CN102680504A

CN102680504A - Method for representing wear manner of ultrahard cubic boron nitride (CBN) cutting tool

Info

Publication number: CN102680504A
Application number: CN2012101452346A
Authority: CN
Inventors: 严学俭; 伏少松
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2012-05-11
Filing date: 2012-05-11
Publication date: 2012-09-19

Abstract

The invention belongs to the field of material micro analysis, and in particular relates to a method for representing a wear manner of an ultrahard cubic boron nitride (CBN) cutting tool. The method is characterized by comprising the following steps of: (1) determining a worn area and an unworn area of a main cutting edge of the CBN cutting tool by adopting a scanning electron microscope (SEM); and (2) respectively carrying out energy spectrum analysis on the worn area and the unworn area by utilizing an energy dispersive spectrum (EDS), and comparing atomic ratios of all the components in different areas, thus the wear manner of the cutting tool is analyzed. The method for representing the wear manner of the cutting tool is simple and accurate, the cutting tool can be conveniently improved by optimizing cutting parameters of the cutting tool on the basis of accurately understanding micro mechanism of cutting wear, and anti-wear performance of the cutting tool is improved, thus cutting efficiency of the cutting tool is improved and service life of the cutting tool is prolonged.

Description

A kind of method that characterizes superhard cubic boron nitride cutting tool wear form

Technical field

The invention belongs to material microanalysis field, be specifically related to a kind of method that characterizes superhard cubic boron nitride CBN cutting tool wear form.

Background technology

Along with developing rapidly of machining industry, superhard cubic boron nitride (CBN, Cubic Boron Nitrid) cutting tool arises at the historic moment.Cubic boron nitride (CBN) micropowder has high microhardness (HV is up to 8000-9000), and higher wearing quality, thermotolerance can reach 1300-1500 ℃; Big to the iron family element chemical inertness; The anti-ability of cohering is strong, and good thermal conductivity causes the reduction of point of a knife place cutting temperature, and the latter is a major reason that produces wearing and tearing; Its friction factor is merely 0.1-0.3, can reduce cutting force.This shows that cubic boron nitride cutting tool is except can be used for High-speed machining hardened steel and high hard cast iron spare, but also difficult-to-machine material such as High-speed machining metallic sintered products and Al-alloy parts.

Cubic boron nitride cutting tool also has the limitation in the use, and its fragility is bigger, and intensity and toughness are relatively poor, is not suitable for the interrupted surfaces processing under the impact load.In addition, during with the soft iron family element material of its processing, be easy to produce long smear metal, scratch cutter rake face also forms built-up edge, thereby causes the fluctuation of cutting force and damage cutter.

Cutter receives strong physical shock and high temperature impact in high-speed machining process, form mechanical stress and thermal stress in inside and make tool wear.Mechanism from wearing and tearing has bonding abrasion, oxidative wear, diffusive wear, abrasive wear (wearing and tearing of hard point) etc., from the process of wearing and tearing, from normal wear to rapid wearing and tearing, cutting tool is lost efficacy.

Cutting tool wear assessment on the conventional production lines is accomplished through range estimation or traditional optical microscope basically, and the form of cutting abrasion is complicated various, estimates like this or only amplify observation through optical imagery all can produce bigger error.The resolution of ESEM (SEM, Scanning Electron Microscope) is than higher, and amplification range is wide, and the depth of field is the hundred times of optical microscope, makes image be rich in stereoscopic sensation, can characterize wear form more clearly.Simultaneously; Analysis for wear form before this also mostly rests on the surface stage; Be difficult to its mechanism is provided reasonable dismissal; And utilize SEM and attachment device power spectrum thereof that this patent proposes disperse spectrum (EDS, Energy Dispersive Spectrometer) microanalysis technology for these problems a kind of brand-new effective solution to be provided just.

The principle of work of scanning electron microscope (SEM) is with a branch of superfine electron beam scanning sample; Inspire electronic secondary at sample surfaces, what of electronic secondary are relevant with electron beam incident angle, that is to say relevant with the surface structure of sample; Electronic secondary is collected by detector; And changed into light signal by scintillater there, and change the intensity that electric signal is controlled electron beam on the video screen into through photomultiplier and amplifier again, demonstrate the scan image synchronous with electron beam.Image is a solid image, has reflected the surface structure of sample.Scanning electron microscope is made up of three parts: vacuum system, electron beam system and imaging system.

