Coating knowledge: chemical knowledge: several typical phosphating processes

Core tip: this kind of work piece of automobile body is made of cold rolled plate by stamping and welding It is required that the work piece should not be rusted, even if there are a few rusty spots, they should be polished before the last work piece The application of cathodic electrophoretic primer requires high pretreatment The typical processes are: (1) manual pre rubbing; (2) Pre degreasing spray, 50-70 ℃, 1min (3) Degreasing spray immersion spray, 50-70 ℃, 0.5-2.0-0.5min (4) Two sprays of water cleaning, normal temperature, 1min (5) Surface regulating spray, normal temperature, 1min (6) Phosphating spray immersion spray, 50 Paint knowledge | precautions for wall paint color selection Recommended introduction: when painting the wall, the owner sometimes has difficulty in choosing what color of the wall paint to paint In fact, there is no ugly color in the wall paint, only the disharmonious color matching The use of wall color contains the knowledge of health Too strong color will stimulate people's perception, make people have a sense of fidgety, affect people's mental health Grasp the basic principles of wall color and paint a colorful space 1、 Wall paint color selection notice 1 Light color is generally used for the top surface Light colors make people feel light, dark colors make people feel heavy Usually, the treatment of rooms is from top to bottom, from shallow to deep For example, the ceiling and walls of rooms are white and Paint Home News: Auto body parts are made of cold-rolled plate by stamping and welding It is required that the parts should not be rusted, even if there are a few rusty spots, they should be polished before the last part The application of cathodic electrophoretic primer requires high pretreatment The typical processes are: (1) manual pre rubbing; (2) Pre degreasing spray, 50-70 ℃, 1min (3) degreasing spray soaking spray, 50-70 ℃, 0.5-2.0-0.5min (4) water cleaning two spray, normal temperature, 1min (5) surface regulating spray, normal temperature, 1min (6) phosphating spray soaking spray, 50-60 ℃, 1.0-3.0-0.5min (7) water cleaning spray, normal temperature, 1min (8) circulating deionized water cleaning spray, normal temperature, 1min (9) Fresh deionized water wash spray, normal temperature, 1min household appliances are generally made of cold-rolled sheet stamping, a small amount of rust is pre polished The main workpieces are refrigerators, washing machines, air conditioners, household appliances, etc After pre-treatment is powder coating, but also part of the electrostatic or air spray Typical processes are: (1) pre degreasing spray, 50-70 ℃, 1min; (2) degreasing spray, 50-70 ℃, 1.5min; (3) water cleaning spray, room temperature, 1min; (4) surface regulating spray, room temperature, 0.5min; (5) phosphating spray, 30-45 ℃, 2.5min; (6) two water cleaning spray, room temperature, 1min; (7) deionized water cleaning spray, room temperature, 1min; (8) drying 10-140 ℃, 10min Generally, the batch of auto parts, household cars and refitted cars is not very large, so the time between processes is long, and the workpiece has rust, oxide skin, oil stain, etc The commonly used processes are: (1) degreasing and derusting "two in one" soaking, 15-40 ℃, 10min; (2) water cleaning soaking, room temperature, 1min; (3) neutralization soaking, room temperature, 1min; (4) surface adjusting soaking, room temperature, 1min; (5) phosphating soaking, 15-40 ℃, 10min; (6) water cleaning two-way soaking, room temperature, 1min; (7) drying 110-140 ℃, 10min Bicycles, motorcycles, tractors, because most of the work pieces have rust, oxide skin, oil pollution, the output is generally large, the processing speed is required to be fast The general process is: (1) oil and rust removal "two in one" soaking, 60-70 ℃, 50-70 ℃, 10min; (2) water cleaning soaking, room temperature, 1min; (3) neutralization soaking, room temperature, 1min; (4) surface adjusting soaking, room temperature, 1min; (5) phosphating soaking, 30-70 ℃, 6min; (6) water cleaning two-way soaking, room temperature, 1min; (7) drying 110-140 ℃, 10min After phosphating, the quality index of the workpiece shall be inspected by item according to its application The main quality control indexes include the appearance of phosphating film, thickness or weight of phosphating film, corrosion resistance of phosphating film or after treatment According to the application of phosphating, it is necessary to test the compatibility between phosphating and paint film, hardness of phosphating film, friction coefficient, scratch resistance and other indexes For the three common indexes of phosphating, please refer to the following standards and methods Appearance of phosphating film: visual inspection method is adopted, relevant standards gb11376-89 "phosphate conversion film of metal" and gb6807-86 "technical conditions for phosphating treatment of iron and steel workpiece before painting" Thickness or weight of phosphating film: the thickness of the film shall be measured by gb6462 "microscopic measurement method for thickness of oxide coating cross section of metal", or by thickness gauge, according to gb4956 "magnetic method for thickness measurement of non-magnetic coating on magnetic metal matrix" or gb4957 "eddy current method for thickness measurement of non-conductive coating on non-magnetic metal matrix" The weight method is used to measure the film weight, which can be in accordance with gb6807 "technical conditions for phosphating treatment of iron and steel workpieces before painting" or gb9792 "measurement of film quality on unit area of conversion film on metal materials" Corrosion resistance: copper sulfate drop method, sodium chloride salt water immersion method and salt spray test method can be used to detect the corrosion resistance of the phosphating film itself According to gb6807-86 "technical conditions for phosphating treatment of steel parts before painting" for drip method and salt water immersion method, the phosphating film after post-treatment, such as oiling, waxing, and after painting, is generally tested by salt spray test Salt spray test can be conducted in accordance with gb1771-79 determination of salt spray resistance of paint film or gb6458 neutral salt spray test of metal coating Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,