Summary of the invention
The object of the invention is to for deficiency of the prior art, a kind of roller thermal treatment zero Decarburization Control method is provided, control the homogeneity of carbon potential, make product meet national standard.
For solving the problems of the technologies described above, the technical solution used in the present invention is: meshbeltfurnace roller thermal treatment zero Decarburization Control method, comprise quenching, tempering and detect three steps, described quenching step is carried out quench treatment in meshbeltfurnace quench zone, adopts methyl alcohol, nitrogen and three kinds of atmosphere control carbon potentials of propane, in quenching heat-processed, Fen San district controlled atmosphere flow, roller heat-up time is 52-60 minute, and quenching temperature is 850 ± 5 DEG C, the stable 0.7-0.8% that is controlled at of carbon potential;
In the described tempering stage, tempering temperature is 160-165 DEG C, and soaking time is 180-210 minute.
Further, described meshbeltfurnace quenching is distinguished three sections ventage is set, each ventage arranges methyl alcohol, propane, nitrogen and passes into mouth, enter stove trend the firstth district, Second Region He 3rd district successively by roller, wherein, the logical propane in the firstth district and nitrogen, propane normal open flow is 0.5-1L/min, and adopt oxygen probe automatic makeup to taste control, flow is 2-3L/min; Nitrogen flow is 2-3L/min; The logical propane in Second Region and nitrogen, propane normal open flow is 0.5-1L/min, adopts oxygen probe automatic makeup to taste control, and flow is 2-3L/min, and nitrogen flow is 2-3L/min; The logical nitrogen in San district and methyl alcohol, nitrogen flow is 6-6.4m
3/ h, methyl alcohol flow is 4-4.5 m
3/ h.
Further, roller is 16-20min in the firstth district heat-up time, and in Second Region, be 18-20min heat-up time, and 3rd district are 18-20min heat-up time.
Further, meshbeltfurnace carbon potential reference gas is arranged on 0.2-0.3 L/min.
Further, carbon-potential control is between 0.7-0.8%.
Beneficial effect of the present invention:
1, the present invention is in quenching heat-processed, and subregion passes into high flow capacity nitrogen, utilizes the acting in conjunction of three air-circulating fans of burner hearth, has ensured in burner hearth that atmosphere is in higher barotropic state, and carbon potential is evenly distributed, and each point scattered error is little, and overall carbon potential fluctuation is little.
2, methyl alcohol of the present invention passes into after adopting the outer cracking of stove, can either reduce the generation of carbon black, again can less methanol decomposition time, fluctuates because furnace temperature around changes the carbon potential causing; Every district propane adopts constant and compensation rate (automatically controlling) to pass into lower value and the higher limit that can ensure respectively carbon potential, thereby make its stable being controlled in less fluctuation range, efficiently solve in conventional control process the realistic problem of easy poor carbon under easy carburetting and low carbon potential under high carbon potential.
Embodiment
Below in conjunction with specific embodiment, technical scheme of the present invention is elaborated.
A kind of meshbeltfurnace roller of the present invention thermal treatment zero Decarburization Control method, comprise quenching, tempering and detect three steps, it is characterized in that: described quenching step is carried out quench treatment in meshbeltfurnace quench zone, adopt methyl alcohol, nitrogen and three kinds of atmosphere control carbon potentials of propane, in quenching heat-processed, Fen San district controlled atmosphere flow, roller heat-up time is 52-60 minute, quenching temperature is 850 ± 5 DEG C, the stable 0.7-0.8% that is controlled at of carbon potential; In the tempering stage, tempering temperature is 160-165 DEG C, and soaking time is 180-210 minute.
Embodiment 1
First, debug meshbeltfurnace roller production line, controlled on request quenching temperature well, tempering temperature, shielding gas flow amount, quenching oil temperature, ensures that all kinds of parameters are in slave mode, produces and carries out early-stage preparations for roller.When setting, 850 ± 5 DEG C of roller quenching temperatures, 160 DEG C of tempering temperatures, allow quenching oil temperature control at 55 DEG C.
