All China Nuts need to be electroplated ten China Nut to achieve aesthetics, and to match the color of the place of use. The purpose of electroplating is to have stronger corrosion resistance and beautiful appearance. The corrosion resistance is based on the environment of the product as the experimental condition. Cooperate to achieve the corrosion of the product environment and determine the success of the experiment.
 
 
 
Set test conditions to test the quality of electroplated products from the following points:
 
1. For appearance:
 
 The surface of the product is not allowed to have partial non-plating, scorching, roughness, dullness, peeling, skinning, and obvious streaks, and no pinhole pitting, black plating slag, loose passivation film, cracking, shedding and serious Passivation marks.
 
 
 
2. For the coating distribution:
 
 With different deposition methods, the way the plating layer gathers on the surface of the fastener is also different. During electroplating, the coating metal is not uniformly deposited on the outer peripheral edge, and a thicker coating is obtained at the corners. In the threaded part of the fastener, the thickest coating is located on the crest of the thread, gradually thinning along the side of the thread, and the thinnest deposit at the bottom of the thread, while hot-dip galvanizing is just the opposite. The thicker coating is deposited on the inner corner and At the bottom of the thread, the metal deposition tendency of the mechanical plating is the same as that of the hot-dip plating, but it is smoother and the thickness is much more uniform across the surface.
 
 
 
3. For coating thickness:
 
 The operating life of a fastener in a corrosive atmosphere is proportional to the thickness of its coating. The general recommended thickness of economical electroplating coating is 0.00015in～0.0005in (4～12um).
 
 Hot-dip galvanizing: The standard average thickness is 54 um (nominal diameter ≤ 3/8 is 43 um), and the minimum thickness is 43 um (nominal diameter ≤ 3/8 is 37 um).
 
 
 
4. For hydrogen embrittlement:
 
 In the process of Bolt Factory's processing and treatment, especially in the pickling and alkali cleaning before plating and the subsequent electroplating process, the surface absorbs hydrogen atoms, and the deposited metal coating then traps hydrogen. When the fastener is tightened, the hydrogen is transferred to the most concentrated part, causing the pressure to increase beyond the strength of the base metal and produce tiny surface cracks. Hydrogen is particularly active and quickly penetrates into the newly formed fissures. This pressure-rupture-infiltration cycle continues until the fastener breaks. It usually occurs within a few hours after the first stress application.