Screw is often used in things, mainly used to connect and tighten each part.

In fact, screws are also divided into many kinds of parts: bolts, screws, studs, nuts, machine screws, tapping screws, washers, pins, rivets, retaining rings and other ten categories, if you do not know how many?

The screw has a combination of bolts and nuts that can be removed, and the rivet type. The rivet type is permanent and can not be used repeatedly. Generally, the bolts and nuts are used more.

Whether permanent or removed screws will face some oxidation, corrosion and other problems, usually use electroplating method to solve, let’s take a look at what kind of effect different electroplating process has, how to distinguish.

How to distinguish stainless steel screws, galvanized and nickel plated screws?

The most intuitive way to do this is by color:

Stainless steel is the primary color of iron. Galvanized screws are white, colored and black. Nickel plated screws are silver.

1.Stainless steel screws are made of stainless steel. The color of stainless steel is mainly an alloy of iron and carbon, so the color is close to the color of iron.

2.galvanized screw surface galvanized white zinc, color zinc, black zinc, etc., so the color of galvanized screw is generally white, color, black;

3.The color of the nickel-plated screw is related to nickel, generally showing a very bright silver.

• 

• 

To distinguish by testing:

1, distinguish with magnets: stainless steel generally does not have magnetic, can not be adsorbed by magnets is stainless steel screws, galvanized and nickel plated screws can be adsorbed by magnets.

2, with oxidizer to distinguish: metal nickel has a strong passivation ability, when electroplating on the surface can quickly generate a layer of very thin passivation.

So the surface of the nickel plated screw has a layer of passivation film, galvanized surface is a layer of zinc, stainless steel surface nothing, can be distinguished with strong oxidizer.

3, distinguish with strong acid and alkali: stainless steel containing chromium and nickel, has a strong anti-corrosion performance, is not corroded by strong acid and strong alkali, nickel plated screw surface has a layer of passivation film, by strong acid and strong alkali erosion is slow, galvanized screw is corroded the fastest.

Conclusion:

The way to distinguish stainless steel screws, galvanized and nickel-plated screws from their appearance is to see the color of the screws. The color of the stainless steel screws is close to the primary color of iron.

Galvanized screw is white, color, black, nickel plated screw is very bright silver: in addition to the magnet, oxidizer and strong acid strong base to distinguish stainless steel screw, galvanized and nickel plated screw.