Application and case analysis in roll processing

Rolling mill is widely used in the metallurgical industry, and the roller as the main working component determines the efficiency of the rolling mill and the quality of the rolling material. Therefore, when turning the roll, selecting a cubic boron nitride (CBN) cutting tool is very important. We discuss the difficulty of turning the roll according to the practical application case and the choice of cubic boron nitride cutting tool (CBN cutting tool) and roll ring rib cutter.

At present, the common rolls are high nickel-chromium alloy cast iron rolls, infinite cold hard cast iron rolls, forged steel cold rolls, high boron steel rolls, re-bar steel rolls, wire high-speed steel rolls, cast high-speed steel rolls; its processing way mainly includes outer round lathe, hole turning, heavy cutting, crescent groove processing, flat end milling, roll repair, and other processing forms.

Rolls processing way:

Problems appear when turning rollers

1. Heavy-duty cutting is not easy. The need to turn the general roller size is significant. Quality is also weighty, compared with ordinary cutting, with significant cutting depth, cutting speed is relatively low, and feed speed is relatively slow. Therefore, the processing technology differs significantly from the standard mechanical cutting technology. Process characteristics exist in the rigidity of the machine tool, reducer stability, tool selection, tool installation, cutting parameters selection, workpiece clamping, and so on. Especially heavy-duty parts with high hardness are the most difficult to process.

2, large size, long processing time. Most of the rolls are large, and the processing time of a single piece is long. The tool is prone to wear before it goes to the end, which leads to rework and frequent tool change, which affect the processing efficiency.

3. High hardness after additive, increasing difficulty in cutting. Because molybdenum, manganese, chromium, and other elements are mixed in the production process of the roll, these elements can extend the service life of the roll, improve the hardness, wear resistance, and thermal strength of the roll, and also increase the difficulty of cutting the roll to a certain extent.

4. The defects and the processing conditions are challenging to avoid. Some of the rollers during turning have defects such as sand clamping, pores, and hard points, and the processing conditions are complex, resulting that tools appearing breaking edge phenomenon.

Case analysis of CBN and PCD tools processing roll

Currently, the common CNC machining tools on the market have carbide, ceramic, and cubic boron nitride cutting tools (CBN cutting tools). Still, with the improvement of the hardness, wear resistance, processing efficiency and processing accuracy of the roll, the traditional cutting tools have been unable to meet the needs of roller processing. 

However, the cubic boron nitride CBN cutting tools can meet the needs of the processing roll. But because the production processes for different enterprises are different, the performance of cubic boron nitride cutting tools (CBN cutting tools) is also slightly different.

1.Rough high nickel-chromium alloy cast iron roll

For high nickel-chromium cast iron rolls with large cutting margins and high hardness, CBN-K1 cubic boron nitride CBN cutting tools can be selected. The relevant case parameters are as follows:

Machining roll material: cast high nickel-chromium alloy cast iron

Hardness: HSD80

Tool material: Solid CBN-K1 RNMN

Cutting parameters:

Vc=25m/min, ap=9mm, f=0.5mm/r

2.Fine forging steel cold roll

During the finishing lathe of the forging steel cold roll, we can select the CBN-S20 cubic boron nitride CBN cutting tool. The efficiency is 5 times higher than that of alloy tools.

The relevant case parameters are as follows:

Processing roll material: forged steel cold roll

Hardness: HRC60

Tool material: CBN-S20 RCMX

3. Processing the roller crescent groove

Suppose it is a pass/groove - roll milling crescent. In that case, you can choose the corresponding PCD rotary milling cutter (also called pcd notching tools) according to the actual needs; whether it is a repair roll or a new roll, PCD rotary milling cutter can be used.

4.Roll lettering

During the lettering roller,usually we widely use the pcd engraving tools

PCD roll milling cutter(pcd notching cutter) and pcd engraving tools can also be customized according to the actual demand.

In addition, the effect of CBN-K1, CBN-S20, CBN-S300 (RNMN, SNMN, RCMN, RCGX, RCMS), and another cubic boron nitride The effect of CBN cutter is good in machining high boron steel roll groove and repairing of spiral steel roll crescent groove/ wire high-speed steel roll /cast high-speed steel roll carving knife.