With the development of science and technology in modern times, the quality requirements for buildings are also getting higher and higher. The quality of a building is the most important thing is its structure and materials. The structure is designed by a dedicated designer, while the material is our own choice. Stainless steel is a building material that is widely used in modern times, and there are many types and models of it. The most popular one is 304 stainless steel. Below we will introduce you to 304 stainless steel and how to identify the true and false.

First of all, let us briefly understand 304 stainless steel.

304 stainless steel, it is a stainless steel material with strong versatility. Its most outstanding point is that it has good high temperature resistance, which can reach a high temperature of 1200 degrees Celsius; secondly, it has remarkable corrosion resistance, and it is often used in humid areas in the south or outdoor areas with high quality requirements. 304 stainless steel decorative panels have strong performance, good quality, and a wide range of applications, but the price is much higher than that of 201 materials， Mainly in the field of food production, chemical engineering, construction and decoration, etc.

304 stainless steel, which is a grade of stainless steel produced according to the American ASTM standard, is equivalent to our domestic 0Cr19Ni9 (0Cr18Ni9) stainless steel. The chemical composition of 304 stainless steel is mainly iron Fe (about 67-71.5%), chromium Cr (about 17.5-19.5%) and nickel N (about 8-10.5%). Different countries have slightly different requirements for the composition of 304 stainless steel. For example, my country's national standard GB/T 24511-2017 stipulates that the chemical composition ratio of 06cr19ni10 stainless steel containing chromium (CR) should be between 18.00% and 20.00%. American ASTM a240 standard requires 17.5-19.5%.

304 stainless steel belongs to austenitic stainless steel. Austenitic stainless steel is a kind of steel that is resistant to weak corrosive media such as gas, steam and water or has stainless steel properties.

There are four commonly used identification methods for 304 stainless steel, which are identified by potion, magnetism, grinding and hand-held X-ray (XRF) analyzer.

In engineering, we generally identify stainless steel grades by identifying potions and sparks.

The solution specially used to detect 304 stainless steel is called N8 test solution, the solution used to test 201 stainless steel is called Ndi test solution, and the M2 test solution is used to test 316 stainless steel.

The following is an introduction to the use of detection potions and identification methods:

1. Put a drop of liquid medicine on the steel surface

2. Power-on electrolysis Note: the red line should not touch the stainless steel under the potion

3. It can be clearly found that the potion has bubbles and color

(The N8 potion is used in the test here. If the potion turns red, then the stainless steel material is 304)

Use the Ndi detection solution to detect stainless steel according to the above method. After energizing and dissolving, when the potion turns red, the material reaches 201, the potion is light red, the material is 202, and the potion does not change color, the material is above 301.

Use N8 detection solution to detect stainless steel. After energized and decomposed, the potion turns red, and the material reaches 304. The potion turns yellow or colorless, and the material does not reach 304.

Use M2 detection solution to detect stainless steel. After the power is turned on and the solution is turned on, the potion turns red, and after the red is turned off, the red color will not disappear within one minute, and the material reaches the 316 standard. If the potion turns black or the red disappears instantly, the material cannot reach to 316.

Stainless steel judging by the sparks thrown by the stainless steel being ground on a grinder.

201 stainless steel, with the most sparks, bright color, spark tail split.

304 stainless steel, less sparks, dark red color, no split or a small part of the spark tail.

316 stainless steel, the least sparks, the darkest color, the tail of the sparks does not split.