Treatment and action of surface phosphation

 The treatment and action of surface phosphation
1 and improve corrosion resistance. Although the phosphate film is thin, but because it is a non-metallic non-conductive isolation layer, can make the metal workman surface of the fine conductor into a bad conductor, inhibit the formation of the metal workman surface microcryst, and thus effectively prevent the corrosion of the coating film.
2, improve the adhesion between the substation and the coating or other organic finishing layer
the
. On the one hand, phosphate film and metal workware is a closely integrated
. On the other hand, phosphate film has porous, so that the coating can penetrate into these pores, the coating and phosphate film closely combined, adhesion increased.
3, provide a clean surface. Phosphate film can only grow on the surface of oil-free and rust-free metal workstations, so phosphated metal works can provide a clean, uniform, grease-free and rust-free surface.
4, improve the cold processing performance of the material.
5, improve surface friction performance to promote its sliding.
Effect of the surface state of metal work parts on phosphate quality
the thickness of the treated gear is corrected uniformly by plate sample block before measurement according to instrument calibration specifications, the thickness of the treated gear is predetermined before phosphation, the thickness of the treated work piece is measured again after phosphation, and the difference between the thickness measured twice is the thickness of the phosphate layer, which is used before phosphate according to different varieties. Coated thickness gauge measures 1 piece of pre-phosphating work, isometrid measuring the base position in the middle of three points, and calculates the average M1, phosphating after the work item sampling, iso-measuring the base position in the middle of three points, and calculates the average M2, inspection report sampling three pieces, the corresponding work piece phosphating film thickness M2-M1, the replacement of different varieties need to repeat the above process.
phosphate film appearance should be crystalline dense, continuous uniform light gray to dark gray film, for light iron phosphate should be continuous color film. The following defects are permitted, such as slight water traces, chromate traces, mild ash hanging, phosphate membrane defects due to different surface states such as heat treatment welding and processing. For the following are not allowed defects: yellowing rust in phosphate film, loose phosphate film, phosphate dew bottom local membraneless, serious hanging ash.
corrosion resistance after phosphate and paint is the most important, it reflects the phosphate film and paint after the overall corrosion resistance.
The surface state of metal work parts of phosphate enterprises has a greater impact on the quality of phosphation, even if the same phosphation process, the same phosphation preparation, the quality of phosphate film in different parts of the same work piece may vary greatly, which is due to differences in the surface state of the work parts. Generally speaking, high, medium carbon steel and low alloy steel easy phosphate, phosphate film black and thick, but phosphate film crystallization has a tendency to become coarse, low-carbon steel phosphate film crystallization dense, lighter color, if phosphate before proper acid washing, can help improve the quality of phosphate film, cold rolling plate because its surface has hardened layer, phosphate before the best proper acid washing or surface adjustment, otherwise the film is not uniform, film thin, low corrosion resistance.
phosphate enterprise mixed parts phosphation treatment process
mixture phosphation treatment process (rust work parts)
(1) degreasing normal temperature to 60 degrees C 3 to 8min
(2) water cleaning normal temperature 0.5 to 1.1. 0min
(3) pickle wash normal temperature to 70 degrees C 3 to 8min
(4) water cleaning normal temperature 0.5min
(5) medium temperature 0.5 to 1.0min
(6) Surface adjustment normal temperature 0.5min
(7) phosphate normal temperature to 90c 3 to 10min
(8) water cleaning normal temperature 0.5 to 1.0min
(9) deionized water Washing room temperature 0.5 to 1.0min
(10) drying <180 degrees C
Unless there are good reasons, acid washing process generally do not use spray treatment, spray will bring equipment corrosion and rust between work parts process and a series of problems. All other processes can be constructed using a combination of full spray or spray-immersion.
For mixed parts (rust-free work, rust-free, oxidizing leather work pieces mixed at the same time), the use of skimming rust removal "two-in-one" instead of step-by-step degreasing method has been applied for decades, the same can be satisfied with the results. For acid washing and degreasing rust "two-in-one" generally using non-volatile inorclement acid is more suitable.
in the phosphate process, different formulations of phosphate are used in the phosphate process due to different performance requirements of each phosphate manufacturer and the application manufacturer. However, only a few major types of scale commercialization applications, such as light iron, zinc, manganese, zinc calcium, the promoter used are basically nitrites, nitrates, nitrites, chlorates, organic nitros compounds and so on. Phosphate treatment temperature is usually 5 to 30 degrees C, low temperature type 35 to 45 degrees C, medium temperature type 50 to 70 degrees C.