Metal Materials of Slurry Pumps
The slurry pump is a pump that conveys a mixture of solids and water. Therefore, the medium will be abrasive to the flowing parts of the slurry pump. Therefore, the slurry pump flowing parts need to be made of wear-resistant materials.
The commonly used metal materials for slurry pumps are divided into cast iron, ductile iron, high chromium cast iron, stainless steel and so on. High chromium cast iron is the third generation of wear-resistant material developed after ordinary white cast iron and nickel hard cast iron. Due to the characteristics of the structure of high chromium cast iron, it has much higher toughness, higher temperature strength, heat resistance and wear resistance than ordinary cast iron. High chromium cast iron has been praised as the best anti-abrasive material in the contemporary era, and it has been widely used day by day.
China's national standard for wear-resistant white cast iron (GB/T8263) stipulates the grade, composition, hardness, heat treatment process and usage characteristics of high chromium white cast iron.
The executive standard for high chromium cast iron in the United States is ASTMA532M, the United Kingdom BS4844, Germany DIN1695, and France NFA32401. Russia developed 12-15% Cr, 3-5.5% Mn and 200mm wall thickness ball mill liners in the former Soviet Union, and now implements the ҐOCT7769 standard.
The main materials used for the flowing parts of slurry pumps at home and abroad are stainless steel, high chromium cast iron and nickel hard cast iron. High chromium cast iron is an ideal candidate material for the flowing parts of slurry pumps. Through the adjustment or selection of carbon and chromium content levels, the best use effects of flowing parts under different industrial and mining conditions can be obtained.
High chromium cast iron is the abbreviation of high chromium white anti-wear cast iron. It is an anti-wear material with excellent performance and special attention; it has much higher wear resistance than alloy steel and much higher toughness and strength than general white cast iron. At the same time, it also has good resistance to high temperature and corrosion, coupled with convenient production and moderate cost, and is known as one of the best anti-abrasive materials in the modern time.
Now A series of high chromium cast iron wear-resistant materials are the commonly used:
The slurry pumps made of A05 (Cr26) material are the most widely used in the mining industry. The micro-structure of the high chromium alloy A05 shows that it consists of hard eutectic chromium carbides in a fully hardened marten-site matrix. In slurry pump applications where both abrasive and corrosive but abrasion dominates, the performance of this material is significantly better than the other white cast irons.
Although the wetted parts made of A07 (Cr15Mo3) material have higher wear resistance, better hardness and longer service life than A05, their cost is twice of that of A05, so the cost performance is lower and the scope of use is smaller.
A49 (Cr30) is essentially a high chromium low carbon white cast iron. The micro-structure is hypo-eutectic and consists of eutectic chromium carbides in an austenite/martensite matrix. The carbon content of high chromium A49 is lower than that of high chromium A05. There is more chromium in the matrix. In a weakly acidic environment, high chromium A49 has higher corrosion resistance than high chromium A05.
For now, the above mentioned are the metal materials commonly used in our slurry pumps. According to the particularity of the transported medium, we will choose the most suitable material.