The two wires that make up the thermocouple pair are made from a range of different alloys and metals and have been standardised by both international and national bodies.

K-type thermocouple wire is a common type of thermocouple composed of two different metal alloys: nickel/silicon alloy (usually referred to as KN or KNX) and nickel/chromium alloy (usually referred to as KP or KPX). ‌

Industry applications:
Industry: refining, chemical, metallurgical, power generation (monitoring boiler and pipeline temperature);
Research: Laboratory high-temperature reaction equipment, material testing;
Civilian: Monitoring of exhaust systems for household appliances (ovens, dryers) and automobiles.

K-type thermocouple wire (composed of nickel chromium nickel aluminum alloy) is one of the most commonly used temperature sensors in industry and scientific research, and its advantages are mainly reflected in the following aspects:
1. Wide temperature range
Applicable temperature:
Standard range:- 200 ° C to+1250 ° C (short-term height measurement up to 1370 ° C).
Covering most industrial scenarios, it can be used from low-temperature refrigeration to high-temperature melting.
Comparative advantages:
More versatile than J-type (-40 ° C~750 ° C) and T-type (-200 ° C~350 ° C), suitable for high temperature requirements;
Compared to precious metal thermocouples (such as R/S type, up to 1600 ° C), it has lower cost and higher cost-effectiveness.
2. High cost-effectiveness
Low material cost:
Made of inexpensive nickel based alloys (positive electrode: nickel chromium; negative electrode: nickel aluminum), the cost is significantly lower than that of precious metal thermocouples such as platinum rhodium.
Low maintenance cost:
Strong durability, longer lifespan in oxidative environments, and reduced replacement frequency.