Function of microtherm ooze boracic layer studies

The Results Showed That Under The Condition Of Boriding At Low Temperature Wear Resistance Andcorosion Resistance Of Boried Layer Were Increased And Its Brittleness Was Reduced.

Keywords: Boron of ooze of 　 of Temperature of 　 of Low of 　 of Layer of 　 of Performance 　 Borided is a boracic infiltration to metallic stuff surface, get boride ooze layer diffuse process. Ooze boracic layer has very tall hardness, admirable wearability to reach be able to bear or endure goodly corrode sex. In recent years, people reached ooze boracic mechanism to have much research to ooze boracic craft. But the place that ooze boracic craft still has his to be not worth, be like: Boride itself brittleness flakes greatly, easily, temperature of traditional ooze boracic craft tall, specific power consumption is big, the workpiece after ooze is boracic is out of shape bigger etc. To overcome these inadequacy, people had indefatigable effort, gained a few success. Be like: Single-phase Fe2B is obtained after people adopts ooze boron or diffuse into travel vacuum after ooze is boracic and obtain single-phase Fe2B[1, 2] , of ooze boron in all brilliant changes processing [3, 4] and in all ooze and compound ooze craft [5, 6] will reduce brittleness of ooze boracic layer. To solve ooze boracic temperature the workpiece after tall, ooze is out of shape wait for a problem greatly, microtherm ooze boron is people place to pay close attention to, microtherm ooze is boracic, point to namely actually in steel critical point (A) the ooze of the following temperature is boracic. The article is with 45 steel exemple, through wearing away experiment, brittleness experiments and the test of zincous polarization curve, studied microtherm ooze is boracic the wearability of boracic to steel ooze layer, brittleness and be able to bear or endure the influence of corrode sex. 1 experiment method 1.

Material of boracic sample of 1 solid ooze is 45 steel, its are specific processing measure is: Recipe → cleans sample → besmear to brush sample of → of sample of sample → drying to load coal tub sealed → enters coal tub furnace ooze boracic → to give coal tub furnace to clear. 1.

Function of boracic layer of ooze of 2 low temperature uses J71 model microscopical what sclerometer measures boride layer and matrix is microscopical hardness, choose load to be 100g. Grind bead to wear away the experiment grinds bead to wear away in what abstain undertake on experiment machine, choose grind bead to be 280 ～ 320 purposes fly ash, load is 1.

16g/mm2, speed is 34r/min. Slip wear away the experiment is disk type is sold to wear away in what abstain undertake on experiment machine; Choose load for 4.

82g/mm, speed 600r/min, without lubricant. Much stronger flake the experiment is to using small-sized punching machine to change those who make is much stronger flake undertake on experiment machine; Chosen drift is the steel ball of diametical 6mm, stroke 25mm, percussion frequency is 250 times / Min. With appearance of potential of HDV-7C transistor constant, it is in chroma 0.

Measure zincously in the vitriolic solution of 5mol/l polarization curve. 2 tests result 2.

1 microscopical hardness to 45 steel boracic sample of ooze of rare earth of 10h of 650 ℃ × is mixed boracic sample of ooze of rare earth of 4h of 840 ℃ × undertakes microscopical hardness is measured, if pursue,as a result 1 is shown. By the graph 1 knowable: Boracic layer of ooze of ① low temperature and boracic layer of high temperature ooze are in boride area is microscopical hardness cost matchs; ② is in microscopical on hardness profile, what microtherm ooze boracic layer compares boracic layer of high temperature ooze is steep. Graph deepness of 1 ooze boracic layer and microscopical hardness relation curve 2.

2 wearability experiment is right 45 steel sample of date of 10h(1 of 650 ℃ × ) sample of boracic sample of rare earth ooze and date of 4h(2 of 840 ℃ × ) boracic sample of rare earth ooze makes grinding bead to wear away mixing sliding wear away comparative experiment, if pursue,as a result 2 ～ are shown 5 times. By the graph 2 ～ 5 knowable: ① is in adjust level, the weightlessness that speed is less than 2 sample is measured and wear away speed; ② wears away in stability level, the weightlessness that speed is less than 2 sample a bit is measured and wear away speed; ③ is in break certain level, the weightlessness of a sample is measured and wear away speed is far the weightlessness that is more than 2 sample is measured and wear away speed. Graph the relation of wear extent of the 2 tatty that wear bead and time pursues the relation of wear extent of 3 slip tatty and time pursues 45 steel of 4 　 are thin circumstance of impress of Vickers of earthy ooze boracic sample (100 × ) graph 5 in 0.

The zincous polarization curve that measures in the vitriolic solution of 5mol 2.

3 brittleness experiment 2.

3.

Experiment of impress of 1 diamond pyramid hardness consults experiment of nitriding layer brittleness and document [the ooze that 7] place recommends is boracic method of layer brittleness assess, according to ooze boron the whole situation of impress of layer surface Vickers comes qualitative assess boron of ooze of rare earth of 10h of 650 ℃ × mixes 45 steel the brittleness of boracic sample of ooze of rare earth of 4h of 840 ℃ × , its are shown 4 times like the graph as a result. By the graph 4 knowable: Below similar craft requirement and to load condition, the impress with microtherm ooze boracic sample and boracic both sample of high temperature ooze is apparently different. The impress border of boracic sample of high temperature ooze is unsharpness, flake much; And the impress of microtherm ooze boracic sample is clear, flake little. This makes clear microtherm ooze boracic layer relatively the brittleness of boracic layer of high temperature ooze rises somewhat. 2.

