How to identify the quality of stainless steel heating pipe

The quality of stainless steel mainly depends on the difference in nickel content. Nickel is a high-quality corrosion-resistant element. The perfect combination with chromium in stainless steel further consolidates corrosion resistance and acid and alkali resistance. However, in order to obtain a pure austenite structure for low carbon nickel steel, the nickel content should reach 24%, and the corrosion resistance of steel in some media can only be significantly changed when the nickel content reaches 27%. Therefore, the heating pipe can choose 800, 840, 316L and other materials, and the anti-corrosion and high temperature resistance performance is better. The nickel content of the 800 stainless steel heating tube is 30%, the 840 tube is 20%, and the 316L stainless steel heating tube is 10%. However, if the worse 304 tube is used, the nickel content is only 8%.

 

The advantages of stainless steel heating tube: good heat resistance, dry burning resistance, low cost. At present, there are many types of stainless steel heating pipes, and the prices of various materials vary greatly. Likewise, stainless steel materials vary widely in quality and performance. Therefore, when purchasing stainless steel pipes for heating pipes, the content of specific elements must be tested to prevent fake and inferior products and buy inferior products at high prices.

 

In addition to this intuitive method, we have the following methods to test its quality.

 

1. Conduct an electrical strength test

 

High-quality products should be able to withstand a withstand voltage of 50Hz for 1 minute under the electrical strength of cold state and operating temperature. After cutting off the current 5mA, there is no breakdown and flashover.

 

2. Carry out an overload test

 

In the case of complete heat release, energize at 1.27 times the rated power for 1.5 hours, cut off the power supply for cooling, and repeat this speculation 30 times to see if the heating tube is damaged.

 

3. Conduct leakage current test

 

The heating tube was placed in a fully heated state and energized at a voltage of 1.15 times. If the leakage current is less than 0.5mA, it is a high-quality electric heating tube.

 

4. Carry out a seal test

 

This sealing test is mainly carried out on the outer casing of the electric heater. Put the heating tube into the acidified water, and then expose both ends of the heating tube to see if the performance requirements meet the requirements of 1 and 3.

 

5. Carry out the sealer test

 

The main performance requirements are the same as the fourth item, but the experimental conditions are different. The experimental conditions were that the electric heating tube was placed in an environment with a temperature of 60 °C and a humidity of 95% for one day.