Stainless steel is a wide-ranging material used for many purposes, including in cookware, jewellery, and industrial use. Two which are used very commonly for industrial fittings, infrastructure, and heavy-duty appliances are the 304 and 316 stainless steel types.
To the uninformed, the 304 and 316 are virtually indistinguishable. But they differ in some properties, which makes them suitable for different uses. The 316 is also more expensive than 304 stainless steel – and we will see why in the next section below.
Type 304 Vs Type 316
Steels are mainly made of iron and carbon, but stainless steels also contain a minimum of 10.5% chromium. Chromium is what gives stainless steel the ‘stainless’ property, which means that it is not easily corroded by most other chemicals.
Type 304 and 316 stainless steels are also similar in that they both contain a significant proportion of nickel. However, what distinguishes them chemically is the presence of molybdenum in Type 316 stainless steel, which is absent in Type 304.
Type 316 stainless steel contains at least 2% of molybdenum, which makes the material even more corrosion-resistant than Type 304. Molybdenum also adds to the cost of the material, which is why Type 316 is more expensive. There are some other stainless steels in the 300 series which contain up to 7% molybdenum, but due to their high cost, those are used only for very heavy-duty applications with high exposure to salinity.
Applications of 304 stainless steel
Type 304 stainless steel offers a good balance of corrosion resistance and value, earning it the title of the most-used stainless steel in the world. It is the most affordable upgrade from standard carbon steel in terms of corrosion resistance.
As such, you will see Type 304 stainless steel everywhere, including dishwashers, refrigerators, cookware, cutlery, kitchen sinks, food processing equipment, nuts, bolts, screws, and pharmaceutical production equipment.
However, no stainless steel is truly immune to corrosion. Type 304’s limitation is its susceptibility to corrosion when exposed to chlorides, which include common table salt and seawater.
Applications for 316 stainless steel
The presence of molybdenum enables Type 316 stainless steel to be more resistant to chlorides as compared to Type 304. For this reason, Type 316 is the upgrade to go for when stainless steel is to be used in more saline or chloride-exposed environments.
For infrastructure near the ocean or coastlines, boat fittings, and even marine equipment, Type 316 is often the go-to choice. Due to their suitability for being used for marine equipment, Type 316 is also called ‘marine grade’ stainless steel.
Other applications for 316 stainless steel include industrial tubings, outdoor furnishings, high-salinity food processing, chemical and petrol processing equipment, and medical implants.
Both 304 and 316 stainless steels are very common in everyday and industrial usage. Understanding their properties will help you choose the right material for your intended purpose.
Here at Pharmchem Engineering, we offer a variety of stainless steel grades for sanitary pipe fittings and valves. Depending on your industry and the medium to be processed, we can provide you with the right fittings according to industry standards and regulations.
Need additional parts and engineering solutions? Explore rubber and Teflon hoses, pipe-pigging equipment, and fabric expansion joints here at Pharmchem Engineering – simply get in touch to consult our experts today!