Distinguish from appearance
First, distinguish by color: stainless steel is the primary color of iron, galvanized screws are white, color and black, and 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. The surface of galvanized screws is galvanized with white zinc, color zinc, black zinc, etc., so the color of galvanized screws is generally white, color, black;
3. The color of nickel plated screws is related to nickel, and generally presents a very bright silver.
Other distinguishing methods
1. Distinguish with magnets: stainless steel generally does not have magnetism, and stainless steel screws cannot be adsorbed by magnets. Galvanized and nickel plated screws can be adsorbed by magnets.
2. Distinguish with oxidant: nickel metal has a strong passivation ability, and a very thin passivation layer can be quickly generated on the surface during electroplating, so there is a passivation film on the surface of nickel plated screws, a layer of zinc on the galvanized surface, and nothing on the stainless steel surface, which can be distinguished with strong oxidant.
3. Distinguish by strong acid and strong alkali: stainless steel contains chromium and nickel, which has strong corrosion resistance and is not corroded by strong acid and strong alkali. There is a passive film on the surface of nickel plated screws, which is slowly eroded by strong acid and strong alkali, and galvanized screws are corroded the fastest.
Summary: the way to distinguish stainless steel screws, galvanized screws and nickel plated screws from the appearance is to look at the color of the screws. The color of stainless steel screws is close to the primary color of iron. Galvanized screws are white, color and black, and nickel plated screws are very bright silver: in addition, magnets, oxidants and strong acids and bases can also be used to distinguish stainless steel screws, galvanized screws and nickel plated screws.