Technical Information The following chapter contains practical information on the behaviour, during and after subsequent treatment, of the alloys delivered by us. This information is intended to assist in selecting the correct alloy for the appropriate application. It cannot, of course, deal with all imaginable applications in the smallest detail. We are, however, at any time prepared to answer your questions and to help solve any problems.
A.
It thus indicates the average variation of the resistivity per degree Kelvin in the temperature range from to to t, referred to the resistance value R at to. 2. When experimentally determining the temperature coefficient as well as during communication between supplier and customer two points must be observed: 1. As already mentioned, the temperature dependence of the resistivity in general does not show a linear, but a curved form.
B. Special Characteristics of Nickel-Chromium Alloys The resistivity of nickel-chromium alloys shows a special characteristic. At temperatures below 500°C it is affected by the rate with which the alloy has been cooled from high temperatures, e.g. after annealing, and it decreases with increasing cooling rate. This behaviour is shown schematically in the graph on the right. The solid line represents the so-called state of equilibrium, i.e. the resistivity of an annealed wire after slow cooling.
C. Surface Loading Capacity Generation of heat has great importance in electrical engineering, no matter whether it should be controlled as far as possible or whether it is intended to be used. n= i 2 ⋅ ρ t ⋅ 0.04053 d3 i = Current in Amps The main questions to be answered in this connection is what temperature a current-carrying wire, ribbon, sheet etc. will reach during operation.
arranged in the form of a spiral permit much smaller surface loads since the heat dissipating wire surface is strongly reduced as compared with freely stretched wires. In case of a bobbin being densely wound with resistance wire, the surface of this structure can be taken as the reference quantity for the value “Watt per cm²”. This means that the diameter of the wound bobbin can be taken as “wire diameter”.
Diameter in mm 0,020 0,022 0,025 0,028 (0,030) 0,032 0,036 0,040 0,045 0,050 0,056 (0,060) 0,063 (0,070) 0,071 0,080 0,090 0,100 (0,110) 0,112 (0,120) 0,125 (0,130) 0,140 (0,150) 0,160 0,180 0,200 (0,220) 0,224 0,250 0,280 (0,300) 0,315 (0,320) (0,350) 0,355 0,40 0,45 0,50 (0,55) 0,56 (0,60) 0,63 (0,65) (0,70) 0,71 0,75 0,80 0,85 0,90 0,95 1,00 (1,10) 1,12 (1,20) 1,25 1,40 1,50 1,60 1,80 2,00 (2,20) 2,24 2,50 2,80 3,00 3,15 (3,20) (3,50) 3,55 4,00 4,50 5,00 5,50 5,60 6,00 6,30 ISOTAN® Resistance in Ω/m 156
Diameter in mm 0,020 0,022 0,025 0,028 (0,030) 0,032 0,036 0,040 0,045 0,050 0,056 (0,060) 0,063 (0,070) 0,071 0,080 0,090 0,100 (0,110) 0,112 (0,120) 0,125 (0,130) 0,140 (0,150) 0,160 0,180 0,200 (0,220) 0,224 0,250 0,280 (0,300) 0,315 (0,320) (0,350) 0,355 0,40 0,45 0,50 (0,55) 0,56 (0,60) 0,63 (0,65) (0,70) 0,71 0,75 0,80 0,85 0,90 0,95 1,00 (1,10) 1,12 (1,20) 1,25 1,40 1,50 1,60 1,80 2,00 (2,20) 2,24 2,50 2,80 3,00 3,15 (3,20) (3,50) 3,55 4,00 4,50 5,00 5,50 5,60 6,00 6,30 ISOTAN® Resistance in Ω/m 156
In the following some examples are given: Example 1 Example 2 Problem: What current is required to increase the temperature by 200°C of ISA13® wire with a diameter of 0.20mm? Problem: What is the temperature increase of ® wire with a ISA-CHROM 60 diameter of 1.0mm, if it is loaded with a current of 8 Amps? Solution: a) From the table can be seen ® that the value for ISOTAN wire with equal diameter is 1.03 Amps.
Current-Carrying Capacity of Flat Wires For round wires the diameter is sufficient to determine the data previously quoted. For ribbons the thickness and above all, the width must be taken into consideration. When making comparisons, the table containing the cross-sectional values of standard ribbons with rounded-off edges vs. those of round wires should be consulted.
