Steel corrosion is everywhere, all the time

To prevent steel corrosion, the most common method is to use coatings to protect the surface of steel products. The surface must be cleaned before coating protection. Hundreds of products and industries including ships, storage tanks, bridges, steel structures, power stations, automobiles, locomotives, military equipment, aerospace equipment, etc. must be surface treated before coating. Metal abrasive is the most effective cleaning medium.

Metallic abrasives

Generally, there are cast steel shots (high carbon steel shot and low carbon steel shot), steel grit, iron shot, iron grit, stainless steel cut wire/conditioned shot, stainless steel grit,  steel cut wire, bearing steel grit, etc. High-performance metal abrasives are not easy to break, low dust, low consumption, high cleaning efficiency, and good overall product performance. It can greatly reduce the consumption level of end user, thereby reducing costs and reducing emissions.

So the question is, how to select high-quality metal abrasives?

To ensure that the surface treatment result is fully up to standard, the two core indicators of metal abrasives: cleaning efficiency and consumption.

Several misunderstandings in the selection of cast steel shots:

Is the cast steel shot rounder the better?

Is the particle size more uniform, the better?

The brighter the appearance, the better?

Is the cast steel shot rounder the better?

Answer:No.

In the process of forming and preparing steel shots, the molten steel is cooled from liquid to solid, and shrinks during the cooling process. This shrinkage is carried out in a free state, and there is no riser like pouring castings to partially supplemented with molten steel where the volume after shrinking is reduced , so elliptical particles with sunken surfaces appear. This kind of particles has undergone sufficient shrinkage, and the shape is not round but the structure is dense. However, if the steel shot that has not been fully contracted, the structure is not dense, there are internal defects such as shrinkage porosity and shrinkage cavities.

Throwing energy E=1/2mv2, if the structure is dense,with same volume, the bigger density quality M is,the impact energy bigger, and also no easy to break. This way, it is not correct: the rounder steel shot the better.

Is the grain size of the steel shot more uniform, the better?

Answer:No.

In the field of cleaning, the surface of the workpiece to be cleaned or spraying will form pits on the cleaned surface. Only when the pits and pits overlap fully, the entire surface can be thoroughly cleaned.

The more uniform the particle size of the steel shot is, the longer it takes to reach the fully overlap of the pits.For steel shots with a certain particle size mixing ratio, the large steel shots mainly used for cleaning, and the small steel shots will clean the interspace between the area treated by large-size steel shots

The brighter the appearance, the better?

Answer: No.

Currently there are two kinds of high carbon steel shot: single quenching steel shot and double quenching steel shot. It is difficult to distinguish from the composition, hardness, and metallographic structure. However, the double quenched steel shot has fine grains and high fatigue life,The grains of the single quenching steel shot are coarse and the fatigue life is low.The single quenching steel shot donot processed with heating and quenching, the Fe3O4 oxide film formed on the surface is thin, it looks very bright; while the steel shot after the second quenching treatment，the Fe3O4 film on the surface becomes thicker, does not reflect light, and does not look shiny. So the brighter surface does not meas the better products, but if it is double quenching steel shot or not is more important issue.