Toyota TSH1108G Phosphate Film Conditions

The "Toyota TSH1108G Phosphate film conditions" standard developed by the Toyota vehicle company describes the conditions for the phosphating process applied to protect the paint and coatings of vehicles from corrosion.

A few areas where the phosphating process is applied include:

• In the process of protecting metals from corrosion with paint and polymer film coatings
• Facilitating cold forming processes such as wire drawing, pipe drawing, deep drawing
• Protecting metals from corrosion with oils and waxes
• In corrosion protection processes without any post-treatment

Phosphating process is carried out with many different applications. The following physical factors are effective when deciding which application to perform:

• Structure of the metal to be coated
• Shape and condition of the metal
• Number of parts to be coated and uniformity of surface condition
• Working intensity of plating bath
• Number of bathrooms

Among the different phosphating processes, a few methods of industrial importance include: zinc phosphate, iron phosphate, and manganese phosphate. These phosphating processes are generally applied to iron and steel surfaces, and less commonly to zinc-coated (galvanized) surfaces. Phosphating aluminum and magnesium is possible with some special phosphating chemicals.

Essentially, a phosphating process consists of the following stages:

• Performing slag removal, polishing and rust removal operations on steel materials
• Performing sandblasting on a steel workpiece
• Surface adjustment on steel material after alkaline washing and acid washing
• Re-surface cleaning of the steel material subjected to surface adjustment
• Placing the processed steel material in the phosphating solution and phosphating it
• Heating the phosphating solution at a temperature of 40-60 degrees
• Rapid cooling of the phosphating solution and heating of the steel material
• Heating the steel material at 400-450 degrees and keeping it for 20-40 minutes
• Removal, cleaning and drying of steel material

This phosphating process has beneficial effects such as the process steps are simple, it is easy to operate, the consumption of energy and phosphating solution during the process is low, the process efficiency is high, and it is easy to disseminate.

Phosphate coatings that bond well and completely cover the metal surface can only be created on clean surfaces free of rust, dirt, soot and other corrosion products. Possible oil and grease films prevent the formation of phosphate coating.

Pretreatments such as cleaning and activation before phosphating greatly affect the thickness and crystal size of the phosphate coating. This situation can sometimes be effective mechanically, chemically, or both. Chemical pretreatments such as alkaline degreasing, solvent degreasing and acid cleaning have a great effect on phosphating. When high alkaline degreasing chemicals are used, the coating weights of zinc phosphate, iron phosphate and manganese phosphate per unit area are higher. When solvent degreasers are used, coating weights are less and phosphating process times are longer.

The vast majority of steel types are suitable for phosphating. All steel used in the automotive industry can be phosphatized. In particular, parts subjected to all kinds of deep drawing processes are painted after phosphating and their corrosion resistance is tested. Electro-galvanized, hot-dip galvanized or zinc coatings containing copper and titanium can also be phosphate coated.

For high corrosion resistance, manganese phosphate coatings are used in almost all branches of the metalworking industry. The most common uses include motor vehicle components in brake and clutch assemblies, engine components, leaf or coil springs, and some small parts. Manganese phosphate coating is applied to many parts in compressors, oil pumps and hydraulic systems.

Among the numerous testing, measurement, analysis and evaluation studies it provides for businesses in various sectors, our organization also provides testing services defined in the "Toyota TSH1108G Phosphate film conditions" standard, with a trained and expert staff and advanced technological equipment.