Outdoor furniture needs to face many challenges from the weather and environment, it has more strict material requirements than indoor furniture. So, does stainless steel is a good choice? The answer is YES!
Stainless steel is good for outdoor furniture, its corrosion resistance makes it withstand sunny, rainy, windy, and snowy weather, which can last for a long time. And stainless steel is flexible, not prone to mold, fire & heat resistant, and climate-proof helps it performs well in outdoor use.
Keep reading to get more details.
Adapt to rainy, snowy, windy, and sunny weather
Rainy, snowy, windy, and sunny are the weather situations that outdoor furniture cannot avoid.
When exposed to constant moisture, outdoor furniture might be deformed, damaged, or rotted. Thus, metal( iron/carbon steel） furniture is easily corroded in a humid environment. Which’s Iron composition will react with the oxygen and moisture in the air and oxidize, slowly weakening the metal and eventually causing discoloration and rusting.
However, the excellent corrosion resistance of stainless steel allows it to withstand wet. Its corrosion resistance comes from chromium; it reacts with water and the oxygen in the air to form a passivation layer – chromium oxide, which acts as a protective layer. It avoids water or moisture reacting with the iron in stainless steel, thus making the stainless steel corrosion resistance.
The most important thing about chromium oxide is it can be rehealing. If it gets damaged, it can be fixed by itself. As long as there is enough chromium, it can repair itself by many times. More chromium, better protection, and higher corrosion resistance.
Most stainless steel for outdoor uses is high-grade, such as stainless steel 304, 316, etc., and it can last for a long time under snow, rain, and wet weather.
Not prone to mold
What comes with humidity are mold and mildew. Moisture and humidity can promote mold growth, a problem outdoor furniture faces.
The non-porous stainless steel makes it less susceptible to mold and mildew, which is good for outdoor furniture.
The growth of mold needs to meet four terms: moisture, nutrient supply, air, and suitable temperature. However, stainless steel doesn’t meet it.
- Stainless steel is a non-porous smooth surface. Moisture is not easy to get into the inner area, and it is hard to save water inside. Therefore, stainless steel lacks a moist environment, which leads to mold not surviving.
- Mold feeds on organic materials and absorbs the nutrients dissolved in the water of it. Stainless steel is an inorganic material, which does not have a food environment for mold. Mold can not extract nutrients from it, making it difficult to survive.
Sunny is the weather that outdoor furniture often gets through; the high temperature under the sun is a challenge for outdoor furniture’s heat resistance. It will weaken furniture’s physical and mechanical properties, such as swell, warp, or crack, and strong ultraviolet light may lead to furniture discoloration and fade.
But stainless steel has good resistance to high temperatures. Stainless steel 304 and 316 can keep long-term resistance to oxidation even under the heat of 800 ° C temperature, and melt at about 1400 ° C. High temperatures won’t affect the mechanical properties of stainless steel; it has a good tensile strength to keep stable at high temperatures.
In Darchem Engineering’s 5-minute metal fire resistance test, stainless steel 316 was exposed to fire with temperatures up to 1000-1050ºC (1832-1922ºF). The test time was extended by 45 minutes from the beginning 5 minutes, and the temperature rose to a staggering 705ºC (1300ºF). Surprisingly, the test results showed that the warp of type 316 stainless steel was only 80.5 mm (3.2 inches), only producing a slight deflection.
Another challenge for outdoor furniture is climate change. Summer is very hot, and winter is very cold. As the seasons’ change, the temperature difference between morning and evening is very large.
If located in these areas where the climate changes significantly, the stress from the drastic temperature change may cause the outdoor furniture to be damaged easily.
But stainless steel works well in this environment. It has strong tensile strength and low carbon content to maintain flexibility, toughness and mechanical strength over a wide range of temperatures.
Stainless steel does not have significant expansion or contraction with temperature differences. It won’t creep, warp or sag and can maintain stable performance during climate change.
Good for use in the coastal/chemical environment
Corrosion of outdoor furniture is more common and severe in coastal areas than inland. Due to the high humidity and salinity in coastal locations, iron in the metal is easily oxidized to form iron oxide. And the high salt content of the air and water accelerates the chemical action, thus promoting more corrosion.
Therefore, the high corrosion resistance stainless steel is a good option for the coastal city as outdoor furniture.
The most popular and selling stainless steel is SS 304, which contains 18% chromium and 8% nickel. Chromium content is much higher than the base standard 10.5% of stainless steel. SS 304 also known as food-grade stainless steel, has strong corrosion and oxidation resistance and can withstand rain and snow.
But most of the coastal areas are high salt and temperature; even if stainless steel 304 can’t get a good performance there, higher grade-stainless steel 316 is a better choice.
Stainless steel 316, also known as “marine grade,” contains 2-3% molybdenum. Molybdenum increases the resistance of stainless steel to corrosion caused by salt and chloride ions in seawater, which makes stainless steel 316 more resistant to corrosion. In coastal environments, outdoor furniture can choose stainless steel 316 to resist corrosion.
Furthermore, Suppose your home is near some large industrial enterprise or in a chemical environment. In that case, the stimulating components of the environment, such as acids, alkalis, and chlorine, will corrode outdoor furniture. Stainless steel 304 can withstand up to 3% sulfuric acid, while stainless steel 316 can up to 20% sulfuric acid. So, for outdoor furniture used in chemical environments, stainless steel 316 is better recommended.
The molybdenum in stainless steel 316 increases its resistance to corrosion caused by chemicals and has excellent resistance to specific types of corrosion, especially the typical pitting caused by chemical compositions.