Classification and prevention of 316 stainless steel square tube corrosion
1. Pitting
Pitting corrosion (as shown in FIG. 1), also known as pitting corrosion and pore corrosion, is one of the common local corrosion of 316 stainless steel square tubes. Generally, the pitting depth is larger than its diameter. When there are some active anions (CI-) in the medium, these anions are adsorbed on some points on the metal surface first, thus damaging the passivation film on the surface of 316 stainless steel square tube. There are defects in steel, impurities and solute the heterogeneity, once the surface passivation membrane damage, on substrate metal surface defect is easy, to assume the activated state, and passivation membrane as the passive state, thus formed the blunt activity - corrosion cell, because the anode area is much smaller than the cathode area, anode current density is very big, the corrosion to the deep development, The metal surface soon corroded into holes.
Pitting on SUS304 steel pipe used in brine
A way to prevent pitting
(1) Selecting pitting resistant materials, adding molybdenum and increasing chromium content in steel, such as 316L steel;
② Using reasonable heat treatment system, the 316 stainless steel square tube matrix is in complete solution state;
③ Reduce the concentration of halogen ions in the solution and improve the PH value of the solution;
(4) stir the solution to avoid local concentration of the solution and prevent impurities from sticking to the surface of the steel;
⑤ Improve the surface finish of 316 stainless steel square tube;
⑥ Reduce the temperature of the medium;
Adopt cathodic protection measures.
| Our 316 Stainless Steel Square Pipe Advantage |
| 1. | The purity of the steel strip is high |
| 2 | Main materials such as nickel, chromium and copper are up to standard and stable |
| 3 | Smooth surface, no peeling, no black spots, no cracks, no strain, smooth weld |
| 4 | Not easy to rust, corrosion resistance, stamping bending, high temperature resistance |
| 5 | Good extension line, solid welding, in the processing range can be flaring, shrinking, bending, cone cracking |
| 6 | Wide scope of application |
| 7 | Good sealing |
| 8 | Various specifications |
| 9 | Save equipment time |
| 10 | Immune to inclement weather |
| 11 | The tube body (inside and outside) is bright, accurate, high hardness, strong strength and stiffness, and easy to handle on the surface |
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