1. Shot blasting is to use a high-speed rotating impeller to throw small steel shots or small iron shots out and hit the surface of the part at high speed, so the oxide layer on the surface of the part can be removed. Sandblasting is a method that uses compressed air to blow out quartz sand at high speed to clean the surface of parts.
2. Generally, shot blasting is used for regular shapes, etc., with several blasting heads up and down, left and right together, with high efficiency and low pollution. Sandblasting is used for complex shapes, easy to remove rust by hand, the efficiency is not high, the site environment is not good, and the rust removal is uneven.
3. Generally speaking, shot blasting (small steel shots) is mostly used in steel plate pretreatment (rust removal before painting) in the repair and shipbuilding industries. Sandblasting (mineral sand is used in shipbuilding and repairing industries) is mostly used on formed ships or sections to remove old paint and rust on steel plates and repaint them.
4. Shot blasting is to use the motor to drive the impeller body to rotate, and rely on the centrifugal force to throw the balls with a diameter of 0.2~3.0 (cast shot, cut shot, stainless steel shot, etc.) to the surface of the workpiece to make the workpiece more beautiful, or Change the welding tensile stress of the workpiece to compressive stress, and improve the service life of the workpiece. Sandblasting is a relatively advanced method in the steel structure. The use of high-strength bolts for connection is a relatively advanced method. Since the high-strength connection uses the friction between the joint surfaces to transmit force, the quality of the joint surface is very high. At this time, it must Treat the bonding surface with sandblasting.
Compressed air is used as the power to form a high-speed jet beam to spray the spray material (copper ore, quartz sand, corundum, iron sand, Hainan sand) to the surface of the workpiece to be treated at high speed, so that the appearance or shape of the outer surface of the workpiece surface changes. .
Due to the impact and cutting effect of the abrasive on the surface of the workpiece, the surface of the workpiece can obtain a certain degree of cleanliness and different roughness, so that the mechanical properties of the surface of the workpiece can be improved, thus improving the fatigue resistance of the workpiece, increasing it and the coating The adhesion between them prolongs the durability of the coating film, and is also conducive to the leveling and decoration of the coating.
Shot peening is the use of high-speed moving projectiles (60-110m/s) to continuously impact the surface of the strengthened workpiece, forcing the target surface and surface layer (0.10-0.85mm) to undergo the following changes during cyclic deformation: microstructure Modification occurs; the non-uniform plastic outer layer introduces residual compressive stress, and the inner surface generates residual tensile stress; the outer surface roughness changes;
Shot blasting is also the name of a mechanical surface treatment process, similar to sandblasting and shot peening. The principle is to use a motor to drive the impeller body to rotate, and rely on the effect of centrifugal force to throw balls with a diameter of 0.2 to 3.0 (cast shot, cut shot, stainless steel shot, etc.) to the surface of the workpiece so that the surface of the workpiece can reach a certain roughness. To make the workpiece more beautiful, or change the welding tensile stress of the workpiece to compressive stress, so as to improve the service life of the workpiece. Almost used in most fields of machinery, shipbuilding, auto parts, aircraft parts, gun tank surfaces, bridges, steel structures, glass, steel plates, pipes, etc.
In terms of method, the shot is projected onto the surface of the part at high speed and long distance by mechanical means, collectively referred to as shot blasting. It includes: throwing projectiles to castings with sand, shoveling sand and core shot blasting; projecting projectiles to casting, forging, welding and heat treatment parts to remove black skin, nodules, oxide films, rust spots surface finishing, etc.; projectiles are shot onto the surface of steel plates and various shapes for shot blasting pretreatment; for parts such as springs, leaf springs, and gears that are subject to variable stress, shot blasting is performed to eliminate stress and improve surface fatigue strength. ; Add color by shot blasting to the decorative parts of household appliances or the appearance of tableware. But in terms of process classification, shot blasting is limited to a finishing process aimed at removing cast, forged, welded and heat-treated parts. The shot blasting mentioned in this lecture is the concept. For those who use projectiles to reach the surface of the workpiece to achieve the relevant process intentions, they are directly named after their process requirements, such as: shot blasting, shot blasting, shot blasting, etc., so that they are different from shot blasting finishing in terms of process.
