Stainless steel material identification methods

Stainless steel types and grades is very much, 304 stainless steel material is stainless steel in the use of more of a nationally recognised food-grade stainless steel, chemical corrosion resistance and electrochemical corrosion performance in the steel inside is better than titanium alloys. 304 stainless steel heat-resistant, heat-resistant, but also resistant to low temperatures and even resistance to ultra-low temperatures, used in the manufacture of high-grade household goods. 304 stainless steel alloy content is higher, so the price is much higher than ordinary steel, which often leads to unscrupulous merchants market more with other stainless steel as 304 stainless steel, and other stainless steel. The price is much higher than ordinary steel, which often leads to unscrupulous business market is more with other stainless steel as 304 stainless steel, we need to know how to identify 304 stainless steel as well as other stainless steel.

Traditional identification methods are:

Method one, the identification of colour and lustre, after pickling of stainless steel, the surface colour and lustre of silver and clean, the surface colour and lustre of stainless steel without pickling: chromium-nickel steel is brownish-white, chromium steel is brownish-black, chromium-manganese nitrogen is black. Cold rolled unannealed chromium-nickel stainless steel, the surface silver white with reflections. This method requires a certain eye for stainless steel, and a variety of stainless steel materials have dealt with experts to distinguish.

Method two, with a magnet to identify, the magnet can basically distinguish between the two types of stainless steel. Because chromium stainless steel can be attracted by magnets in any state, but high manganese steel containing high manganese is non-magnetic, these two can be identified using magnets. Therefore, although the magnet can basically distinguish chromium stainless steel and chromium-nickel stainless steel, but can not correctly distinguish some of the special properties of the steel, and can not distinguish the specific steel number.

Method three, potion detection, there is a stainless steel testing liquid on the market, according to the time of discolouration, determine the stainless steel model. 10 seconds or so red for the ordinary 201 stainless steel; 50 seconds or so red for the authentic 201 stainless steel; 1 minute or so red for 202 stainless steel; 301 stainless steel in 2-3 minutes will be red, but the colour is very light, you need to look at it carefully; 3 minutes the colour is no change, the bottom colour is slightly darker, the colour of the bottom of the stainless steel. Change, the bottom of the colour slightly darker, is the authentic SUS304 stainless steel. However, this method of distinguishing stainless steel types is relatively limited, only to distinguish several types of stainless steel.

The above methods of identification not only to use several methods of integrated testing, and its test results can only determine a certain type of stainless steel, can not determine which types of alloying elements contained in the steel and specific content. Therefore, these identification methods are currently extremely imperfect, some may be wrong, so we need more accurate detection means to identify stainless steel. In recent years, the more widely used method is X-ray fluorescence spectrometry detection, this detection technology not only achieves a completely non-destructive testing, but also fast measurement speed, the results are more intuitive, the operation is also very simple. Due to the design of the instrument is small and portable, to the field inspection and trade has brought great convenience.

Post time: Aug-25-2023