Key Features Of 316 Stainless Steel Tubes: What Makes Them Highly Applicable?

316 grade is a steel alloy that contains at least 10% chromium. It is a popular grade of steel and is generally composed of 16 to 18% chromium, 2-3% molybdenum, 10-14% nickel, and a small amount of carbon. The molybdenum added to the stainless steel increases its corrosion resistance. When checking the 316 stainless steel tube price, you should also be aware of its unique features, which we have listed in this post. The amazing properties of 316 stainless steel make it one of the most widely used steel grades, as it can be used in corrosive environments like refineries, marine equipment, and chemical plants. 

Formation Of 316 Stainless Steel

The principle of passivation plays an important role in stainless steel. It is a process where the metal becomes unreactive or passive to oxidation compounds that are commonly found in the atmosphere and process fluids. This is done by exposing the stainless steel to air, which builds chromium oxides on the surface.

Passive Film

The formation of this passive film is enhanced by introducing the alloy to a chemical treatment in which it is thoroughly cleaned by submerging it in acidic passivation baths of nitric acid. The contaminants are removed so that they do not interfere with the creation of the passive layer. The alloy is then neutralized in aqueous sodium hydroxide. The descaling process eliminates the other oxide films formed during the high-temperature milling operations. Let us now see  the special characteristics of the alloy that justifies the 316 stainless steel tube price. 

What Role Does Each Of Its Constituents Play?

• Carbon: Although carbon makes up very little of its composition, it gives it hardness and strength. But the scarce amounts also make the alloy brittle, improve its ductility, and allow it to respond to heat treatment. 
• Chromium: The layer of chromium oxide, which is formed at the surface, protects the material from corrosion and stabilizes stainless steel. 
• Nickel: This element is added to form an austenitic microstructure at room or low temperatures. 
• Molybdenum: It is added to maintain the toughness of stainless steel at high temperatures.  
• Manganese: When added with nitrogen, it helps decrease the amount of nickel required to maintain an austenitic microstructure.
• Nitrogen: This helps to promote the austenitic microstructure. Since it has a lesser tendency to react with chromium, it can be added in higher amounts to increase the strength of steel.
• Silicon: This is a deoxidizer that also improves the strength of the alloy. 

General Properties Of 316 Stainless Steel

• Corrosion Resistance: The presence of molybdenum improves the corrosion resistance of 316 stainless steel, especially pitting corrosion, a highly localized type of corrosion that creates shallow holes on the surface. Pitting corrosion is mostly noticed in seawater. 
• Weldability: 316 stainless steel is the least impacted by welding. It is able to retain its toughness and impact strength as welding does not transform it into martensite. This steel grade is also less susceptible to cold cracking, making it highly suitable for welding fillers. 
• Toughness: 316 stainless steel can retain its toughness over a wide range of temperatures. 
• Hardenability: Since 316 stainless steel is austenitic, heat treatment cannot harden it. Hence, the hardness is obtained by cold-working.
• Heat Resistance: This alloy shows good resistance to oxidation in continuous service to 925 degrees and intermittent service to 870 degrees Celsius. But continuous service at 425-860 degree Celsius is not recommended if the application requires corrosion resistance in the water. In such cases, 316L is recommended as it has high resistance to carbide precipitation. 
• Fabrication: 316 stainless steel can be fabricated only with tools that are dedicated to working with stainless steel materials. The work surfaces and tooling should be thoroughly clean to avoid cross-contamination by easily corroded metals, as it could discolor the surface of the fabricated product.
• Cold Working: 316 stainless steel can be readily roll formed into a variety of parts and is also suited for heading, drawing, and stamping. However, post-work annelation is a must in order to relieve internal stresses. Cold working of 316 stainless steel increases its strength and hardness. 
• Hot Working: 316 stainless steel is suitable for all common hot working processes, but it should be avoided below 927 degrees Celsius since the ideal temperature range is 1149-1260 degree Celsius. To ensure optimum corrosion resistance, post-work annelation is recommended. 
• Machinability: 316 stainless steel has good machinability, which can be enhanced by keeping the cutting edges sharp; keeping the cuts light but deep enough to prevent work hardening; employing chip breakers to ensure that the swarf remains clear; and maintaining low thermal conductivity. 

Wrapping Up

We can conclude that 316 stainless steel alloy has chromium, nickel, and molybdenum as its primary elements, which makes the tubes corrosion-resistant.

Since it belongs to the austenitic group, it exhibits some excellent characteristics like high-temperature stability, low-temperature toughness, weldability, and good formability, which makes 316 stainless steel tubes extremely efficient and widely applicable in various industries.