There are a large number of carbides in the material of chilled cast iron rolls, which are composed of pearlite, cementite and ledeburite. The hardness of the roll itself can reach 65HRC or more, and there are often defects such as impurities and hard spots in the roll blank. When using tools for processing, the defects of the roll itself will cause severe impacts on the tools, and the increase in cutting temperature will increase the wear of the tools, so it is a kind of material that is more difficult to process.
1.Like wear-resistant alloy cast iron, chilled cast iron is a typical brittle and hard material with high surface hardness. During rough machining, the unit cutting force can reach 3000 MPa, and strong impact can easily cause vibration and aggravate tool wear.
2. Chilled cast iron rolls have relatively large structural dimensions and large machining allowances. Therefore, large cutting depths and feeds must be used in machining and turning, which require relatively high tool strength and process system rigidity.
3. Chilled cast iron rolls have strong hardness and thermal strength. Therefore, if the tool continues to work for a long time during cutting, the tool temperature will be very high, and the tool body will be easily deformed or the welding blade will be unsoldered, which will cause the tool to be damaged.
4. The surface structure of chilled cast iron rolls is white, hard and brittle in nature, so when the cutter is cutting in or out, it is prone to edge chipping, which will damage the cutter or produce waste workpieces.
5. The surface machining allowance of the chilled cast iron roll blank is uneven, and there are often casting defects such as pores, magazines, and sand holes. When the tool is cut, the impact force is relatively large, and it is easy to cause damage to the tool.
Selection of Chilled Cast Iron Roll Machining Tools
Judging from the reasons and processing characteristics of chilled cast iron rolls, the tool to be selected must have a series of advantages such as high hardness, high heat resistance, high wear resistance, and impact resistance. Therefore, Moresuperhard PCBN (cubic boron nitride) ) Blade is a more suitable choice.
The hardness and wear resistance of PCBN blades are second only to diamonds, heat resistance, chemical stability, and compression and impact resistance are also outstanding. They are widely used in the cutting of hardened (above HRC50), pearlite cast iron, and chilled cast iron.
Tool cutting roll solution
The hardness and strength of chilled cast iron rolls are very high, so the rough cutting is mostly interrupted cutting, so the cutting edge of the tool is required to have sufficient strength. At the same time, there are certain requirements for the geometric angle of the tool:
Should be less than 45°
Choose smaller when roughing
Choose bigger when finishing
In the choice of cutting parameters, it must be determined according to the specific situation. Choosing appropriate cutting parameters can give full play to the effectiveness of machine tools and tools.
Workpiece material: chilled cast iron
Cutting inserts model: RNMN2010 S2075
Compared with other brands of CBN tool life increased by more than 30%
In summary, choosing PCBN blades for turning of chilled cast iron rolls can achieve the effect of turning instead of grinding, which not only improves processing efficiency, but also reduces production costs, and can replace other cemented carbide tools and ceramic tools. .