| What are the characteristics of cutting stainless steel? | |
| 雙擊自動滾屏 | 發(fā)布者：manager 發(fā)布時間：2015/8/14 閱讀：3509次 |
The cutting of stainless steel machining much worse than medium carbon steel. In ordinary cutting processability as 100% of 45 # steel, austenitic stainless steel 1 cr18ni9ti relative cutting machining is 40%; 1 cr28 ferritic stainless steel is 48%; Martensite stainless steel 2 cr13 was 55%. Among them, in order to austenite and ferrite austenite stainless steel cutting machining is the worst. Stainless steel in the cutting process has the following several aspects: Work hardening is serious: in stainless steel, with austenite and ferrite austenite stainless steel work hardening phenomenon is most prominent. Such as the strength of the austenite stainless steel hardening after sb 1470 ~ 1470 mpa, and the increase of sb, higher yield limit ss; Annealing state of austenitic stainless steel ss does not exceed the sigma b30 % ~ 45%, and 85% ~ 95% after work hardening. Work hardening layer depth of cutting depth of a third or more; Hardening layer's hardness is increased by 1.4 ~ 2.2 times than the original. Because of stainless steel and plastic, plastic deformation character contorted, strengthening coefficient is very big, And austenite is not stable, under the action of cutting stress, experience of austenite into martensite; Combined with compound impurities under the action of heat cutting, easy to decompose a diffuse distribution, make produce when machining hardened layer. A feed or before the procedure, the work hardening phenomenon seriously affect the follow-up process smoothly. Cutting force big: stainless steel plastic deformation in the process of cutting, especially the austenitic stainless steel (the elongation is more than 1.5 times more than 45 # steel), the cutting force increases. At the same time, the work hardening of stainless steel, high hot strength, further increasing the cutting resistance, chip curling broken is more difficult. So processing stainless steel cutting force is large, such as 1 cr18ni9ti turning unit cutting force is 2450 mpa, 25% higher than that of 45 steel. High cutting temperature, cutting the plastic deformation and friction between the tool and are very big, the cutting heat; Combined with the coefficient of thermal conductivity of stainless steel of 45 # steel is about 1/2 level ~ fell, a large number of cutting heat is concentrated in the cutting area and the knife - crumbs in contact interface, poor heat dissipation condition. Under the same conditions, 1 cr18ni9ti cutting temperature about 200 ℃ higher than 45 steel. Chip is not easy to break and easy to bond: the plasticity and toughness of stainless steel are big, car processing chip continuously, not only affect the operation smoothly, chip will hurt has been processed surface. Under high temperature and high pressure, stainless steel and other metal affinity is strong, easy to produce adhesion phenomenon, and form the devolop tumor, exacerbating the cutting tool wear and tear phenomenon will appear again and make the machined surface has been deteriorating. Low carbon content of the characteristics of martensitic stainless steel is more apparent. Affinity function in the process of cutting tool wears: cutting stainless steel, the knife - the generation between chip bonding, diffusion, which produce adhesion wear, diffusion wear of cutting tool and the tool rake face of produce crater, cutting edge can also form tiny flake and gap; With stainless steel of carbide particles (TiC) hardness is high, direct contact with the tool when cutting, friction, abrasion cutting tools, and work hardening phenomenon, all can make the tool wear. The linear expansion coefficient of linear expansion coefficient of large: stainless steel which is about 1.5 times that of carbon steel in the function of cutting temperature, easy to produce hot deformation of workpiece, dimension precision are harder to control. |
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