丨
Shot blasting is a kind of shot blasting surface treatment method which has been applied in developed countries in Europe and America. A variety of non-metallic surface roughness removal equipment was first applied in the world 100 years ago. After a century of development, shot blasting process and equipment has been quite mature, its application is not only in various heavy industry factories. With the birth of the world's first horizontal mobile shot blasting equipment in blastrac of the United States, its application field has rapidly expanded to concrete surface coating treatment and ship deck metal surface treatment, and directly guided the industry standard formulation and industry construction method specification.
1. Working principle of shot blasting process and equipment
Shot blasting refers to the technology that shot material (steel shot or sand) is shot onto the working surface at a high speed and at a certain angle by mechanical method, and then the shot material is cleaned by the air flow of the vacuum cleaner inside the machine to separate the shot material and the impurities removed, and make the shot material can be reused. The shot blasting machine is equipped with dust remover, which can achieve dust-free and pollution-free construction, improve efficiency and protect the environment. Shot blasting machine can be divided into three types according to its walking form: hand push type, vehicle type and self-propelled type.
During the operation of shot blasting machine, the shot flow rate is controlled by controlling and selecting the particle size and shape of shot, and adjusting and setting the walking speed of the machine, so as to obtain different shot intensity and different surface treatment effect.
1.2 quality control of surface shot blasting
According to the different surface to be treated, three parameters are used to control the surface condition after shot blasting. Select the size and shape of shot; the walking speed of equipment; the flow rate of shot. The above three parameters cooperate with each other to obtain different treatment effects and ensure the ideal surface roughness after shot blasting.
For example, the surface roughness of C50 concrete treated with S330 steel shot and flow rate of 10A can reach 90%; the flooding layer can be removed and the roughness can reach 80 when the asphalt surface is treated; the cleanliness standard of SA3 can be reached when the steel plate is treated.
Chain walking shot blasting cleaning machine: the sand and oxide scale on the surface of casting can be removed by multi position fixed-point shot blasting cleaning, so that the casting can reappear the original metal color.
Crawler type shot blasting cleaning machine: the workpiece is loaded by high-strength wear-resistant rubber track or manganese steel track, and the high-speed projectile is thrown to the workpiece overturned on the track by the shot blasting device to achieve the purpose of cleaning.
Drum type shot blasting cleaning machine: it uses the impeller placed at high speed to throw the shot to the casting and forging parts which are constantly turned over by the roller, so as to remove the oxide skin, and make the surface of the workpiece get uniform cleaning, showing the primary metal color.
Rotary table shot blasting cleaning machine: through frequency conversion shot blasting machine, the surface of the workpiece is subject to uniform steel shot impact force, and the steel shot coverage rate of the surface reaches more than 98%, so as to achieve the strengthening effect.