Energy dispersive spectrometer (EDS) is to be used for to material micro-area composition element kind and content analysis thereof, cooperates the use of scanning electron microscope and transmission electron microscope.Its ultimate principle is the X ray characteristic wavelength that various elements have oneself; The size of characteristic wavelength then depends on the characteristic energy △ E that discharges in the energy level transition process, and energy spectrometer utilizes different these characteristics of different element x-ray photon characteristic energies to carry out constituent analysis.

Summary of the invention

The objective of the invention is to utilize SEM and EDS microanalysis technology, a kind of method that characterizes the cutting tool wear form simply, accurately is provided,, increase the stock-removing efficiency and the serviceable life of cutter so that further study the microscopic mechanism of cutting abrasion.

The invention provides a kind of method that characterizes the cutting tool wear form, it may further comprise the steps:

1) adopt scanning electron microscope (SEM) to confirm the eroded area and the eroded area not of the main cutting edge of CBN cutter;

2) utilize energy dispersive spectrometer (EDS) to eroded area and not eroded area carry out energy spectrum analysis respectively, the atomic ratio of each composition in the zones of different relatively, thus analyze the wear form of cutting tool.

Through above-mentioned sign, can further analyze and micromechanism.

The present invention is high through the image resolution ratio that SEM scanning obtains, and the depth of field is big, has improved the degree of accuracy of measuring; Reduced the error that original range estimation or optical microscope cause; The energy of EDS disperses analysis of spectrum then to express the main wear form of cutting edge quantitatively, and its method that characterizes the cutting tool wear form is simple, accurate, is convenient to us on the basis of the micromechanism of accurately understanding cutting abrasion; Through optimizing the cutting parameter of cutter; Improve the component and the form of cutter, the wear resistance of cutter is improved, thereby increase the stock-removing efficiency and the serviceable life of cutter.

Description of drawings

To combine accompanying drawing and embodiment that the present invention is done further detailed description below.

Fig. 1 is the SEM figure of the main back knife face of BZN9100 type CBN cutter.

Fig. 2 is the not EDS spectrogram of eroded area of the back knife face of leading of BZN9100 type CBN cutter.

Fig. 3 is the EDS spectrogram in the main wear of the tool flank zone of BZN9100 type CBN cutter.

Fig. 4 is former in the eroded area of traditional C BN cutter and the column diagram of each element atomic ratio of eroded area not.

Fig. 5 is the eroded area of BZN9100 type CBN cutter and the column diagram of each element atomic ratio of eroded area not.

Fig. 6 is the wear extent VB comparison diagram of BZN9100 type CBN cutter and original CBN cutter.

Fig. 7 is that the durability of BZN9100 type CBN cutter increases synoptic diagram.

Embodiment

The BZN9100 type CBN blade characteristics of using among the present invention are following: CBN content, 90%; The CBN grain size, 2 μ m; Cementing agent, the titanium base; Matrix, wimet.

Original traditional B ZN9000 type CBN blade characteristics of using among the present invention are following: CBN content, 75%; The CBN grain size, 4 μ m; Cementing agent, the titanium base; Matrix, wimet.

CBN cutter of the present invention is in order to processing seat ring hole, and used lathe is the Italian Urane25 of Comau Inc. series numerically-controlled machine.Installed power 60KW, maximum speed 24,000 rpm.Whole working angles adopts cutting fluid lubrication, cutting fluid concentration 7-13%, pH value 8.5-9.8, pressure 70bar.The seat ring material is a high-temperature alloy material, and principal ingredient comprises elements such as Fe, Cu, Mo, C, Ni, Cr.

The test parameters of Tool in Cutting processing is following among the present invention: rotating speed S, 4800r/min; Feeding F, 891mm/min; Cutting diameter d, 30.2mm; Back engagement of the cutting edge a _p, 0.3mm.

