One of five 12″ CF8M Metal Seated Ball Valves w/ AIT Gears
MEGA Seal Metal Seated Ball Valves
- Dirty, Erosive and / or Mild Corrosive Service to 850F
- Graphite Energized Seats with Seat and Ball Coating based on Service Conditions. Class 150, 300 and 600
- Applications Include Ethylene, VCM, Catalyst / Powder Feed, Furnace Transfer Lines
- Generally Manual Valves or infrequent on/off where contaminants can “lock” more Severe Service Valves
MEGA Seal Graphite Seated Ball Valves
- “Clean” Service, 450F to 1000F
- Strong Acids and Oxidizers where Coatings of Metal Seated Valves will not Function (e.g. HF, Chlorine)
- 50% Torque Requirement vs. Metal Seated
- P/T Rating to ASME B16.34 Valve Body. Generally Class 300 and 600.
12″ CF8M Metal Seated Ball Valves
|GRAPHITE SEATED||METAL SEATED|
|Class 300 and 600||Class 150 – 600|
|Flanged Ends||SW/BW, RFF, RTJ End Connection Possible|
|¾” – 8”||.5” – 14”|
|Split Body or Unibody, Full or Reduced Port||Split Body or Unibody, Full or Reduced Port|
|Target Market: SPECIALTY CHEMICALS. Clean High Temperature and Acid Service with Temperatures above 450F (up to 1000F)||Target Market: Petrochemical and Chemical|
•ETHYLENE and VCM
•Alloy Options include 316SS, Monel, Inconel, etc.
|API 598 Shutoff||API 598 Shutoff (HP Test Included)|
|Full Alloy Options (Hastelloy, Inconel, Incoloy, Monel, etc.)|
What are “Metal Seats”?
- Base Metal Contact (Gate and Globe Valves – Not Sliding Wear)
- Coated or Modified Metal (Most Common)
- Stellite Weld Overlay (Usually Stellite VI – Cobalt Based)
- “Surface Modification” of Sealing Surfaces: Ex. Nitriding, Boronizing, etc.
- Plating: Ex. Chromium Plating or ENP (Electroless Nickel Plating)
- HVOF Coating: Tungsten and Chromium Carbide are the most common
- Fused or Vacuum Deposition of “Coating” typically Tungsten Carbide
- There is no “One size fits all” for “Metal-to-metal” sealing. Coatings are very application dependent.
Metal Seated Valve Coating – Metal seated valves represent the fastest growing (by %) segment of the valve industry. These seats can be found in ball valves, butterfly valves, plug valves and others.
1. HP-HVOF Process
- Chrome Carbide, Tungsten Carbide, Chrome Oxide and other specially formulated coatings.
- WC-Co / WC-Ni / WC-Co-Cr / WC-CrC-Ni
- Coating mechanically bonds to the Substrate Material.
- Mechanical bond – >12,000 psi bond strength for Carbides, 5,000 – 7,000 psi for Chrome Oxide Ceramic.
- Robotically positioned spray gun creates high kinetic energy allowing the coatings to be applied in a compressive state.
- Porosity – Poor Sealing on Gas
- Carbon Content makes these coatings vulnerable to Oxidation.
2. Spray & Fused Process
- Substrate material becomes annealed due to fusing temperatures; subsequent heat treatment required.
- Semi-molten coating “sags” or “sloughs” – gravity effect
- Coated Surface is “finish” machined using either CBN (cubic boron nitride) or PCD (polycrystalline diamond) tooling.
- Very Low Porosity – Best for small molecule gas and particles smaller than 1 micron.
Vacuum Testing of Valve Trim Sets Prior to Installation
Key Petrochemical Processes for Ladish MEGA Seal & “S” Series Ball Valves
- VCM (Vinyl Chloride Monomer) – Stainless, Monel and Inconel Valves for Acid from Chlorine. Nickel Alloys becoming more Prevalent at 600+ F
- Ethanol/Methanol – Stainless Steel for Acid Attack
- Propylene / Ethylene Oxide / PDH – Reactive Chemicals require High Alloy valves with little Corrosion. Oxygen Service Valves are common and use Stainless and Hastelloy
- Polyethylene / Polypropylene Production – Business is in Additive Handling and Ball Valves. Hastelloy and Stainless Steel are used so that Iron (from Carbon Steel) does not contaminate the process.
- Phenol, Cumene, Butadiene – These are Reactive Chemicals requiring Nickel Alloys due to ORGANIC Acids.
- Ammonia / Nitric Acid – Stainless (304) and Monel to Resist Attack
- Ethylene: Pyrolysis Oils and Start-Up Vent Valves
Once again, Ladish will continue To Mark Progress.