Experiment of carbon of tone of the substance in small nitrogen studies

5 ～ 2.

The cementite of 0mm, the drop that uses equipment to be used generally for our country registers heat of cementite of gas of type well type, cementite temperature is lower than groovy cementite temperature 100 ℃ of 40 ～ . It is give priority to with cementite, at the same time the nitrogen to minim of person of workpiece interior ooze, ooze agent uses alcohol and kerosene, add certain amount among them express and activator and carburet agent. This craft in terminus of ooze agent recipe, exhaust process of test, cementite is controlled, and quench the method is creative, its craft is simple, reappearance is good, quality is high, not only the ooze layer organization of attainable ideal, and can decrease be out of shape, raise gear precision. 2. Craft characteristic (the success that the exhaust terminus that 1) goes easily simply checks exhaust effect to affect cementite directly and cementite quality, the key that because this exhaust is terminal,the accuracy of the test is control cementite one annulus. Its check a method is after using 5min of cementite of mild steel silk, take out grind on grinder, if the surface has tall carbon scintilla to think exhaust period ends, can undertake issueing a job order. This method is simple and feasible, , accuracy is very tall. (The exhaust of alcohol drop agent that big amount uses after lukewarm cementite uses workpiece of two paragraphs of exhaust to enter furnace in 2) small nitrogen, appearance arrives inside lukewarm 30min it is good to use alcohol and kerosene exhaust effect, because ooze agent is medium,join know clearly at the same time clean agent, make workpiece surface activation, offerred good condition for strong ooze. Strong ooze - come loose to undertake cementite is handled alternately, inside the furnace after exhaust ends carbolic situation already was achieved 1. 2 ％ above, can raise workpiece quickly to express the grinding quantity that contain carbon, quicken carbon the infiltration to workpiece surface, if strong ooze time is too long, easy the aggravation that causes metallographic tissue, its reason is alloy steel forms carbide and austenite two-phase coexistence easily in cementite process organization, cementite time is too long, the meshy carbide that the organization appears is eliminated very hard. Strong ooze - those who diffuse is alternant undertake, its purpose is the carbide up to mark after strong ooze undertake diffusing when upper limit, make its carbide reachs floor level, undertake the opportunity that makes carbide net is formed is reduced greatly repeatedly so, also formed good constituent form. Strong ooze - diffusing circular number should decide according to ooze layer deepness. Because craft is contained in drop agent a few the agent that offer neon, clean agent and agent of carbolic situation heighten, add a person by atmosphere to workpiece surface carbon deliver rate, and the osmosis of the work of azotic improvement yard of the minim in ooze layer, quickened carbon diffuse, make gear obtained small metabolic result. (When 3) quenchs temperature, cooling medium reachs the medium, floor level that quenchs the method achieves a technology to ask in ooze layer, can use heat inside beforehand cold (drop in temperature diffuse) , control of power of the carbon inside furnace is in 0.

8 ％ are controlled, beforehand cold to quench furnace goes out to quench after temperature, quench the choice of temperature is reached with the Ar3 of material be out of shape the demand will decide, temperature is lower deflection is smaller, but must be the core after quenching does not appear F and exterior A have sufficient carbolic dissolve amount. Quench in order to assure the requirement of hardness. Because cementite quenchs be out of shape is,give priority to with thermal stress, use reduce quench temperature is mixed raise oil lukewarm it is a kind of effective method. Because quench temperature is low, the operation when quenching wants rapid, make workpiece enters cooling medium very quickly, oily lukewarm control is in oily flash point. This craft handles workpiece quality stability, have good cementite uniformity. As a result of each phase in cementite, this work skill is offerred tall, effective available carbolic quantity, because this has good cementite uniformity, line of the hardness of helical gear and this straight gear after from the course this craft is handled, axis straight gear, public law and axial selective examination jumpily can see in the result. 2, applied circumstance and effect 1. One of characteristics of lukewarm gas cementite in small nitrogen of basis of circumstance of change of line of gear public law, control ooze layer to organize configuration to achieve control metabolic goal namely, straight gear of the one straight gear that we get on to 40t scraper transport early or late, helical gear, axis and gear of electric power engine undertake craft experiments. Former technology is: 920~C kerosene cementite, strong ooze 2h, diffuse 3~4h, drop in temperature to quench with heat giving after 30min of 830 ℃ constant temperature. We are draw-out around of cementite of classics of fair to its normal enters straight gear to check all right, discover public law line by 95 original.

99mm became 96.

07mm, it is before cementite of variation of public law line 0.

02mm, it is after cementite 0.

08mn, along line of tine direction public law change is 0.

042mm, out of tolerance of public law line cannot satisfy a technology to ask. Watch 1 for line of public law of 40t straight gear change contrasts watch. From the watch 1 can see, the after lukewarm cementite fair normal in using small nitrogen goes up on average big O.

072mm, it is along tine direction 0.

068mm, the specification uses this craft to be out of shape than former technology small. The material of helical gear is 20CrMnTi, public law line is 98.

57-0.

36mm. Use this technology after two loops cementite is handled, we selective examination checked 139 data, variation of public law line distributings to be centered quite, the effect is idealer (see a table 2) 2. Axis kind of gear be out of shape circumstance axis kind of gear bend be out of shape is the common and inevitable circumstance in heat treatment process. Past is use after cementite quenchs cold press and heat up alignment to solve bend be out of shape, worker labor strength is very great, also raised manufacturing cost. We use small nitrogen in after lukewarm cementite, bend be out of shape had relatively substantially drop, deflection also by 0 original.

3~0.

5mm drops 0.

2~0.

35mm, percent of pass raises 75 ％ ~90% by ％ of original 50 ％ ~70. Watch 3 for sampling observation of gear of 7 furnace axis be out of shape circumstance. 3. The constituent function after using new technology to handle uses this technology the gear that we handled layer of a batch of different modulus, ooze to ask to differ, experiment of classics metallographic examination, hardness and layer are deep measure, can see this craft ooze fast faster, craft is very stable, uniformity is good, hardness is fluctuant and lesser, in-house organization can be controlled in 3 class less than. Specific amount sees a table 4. CNC Milling