Protective measures against weaknesses of stainless steel pipe fittings

1. Starting from the pipe material, the quality of raw materials shall be strictly controlled.

Strict on-site inspection shall be carried out for stainless steel pipes and fittings. To ensure that the materials meet the requirements. In terms of material selection, comprehensive consideration shall be given to economy and function. Under special operating conditions, austenitic stainless steel with high nickel content, duplex stainless steel, titanium and titanium alloy, glass fiber reinforced plastic, etc. with stronger corrosion resistance can be considered.

When selecting materials, appropriately increase the corrosion allowance of pipes and stainless steel tee fittings to meet the service life requirements of the pipeline system.

2. Surface coating protection For the corrosion of stainless steel pipe fittings in the environment, in addition to selecting materials with strong corrosion resistance, the corrosion resistance can also be improved by coating the surface of stainless steel pipe fittings. In view of the problem that the surface of stainless steel pipe substrate is relatively smooth and the adhesion of conventional stainless steel reducing pipe anti-corrosion coating on its surface is relatively poor, an effective anti-corrosion coating for stainless steel pipe fittings in the marine environment, epoxy powder coating, has been developed. The coating is a new type of coating which is completely solvent free and is sprayed into a film in the form of powder.

3. Electrochemical protection

The electrochemical protection methods mainly include protective device, cathodic protection and anodic protection.

(1) The protector protection method refers to connecting the metal with low electrode potential and the protected metal together to form a galvanic cell. The metal with low electrode potential is dissolved as anode, and the protected metal is used as cathode to avoid corrosion.

(2) Cathodic protection means that DC power is applied to connect the protected metal to the negative electrode as the cathode, so that the potential of the protected stainless steel flange metal can be negatively adjusted and enter the non corrosive area of the E-pH diagram; The waste metal is connected to the positive pole as the anode to make the waste metal corrode and protect the cathode.

(3) The anode protection method refers to the use of an external DC power supply to connect the protected metal to the anode as the most anode, move the electrode potential in the positive direction (i.e., anodic polarization), and enter the passivation area of the E-pH diagram, so that the protected metal can be "passivated" and protected.