CNC Turning of 3Cr13 stainless steel machines technology research

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Summary: The characteristic that machines to CNC Turning of stainless steel material undertakes an analysis, discussed when spare parts of CNC Turning stainless steel, cutting tool of cutting of the hardness that through reasonable change rolled steel expects, choice and cutting dosage and choose proper cooling fluid to wait for treatment technology measure, can improve the efficiency of turning of stainless steel spare parts significantly. Although preface is right on common lathe stainless steel kind material has rough machining, semifinishing machining and precision work, already not was too difficult issue. But, on the numerical control lathe of tall productivity, the cutting muscularity that in how solving cutting of stainless steel material, exists, temperature tall, cutting tool wears away serious, durability difference of quality of surface of low, treatment, productivity is low problem, in cutting treatment can achieve the requirement of the design, achieve not easily still. The author is in process of material of treatment 3Cr13 stainless steel, of the dosage of affirmatory, cutting of angle of geometry of the choice from cutting tool material, cutting tool, structure choose, the supply of semifinished product is condition, lubricant with refrigerant choose waited for a respect to undertake iteration experimenting, gained certain successful experience. When characteristic of CNC Turning of 1 3Cr13 stainless steel reachs an analysis to try treatment in stainless steel spare parts, above all the author presses turning the technique of common carbon steel undertook to 3Cr13 steel turning experiments, the result is cutting tool wears away serious, productivity is low, short of of quality of spare parts surface asks. The mechanical performance that compares 45 40 3Cr13 steel, steel, steel to wait for steel of carbolic element structure, the index such as function of shrinkage of the intensity of 3Cr13 steel, outspread rate, section, concussion compares 45 40 steel, steel tall, it is a kind of intensity tall, plasticity is good in carbolic martensite stainless steel. Because the treatment when cutting is sclerotic serious, cutting fights muscularity, cutting temperature is high, cause cutting tool to wear away serious, make worry knife number increase, increased machine down time and machine tool settling time, reduced productivity. Because stick a knife easily, generation accumulates bits tumour, the change that causes work measure affects exterior surface roughness, and cut bits not easy and curly and break off, injure workpiece to already machined the surface again, affect the quality of the spare parts directly. So, cannot use cutting the craft of 45 steel comes cutting 3Cr13 steel. The treatment method that also cannot get on common lathe copies numerical control lathe to come up. Because knife of outfit of lathe of ordinary numerical control is less, the requirement can make machine the surface to achieve the dimension of the requirement and exterior surface roughness with least frequency taking a knife, in order to assure taller productivity. Be aimed at afore-mentioned problems, the author took step of craft of the following treatment. T(min) of cutting tool durability machines the dosage of cutting of hardness of turning circumstance material that the measure of main treatment technology of stainless steel of 2 turning 3Cr13 expresses steel of 3Cr13 of 1 different hardness anneal of RaµmVc(m/min)fmm/rHB240(of exterior surface roughness) 45 ～ 550.

190 ～ 1156.

3 ～ 3.

Shift of 2HRC25 ～ 30(is simple) 45 ～ 550.

195 ～ 1103.

Shift of 2HRC35 ～ 38(is simple) 45 ～ 550.

160 ～ 753.

The 2 cutting performance that express material of a few kinds of 2 cutting tool are comparative T(min) of cutting tool durability machines dosage of material hardness cutting ～ of RaµmVc(m/min)fmm/rYG845 of exterior surface roughness 550.

172 ～ 823.

2YT1445 ～ 550.

180 ～ 953.

2YW245 ～ 550.

190 ～ 1103.

26.

3(is cut off) TiC-TiCN-TiN45 ～ 550.

1128 ～ 1853.

2 ～ 1.

