Cutting liquid choice
Rational cutting fluid choice, can availably reduce cutting process Medium friction, improve heat dissipation condition, low cutting force, Cutting temperature and Tool wear, Improve tool durability and cutting efficiency, ensure processed surface quality and reduce tooling cost. With the development of science technology and machining industry, some new and high performance engineering materials have been widely used. Most of these materials belong to the difficult cutting materials which are difficult to cut, which poses a problem for cutting machining. Processing problem solved in order to make the hard cutting material, in addition to choose the cutting tool material, cutting tool geometry parameter and cutting dosage and grasp the operation technology, such as cutting conditions, reasonable choice is also very important condition for cutting fluid.
In the hard cutting materials, some hardness is as high as 65 ~ 70HRC. The tensile strength of the tensile strength is about three times higher than that of steel 45, which causes the cutting force to be 200% ~ 250% higher than that of cutting 45 steel. Sometimes material coefficient of thermal conductivity coefficient of thermal conductivity is only 45 steel 1/4 ~ 1/7 or less, cutting zone caused by heat conduction go out soon, the formation of high cutting temperature, limit cutting speed increase; Some materials have high temperature hardness and high strength, and some materials can be hardened to the degree of 50% ~ 200%, and the depth of hardening reaches 0. L ~ 0.3mm, causing the difficulty of cutting. Some materials have a large chemical activity, which produces affinity for cutting and cutting tool materials, causing serious adhesion and spreading wear of the cutter. Some materials have minimal elastic modulus and elastic recovery and elongation.
The commonly used cutting fluid is: aqueous solution, common emulsion, extreme pressure emulsion, mineral oil, vegetable oil, animal oil, extreme pressure cutting oil, etc. Among them, the water solution has the best cooling effect, the extreme pressure cutting fluid has the best lubrication effect. General of cutting fluid, in 200 ℃ or so, losing the ability to lubrication. But the extreme pressure additive is added in the cutting fluid (such as chlorinated paraffin, carbon tetrachloride, thiophosphate, dialkyl disulfide, generation of zinc phosphate), became good extreme pressure lubrication performance cutting fluid, can be in 600 ~ 1000 ℃ high temperature and under the condition of 1470 ~ 1960 mpa pressure lubrication. Therefore, the emulsion and cutting oil of extreme pressure additives such as sulfur, chlorine and phosphorus are especially suitable for the cooling and lubrication of difficult cutting materials. The following is the selection of cutting fluid for difficult cutting materials.
Stainless steel: in rough machining, choose 3 % ~ 5 % emulsion or 10 % ~ 15% extreme pressure emulsion, extreme pressure cutting oil, sulfide oil; Choose in finish machining, the extreme pressure cutting oil or 10% ~ 20% of extreme pressure emulsion, vulcanized oil, vulcanized oil, 80% ~ 85% plus CCl415 % ~ 20%, 78% ~ 80% black oil, mineral oil or vegetable oil and lard oil 90% 18% 1.7% and total loss system plus CCl410 %, 50% plus 25% oleic acid and kerosene, vegetable oil, kerosene and turpentine 20% plus 60% oleic acid 25% and 60%; When pulling, tapping, and reaming holes, 10% ~ 15% extreme pressure emulsion or extreme pressure cutting oil, soybean oil or vegetable oil; Add 10% ~ 20% CCl4 in vulcanization oil, 20% ~ 30% CCl4 in lard, or 10% ~ 15% kerosene in sulfide oil for reaming; Add 15% ~ 20% CCl4 to sulfide oil or use white lead oil and total loss system oil or use kerosene to dilute chlorinated paraffin or use MoS2 ointment for tapping; When rolling teeth or insert teeth, use 20% ~ 25% pressure emulsion or extreme pressure cutting oil; When drilling, use 10% ~ 15% emulsion or 10% ~ 15% extreme pressure emulsion, extreme pressure cutting oil, sulfide oil, MoS2 cutting agent.
High temperature alloy, in addition to cutting fluid used in the cutting stainless steel, when the rough machining, using potassium sulphate 2% plus 1% potassium nitrite and triethanolamine 1% plus 7% ~ 10% boric acid and glycerin 7% ~ 10% water margin; Or the amount of sodium nitric acid 7% ~ 10% plus sodium nitrite 5% plus triethanolamine 7% ~ 10% plus boric acid 7% ~ 10% plus glycerol 7% ~ 10% plus water allowance.
Titanium alloy: in rough machining, it adopts 3% ~ 5% emulsion or 10% ~ 15% pressure emulsion; When finishing machining,use extreme pressure cutting oil or extreme pressure water solution, CCl4 plus equivalent amount of alcohol; When broaching, tapping and reaming, adopt plate pressure cutting oil or castor oil, oleic acid, sulfide oil, chlorinated oil, castor oil 60% plus kerosene 40%; When drilling hole, use extreme pressure emulsion or extreme pressure cutting oil, sulfide oil, electrolytic cutting fluid.
In the process of high strength steel cutting, it is better to use soybean oil or rapeseed oil as the tapping liquid than the usual cutting fluid and extreme pressure cutting fluid. When processing copper, use CCl4 + N32 total loss system oil or MoS2 grease for lubricant; When the pure iron is processed, the castor oil is diluted with alcohol. When cutting soft rubber, use alcohol or distilled water for cutting fluid.