Surface of Flat Wires in cm² · m-1 thickness a in mm Flat Wires of ISOTAN® - Grams per Meter (g · m-1) width / b in mm 6 thickness 1 2 3 4 5 7 8 20,6 40,6 60,6 80,6 101 121 141 161 0,06 20,7 40,7 60,7 80,7 101 121 141 0,07 20,8 40,8 60,8 80,8 101 121 141 0,08 20,9 40,9 60,9 80,9 101 0,09 21,0 41,0 61,0 81,0 0,10 21,1 41,1 61,1 81,1 0,12 21,4 41,4 61,4 0,14 21,6 41,6 0,16 21,8 41,8 0,18 22,1 0,20 22,3 0,22 9 10 width / b in mm a in mm 1 2 3
Current-Carrying Capacity of Flat Wires of ISOTAN® in Amps for an Overtemperature of 100°C Horizontally stretched in still air of 20°C thickness a in mm 0,05 0,06 0,07 0,08 0,09 0,10 0,12 0,14 0,16 0,18 0,20 0,22 0,24 0,26 0,28 0,30 0,35 0,40 0,45 0,50 0,60 0,70 0,80 0,90 1,00 1,20 1,40 1,60 1,80 2,00 1 0,93 1,02 1,10 1,17 1,25 1,31 1,44 1,55 1,66 1,76 1,85 1,95 2,03 2,12 2,20 2,27 2,46 2,62 2,78 2,93 2 1,60 1,75 1,89 2,02 2,14 2,25 2,45 2,67 2,85 3,02 3,19 3,34 3,49 3,64 3,77 3,91 4,22 4,51 4,78 5,04 5,5
Current-Carrying Capacity of Flat Wires of ISOTAN® in Amps for an Overtemperature of 300°C Horizontally stretched in still air of 20°C thickness a in mm 0,05 0,06 0,07 0,08 0,09 0,10 0,12 0,14 0,16 0,18 0,20 0,22 0,24 0,26 0,28 0,30 0,35 0,40 0,45 0,50 0,60 0,70 0,80 0,90 1,00 1,20 1,40 1,60 1,80 2,00 1 1,94 2,12 2,29 2,45 2,59 2,73 2,99 3,23 3,46 3,66 3,86 4,05 4,23 4,41 4,57 4,73 5,11 5,46 5,80 6,11 2 3,09 3,38 3,66 3,91 4,14 4,36 4,77 5,16 5,52 5,85 6,17 6,47 6,76 7,04 7,30 7,56 8,17 8,72 9,26 9,72 10,
D. Technical Terms of Delivery and Tolerances Availables Types Dimensional Range Our alloys are available in the form - Bare wires of - annealed bare wires; on request - Insulated ISOTAN®, ISA-CHROM 60® and wires ® can be ISA-CHROM 80 manufactured with an insulation - Flat wires oxide film; 0.01 – 8mm ∅ The dimensional ranges are illustrated in the following diagram; details are given on request. 0.01 – 2mm ∅ 0.
Packing Wires of less than 1mm diam. and flat wires of less than 0.80mm thickness and a maximum width of 5mm are delivered on plastic spools according to DIN IEC 264 resp. on American standard spools in accordance with the tables on the right. Spools according to DIN IEC264 Spool Dimensions (mm) Spool Diameter Spool Width Weight of Wound-Up Wire On Plastic Spools Round Wires up to 1.0 Diam. Flat Wires up to 5.0mm Width and 0.8mm Thickness
For certain applications, especially if insulated wires are used for heating bimetals, a combination of several insulation types is recommended. Flat wires of resistance alloys are standardized in DIN 46465. It should be noted that the nominal dimensions quoted there often will not meet the requirements of our customers and that for this reason we have chosen a different gradation. For resistance alloys supplied as ribbon or sheet, no special standard exists.
F. Instructions for Treatment The alloys delivered by proven its value. The immersion Isabellenhütte have good working period lasts for 1 to 10 minutes depending on the alloy. characteristics. The following instructions should be observed: Soldering, Brazing and Welding of Resistance Alloys Winding Soldering The copper alloys manufactured by Isabellenhuette can be soldered like pure copper, using normal solders and fluxes. Light abrasion of the areas to be soldered is recommended.
