KANTHAL OR NIKROTHAL

There are two main types of electric resistancealloys. Nickel-chromium (e.g. 80 Ni, 20 Cr) calledNIKROTHALwas developed around the beginningofthe 20th century and was soon used as heatingelement material in industrial furnaces as well as inelectric household appliances.In the thirties Kanthal inrroduced a new resistanceheating alloy (called KANTHAL) based on ironchromium-aluminium with a longer life and a highermaximum operating temperature than nickel-chromium.Kanthal manufactures both types of alloysunder the names NIKROTHAL (nickel-chromium)and KANTHAL (iron-chromium-aluminium).The two main types of alloys have their own specificproperties, with advantages and disadvantages, andare supplied in many different grades and forms.In general KANTHAL type alloy is superior toNIKROTHAL in respect of performance and lifeand is therefore nowadays a standard material choicewhen it comes to metallic heating elements for industrialfurnaces.The NIKROTHAL alloy may have special advantagesifyou need a heating element havingvery goodmechanical properties in the hot state. KANTHAL APM has, however, creep strength at elevated temperatures in the same level as NIKROTHAL.

For the furnace user, using KANTHAL results in lessamount of marerial at a lower price and also - a longerlife. Table I shows an example ofweighc saving - anclower cost - obrained by usingKANTHAL instead ofnickel-chromium alloys. This lower element weightwiII alsor esult in considerablec oscs avingsr egardingsupport system,b ecausef ewer suspensionh ooks are necessary.

Element Data	Nikrothal	Kanthal
Furance Temprature[ºC]	1000	1000
Element Temprature[ºC]	1068	1106
Hot Resistance[Rw]	3.61	3.61
Temprature Factor[C1]	1.05	1.06
Cold Resistance[R20]	3.44	3.41
Wire Diameter[mm]	5.5	5.5
Surface Load[W/CM2]	3.44	3.41
Wire Length[m] 3 Elements	224.9	174.6
Wire Weight[Kg] 3 Elements	44.4	29.6

Physical and Mechanical Properties

KANTHAL and NIKROTHAL alloys are generally available in wire, ribbon or strip form. Physical and mechanical properties ofthe alloys are listed in Table .

	Kanthal APM	Kanthal A-1	Kanthal AF	Kanthal D	Nikrothal 80	Nikrothal 70	Nikrothal 60	Nikrothal 40
Nominal Composition[%]Cr	22	22	22	22	20	30	15	20
Al	5.8	5.8	5.3	4.8	-	-	-	-
Fe	Balance	Balance	Balance	Balance	-	5%	Balance	Balance
Resistivity at 20ºC [Ωmm.2m-1]	1.45	1.45	1.39	1.35	1.09	1.18	1.11	1.04
Density[g/cm3]	7.10	7.10	7.15	7.25	8.3	8.1	8.2	7.9
Coefficient of 20-750ºC Termal Expansion, K-1 20-1000º	14 ×10-6 15 ×10-6	14 ×10-6 15 ×10-6	14 ×10-6 15 ×10-6	14 ×10-6 15 ×10-6	16 ×10-6 17 ×10-6	16 ×10-6 17 ×10-6	17 ×10-6 17 ×10-6	18 ×10-6 19 ×10-6
Thermal Conductivity at 20ºC [Wm-1 K-1]	13	13	13	13	13	13	13	13
Specific Heat Capacity at 20ºC [KJkg-1 K-1]	0.46	0.46	0.46	0.46	0.46	0.46	0.46	0.50
Meeting Point [ºC]	1500	1500	1500	1500	1400	1380	1390	1390
Mechinical Properties (approx.)*
Tensile Strength [N mm-2]	680	680	680	650	810	820	730	675
Yield Point [N mm-2]	470	475	475	450	420	430	370	340
Hardness [Hv]	230	230	230	230	180	185	180	180
Elongation at Rupture [%]	20	18	18	18	30	30	35	35
Tensile Strength at 900ºC [N mm-2]	40	34	37	34	100	120	100	120
Crrep Strength at 800ºC [N mm-2] at 1000ºC [N mm-2]	11 3.4	6 1	8 1.5	6 1	15 4	15 4	15 4	20 4
Magnetic Properties	Magnetic (Curie Point 600ºC)				non	non	Slightly	non
Emissivity, Fully Oxidized Condition	0.70	0.70	0.70	0.70	0.88	0.88	0.88	0.88

Product forms and size ranges Kanthal resistance heating alloys are available in the following product forms and sizes:

   ◊ Round wire: 0.10-12 mm (0.00394-0.472 inch)
   ◊ Ribbon (flat wire): thickness: 0.023-0.8 mm (0.0009-0.031 inch) Width: 0.038-4 mm (0.0015-0.157 inch) Width/thickness ratio max 40, depending on alloy       and tolerance
   ◊ ;Strip: thickness 0.10-5 mm (0.00394-0.1968 inch), width 5-200 mm (0.1968-7.874 inch) Other sizes are available on request.

