Type K Thermocouple: Characteristics, Functions and More

A thermocouple can be defined as an electrical connection or circuit which is utilized to examine temperature. It uses two different metals to form a connection that produces an electrical current that can be linked with temperature. Different kinds of metal combinations are put to practice as it completely depends upon the kind of measuring needs. One in particular is the Type K thermocouple which will be discussed here.

What’s A Type K Thermocouple?

The Type K thermocouple is one of the most common form of thermocouples type. The general measuring ranges of a Type K thermocouple is between 200° C to +1,350° C. Beyond this temperature range Type K thermocouple cannot be used. This is because the alloys used to make this thermocouple have a low melting point.


A Type K thermocouple consists of two alloys. The first alloy is Alumel that has 95 percent nickel, 2 percent aluminum, 2 percent manganese and 1 percent silicon, and the second alloy is Chromel which comprises 90 percent nickel and 10 percent chromium. As both these alloys have a fine quantity of nickel and nickel possesses magnetic qualities. This is the reason that any Type K thermocouple showcases magnetic properties beyond a temperature of 350° C.

The Function or Uses Of Type K Thermocouple

All devices that make use of Type K thermocouple should always make use of the appropriate Type K thermocouple wire as this is important. Every wire measures a specific temperature range. Because of the wide temperature range Type K thermocouple wire is very popular among its kinds. Also it has a superior margin of error than its counterparts. This is an added reason for the popularity of the product. Type K thermocouple chart is used to determine the millivoltage produced at different temperature. This chart helps to keep a check at the efficiency of the product and at the same time the amount of voltage produced.

Type K Thermocouple Probe Type

Since Type K thermocouple utilizes two different metals and calibrations, it produces different probes that are useful in different environment and temperature ranges. Their utility and application varies depending upon various other factors and not on just the metals that are used to make them. Type K universal thermocouple probe can have any of the three types of junction. They can be ungrounded, grounded or exposed.

  • Grounded probes: these are attached to the probe wall for optimal heat transfer, ungrounded probes are not attached from the probe wall while an exposed junction gives out the best response time, but at the same time it is susceptible to corrosion and prominently used only in dry applications. Penetration probe is a different kind of probe that is particularly designed to compute temperatures in hard substances as well as semi-solid substances.
  • Ungrounded or surface probes: these are used to measure temperatures without the use of penetration. For measuring the temperatures of liquid and semi-solid materials Flexible insulated wire probes are used.
  • Exposed or uncoated wire probes: these showcase a quick response time to measure temperature. Coated Type K thermocouple wires show different response times in different environment. A bare Type K thermocouple wire shows a response time of over just 0.6 seconds.

In conclusion, Type K thermocouple wires are the most preferred because of:

  • Effectiveness in a wide range of Temperature 200° C to +1,350° C
  • Use Alumel and Chromel, and both have magnetic qualities.
  • Quick response time

Fairly priced and easily available