一 、 Core difference: Material determines essence
1. Carbon steel flange
Ingredients: Mainly iron and carbon, containing small amounts of other elements such as manganese and silicon. It can be understood as' ordinary steel '.
Core features: high strength, high hardness, and very low price.
Fatal weakness: easy to corrode and rust. Exposure to air, water vapor, humid environments, or corrosive media can cause rapid rusting. Therefore, carbon steel flanges usually require surface anti-corrosion treatment, such as coating with anti rust paint, hot-dip galvanizing, etc., in order to be used in certain environments.
2. 304 stainless steel flange
Ingredients: In addition to iron, it contains a high proportion of chromium (Cr ≥ 18%) and nickel (Ni ≥ 8%).
Core feature: Excellent corrosion resistance. Chromium element will form a very thin but dense chromium oxide passivation film on the surface, which can prevent the internal metal from being further corroded, thus achieving "stainless".
Main disadvantages: high cost due to the presence of precious metal nickel; Strength and hardness are usually lower than carbon steel under the same specifications (but fully meet the pressure requirements of the vast majority of pipelines).
二，
feature | Carbon Steel Flange | 304 stainless steel flange |
| corrosion resistance | Poor, prone to rusting, requires surface treatment | Excellent, resistant to water, atmospheric, and various chemical corrosion |
| mechanical strength | tall | Good, sufficient for use |
| cost | Low, affordable | High, usually several times the price of carbon steel |
| High and low temperature resistance | Easy to oxidize at high temperatures, may become brittle at low temperatures | Good high-temperature oxidation resistance and excellent low-temperature toughness |
| Hygiene and Aesthetics | Poor, prone to pollution, not aesthetically pleasing | Excellent, easy to clean, shiny appearance, in compliance with food hygiene standards |
| Maintenance Requirements | High, regular inspection of the anti-corrosion coating is required | Low, almost maintenance free |
| Common applications | Non corrosive environment: tap water, air, oil and gas, steam pipelines (internal medium is non corrosive) | Corrosive/Sanitary Environment: Chemical, Food, Pharmaceutical, Marine, Drinking Water Systems |
三， How to choose?
1. Transport medium (most critical factor)
Choose carbon steel: If conveying non corrosive media such as dry air, nitrogen, ordinary tap water, non corrosive oil, etc.
Choose 304 stainless steel: If conveying corrosive media such as chemicals, seawater, acids, alkalis, or media with extremely high purity requirements such as food, drugs, and beverages.
2. Operating environment
Choose carbon steel: for indoor and dry environments. If used outdoors or in damp workshops, high-quality anti-corrosion measures must be taken.
Choose 304 stainless steel: suitable for corrosive environments such as outdoor, humid, coastal areas, and chemical plants.
3. Budget and Long term Costs
Choose carbon steel: the first choice for those with limited initial investment budget and good economic efficiency.
Choose 304 stainless steel: Although it is expensive to buy, it has a long service life and requires almost no maintenance. From the perspective of the entire usage cycle, the overall cost may be lower.
4. Hygiene and appearance requirements
Choose 304 stainless steel: For the food, pharmaceutical industry, or occasions with aesthetic requirements (such as exposed pipelines in buildings), 304 stainless steel is a necessary choice.