Molybdenum is silver gray and its chemical properties are similar to tungsten. The hardness of molybdenum itself is not high (HB35 ~ 125), but the hardness of molybdenum material is high and the brittleness is high at room temperature. When the temperature reaches 350℃ ~ 450℃, the plasticity increases obviously and the hardness decreases somewhat.
The molybdenum has a large bending strength ratio and the cutting hardening tendency is serious. Molybdenum has a very high elastic modulus (343,350 MPa), and the cutting deformation consumes much work and the cutting force is large. Molybdenum and cutting tool material has a strong adhesion, the tool is easy to produce bonding wear, cutting molybdenum and its alloy, should choose to have enough strength and toughness, adhesive resistance, good wear resistance tool materials, such as YW1, YW2, etc..YG6, YG8, YS2(YGL0H) and other grades of cemented carbide with higher strength can be used when cutting molybdenum ingot and sintering bar.
When cutting molybdenum and its alloys, it is required to make the cutting edge as sharp as possible under the condition of ensuring the strength of the cutting head. Large rake Angle, small main Angle and negative blade Angle can be used when selecting cutter geometric parameters. Generally seek: γO=15º～20ºαO=10º～12ºΚr=45ºΚ′r=15ºλs=-5ºγO1=-2º～-5º,bγ=0.1～0.3mm. The radius of the chip coiling groove is Rn=6 ~ 8mm, and the surface roughness of front and back is Ra≤0.4μm.
In order to avoid high cutting temperature and maintain a certain tool durability, lower cutting speed, larger cutting depth and feed quantity should be selected when cutting molybdenum and its alloys. Reference cutting amount is: rough turning time: νC=35～75m/min，ap=4～7mm，f=0.2～0.5mm/r; Half finishing time νC=50～120m/min，ap=0.2～0.4mm，f=0.15～0.4 mm/r.
When cutting molybdenum and its alloy, attention should be paid to sufficient cooling and lubrication. The mixture of CC14 and No. 20 oil or MoS2 can be used as lubricating oil (grease), but CC14 has toxic and corrosive effect, so protective measures should be adopted when using.
