Grinding observation and operating efficiency of forged grinding balls

- Jun 01, 2018 -

Forging grinding ball to a certain extent, with its appropriate screening residual curve should be a warehouse with a greater decline in the slope of the inlet end, the entire product of the end of the warehouse will be closer to the mill exit 0.5~0.8, at a certain degree There will be a flat decline, if a warehouse decline is not obvious, indicating lack of smashing capacity; if the end of a longer horizontal section, clearance should be removed from the small grinding body. Check the remaining value of the screen before and after the partition board. If the difference is too large, it means that the two positions are unbalanced. Change the length of the position or adjust the load of the grinding body to balance the capacity of the two positions.

The forged grinding ball will stop grinding under normal feeding observation. If most of the steel balls in one bin will expose half of the material surface, it is more reasonable if the material at the end of the forging is just over the sphere. If one stock surface exceeds the sphere, it means that the ball diameter is too small or the load is insufficient. Otherwise, the ball diameter is too large and the load is too much. If there is too much material in the material level in the last position, it means that the load is insufficient, otherwise it means that the load is too much. If each stock layer is very thick and the yield is low and the fineness is not good enough to control, check whether the partition board and the exit screen board are caused by excessive moisture in the material and cause the phenomenon of paste and jam.

The forged grinding ball will effectively measure the grinding, material return, and fineness of finished products to a certain extent, calculate the parameters of grinding and classifying powder, and analyze and judge the operation efficiency of the mill operation. If the residual values of all three are higher than the normal value, it is necessary to add appropriate amount of medium or small-sized grinding bodies or readjust them.

The advantages of forged grinding balls are gradually highlighted and widely used. Large ball mills will inevitably require the use of large-diameter grinding balls. Therefore, it is of great significance to prepare high-performance and large-diameter grinding balls. This paper aims at the cracking problem of 65Mn forging balls in the process of manufacturing 65Mn forging balls in a certain factory, and discusses the causes of cracks in 65Mn forged balls using metallographic observation, SEM microscopic morphology observation, EDS energy spectrum analysis, Rockwell hardness test, and impact toughness test. An optimization scheme was proposed to prepare 65Mn large-diameter forging balls with good mechanical properties.

Forging grinding ball will produce its internal stress to a certain extent to a certain extent, to a certain extent, it will exceed the fracture toughness of the material. In the operation, the optimized preparation process is: high quality original bar (Φ90mm)— Cutting short rods - heated to 1050 °C - forging - transfer (900-920 °C) - 800-820 °C quenching, quenching fluid concentration of 2.5% - tempering (220 °C -4h). After the optimization of the process, no sub-surface layer of 65Mn forgings saw Wei's microstructure, the hardness change trend was stable, the surface hardness increased by about 3HRC, and the depth of hardened layer increased by about 2mm.

Spiral plate condenser is mainly used in its new structure. It is very simple to operate. It is very reasonable in the process of design. The single heat exchange area can be increased from the original 260m2 to 800-100m2. The working efficiency is original. 3-4 times, and can use the existing machine, rolling equipment manufacturing. It has the advantages of easy evacuation, even distribution of vapor and non-condensable gas, low gas pressure difference, and significant condensation effect.