Nickel-Chromium Wire Inspection Standards

Nickel-chromium wire is a type of nickel-chromium alloy wire, which is available in two forms: bare nickel-chromium wire and enameled wire. The wire diameter can be as fine as 0.025 mm. Fine wires are used in various electric heating appliances and products. They have a small temperature coefficient of resistance after heating, resulting in minimal power variation. Specifications of 1.0 mm and above are widely used in electric heating products, spray coating industries, evaporation, dust removal, woven mesh belts, and other applications. Large-diameter specifications ranging from 3.0 mm to 1.2 mm and above can also be supplied in bright annealed soft condition upon customer request.

Inspection Standards for Nickel-Chromium Wire:

Flexibility (Bendability): During winding or elongation, inspect whether the enamel film cracks or develops pinholes.

Pinholes: Microscopic pinholes in the enamel film that cannot be visually detected, tested over a specified length of the material.

Aging Resistance: Under specified heating conditions, evaluated by whether pinholes occur in the enamel film or by the value of the insulation breakdown voltage.

Abrasion (Wear) Resistance: Using an abrasion testing machine to abrade the enamel film, evaluated by the number of cycles until the conductor becomes visible or by the abrasion failure value.

Insulation Breakdown Voltage: Two strands of enameled wire are twisted together, and voltage is applied between the conductors; the breakdown voltage of the enamel film is measured.

Adhesion: During rapid stretching, inspect whether the enamel film cracks.

Heat Resistance (Softening Resistance): Crossed enameled wires are heated under specified conditions, and after energization, inspected for short circuits or the temperature at which short circuits occur. Alternatively, two twisted strands of enameled wire are heated under specified conditions to observe whether the enamel film shows any abnormality.

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