The stainless steel products are very common in our lives. For example, pipe nipple, pipe fitting and all kinds of goods. Are you sure the product you bought is true stainless steel. Are you sure the product you bought is not Ferritic stainless steel or Martensitic stainless steel. What is true stainless steel?

The stainless steel covers a wide range of alloys with different properties. One property common to all stainless steels is that they contain at least 12% chromium. The stainless steels can be divided into three main groups and a few mixed types according to the structure of the steel:

1. Austenitic stainless steel

2. Ferritic stainless steel

3. Martensitic stainless steel

Austenitic stainless steel is the most important, representing approx. 90% of total stainless steel consumption. Austenitic stainless steel is also the only stainless steel suitable for drainage installations.

Alloying elements Austenitic stainless steel contains at least 18% chromium and 8% nickel – thus the well-known designation (18/8) steel. Corrosion resistance generally increases with the increase of chromium content. In alloys with 12-13% chromium, the passive layer is strong enough to prevent the steel from corroding in normal or mildly aggressive media. The main effect of the alloying element nickel is on the structure of the steel and its mechanical properties. The steel’s structure is austenitic with an adequate content of nickel. In contrast to the pure chromium steels (ferritic stainless steel), this results in significant changes in the mechanical properties, such as increased workability and ductility, better resistance to thermal stress and improved weldability. The austenitic structure also results in a change in the physical properties of the steel. For example, the steel is a little magnetic and has higher thermal conductivity.

Nickel also increases resistance to corrosion caused by certain media. Molybdenum has the same effect on the structure as chromium, but it also has a strongly positive influence on corrosion resistance. Molybdenum-containing steel is normally designated (acid-resistant) because of the resistance of these steels to certain types of acids. But acid-resistant stainless steel also has limited resistance to some media such as chlorine-containing media.

Cangzhou Minchuang Pipe Fitting Co., Ltd in China supplies all kinds of Pipe Nipples&Fittings to global market with good quality Austenitic stainless steel. If you know what is true Austenitic stainless steel, please choose Cangzhou Minchuang Pipe Fitting Co., Ltd in China.

We'll see next time. Why is steel "stainless"?