With the development of automation and intelligent steelmaking-rolling in the metallurgical and steel industry, the requirements for rolling speed and roll material are becoming higher and higher. Tungsten carbide (tungsten steel) roll rings are one of the hardest metal rolls at Rolling speed is generally above 75m / s, and the highest rolling speed has reached 120-140m / s, so it is widely used in high-speed wire rolling mills. Production process of tungsten carbide (tungsten steel) roll rings:
Tungsten carbide (tungsten steel) roll rings are produced by powder metallurgy using tungsten carbide powder and cobalt powder (a small amount of other hard phases or alloy elements can also be added) as raw materials. Its production process is as follows: alloy material preparation—press forming—vacuum sintering and HIP hot isostatic pressing—flat grinding rough machining—ultrasonic non-destructive testing—flat grinding finishing—milling inner hole—milling outer circle—chamfering processing—grooving (Including thread grooves)-laser marking-comprehensive inspection-packaging delivery.
Blade selection for cutting tungsten carbide (tungsten steel) roll rings
Due to the extremely high hardness of tungsten carbide (tungsten steel) roll rings, which is beyond the range that traditional cutting tools can bear, the cutting and processing of tungsten carbide (tungsten steel) roll rings are mainly diamond blades, and some companies will choose CBN tools Used for cutting tungsten carbide (tungsten steel) roll rings below HRA88.
The turning process is not necessary in the cutting process of tungsten carbide (tungsten steel) roll rings. Many companies choose the grinding process, but for the companies that use the turning process, the diamond blades during the machining of tungsten carbide (tungsten steel) roll rings are The preferred material is to be cautious during the turning process, to do chamfering in advance, or to leave enough finishing allowance, so as to avoid problems such as chipping during turning and scrapping the workpiece. The cutting edge form of diamond blade is often dominated by the sharp edge (F).
Milling is an important part in the process of cutting tungsten carbide (tungsten steel) roll rings. For example, the protrusions on the rebar are called crescents. These are already done during the manufacture of tungsten carbide (tungsten steel) roll rings Therefore, the process of milling meniscus is an important process. PCD rotary milling cutters (also known as flying cutters) are mainly used, as shown in the figure below: The area circled by the red circle in the middle is the position where the diamond blades are placed. Crescent.
Both new rolls and repair rolls require the use of PCD rotary milling cutters and diamond blades. Diamond blades are available in welded and veneered constructions with diameters of 4mm and above (up to a maximum of 9mm). Welded constructions are available. Below 4mm is mainly full veneer. At the same time, a rotary milling cutter generally needs to be replaced with two diamond blades after processing to prevent fatigue fracture. The precision of tungsten carbide (tungsten steel) roller ring crescents is extremely poor.
Further reading: Introduction of CBN inserts when turning tungsten carbide (tungsten steel) roll rings
When the hardness of the tungsten carbide (tungsten steel) roll ring is less than HRA88, select the BN-S300 overall polycrystalline CBN tool to turn the tungsten carbide (tungsten steel) roll ring. Its grade is a block material made of CBN fine powder as a whole. There is no alloy substrate. Because non-metal is used as a binder, it has excellent high-temperature red hardness, and a large amount of turning carbide rolls and tools do not crack and burn.
At the same time, in the process of selecting CBN inserts for turning tungsten carbide (tungsten steel) roll rings, the shape of the cutting edge of the insert is based on the hardness of the tungsten carbide (tungsten steel) roll ring and the rigidity of the machine tool. Generally, it is better to be specified by the user based on past experience. The mouth form is mainly E (passivation), S02020 (chamfer + passivation).
CBN insert case parameters for machining tungsten carbide (tungsten steel) roll rings
(1) Cutting parameters for processing tungsten carbide roll rings of HRA88: BN-S300 grade is used, and the cutting parameters are: Vc = 15m / min, ap = 1mm, Fr = 0.3mm / r
(2) Cutting parameters for processing HRA88 tungsten steel roller rings: BN-S300 RNGN120400E, the cutting parameters are: Vc = 20m / min, ap = 0.5mm, Fr = 1mm / r
Remarks: BN-S300 is an integral polycrystalline CBN insert. When turning tungsten carbide (tungsten steel) roll rings, it is only recommended for rough machining procedures within HRC88. Diamond inserts are recommended in other cases.
