Hundred or so hard to have "stainless" stainless steel nickel content determines whether it is rusty

Nickel content determines whether to rust

In some stainless steel merchants, the reporter saw a number of brands such as Yuehua, Zhengcai, Great Wall, and Gumei in the store. "The price of stainless steel with good quality is more than 200 yuan per square meter, and it's good also between 150-160 yuan. Almost 110-120 yuan, the worst 80-90 yuan or even lower." Businesses said. And there are many stainless steel materials in the shop without any brand logos being processed.

Better quality stainless steel in the mouth of the merchant, the surface is smooth, the texture of the touch is better; In contrast, 80-90 yuan per square meter of stainless steel touch is rough. "304 stainless steel can not have such a price." Businesses outspoken, "120 yuan per square meter of stainless steel quality is more difficult to guarantee." As for 80-90 yuan per square meter of stainless steel sales, businesses simply represent Some construction and renovation projects will be used, but the specific situation is not willing to say more.

The reporter found that there are price differences between different brands of stainless steel, a difference of 50-60 yuan per square meter. According to the merchant, one of the reasons for the large difference in the price of stainless steel of different brands is its elemental composition, which is related to the content of nickel element. 200 series 201 model stainless steel is mingled with manganese, and the nickel content is relatively low, its price is relatively low, it is easier to rust; while the 304 series of stainless steel 304 only has two elements of chromium and nickel, nickel elements can generally The proportion of 8%, which ensures the stability of stainless steel. Since nickel is an industrial element with a wide range of uses, its price is relatively high. Therefore, the difference in content causes price differences.

Businesses told reporters that the 200 series of 201 stainless steel is less stable and rustable; and the 300 series of 304 stainless steels generally do not need to be cured unless strong acid substances are encountered. In general, the regular stainless steel will have its own brand, series, model and other related signs, on the contrary the poor quality of stainless steel will be omitted.

Color identification is more convenient

So how do ordinary consumers distinguish between different types of stainless steel? According to industry insiders, sensory identification can not distinguish specific steel (species) number, can only basically distinguish between chromium stainless steel, chromium nickel stainless steel and chromium manganese nitrogen stainless steel three major categories.

For example, the use of magnets can only basically distinguish between two types of stainless steel. Because the chromium stainless steel can be attracted by the magnet in any state; the chromium nickel stainless steel is generally non-magnetic in the annealed state, and after the cold working, some are magnetic. However, manganese-rich steels with higher manganese content are non-magnetic; chromium-nickel-nitrogen-based stainless steels have more complex magnetic properties: some are non-magnetic, some are magnetic, and some have a non-magnetic vertical surface and a magnetic surface. Therefore, although magnets can basically distinguish between chromium stainless steel and chromium-nickel stainless steel, they cannot correctly distinguish some special-purpose steel grades, let alone distinguish specific steel grades.

If you identify with copper sulfate, the method is more convenient, and the effect is more obvious. "Remove some of the oxide layer on the steel, put a drop of water, rub with copper sulfate, and if it does not change color after rubbing, usually stainless steel; if it becomes purple, non-magnetic high manganese steel."

“While grinding the stainless steel on a grinder, observe the sparks that appear. If the sparks are streamlined and there are more dense knots, it is a high manganese or manganese nitrogen steel with higher manganese content; Steel or chromium-nickel stainless steel.” Industry insiders said that the method of using the grinder is also more intuitive and rapid.