The 6 hardness martensite stainless steel that use heat treatment to change material are in the different hardness after heat treatment, the impact that machines to turning is very big. Expressing 1 to show is the lathe tool that uses YW2 data the turning circumstance of the 3Cr13 steel to hardness differring after heat treatment. Visible, the martensite stainless steel of anneal condition although hardness is low, but turning performance is poor, because material plasticity and tenacity are big,this is, the organization is inhomogenous, adhesiveness is strong, tumour of cutting of cutting process easy generation, acquire better exterior quality not easily. And the hardness after tone is handled character is in the 3Cr13 material processability under HRC30 is better, amount to the exterior quality with arrive better easily. And the part that the treatment when hardness is more than HRC30 gives, although exterior quality is better, but cutting tool is easy wear away. So, after material takes a plant, advanced travel attune handles 1 hardness to achieve HRC25 ～ character 30, undertake cutting is machined again next. The chooses cutting tool material cutting property of cutting tool material is concerning the durability of cutting tool and productivity, the craft sex of cutting tool material is affecting the production of cutting tool itself and blade to grind quality. Because appropriate of material of this cutting tool chooses hardness the cutting tool stuff with fight sex of caking property He Ren tall, good. The author falls in the condition with cutting same parameter, undertook to the cutting tool of a few kinds of material turning contrast experiments, from the watch 2 visible, use bit of TiC-TiCN-TiN compound coating outside round lathe tool, durability is taller, workpiece surface quality is good, productivity is tall. This is the razor blade because of material of hard alloy of this kind of coating, have better strength and tenacity, express a mask to have taller hardness and wearability because of its again, smaller coefficient of friction and taller hear resistance, and the material of good cutting tool that makes stainless steel of turning of numerical control lathe, be treatment 3Cr13 stainless steel outside the first selection material of round lathe tool. Cut off bit as a result of what do not have this kind of material, experiment through expressing the contrast of 2 knowable, the cutting performance of YW2 hard alloy is good also, because this is optional,serve as with the razor blade of YW2 material cut off a knife. Of the geometrical angle of cutting tool and structure choose to good cutting tool stuff, the geometrical angle with logical choice appears particularly important. When processing stainless steel, the geometrical appearance of cutting tool cutting part, answer commonly once upon a time horn, hind the choice of horny respect will consider. When the horn before the choice, should consider to coil bits chamfer, those who do not have arris and blade dip is bearing the element such as angle size. Why to plant no matter cutting tool, when processing stainless steel, must use bigger before horn. The horn before adding what bolo provides can be reduced cut bits to cut the resistance that leave and encounters in cleared process. Requirement of choice of the horn after be opposite is very not strict, but should not be too small, horn crosses Xiaorong to be mixed easily after workpiece surface produces serious clash, make machine aggravation of exterior surface roughness, quicken cutting tool to wear away. And because chafe strongly, the angle after enhancing stainless steel surface to machine sclerotic effect T cutting tool also shoulds not be too great, horn passes after big, make the wedge horn of cutting tool is reduced, reduced the intensity of cutting blade, quickened cutting tool wear away. Normally, horn should compare treatment after when common carbon steel somes big properer. When stainless steel of general turning martensite, g0 of the horn before cutting tool takes 10 ° ～ 20 ° are relatively appropriate. Horny A0 takes 5 ° ～ after 8 ° are more appropriate, the biggest do not exceed 10 ° . In addition, blade dip Ls, negative blade dip can protect point of a knife, increase edge strength, choose G0 to be commonly - 30 ° of 10 ° ～ . Kr of tool cutting edge angle should be mixed according to place of the appearance of workpiece, treatment the case that hold a knife will choose. Point surface surface roughness should be Ra0.

4 ～ 0.

2µm. On cutting tool structure, external round lathe tool is used outside inclined circular arc breaks bits chamfer, rely on place of point of a knife to cut bits curly radius is big, place of the predestined relationship outside leaning cuts bits curly radius is small, cut bits breaks up to work surface and break off, the case that break bits is good. To cutting off a knife, but will deputy slant horny control is in 1 ° less than, can improve the condition that discharge bits, service life that prolongs cutting tool so. Cutting dosage is opposite dosage of logical choice cutting impact of productivity of durability of workpiece surface quality, cutting tool, treatment is bigger. And cutting theory thinks, cutting speed V is the biggest to the influence of cutting temperature and cutting tool durability, feed F take second place, ap is the smallest, and the appearance that takes knife treatment last time in numerical control lathe, its cut deep quantity Ap is decided by work measure and dimension of material semifinished product, it is 0 ～ 3mm commonly. The cutting rate that the cutting speed of difficult treatment material often compares common steel is low much, because of speed rise, can make cutting tool wears away badly, and different stainless steel material has the optimal cutting rate that differs severally again, speed of this optimal cutting can concern a data to decide through experiment or consulting only. When undertaking machining with hard alloy cutting tool, recommend 80m/min of ～ of cutting speed V=60 commonly. Feed F is inferior to cutting speed to influence of cutting tool durability big, but can affect bits and platoon bits, affect workpiece surface thereby pull injury, abrade, affect the exterior quality of treatment. By treatment surface surface roughness when the cost is not high, f is chosen 0.

1 ～ 0.

2mm/r. Anyhow, to difficult treatment material, choose inferior cutting career commonly, medium feed. Choose the cooling lubricating fluid that stainless steel of proper turning of cooling lubricating fluid uses, it is better to should have high cool performance, tall lubricity to be able to be mixed osmotic. High cool performance, assure to be able to take away many heat in metal cutting. Stainless steel tenacity is big, easy generation accumulates bits tumour when cutting, aggravation machines the surface, this asks cooling lubricating fluid has taller lubricity to be able to be mixed better osmotic. Lubricating fluid of commonly used refrigeration of treatment stainless steel has soya-bean oil of sulfurized oil, vulcanization, kerosene to cheer acid or vegetable oil, 4 catch change carbon to add mineral oil, emulsion to wait. It is certain to have to the machine tool considering sulfur corrode action, the plant is oily (like soya-bean oil) add easily on the machine tool the knot is crazy with metamorphism. The author chose 4 catch change carbon and engine oil to compare by weight for 1: The mixture of 9. Among them 4 catch change carbon osmotic good, the lubricity of engine oil is good. The experiment proves, this kind of cooling lubricating fluid applies to exterior surface roughness to be worth the semifinishing machining of the stainless steel part with small requirement and finish machining working procedure, special agree with martensite kind the turning treatment of stainless steel spare parts. Adopted above to machine technology measure, be in whack completely already to the treatment of material of 3Cr13 stainless steel. The frequency that grind a knife has the 1/3 when trial production only, manufacturing efficiency has bigger rise, spare parts quality achieves design requirement completely. CNC Milling CNC Machining