When the parts are shot blasted, the equipment that can make the parts continuously replace the cleaned surface in the shot flow to meet the requirements of uniform shot blasting is called shot blasting equipment or shot blasting machinery. Due to the ever-changing workpieces to be cleaned, there is also various shot-blasting equipment. A certain specification of shot blasting equipment is only suitable for finishing parts within a certain range. The special equipment is suitable for a certain kinds of parts.
Sandblasting is a method of cleaning the surface of parts by blowing out quartz sand at high speed with compressed air. It is also called sand blowing in the factory. It not only removes rust but also removes oil by the way, which is very useful for painting. It is often used to remove rust on the surface of parts; to modify the surface of parts (the small wet sandblasting machine sold in the market is used for this purpose, the sand particles are usually corundum, and the medium is water); in steel structures, it is a relatively advanced method to use high-strength bolts for connection. The best method is because the high-strength connection uses the friction between the joint surfaces to transmit force, so the quality of the joint surface is very high. At this time, the joint surface must be treated by sandblasting. The sandblasting process is divided into dry sandblasting and wet sandblasting.
There are two types of dry sandblasting: mechanical sandblasting and air pressure sandblasting, each of which is divided into manual, non-automatic or continuous active methods. medium and small parts.
The abrasives used in wet sandblasting are the same as those used in dry sandblasting. Abrasives can be mixed with water to form a mortar. Abrasives generally account for 20%-35%, and they are constantly stirred to prevent sinking. Press the compressed air into the nozzle to spray the parts, and the sand and water can also be mixed. Put them into the tank respectively, mix them before flowing to the nozzle, and then spray them on the parts. In order to avoid the corrosion of steel parts, corrosion inhibitors such as sodium nitrite must be added to the water. In addition, the sand should be dried before the next use. There are also many types of equipment for wet sandblasting machines, and the most commonly used is the sandblasting room.
But whether it is shot blasting or sandblasting, compressed air can be used. Of course, it is not necessary to use a high-speed rotating impeller for shot blasting. Generally speaking, shot blasting (small steel shot) is mostly used in steel plate pretreatment (rust removal before painting) in shipbuilding and repairing industries; sandblasting (ore sand is used in shipbuilding and repairing industries) is mostly used in formed ships or sections, The effect is to remove the old paint and rust on the steel plate and repaint it. In the repair and shipbuilding industry, the primary effect of shot blasting and sandblasting is to increase the adhesion of steel plate coating paint.
Compressed air is used as the power to form a high-speed jet beam to spray the spray material (copper ore, quartz sand, corundum, iron sand, Hainan sand) to the surface of the workpiece to be processed at high speed, so that the appearance or shape of the outer surface of the workpiece changes. .
Due to the impact and cutting effect of the abrasive on the surface of the workpiece, the surface of the workpiece can achieve a certain degree of cleanliness and different roughness, so that the mechanical properties of the surface of the workpiece are improved, thus improving the fatigue resistance of the workpiece, increasing it and the coating The adhesion between them prolongs the durability of the coating film, and is also conducive to the leveling and decoration of the coating. Shot blasting is the use of high-speed moving projectiles (60-110m/s) to continuously impact the surface of the strengthened workpiece, forcing the surface and surface (0.10-0.85mm) of the target to undergo the following changes during the cyclic deformation process: microstructure Modification occurs; the non-uniform plastic deformation outer layer introduces residual compressive stress, and the inner surface generates residual tensile stress; the roughness of the outer surface changes; both shot blasting and sandblasting can clean and decontaminate the workpiece, the intention is Prepare for the next sequence, that is, to ensure the roughness requirements of the next process, and for some to ensure the consistency of the appearance, the shot peening has a strengthening effect on the workpiece, and the sandblasting is not obvious. Generally, shot peening is small steel balls, and sandblasting is quartz sand. According to different requirements, the number of subheads. Fine casting uses sandblasting and shot-blasting processes almost every day.
