Causes and solutions for incomplete galvanizing of seamless steel pipes:
1. Unclean surface of the seamless steel pipe:
(1) Paint, grease, or welding residue on the surface can be removed by grinding or cleaning with a suitable solvent.
(2) Iron oxides; insufficient pickling; continue pickling.

2. Pickling and operation of seamless steel pipes:
(1) Insufficient or excessive pickling. Insufficient pickling leaves iron oxides (rust spots) on the surface; excessive pickling damages the surface structure of the steel substrate, causing the Si and small amounts of refractory oxides of active metals to adhere to the surface, preventing the bonding of iron and zinc. Alternatively, excessive pickling may cause the component to absorb hydrogen; during galvanizing, the hydrogen expands due to heat and escapes, resulting in incomplete galvanizing. Solution: Strictly control pickling and manage the pickling time. 
(2) Stacking and compaction of workpieces during pickling can cause missed pickling or insufficient agitation during pickling, due to the structure of the workpieces, which can cause vortex formation and missed pickling. Solution: Spread out the workpieces as much as possible during pickling and agitate them frequently.

3. Fluxing of Seamless Steel Pipes
(1) Low flux concentration results in unsatisfactory fluxing effect; Solution: Adjust the flux concentration appropriately.
(2) Improper flux ratio, high zinc salt content, makes the flux salt film easily absorb water and deliquesce, causing hydroxides to decompose into gas and explode, resulting in missed plating. Solution: Adjust the flux ratio.

4. Zinc Bath Composition and Boiler Operation for Seamless Steel Pipes:
(1) High aluminum content in the zinc bath causes missed plating. Solution: Add zinc or use ammonium chloride to reduce the aluminum content.
(2) Slow loading speed causes flux to decompose and become ineffective due to heat, resulting in missed plating. Adjust the loading speed appropriately.
(3) Insufficient zinc immersion time prevents the iron-zinc reaction from proceeding properly.
(4) Failure to clean zinc ash from the zinc bath surface before plating causes overheated zinc ash to burn the additives, resulting in incomplete plating.
(5) During plating, due to process holes or structural issues, high-temperature gases escaping from the plating workpiece can burn the additives, causing incomplete plating. Solution: Sprinkle an appropriate amount of ammonium chloride.

5. Material of Seamless Steel Pipe Plating Parts
(1) The steel surface contains refractory oxides of elements such as silicon and aluminum, which inhibit the iron-zinc reaction.
(2) Excessive carbon in the steel matrix, or excessive iron carbide produced during steel refining, makes iron-zinc bonding difficult, causing incomplete plating.
(3) Defects in the processing and forming of the plating material cause cracks, allowing acid, moisture, and additives to enter, leading to incomplete plating. Currently, there is no good solution other than using ammonium chloride.