Stainless steel sheets market chaos, there are true and false true and false difficult to distinguish, so how to buy stainless steel sheets?
The following is to provide you with the purchase of stainless steel sheets skills:
1. Identify whether the steel seal material "304" is made on the pipe surface, and ask for the manufacturer's quality certificate and quality guarantee certificate.
2. with acid reagent test, 30 seconds after the material 304 does not change color, 201 turned black.
3. Watch whether the color of the outer surface and the inner wall of the tube is bright and smooth, whether the thickness is uniform or rough.
4.when the purchase should choose by the quality and technical supervision bureau evaluation of the provincial brand products above.
In the customer has a long time to use witness and good reputation is the most direct and effective selection method.
1 nitric acid point test stainless steel sheets is a significant characteristic of concentrated and dilute nitric acid has inherent corrosion resistance.
This property allows it to be easily distinguished from most other metals or alloys.
However, high carbon 420 and 440 steels are slightly corroded in nitric acid point test, and non-ferrous metals will be corroded immediately when they encounter concentrated nitric acid.
Dilute nitric acid is strongly corrosive to carbon steel.
2. The copper sulfate point test is the simplest and easiest way to quickly distinguish ordinary carbon steels from all types of stainless steel sheets.
The concentration of the copper sulfate solution used is 5 to 10%.
Before the point test, the test area should be thoroughly cleaned of grease or various impurities, and a small area should be polished with a soft cloth, and then a drop bottle should be used to drop copper sulfate solution into the cleaned area.
Ordinary carbon steel or iron forms a surface layer of copper in a few seconds, while the surface of stainless steel sheets do not deposit copper or show copper color.
3. Sulphuric acid test Sulphuric acid immersion stainless steel sheets test can distinguish 302 and 304 from 316 and 317.
The cut edge of the sample shall be finely ground and then cleaned and passivated for half an hour in nitric acid (specific gravity 1.42) at a volume concentration of 20~30% and a temperature of 60~66℃.
The volume concentration of sulfuric acid test solution is 10%.
When heated to 71℃, 302 and 304 steels are immersed in this hot solution, they are rapidly corroded and produce a large number of bubbles, and the sample turns black in a few minutes.
In contrast, the 316 and 317 steel samples are not corroded or react slowly (no bubbles are produced), and the samples do not change color within 10 to 15 minutes.
More accurate tests can be made if samples with known components are used for approximate comparison.
4. Finally, the magnetic test is the simplest method to distinguish annealed austenitic stainless steels from ferritic stainless steel sheets.
Austenitic stainless steel sheets is a non-magnetic steel, but it will have mild magnetic properties after cold processing under high pressure. While pure chrome and low alloy steels are strongly magnetic steels.
First, tensile test. Tensile test is mainly used to test the toughness and plasticity of stainless steel sheets material, through the detection of tensile test, to ensure the plasticity and forming performance of stainless steel sheets material.
Two, bending test. Bending test is an effective method to test the bending resistance of stainless steel sheets and coating.
In the bending test, can find the stainless steel sheets defects in time and repair in time.
Bending test, as one of the important inspection steps in stainless steel sheets manufacturing, provides an important basis for ensuring the bending resistance of stainless steel sheets materials.
Three, cup protrusion test. The cup burst test is an effective method to test the stamping performance of stainless steel sheets.
In some application fields, there are strict standards for the stamping of stainless steel sheets materials, such as machinery manufacturing, automobile and ship plates, etc., in the process of mechanical forming if the stamping performance is not up to standard, easy to lead to stainless steel sheets cracking, seriously affect the quality of products.
Therefore, in the manufacture of stainless steel sheets, cup test is indispensable.
Four, impact test. Impact test is similar to cup burst test, which is an important step to test the impact toughness of stainless steel sheets materials.
Impact test is to impact the stainless steel sheets material through the external force of the equipment. In this process, the toughness of the material itself can be effectively released.
The impact test has the characteristics of reliability and effectiveness.
I believe that through the above four detection methods, we will know how to buy stainless steel sheets products to meet the requirements, in order to meet the needs of different applications.
For more information about Stainless Steel Sheets, please Contact Us Sunning Steel Limited.
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