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| Brand Name: | Yuhong |
| Model Number: | ASTM A335 P22 Studded Tube With 11Cr Stud Fins |
| MOQ: | 200~500 KGS |
| Price: | Negotiable |
| Payment Terms: | TT, LC |
| Supply Ability: | According to Clients' requirements |
ASTM A335 P22 Studded Tube With 11Cr Stud Fins For Furnace Walls and Roofs
An ASTM A335 P22 Studded Tube with 11Cr Stud Fins is a high-performance engineered component designed for extreme service. It consists of:
1. Base Tube: ASTM A335 P22 seamless pipes
(1). Chemical Composition
| Element | Composition (%) - Product Analysis (Heat analysis is slightly different) |
| Carbon (C) | 0.05 - 0.15 |
| Manganese (Mn) | 0.30 - 0.60 |
| Phosphorus (P) | 0.025 max |
| Sulfur (S) | 0.025 max |
| Silicon (Si) | 0.50 max |
| Chromium (Cr) | 2.00 - 2.50 |
| Molybdenum (Mo) | 0.87 - 1.13 |
(2). Mechanical Properties
These are the minimum requirements for the finished seamless pipe in the normalized and tempered heat-treated condition.
| Property | Value (Minimum) | Notes / Test Standard |
| Tensile Strength | 415 MPa (60,000 psi) | |
| Yield Strength (0.2% offset) | 205 MPa (30,000 psi) | |
| Elongation in 2 inches (50.8 mm) | See formula below | For walls ≤ 0.75 in: 30% min For walls > 0.75 in: 28% min |
| Elongation (Alternative Formula) | Longitudinal: El% = 625000 x A⁰·² / UTS⁰·⁹ Transverse: El% = 310000 x A⁰·² / UTS⁰·⁹ |
Where: A = cross-sectional area (in²), UTS = tensile strength (psi). Governs when it gives a higher minimum than the fixed percentage. |
| Hardness | Typically ≤ 197 Brinell HBW | Often specified to ensure weldability and ductility. |
2. Studded Tube (The Design)
This describes the physical form.
Instead of being a smooth pipe, the outer surface has studs (small, cylindrical pins) welded on in a regular pattern.
The purpose of these studs is to act as an anchor or reinforcement for a lining or coating, significantly increasing the surface area for heat transfer.
3. 11Cr Stud Fins (The Critical Feature)
This is the most specialized part of the specification.
11Cr: Stands for 11% Chromium. This is a martensitic stainless steel alloy (like Grade 410, but often a proprietary variant).
Stud Fins: shaped more like short, robust fins or pins.
Why 11Cr? The base tube (P22) is chosen for its high-temperature strength in the tube metal temperature range. However, the studs/fins themselves are exposed to an even harsher environment—the hot flue gas or firebox atmosphere, which can be highly corrosive due to sulfur, vanadium, and other combustion by-products.
Primary Applications
1. Petrochemical & Refinery Process Heaters (Fired Heaters)
This is the most common application.
Location: The radiant section/firebox walls and roof of heaters like:
Role: They form the waterwall or steam-generating wall of the firebox. The studded/refractory lining:
Protects the tube from direct flame impingement and peak radiant heat, keeping the tube metal temperature within P22's safe limit.
Absorbs and transfers enormous amounts of heat to generate high-pressure steam or superheat process fluids.
Withstands the corrosive atmosphere from burning refinery fuel gas/oil, which contains sulfur and other contaminants.
2. Ethylene Cracking Furnaces
Location: The radiant coil section walls (the "firebox").
Role: These tubes form the walls surrounding the reaction coils where ethane or naphtha is cracked into ethylene at extreme temperatures (1500°F+ / 815°C+). They protect the structure and recover waste heat to produce steam, a critical utility for the plant.
3. Power Generation - Waste Heat Recovery (HRSG) & Specialty Boilers
Location: In Heat Recovery Steam Generators (HRSGs) following gas turbines in refineries or chemical plants, especially when firing supplemental (duct) burners.
Role: Used in the evaporator sections exposed to the hottest flue gas, particularly when the fuel may have corrosive elements.
Circulating Fluidized Bed (CFB) Boilers: For walls in areas subject to high erosion and moderate corrosion, the studded refractory lining provides excellent protection.
4. Carbon Black & Syngas Production Units
Location: Reactor walls in processes involving the pyrolysis or partial oxidation of hydrocarbons.
Role: These environments are exceptionally harsh, with high temperatures and potentially reducing atmospheres. The 11Cr studs and refractory lining are essential for longevity.
