Letters after stainless steel grades indicate specific modifications. These changes or modifications affect the properties of the material. Understanding these letters can help you select the most appropriate stainless steel pipe and fittings.
What Are Letters After Stainless Steel Grades? Hidden Meanings!
The letter following a stainless steel grade indicates a particular property of the stainless steel. This may be a chemical modification or it may indicate a special property. These letters tell you how the alloy will perform and help ensure that the stainless steel is suitable for your application.
Common Letters after stainless steel grades and Their Impact
Indicates that this stainless steel has a very low carbon content (304L stainless steel, 316L stainless steel). It prevents sensitisation during welding and minimises intergranular corrosion.
This suffix indicates that the stainless steel has a high carbon content (304H stainless steel, 316H stainless steel). Increased high temperature strength and improved creep resistance.
Indicates that titanium has been added (316Ti stainless steel). Titanium adsorbs carbon, so it prevents carbide formation. This provides excellent resistance to intergranular corrosion.
This suffix indicates the addition of nitrogen (304N stainless steel, 2205N stainless steel). Nitrogen increases strength and pitting resistance and is common in duplex stainless steels.
This indicates the addition of sulphur (303F stainless steel). Sulfur improves machinability and makes the material easier to cut. However, it slightly reduces corrosion resistance.
What We Do
Letters after stainless steel grades Impact on Pipe & Fittings
| Suffix | Impact on Performance | Ideal Pipe/Fitting Use |
|---|---|---|
| L | Prevents sensitization from welding heat | Welded chemical lines, pharma pipes |
| H | Stronger at very high temperatures, resists creep | Boiler tubes, furnace components |
| Ti | Excellent for high-temp welded applications | Exhaust systems, hot process lines |
| N | Higher strength for thinner sections, better pitting | Pressure vessels, structural pipe |
| F | Easier to machine, but less corrosion resistant | Machined fittings where corrosion is minor |
| Cu | Better for specific acid environments | Specialized chemical transport pipes |
Sourcing Stainless Steel Pipe and Fittings with Specific Suffixes
Always ask for material test reports. This is used to confirm the exact composition, including the presence and content of alloying elements.
Match the grade suffix to your needs. For example, ‘L’ grades are used for welded tubes,and ‘H’ grades are used for high temperature service.
Work with knowledgeable suppliers. They understand these special grades and can ensure proper production controls. And verify that they are certified (e.g., ISO 9001 and CE-PED).
Grades such as ‘L’ and ‘Ti’ are designed for better welding. Learn the welding process for each different grade of stainless steel.
The ‘H’, “Ti” and ‘N’ grades typically cost more. However, in critical applications, their increased performance justifies the investment.
You May Also Want To Read:
What Are H and L Stainless Steel – Duplex Pipe
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