Concrete: furnace temperature is arranged to 850 DEG C, and the heating phase of quenching adopts dissociated methanol gas and nitrogen as carrier gas, adopts Deposition During Propane Pyrolysis gas as enriched gas, meshbeltfurnace quenches and distinguishes three sections ventage is set, and each gas port arranges methyl alcohol, propane, nitrogen and passes into mouth.Entering stove by roller moves towards meshbeltfurnace quench zone and sets gradually the firstth district, Second Region He 3rd district, control methyl alcohol, nitrogen and propane flow well, described meshbeltfurnace quenching is distinguished three sections ventage is set, each ventage arranges methyl alcohol, propane, nitrogen and passes into mouth, enters stove trend and sets gradually the firstth district, Second Region He 3rd district, wherein by roller, the logical propane in the firstth district and nitrogen, propane normal open flow is 0.6L/min, and adopts oxygen probe automatic makeup to taste control, and flow is 2.2L/min; Nitrogen flow is 2.2L/min, and the firstth district is 16min heat-up time; The logical propane in Second Region and nitrogen, propane normal open flow is 0.6L/min, adopts oxygen probe automatic makeup to taste control, and flow is 2.2L/min, and nitrogen flow is 2.2L/min, and Second Region heat-up time is 18min; The logical nitrogen in San district and methyl alcohol, nitrogen flow is 6m
3/ h, methyl alcohol flow is 4 m
3/ h.Wherein, carbon potential reference gas is set to 0.2 L/min, and San district is 18min heat-up time.
Each district constant flow, has ensured height in burner hearth and stable malleation; First, second district's propane adopts two portions control, a part adopts constant low flow 0.6L/min, another part utilizes oxygen probe automatic makeup to attempt controlling, carbon potential passes into 2.2L/min when not enough, when carbon potential arrives setting point, stop leading to this, so go round and begin again, maintain continual and steady carbon potential level in burner hearth.
Then,, by entering burner hearth through the roller cleaning, dry by certain speed, make regular check on the flow accordance of each district methyl alcohol, nitrogen and propane.Pay close attention to carbon potential changing conditions, stable being controlled between 0.7-0.8%.
Embodiment 2
Debug meshbeltfurnace roller production line, controlled on request quenching temperature well, tempering temperature, shielding gas flow amount, quenching oil temperature, ensures that all kinds of parameters are in slave mode, produces and carries out early-stage preparations for roller.When setting, 850 ± 5 DEG C of roller quenching temperatures, 165 DEG C of tempering temperatures, allow quenching oil temperature control at 65 DEG C.
The logical propane in the firstth district and nitrogen, propane normal open flow is 1L/min, and adopts oxygen probe automatic makeup to taste control, flow is 3L/min; Nitrogen flow is 3L/min, and the firstth district is 20min heat-up time; The logical propane in Second Region and nitrogen, propane normal open flow is 1L/min, adopts oxygen probe automatic makeup to taste control, and flow is 3L/min, and nitrogen flow is 3L/min, and Second Region heat-up time is 20min; The logical nitrogen in San district and methyl alcohol, nitrogen flow is 6.4m
3/ h, methyl alcohol flow is 4.5 m
3/ h.Wherein, carbon potential reference gas is set to 0.3 L/min, and San district is 20min heat-up time.
Each district constant flow, has ensured height in burner hearth and stable malleation; First, second district's propane adopts two portions control, a part adopts constant low flow 1L/min, another part utilizes oxygen probe automatic makeup to attempt controlling, carbon potential passes into 3L/min when not enough, when carbon potential arrives setting point, stop leading to this, so go round and begin again, maintain continual and steady carbon potential level in burner hearth.
Roller is quenched, tempering surface de-, poor carbon state-detection: require, poor carbon state de-to roller to check in strict accordance with JB/T1255-2001 standard and SKF to heat treated special control, if bus face and chamfering place all do not have poor carbon or carburetting, it is qualified to be judged to; Even if exist slight carburetting Huo Pintan district to be all judged to defective.
Adopt the thermal treatment zero decarburization first-time qualification rate of the roller of ordinary method control to be not more than 85%, adopt the first-time qualification rate of heat treating method roller of the present invention all more than 99.5%.