Thermocouples

Thermocouples (Thermocouples) are a type of sensor used to measure temperature. It consists of two different metals brought together at one end. The other end of each metal is connected to a measuring device that measures the voltage difference between the two metals, which is proportional to the temperature difference between the two ends of the thermocouple.

In heat treatment furnaces, temperature sensors are often used to measure the temperature of the furnace and the product being processed. The thermocouple is usually inserted into the oven through a small opening or port and placed near the product being processed.

There are various types of thermocouples available, each with their own unique features and advantages. Some of the most commonly used thermocouples in heat treatment furnaces include:

Type K thermocouples: These are the most commonly used thermocouples in heat treatment furnaces. They are made of chromel (90% nickel and 10% chromium) and alumel (95% nickel, 2% manganese, 2% aluminum and 1% silicon) and can measure temperatures up to 1,200°C.

Type N thermocouples: These are made of Nicrosil (84.2% nickel, 14.2% chromium, 1.5% silicon and 0.1% magnesium) and Nisil (95% nickel and 5% silicon) and are rated at 1,300°C. It can measure temperatures up to . They are generally used in high temperature applications.

Type S thermocouples: These are made of platinum and platinum-rhodium alloys and can measure temperatures up to 1,600°C. They are generally used in applications requiring high accuracy and stability.

Type R thermocouples: These are also made of platinum and platinum-rhodium alloys and can measure temperatures up to 1,600°C. They are similar to type S thermocouples but are more commonly used in industrial applications.

Thermocouples (Thermocouples); According to the AMS 2570 standard published on temperature measurement in the aviation industry, digital instruments that measure data from thermocouples, TUS (Temperature Uniformity Survey) that describes the measurement of temperature homogeneity in a certain volume, SAT (System Accuracy Test) that measures the accuracy of thermocouples, and extensive and detailed information about test environments. available. Here, what deviations can be allowed from a certain type of thermocouple at what temperatures, test frequencies and classes of furnaces are defined in detail.

Selection of the appropriate thermocouple for a particular heat treatment process depends on several factors, including the temperature range, accuracy requirements, and the environment in which the thermocouple will be used.