion boats

Electronic and high current appli-cations, from insulation bushes tocomponents for electron tubes

Whatever the requirement, we believeHALDENWANGER is your competentpartner right at the planning stage.

When you are next confronted with an engineering challenge for which the solution could be ceramics thenremember, HALDENWANGER is the specialist.

HALDENWANGER

TECHNICAL CERAMICS

19

S O L U T I O N S

Alsint 99,7 insulating ring (Ø 320 mm, 4 mm wallthickness) for the satellite “COS-B”

Special parts designed for customer applications

haldenwanger ceramics for kilnscomponents having higher thermal shock resistance allowing increased...

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