For metal cutting tool, the wearing and tearing of cutting edge comprise various ways, for example: abrasive wear, bonding abrasion, diffusive wear, phase transition wear, oxidative wear and thermoelectric wearing and tearing etc.The uniform wear amount VB that national Specification will be led the back knife face is used as the standard that the degree of wear is differentiated.Knife face and rake face cutting edge carried out uniform wear amount VB analysis after the present invention adopted the micro-sign of 3D to the master of BZN9100 type CBN cutter and original traditional C BN cutter.

Fig. 1, Fig. 2, Fig. 3 are respectively the EDS spectrogram of leading the SEM figure of back knife face, non-eroded area and eroded area of BZN9100 type CBN cutter.

Adopt SEM and EDS microanalysis technology; Eroded area and non-eroded area to the main back knife face of BZN9100 type CBN cutter carried out detailed sign, atomic ratio newly occurred at eroded area and be respectively 0.22%, 0.26%, 1.98% Mo, Fe and Cu various element; And the atomic ratio of C also is increased to 36.16% by 21.25%; Just in time comprise these elements and process used seat ring material principal ingredient, hence one can see that, and the wear form of CBN cutter has bonding abrasion and diffusive wear.Simultaneously we find, eroded area O atomic ratio obviously is increased to 8.38% by original 2.72%, in this explanation working angles oxidative wear has taken place also.

Fig. 4 and Fig. 5 are respectively the comparison diagram of each element atomic ratio of eroded area and the non-eroded area of original traditional C BN cutter and BZN9100 type CBN cutter.

Adopt SEM and EDS microanalysis technology; Each atoms of elements that has compared original traditional C BN cutter and BZN9100 type CBN cutter is than variable quantity, wherein the Discrepancy Description of the difference of CBN material principal ingredient (B, N) content and Cu, W element atomic ratio strong than original traditional C BN blade of anti stick wearing and tearing ability and the anti-diffusive wear ability of BZN9100 type CBN cutter; The eroded area of original traditional C BN and not the O atom percentage content of eroded area differ 6% ~ 10%; The eroded area of BZN9100 type CBN and not the O atom percentage content of eroded area only differ 2% ~ 4%, this shows that the oxidation resistance of original traditional C BN Tool in Cutting sword is more far short of what is expected than BZN9100 type CBN cutter.

Can know that from above test with analyzing the wear form of CBN cutter is mainly bonding abrasion, diffusive wear and oxidative wear.These wearing and tearing all with cutting process in high temperature and high impact forces relevant.Therefore, can reduce tool wear, increase serviceable life and raising machining precision through aggregate measures such as friction factor, the kind of improving used cooling lubricant when cutting and flow between content, interpolation oxidation-resistant material, minimizing cutter and this a pair of friction pair of workpiece to be machined of the superhard crystal grain of raising in the CBN cutter and optimization cutting parameters.

Shown in Figure 6 is the VB wear extent comparison diagram of two groups of BZN9100 type CBN cutters and original CBN cutter.

Adopt original CBN cutter (the 1st group) and BZN9100 type CBN cutter (the 1st group) to process 300 workpiece simultaneously; Record the wear extent VB=204 μ m of original CBN cutter; The wear extent VB=120 μ m of BZN9100 type CBN, the antiwear property of novel CBN cutter are about original 1.6 times.

Adopt original CBN cutter (the 2nd group) and BZN9100 type CBN cutter (the 2nd group) to process 300 workpiece more simultaneously; Record the wear extent VB=210 μ m of original CBN cutter; The wear extent VB=135 μ m of BZN9100 type CBN cutter, novel CBN cutter antiwear property is about original 1.5 times.

The durability (promptly using the life-span) of BZN9100 type CBN cutter is brought up to 350 from 300 of original CBN cutter processing, has increased by 13.3% (Fig. 7), annual spending of having saved hundreds thousand of units for factory.

Claims

1. method that characterizes superhard cubic boron nitride cutting tool wear form is characterized in that concrete steps are:

(1) adopt scanning electron microscope SEM to confirm the eroded area and the eroded area not of the main cutting edge of CBN cutter;

(2) utilize energy dispersive spectrometer EDS to eroded area and not eroded area carry out energy spectrum analysis respectively, the atomic ratio of each composition in the zones of different relatively, thus analyze the wear form of cutting tool.