Apa is the expansion of the stainless steel heating tube body?

Apa is the expansion of the stainless steel heating tube body?

Tube expansion refers to the phenomenon where the diameter of an electric heating tube becomes noticeably thicker due to high temperature transfer or power on, and after cooling, it cannot return to its normal diameter, even resulting in tube burst. Example: Analysis of the reasons for solid expansion in SUS304 stainless steel pipes. SUS304 stainless steel wire expansion coefficient (10-6/ degree ) is related to temperature ( degree ) and is divided into 5 temperature ranges: ① The linear expansion coefficient is 16.0 at 20~100 degree ; ② The linear expansion coefficient is 16.8 at 20-200 degree ; ③ The linear expansion coefficient is 17.5 at 20-300 degree ; ④ The linear expansion coefficient is 18.1 at 20-400 degree ; ⑤ The linear expansion coefficient is 19.0 at 20~800 degree .

The calculation formula for the diameter expansion of stainless steel heating pipes is ∆ d{{0}} In the formula x d0 x (t1 t0), ∆ d - diameter expansion, mm; --- Expansion coefficient of 304 stainless steel wire; D0-- Initial pipe diameter, mm; T0- initial temperature, degree ; The temperature after t changes, degree . When the electric heating tube with a diameter of 6.6mm is energized to reach the working temperature, the surface temperature of the tube can reach approximately 800 degree . By substituting the corresponding parameters into the formula, ∆ d=19.0 × 10-6 × 6.6 × (800-20)=0.097812mm. Based on this calculation result, when the surface temperature of the tube reaches 800 degree , if it is SUS304 tube, it is normal for the tube diameter to expand from 6.6mm to around 6.7mm. But if it is not a pure SUS304 pipe material containing metal elements with high linear expansion coefficient, there will be greater expansion, even bursting of the metal pipe. After dissection, it will be found that there is a clear gap between the pipe wall and the insulation layer of magnesium oxide. The quality of the pipe is unqualified, the wall thickness is uneven, and there are impurities, virtual welds, missing welding points, etc. in the welded pipe, which cannot withstand the heat expansion after heating and cause the pipe body to expand and burst.

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