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You May Not Know These Little Knowledge Of Stainless Steel Pipes

Feb 28, 2021

1. Weight calculation formula of stainless steel plate: length * width * thickness * specific gravity = weight

For example: 1.5mm*1000mm*2000mm, 1*2*1.5*7.93=23.79 kg


2. Weight calculation formula of stainless steel pipe: (diameter-wall thickness) * wall thickness * specific gravity = meter weight

For example: 108*4mm tube, (108-4)*4*0.02491=10.36 kg


3. What is the difference between stainless steel pipe 304 and 201:


1. The price is different: 304 has better quality, but the price is more expensive, 201 is worse, but the price is cheaper.

2, the composition is different: 304 is 8 nickel 18 chromium, 201 is 1 nickel 13 chromium

3. Different anti-rust performance: 304 has strong anti-rust performance, 201 has weak anti-rust performance

4. The strength is different: the yield point of 304 steel is 205MP, the tensile strength is ≥515Mpa, the yield point of 201 steel is 275MPa, the tensile strength is ≥520MPa


4. Why does stainless steel rust:

1. Many people think that stainless steel pipes will definitely not rust. This is a wrong one-sided view. First of all, the rust resistance and corrosion resistance of stainless steel pipes are conditional. Stainless steel pipe is a steel pipe that does not produce rust in the atmosphere, fresh water and other weak corrosive environments, and the chromium content in the steel must be ≥12%. If the chromium content is low or it is not used in a weakly corrosive environment such as the atmosphere (including in a weakly corrosive environment such as the atmosphere, but under the condition of local enrichment and concentration of Cl-), rust will occur. Acid-resistant steel pipe is a steel pipe that is resistant to corrosion in strong corrosive media such as acid, alkali, salt, etc., but it is also corrosion-resistant under certain conditions, such as medium type, temperature, concentration, impurity content, flow rate, pressure, etc. There is no stainless steel pipe in the world that does not rust and is corrosion-resistant under any conditions.


2. The surface of stainless steel accumulates dust containing other metal elements or attachments of dissimilar metal particles. In humid air, the condensed water between attachments and stainless steel connects the two into a micro battery, which initiates an electrochemical reaction , The protective film is damaged, which is called electrochemical corrosion.


3. Organic juices (such as melons, vegetables, noodle soup, etc.) adhere to the surface of stainless steel. In the presence of water and oxygen, organic acids are formed, and organic acids are formed to corrode metal surfaces for a long time.


4. The surface of stainless steel adheres to acid, alkali, and salt substances (such as alkali water and lime water spray test for decoration walls) causing local corrosion.


5. In polluted air (atmosphere containing a lot of sulfides, oxides, and hydrogen oxides), contact with condensed water will form nitric acid and acetic acid liquid spots, causing chemical corrosion.