How to Address Valve Erosion and Corrosion

Erosion and corrosion are phenomena where the internal metal surface of a valve pipeline is damaged due to high-speed relative motion between the metal and fluid. This interaction results from the combined effects of erosion and corrosion, leading to significant local corrosion. This issue is prevalent in the elbows of valves and pipelines in the oil, chemical, energy, and power industries, especially in high-pressure, high-temperature fluid transportation pipelines with solid particle flow, liquid-solid mixed flow, and liquid-gas-solid three-phase flow. Consequently, erosion and corrosion problems have garnered significant attention.

When valves in pipelines are affected by erosion and cavitation, it can cause local thinning of the pipe wall and internal corrosion of the flow channel. Excessive pressure may lead to leaks or ruptures. Typically, corrosion areas can be detected by ultrasound, but edges or overheated pipelines cannot be detected using this method. Therefore, erosion and cavitation remain particularly challenging issues in industrial production.

I. Analysis of Erosion Causes

1. Flash evaporation of fluid medium causes erosion to the valve.
2. Hard impurities in the fluid medium cause severe erosion and wear to the valve components.
3. Valve opening between 30%-40%, resulting in a small flow area and accelerated fluid velocity, leading to high-pressure erosion of the valve components.
4. The fluid medium's flow trajectory at 30% valve opening (see Figure 1) shows direct impact on the valve body outlet inner wall and flange edge, causing erosion.
5. Conventional imported valves are also unsuitable for erosion conditions (see Figure 2).

Figure 1: Original valve medium flow trajectory

Figure 2: Damage to imported brand valves

Figure 3: Damage to domestic brand valves in metallurgy and chemical industries

Slurry (contains 5% seawater)

II. Solutions

To address the erosion problem of the on-site valve body, our company uses a sealing seat with an open baffle design and special wear-resistant metal materials plus aerospace wear-resistant treatment (see Figure 3). This structure slightly reduces the diameter of the valve seat, increasing valve opening and allowing hard media such as slurry to flow through the valve chamber, significantly reducing erosion and wear on the valve body walls. The baffle structure of the sealing seat provides a first layer of protection, ensuring that even if the baffle is worn, the sealing effect of the valve is not compromised. The valve core and the sealing surface of the valve seat, along with the inner wall, are treated with wear-resistant coatings (e.g., hard chrome plating, WC spraying, or aerospace hard alloy overlay welding), extending the service life of valve components and overall valve durability.

Figure 3: Sealing Seat with V-shaped Open Baffle                     Figure 4: Conventional Valve Sealing Seat

III. Ordering Instructions

This solution is suitable for erosion conditions, with a specially designed baffle structure on the valve seat to effectively prevent fluid medium erosion. To improve effectiveness, it is recommended to provide specific technical parameters from the site (e.g., medium, medium pH value, valve opening, flow rate, pressure difference, closing pressure, medium temperature) to select the most appropriate sealing materials and special component treatments. Valve materials available include 304, 304L, 316, 2205, SMO, etc., for reference.

Figure 5: GRAT Control Valve Erosion-resistant Wafer Ball Valve (available with flanged connection)