Let's start with a fact:
Austenitic stainless steel pipes are commonly used in a variety of corrosive environments. However, if you are careful, you will find that in the design documents of some units, as long as DN≤40, all kinds of materials are basically adopted. In the design documents of other units, stainless steel pipes, no matter how small the caliber is, they also use butt-welded pipe fittings instead of tube fittings.
As the saying goes: in order to ensure the welding quality of small-caliber pipes and avoid welding penetration during large current welding, socket connection is often used instead of butt welding connection. So, why do other units of stainless steel small caliber pipes not bear intubation pieces? This involves a problem: crevice corrosion.
Let's talk about what is crevice corrosion?
When there is a gap (generally 0.025-0.1mm) on the surface of metal components due to foreign bodies or structural reasons, it is difficult to migrate the corrosive medium in the gap, which leads to metal corrosion, called gap corrosion. Crevice corrosion often becomes the inducement of other corrosion (such as pitting corrosion, stress corrosion), so the project strives to avoid the occurrence of crevice corrosion. The existence of cracks should be avoided in the design of pipeline structure for the medium that is prone to crack corrosion.
Stainless steel 304 flange
It is because there is a gap in the socket connection, so some units in order to avoid the gap corrosion, for the existence of corrosion of stainless steel pipes, small caliber pipeline often use butt welding connection, welding process control to ensure quality, avoid the use of intubation.
304 is a universal stainless steel, it is widely used in the production of equipment and parts requiring good comprehensive performance (corrosion resistance and formability).
304 stainless steel is a brand of stainless steel produced in accordance with ASTM standards in the United States. 304 is equivalent to China's 0Cr19Ni9 (0Cr18Ni9) stainless steel. 304 contains 19% chromium and 9% nickel.
304 is a widely used stainless steel, heat resistant steel. Used in food production equipment, xitong chemical equipment, nuclear energy, etc.
304 stainless steel butt welding flange is a widely used chromium - nickel stainless steel, with good corrosion resistance, heat resistance, low temperature strength and mechanical properties. Corrosion resistance in the atmosphere, if it is an industrial atmosphere or heavily polluted area, it needs to be cleaned in time to avoid corrosion. Suitable for food processing, storage and transportation. It has good machinability and weldability. Plate heat exchanger, bellows, household goods, building materials, chemicals, food industry, etc.