3.

2 much stronger flake the experiment is opposite below the circumstance that boracic sample of ooze of rare earth of boron of ooze of rare earth of 10h of 650 ℃ × and 4h of 840 ℃ × pounds 45 steel of 　 500 times, flake with indentation surface the bulk of the area comes relatively of qualitative and comparative both much stronger flake fight force [8] . Test result makes clear: What boracic sample of high temperature ooze compares microtherm ooze boracic sample is opposite flake the area wants a little bit big. 2.

4 anti-corrosive the experiment is right 45 steel boracic sample of ooze of rare earth of 10h of 650 ℃ × (1) with date of 4h(2 of 840 ℃ × ) if the zincous polarization curve that boracic sample of rare earth ooze measures pursues show 5 times, the data that the feature on the curve nods is expressed as follows. Number of sample of data of dot of 5 on-line feature sends chart Ib/mA of blunt current density.

Ip/mA of current density of Cm-2 Wei Dun.

Cm-2 sends blunt potential Eb/mV, ep/mV of potential of VsSCE passive state, vsSCE1180.

830.

98+800+9002213.

331.

Of 20+900+1000 　 metal corrode speed and density of its corrosion current to become direct ratio, and corrosion current density is to pass polarization current density to mirror on polarization curve. Accordingly, can use will corrode speed quite with density of the polarization current below potential. From the graph 5 and go up the watch is knowable: ① of a sample send Ib of blunt current density far relatively 2 sample are small, the ② of; of active and deliquescent speed that ooze layer can reduce significantly after showing microtherm ooze is boracic of a sample send blunt potential; far relatively 2 sample are lost, the ③ of ooze layer easy passivation after showing microtherm ooze is boracic the Wei Dun current density of a sample relatively somes 2 sample are small, the deliquescent rate of stable passivation phase can be lowered after showing microtherm ooze is boracic, the ④ of passivation function; that can raise ooze layer namely the passive state potential of a sample is far relatively 2 sample are small, and its passivation region is remote those who compare 2 is wide. Namely the stable passivation phase of layer of the ooze after microtherm ooze is boracic is far relatively the length of layer of the ooze after high temperature ooze is boracic. This makes clear in be able to bear or endure electrochemistry corrodes performance side, microtherm ooze boracic layer is apparent boracic layer of ooze of excel high temperature. 3 discuss afore-mentioned test results to make clear, microtherm ooze boracic layer and photograph of boracic layer of high temperature ooze are compared, its wearability, be able to bear or endure corrode sex rises somewhat, its brittleness is improved somewhat. Function is decided by the organization, microtherm ooze boracic layer and boracic layer of high temperature ooze are in wearability, be able to bear or endure because the organization of microtherm ooze boracic layer compares the organization of boracic layer of high temperature ooze,the reason of the difference on corrode sex and brittleness basically is compact, loose hole is little cause. Wear away when the experiment, the loose hole of ooze layer surface layer produces crackle as a result to flake easily [9] . As a result of microtherm ooze boracic layer relatively boracic layer of high temperature ooze is compact, loose hole is little, reason is in adjust level, of microtherm ooze boracic layer wear away speed is far those who be less than boracic layer of high temperature ooze wear away speed. The boracic needle with because microtherm ooze is boracic medium layer relatively the boracic needle in boracic layer of high temperature ooze is some closer, reason wears away in stability level, of microtherm ooze boracic layer wear away of boracic layer of ooze of speed comparing high temperature wear away speed slightly small. Because microtherm ooze boron is layer upon layer deep relatively boron of high temperature ooze is layer upon layer depth, boracic layer of ooze of reason low temperature is entered acuteness wear away the time of level should compare boron of high temperature ooze the layer is early. Can infer, boracic layer of ooze of if low temperature has the depth with as boracic as high temperature ooze identical layer, its wearability will rise greatly. The loose hole of ooze layer surface layer is the way that crackle is produced and expands [9] , when getting concussion load, bring about ooze boron extremely easily layer craze and flake. Because microtherm ooze is boracic boracic layer of ooze of layer comparing high temperature is compact, loose hole is little, boracic layer of ooze of reason low temperature has the brittleness with more boracic than high temperature ooze low layer. The loose hole place of ooze layer surface layer gathered extremely electronegative strong active element (like Re) with element of a few impurity, make potential of the place electrode and differ somewhere else, form small cell easily in solution, below electrolyte action, produce electrochemistry to corrode. Apparent, loose hole is more, the small cell number of generation is more, electrochemistry is corroded more serious. Because microtherm ooze is boracic boracic layer of ooze of layer comparing high temperature is compact, loose hole is little, the corrosion resistance of boracic layer of ooze of reason low temperature is apparent the corrosion resistance of boracic layer of ooze of excel high temperature. CNC Milling