Apply at the welding wire of v medicine core of rehabilitate of head of aegis compose knife

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In construction of subway aegis compose, cutting tool wears away serious, affected construction time limit for a project and cost badly. Through choosing right v stuff, improved performance of knife head surface, prolonged its service life effectively. The subway 5 lines use method of aegis compose construction at channel of Beijing city subway to build first, the crucial equipment of construction of subway aegis compose is machine of aegis compose driving. The earthy pressing that 5 lines construction uses Beijing subway balances aegis compose machine is a cost 48 million yuan of or so newest large scale computer that introduces from Germany fetterses. Classics experiment paragraph construction of compose of subterranean channel aegis, gathered a large number of experience and experimental data, also show a few issues. The component of aegis compose machine still needs an import, and the aegis compose cutting tool that serves as running stores is a when make influence construction time limit for a project and cost serious problem more. Begin research around the service life that improves cutting tool of aegis compose machine, what realize cutting tool of aegis compose machine then is homebred change already became treat one of settlement problems urgently. Beijing industry university is relevant task group is reached with respect to the rehabilitate of cutting tool of aegis compose machine homebred change undertook study. The repair method of cutting tool point chooses to be v; The choice respect of material, the function of the research experience that joins task group and cutting tool of aegis compose machine asks to be medical core welding wire certainly. Beijing subway compose of 5 lines aegis experiments paragraph belong to arenaceous pebble layer, grit content is big. Content is as high as the quartz in layer 45% , make cutting tool wears away speed is accelerated. Diameter of bit body of aegis compose machine is 6.

2m, linear velocity of cutting of cutting tool of bit body ragged edge can amount to 1m/s most, circumjacent knife gets very big wallop. Analyse through above knowable, in construction of arenaceous pebble layer, the invalidation form with main cutting tool of aegis compose machine wears away to concussion is destroyed and wear bead. Head of aegis compose knife is standing not only in construction process grit wears away, still suffer strong impact. This wants to have tall hardness not only with respect to requirement v alloy, have better tenacity even, in repeatedly intense percussive circumstance falls to happen not easily fall off. V material chooses Tiejidui change of seam gold performance is sweeping, tenacity and wearability had cooperated, can satisfy different need, and the price is low, because this research employs iron radical alloy certainly,be. To iron base for alloy, c is the most important element, c content is inside certain limits, layer hardness and wearability follow v to contain C quantity to increase and increase, the impact resistance of v layer also can rise subsequently, but C content is too high, performance of the tenacity when v layer is pounded is poorer, be had especially by the meeting when relatively strong impact craze and flake phenomenon. To avoid the impact of v layer craze is mixed flake, this research asks to limit the content of the carbon in v layer, use Mo to wait have the integral performance that refines as grain, strong as carbolic union ability alloying element to improve v layer, join Ni to raise the tenacity of v layer at the same time. Can mix to assure the wear-resisting bead abrasiveness of v layer impact resistance can, affirmatory Cr-Ni-Si-Mn-Mo is multivariate the main constituent that aggrandizement alloy department regards medical core as the recipe. To make sure welding wire is mechanical function, composition of core of Chinese traditional medicine of welding wire of v medicine core is alloyed powder end for the most part (quality mark 75% ～ 80% ) . Contain in core of medicine of medical core welding wire a few firm arc agent and slagging agent (quality mark 20% ～ 25% ) , basically be solder with what will assure medical core welding wire technical properties, include to solder the stability of electric arc, welding line shapes, the sex that take off broken bits, splatter, solder soot. Generally speaking, below the premise that v layer asks in contented and mechanical function, do not have special requirement to the content of nitrogen, hydrogen, oxygen, sulfur and phosphor, but stem from pair of operating mode and welder art the requirement of the respect, the requirement has strict control to the crackle of welding line, namely surface of the welding line after v is flawless. Basic slag fastens splatter, the sex that take off broken bits is hard to control than acid slag department, and the stability with the basiccer electric arc that acid slag fastens, welding line shapes beautiful. Additional, the quantity sending this world that solders, the quantity sending this world that basic slag fastens and hair dirt rate all prep above acid slag is. What because this is choosing broken bits,fasten is affirmatory fasten for acid slag. When recipe of core of medicine of medical core welding wire is designed, affiliation mineral white basically has grey rock of stone of rutile, quartz, fluorite, ferric oxide, zirconium, silicon. By the operating mode of aegis compose cutting tool knowable, cutting tool should have taller hardness already in order to resist of tall stress grind bead to wear away, want to enough tenacity will absorb the concussion of arenaceous pebble again. So choice Cr-Ni-Si-Mn-Mo regards v as the bases of welding wire, specific ingredient sees a table 1. Before welding wire solder need not warm-up, solder hind need not have heat treatment, v layer surface is flawless. Express bases of 1 v metal (quality percentage % ) C Cr Mn Si Ni Mo Fe0.

1~0.

3 5~10 0.

5~2 <1 1~3 <0.

Organization of layer of 5 surplus v basically is martensite of mild batten shape, this martensite is the austenite that falls by high temperature transform in cooling process and come, have in place of former austenite crystal boundary did not transform complete austenite remains. V layer function undertakes sample v with the medical core welding wire of development, the influence that goes up to v layer composition, function for purify mother capable person, v three-layer above wants when the experiment. If the Rockwell hardness of v layer expresses 2 to show. Express hardness of 2 v layer to be worth v layer hardness (HRC) hardness average (HRC) ground floor 50.

0 53.

4 53.

4 52.

8 51.

3 52.

18 the 2nd 54.

7 56.

2 53.

4 53.

2 55.

5 54.

60 three-layer 55.

0 54.

5 56.

2 53.

4 52.

8 54.

38 in abstain concussion wearing to go up to employ mass respectively for 3.

5kg and 7.

The shot of 5kg is undertaken pounding to sample by 1m height, number of blows is respectively 5, 10, 20 mix 30 times. Change of the hardness after concussion pursues as follows. Concussion pursues to the influence of solder layer hardness by v layer Rockwell hardness change is seen, increase along with number of blows, v layer hardness is shown increase a current, but hardness has upper limit value. And shot pounds hardness of above v layer 10 times to be able to be close to this upper limit to be worth (HRC58.

5 the left and right sides) , showed pair of solder layers to show apparent ground to pound aggrandizement phenomenon in the concussion of less time, this is in of cutting tool of aegis compose machine enlist in army important sense has in the process: A few pebble concussion can make cutting tool of aegis compose machine shows taller hardness, raise the wearability of cutting tool quickly thereby. Carry a series of experiment research, knowable welding wire of core of this v medicine solders technology is good, as welded hardness can amount to HRC55, before solder need not warm-up, after solder need not heat treatment, v layer is flawless generation. CNC Milling CNC Machining