Thermal spray wire

Thermal spraying wire in a wide range of alloys for high-temperature corrosion protection, bonding layers, build-up coating and sealing.Spray wire alloys. The Kanthal program of tspray wire includes the following types of alloys:
   ◊ FeCrAl and FeCrAlY alloys
   ◊ NiCr and NiCrFe alloys
   ◊ NiAl alloys
   ◊ NiFe alloys
   ◊ CuNi alloys

Kanthal spray wire alloys

List of Kanthal alloys for thermal spraying. More information about each grade, such as chemical composition and typical coating properties, such as chemical composition, is available in the datasheet for the respective grade.

Grade	Type of alloy	Bond coating	Protective coating	Build-up coating
Kanthal SW 010	FeCrAl	√	√	-
Kanthal SW 030	FeCrAl	√	√	-
Kanthal SW 100	FeCrAlY	√	√	-
Kanthal SW 200	NiCr	-	√	-
Kanthal SW 210	NiCrFe	-	√	-
Kanthal SW 230	NiCrFe	-	√	-
Kanthal SW 775	NiCrMo	-	+	√
Kanthal SW 801	CrNiMo	-	√	-
Kanthal SW 806	NiAl	√	√	√
Kanthal SW 782	NiFe	-	-	√
Kanthal SW 821	CuNi	-	√	-
Kanthal SW 921	CuNi	-	√	-

In particular in marine and chemical applications Sizes Standard sizes are 1.20, 1.60 and 2.00 mm (0.0472, 0.0693 and 0.0787 inch). Other sizes can be offered on request. The standard delivery form is tight wound on SD 300K spools. Typical applications Kanthal thermal spraying wire is used in a variety of applications, such as:
   ◊ High-temperature oxidation protection used, for example, to resist gases in boiler atmospheres.
   ◊ Coatings to resist heat and prevent scaling of conventional low alloy steels.
   ◊ Bond coats for imprving the adhesion of top coatings.
   ◊ Coatings on moulds in the glass industry.

Thermocouple wire and strip

Thermocouple wire and thermocouple strip for use at temperatures up to 1260°C (2300°F). Kanthal thermocouple wire is supplied with bright or oxidized surface according to standard or special EMF requirements. Each individual arm is calibrated against platinum and the EMF values are shown on each coil or spool.
Sandvik's product program for thermocouples includes:
   ◊ Thermocouple wire - round and flat.
   ◊ Thermocouple strip.
   ◊ Extension leads/extension cables.
   ◊ Compensating cables.
   ◊ Bunched wire.
   ◊ Thermocouple protection tubes.
Our program also includes a bi-filar side-by-side configuration in some size ranges. Types of thermocouple wire.

Code	+Positive leg	-Negative leg
N	Nicrosil (NP)	Nisil (NN)
K	Thermothal P (KP)	Thermothal N (KN)
E	Thermothal P (EP)	Cuprothal (EN)
J	Iron (JP)	Cuprothal (JN)

Size range Wire: Kanthal thermocouple wire ranges from 0.05 to 8.0 mm (0.0019 to 0.315 inch). Thermocouple wire in the size range 0.0254 mm to 0.51 mm (0.001 to 0.0201 inch) can be supplied with or without an insulating coating.
Strip: Standard sizes for thermocouple strip range from thickness 0.10 to 3.0 mm (0.0039 to 0.181 inch) and width from 4 to 195 mm (0.157 to 7.68 inch).
Standards : Kanthal thermocouple alloys are supplied according to the following standards shown below. Where older standards are still in use (which are not equivalent to those listed below), we can supply different EMF values upon request.

ASTM	(American Society for Testing and Materials) E 230
ANSI	(American National Standard Institute) MC 96.1
IEC	(European Standard by the International Electrotechnical Commission 584)-1/2/3
DIN	(Deutsche Industrie Normen) EN 60584 -1/2
BS	(British Standards) 4937.1041, EN 60584 - 1/2
NF	(Norme Française) EN 60584 -1/2 - NFC 42323 - NFC 42324
JIS	(Japanese Industrial Standards) C 1602 - C 1610
GOST	(Unification of the Russian Specifications) 3044