Nichrome Alloys
Aurico Alloys LLP supplies nichrome resistance alloys from Mumbai in a full range of forms — sheet, plate, coil, strip, foil, bar, wire and tube. Held in stock or arranged with the manufacturer, depending on grade and quantity.
Nichrome is nickel-chromium wound or formed into something that is meant to get hot and stay intact. Its usefulness rests on three properties at once: high electrical resistivity, so a manageable length gives the wanted resistance; a resistance that barely changes as the element heats; and a tight, adherent chromium oxide skin that stops the element burning away.
Grades are named by their nickel-to-chromium ratio, and the ratio is the whole specification. More nickel means a higher usable temperature and a longer life, and costs more. The lower-nickel grades substitute iron, which is cheaper and works perfectly well at lower temperatures.
Key Properties
- High electrical resistivity, so a manageable length of wire gives the wanted resistance
- A low temperature coefficient, so resistance barely changes as the element heats
- An adherent chromium-oxide scale that stops the element burning away
- Higher-nickel grades (80/20) for higher temperature and longer life; iron-substituted grades for lower cost at lower temperature
- Supplied as sheet, plate, round bar, foil and pipe
What Is Nichrome? Composition, Melting Point and Properties
What is nichrome made of?
Nichrome is a family of nickel-chromium alloys made for electrical resistance heating, and its grades are named by their nickel-to-chromium ratio. The nickel-based grades are NiCr 80/20 (chromium 19–21%, nickel the balance), NiCr 70/30 (chromium 29–31%, nickel the balance) and NiCr 60/15 (chromium 14–17%, at least 57% nickel, iron the balance). The iron-bearing grades trade nickel for iron: NiCr 40/20 (chromium 18–22%, at least 37% nickel, iron the balance), NiCr 30/20 (chromium 18–22%, at least 28% nickel, iron the balance) and NiCr 20/25 (chromium 23–27%, at least 18% nickel, iron the balance).
What is the melting point of nichrome?
NiCr 80/20 and NiCr 70/30 melt at about 1,400 °C, and NiCr 60/15 melts at about 1,390 °C, according to the manufacturer's data sheets. The data sheet for NiCr 40/20, NiCr 30/20 and NiCr 20/25 publishes no melting point, so none is stated here. The temperature an element can be run at in air is lower than the melting point: the data sheets give 1,200 °C for NiCr 80/20 as a heating element, 600 °C for NiCr 80/20 as a resistance alloy and approximately 1,250 °C for NiCr 70/30.
Nichrome properties by grade
| Grade | Chromium | Nickel | Density (g/cm³) | Melting point (°C) | Resistivity at 20 °C (µΩ·cm) |
|---|---|---|---|---|---|
| NiCr 80/20 | 19–21% | the balance | 8.3 | about 1,400 | 108–112 |
| NiCr 70/30 | 29–31% | the balance | 8.1 | about 1,400 | 116–119 |
| NiCr 60/15 | 14–17% | at least 57% | 8.2 | about 1,390 | 113 |
| NiCr 40/20 | 18–22% | at least 37% | 7.95 | not published | — |
| NiCr 30/20 | 18–22% | at least 28% | 7.90 | not published | — |
| NiCr 20/25 | 23–27% | at least 18% | 7.80 | not published | — |
Figures are read from the manufacturers' data sheets: VDM Metals VDM Alloy HT 80 Basic Information sheet 03/2020; VDM Metals VDM Alloy HT 70 Basic Information sheet 03/2020; VDM Metals VDM Alloy HT 60 Basic Information sheet 03/2020; JLC Electromet Nickel-Chromium Heating & Resistance Alloys data sheet (December 2020). Resistivity differs by standard where a sheet prints two values, so a range is shown, and a dash means this page states no figure for that grade. Confirm the property you are relying on against the mill certificate for the batch supplied.
Grades Supplied
| Grade | UNS | Type | Chosen for |
|---|---|---|---|
| NiCr 80/20 | N06023 | 80% Ni, 20% Cr | The highest usable temperature of the family; furnace elements |
| NiCr 70/30 | N06003 | 70% Ni, 30% Cr | Higher resistivity, good oxidation resistance |
| NiCr 60/15 | N06024 | 60% Ni, 15% Cr | General purpose heating, iron balance |
| NiCr 40/20 | — | 40% Ni, 20% Cr | Moderate temperature elements and resistors |
| NiCr 30/20 | — | 30% Ni, 20% Cr | Lower temperature service at lower cost |
| NiCr 20/25 | — | 20% Ni, 25% Cr | The most economical of the range |
Designations are as stated on each grade page. Confirm the specification against the mill certificate for the batch supplied.
Available Forms
Where These Alloys Are Used
- Industrial furnaces — heating elements, coils and strip elements
- Domestic appliances — toasters, heaters, hair dryers and ovens
- Heat treatment — furnace windings and muffle elements
- Resistors — precision and power resistance components
- Ceramics and glass — kiln elements
Certification and Cutting
Material is supplied against EN 10204 3.1 mill test certificates, with chemical composition and mechanical properties for the batch. Cutting to size is done in house.
Ask for a Quotation
Tell us the grade, the form, the size and the quantity, and we will confirm availability, lead time and price. Contact us for stock availability, pricing and material test certificates.