Kanthal ABt Hallstahammar, Sweden.

Fig. 1 Range of KANTHAL SUPER 6/12. 9/18, 12/24 lments and SUPERTHAL heating modules Flg. 2 Range of KANTHAL SUPER 3/6 and 4/9 驩lments

Kanthal Super Handbook Introduction 9 Introduction This is KANTHAL SUPER Composition KANTHAL SUPER is a dense cermet material consistlng of MoSi2 and an oxide component, mafnly a glass phase. KANTHAL SUPER has the abillty to wtthstand oxldatlon at hlgh tempratures. This is due to the formation of a thin and adhestve protective layer of quartz glass on the surface. When MoSl2 reacts wlth oxygen ln the atmosphre, the layer of quartz glass is formed and under this a thin layer of molybdenum silicide wlth a lower silicon content Mo5Si3. When KANTHAL SUPER 騩lments are operated at tempratures around...

10 Introduction Kanthal Super Handbook Quality and product summary Type of lment Max. 驩lment temprature in air General applications KANTHAL SUPER 1700 1700 °C(3090°F) Most types of industrlal fumaces for heat treatment forging, sintering, glass melting and refining and for use in radiant tubes. KANTHAL SUPER 1800 1800 °C (3270 °F) Laboratory furnaces, testing equipment and high temp驩rature sintering production fumaces. KANTHAL SUPER 1900 1850 °C (3360 °F) Laboratory fumaces, testing equipment and high temprature sintering furnaces. SUPERTHAL SMU/SHC 1600 °C (2910 "F) 1650 °C (3000 °F) KANTHAL...

12 Properties Kanthal Super Handbook Chemical rsistance Atmosphres KANTHAL SUPER can be used ln most fijrnace atmosph騨res. Most favourable are oxidlzlng atmosphres such as air, carbon dloxlde and water vapour, but KANTHAL SUPER l詩ments are also operatlng successfiilly ln neutral. reduclng and carburizlng atmosphres. Table 2 mdlcates the maximum recommended l詩ment tempratures ln some com mon types of fumace atmosphres and gases. Air At low temp騩ratures, an oxidatlon of molybdenum and slllcon on the surface of the lments can occur at temp驩ratures around 500 °C (930 °F). The oxidatlon product is...

14 Properties Kanthal Super Handbook Noble gases, argon and hlium Thse gases are lnert and do not react chemlcally with KANTHAL SUPER Howe\-er, if there Is a gas flow around the 騩lments, it wlll dlsturb the chemIcal equilibrium existing around the l驩ments. At high tempratures the glaze ls consumed. When uslng thse gases. a r騩gnration of the glaze ls recommended before the old glaze has disappeared compl驩ter/. Hydrogen In dry hydrogen the si lira layer ls reduced and MoSl2 dlslntegrates by formlng gaseous silicon and silicides wlth lower silicon content. This reaction is dpendent on temprature...

Kanthal Super Handbook Elments and tubes 19 Cl Lu a a 12 mm .50 in. 18 mm .70 in. 鯯 f 0 c 0 c f h = 15 mm .59 in. (6/12) 20 mm .79in. (9/18) 40 mm 1.57 in. (12/24) Leh = Le - 6 mm .24 in. (6/12) - 9 mm .35 in. (9/18) - - 27 mm 1.07 in. (12/24) 0 Leh Le 0 d

30 SUPERTHAL Kanthal Super Handbook Fig. 21 SUPERTHAL tube furnace for materials testing and as IR-heater at plastic pipe manufacturing

Kanthal Super Handbook Installation 73 The weight of the lment sels 1s canted by the outer Itning. Espectally useftil in rumaces for very high temp驩ratures. FQ.38 KANTHAL SUPER lments in ceramtc fibre Hned fumaces. The passage pk/gs are drvkJed in two pi驨ces. Ftg.39 KANTHAL SUPER lments in cor amie fibre hnod fumaces. The passage ptugs and 驩lments are supported by the cokJ side of the roof

Elment holders and anchor Systems Single-shank holders Stngle-shank holders can be used for ail klnds of KAWTHAL SUPER quallties. It ls essentlal that the terminais are able to move freely and lndependently of each other. otherwlse mechanlcal stresses may cause the l驩ment to break. Thls ls Important at very hlgh tempratures. Two-shank holders Two-shank holders are used when the l驩ments need to be anchored to the passage brick. Fig. 40 Single-shank holders. Flg. 41 Two-shank holders.

76 Installation Kanthal Super Handbookk "Air cooled" anchor System By uslng thc "air cooled" design lt ls possible to blow coollng air down along the terminais. In fumaces wherc lmpurltles In the form of dust or fumes occur, e.g. glass meltlng furnaces. lt ls essenual that such substances be prevented from deposltlng and condenslng In the holes of the passage bricks; otherwise, corrosion may occur on the lment terminais. The 驩lment may also be Jammed In the hole, thus preventlng free movement and posslbly leadlng to l驩ment breakage. Thls ls partlcularly important ln glass meltlng fumaces. slnce...

Kanthal Super Handbook Installation 77 Sealed anchor System KANTHAL SUPER lments are often used tn turnaces with controlled atmosph驨res. When the lments operate dlrectly ln the atmosph驨re, lt ts essentlal that the terminais be sealed. A lead-through. which ls sealed and bolted to the shell of the fumace, ls shown in the figure below. Fig. 44 Elment holder and anchor System Sealed design

78 Installation Kanthal Super Handbookk Contacts Each contact consiste of a double-folded alumlntuni brald, whlch ls secured a round the alumlnlzed end ol the terminal by means of a sprint» or screw clamp. Trie busbar end of the brald ls relnforced wlth an aluminium sleeve. The standard slzes and types avallable are shown on pages 111-118, Appendlx 1. It ls essentlal that no mechanical stresses should be transmitted to the lments through the aluminium braids. The lcngth of the brald should therefore be longer than the straight distance between the 驩lment and the busbar. When tlghtenlng the bolts...

Kanthal Super Handbook nstallation 79 When uslng KANTHAL SUPER lments the current ls hlgh. Consequently. the transition r驩sistance between contact and terminal must be kept low. Trie voltage drop across the contact should not exceed 0.01 V. Aluminium oxldlzes easlly, and the alumina layer bullt up on the surface ls a good lnsulator. Furthermorc, the creep strength of aluminium ls low and the temprature at the contacts should not exceed 300° C (570 °F). When screw clamps are used. lt ls essentiel that the bolts be fully tlghtened. The contacts are deslgned for a contlnuous current of: Elment size:...