What Materials Are Commonly Used Milling Cutters

Basic requirements for milling cutter cutting part materials

1) High hardness and wear resistance: at normal temperature, the cutting materials must have sufficient hardness to cut into the workpiece; With high wear resistance, the tool will not wear and prolong its service life.

2) Good heat resistance: the tool will generate a lot of heat in the cutting process, especially when the cutting speed is high, the temperature will be very high. Therefore, the tool material should have good heat resistance, which can maintain high hardness at high temperature and continue cutting. This property with high temperature hardness is also called thermal hardness or red hardness.

3) High strength and good toughness: in the cutting process, the tool has to bear a great impact, so the tool material should have high strength, otherwise it is easy to fracture and damage. Because the milling cutter will be impacted and vibrated, the milling cutter material should also have good toughness to prevent edge collapse and fragmentation.

Common materials of milling cutter

(1) High speed tool steel (referred to as high-speed steel, front steel, etc.) is divided into general-purpose and special-purpose high-speed steel.

1) The content of tungsten, chromium, molybdenum and vanadium is high, and the quenching hardness can reach hrc62-70. It can still maintain high hardness at 600 degree .

2) The cutting edge has good strength and toughness and strong vibration resistance. It can be used to manufacture tools with general cutting speed. For machine tools with poor rigidity, high-speed steel milling cutter can still cut smoothly.

3) Good process performance, easy forging, processing and grinding, and can also manufacture tools with complex shapes.

4) Compared with cemented carbide materials, it still has some disadvantages, such as low hardness, poor red hardness and wear resistance.

（2）

Cemented carbide

: it is made of metal carbide, tungsten carbide, titanium carbide and metal binder mainly cobalt by powder metallurgy process.

1) It can withstand high temperature and maintain good cutting performance at about 800-10000c. The cutting speed can be 4-8 times higher than that of high-speed steel.

2) High hardness and good wear resistance at room temperature.

3) The bending strength is low, the impact toughness is poor, and the blade is not easy to grind. It is very sharp.

Commonly used cemented carbide can be divided into three categories:

① Tungsten cobalt cemented carbide (YG)

Commonly used brands YG3, YG6 and YG8, in which the number indicates the percentage of cobalt content. The more cobalt content, the better toughness, impact and vibration resistance, but the hardness and wear resistance will be reduced. Therefore, the alloy is suitable for cutting cast iron and non-ferrous metals. It can also be used to cut rough parts with high impact and quenched steel and stainless steel parts.

② Titanium cobalt cemented carbide (YT)

The commonly used brands are YT5, YT15 and yt30, and the number represents the percentage of titanium carbide. Cemented carbide containing titanium carbide can improve the bonding temperature of steel, reduce the friction coefficient, and slightly improve the hardness and wear resistance, but reduce the bending strength and toughness and make the properties brittle. Therefore, this kind of alloy is suitable for cutting steel parts.

③ General purpose cemented carbide

Adding an appropriate amount of rare metal carbides, such as tantalum carbide and niobium carbide, to the above two kinds of cemented carbide can refine its grain, improve its normal temperature hardness and high temperature hardness, wear resistance, bonding temperature and oxidation resistance, and increase the toughness of the alloy. Therefore, this kind of cemented carbide cutter has good comprehensive cutting performance and versatility. Its brands are yw1 Yw2 and ya6 are mainly used for difficult to process materials, such as high-strength steel, heat-resistant steel, stainless steel, etc.

(3) Ceramics: also known as oxidation milling cutter,

1) Extremely high hardness, heat resistance up to 1200 degrees, and high compressive strength,

2) The brittleness is too large, so the strength is not high, so the cutting amount cannot be too large. Therefore, it is more suitable for final finishing, or other highly wear-resistant non-metallic processed products.

According to its main components, new ceramic tool materials can be divided into three categories: alumina system, silicon nitride system and composite silicon nitride alumina system. All kinds of ceramic tool materials can only be applied to a certain range of cutting according to their composition and properties. For example, when milling steel (hardness lower than 35hrc), only hot pressed ceramic milling cutter can be selected; When milling gray cast iron, Sialon ceramic tool material (i.e. composite Si3N. - Al2 () 3 ceramic tool, which is the general name of various compound groups composed of Si-Al - () - N series elements) should be preferred, followed by hot pressing ceramic tool material; When milling nickel base alloy (mouth Less than or equal to 6.35mm, f = 0.13 0.30mm), Sialon ceramic tool is more suitable.

(4) Superhard tool material: diamond and cubic boron nitride.

1) It is excellent in hardness, wear resistance and heat resistance. It has sufficient toughness and can withstand temperature up to 2000 degrees,

2) The brittleness is too large and the strength is not high, which is more suitable for final finishing

3) Diamond is widely used in milling cutters, mainly processing all kinds of non-ferrous metals, non-metallic materials and composite materials. Cubic boron nitride (CBN) is mainly used in face milling cutters, and the typical brand is ldp-j-cxf (composite polycrystalline cutter block).

(5) Coated tool material.

It refers to coating a layer of metal compound with high strength and high wear resistance several microns thick on the surface of cemented carbide or high-speed steel tools. It not only has the impact toughness of the matrix, but also has high surface hardness, which expands the application range of the coated blade and greatly improves the cutting performance.