JPS648073B2 - - Google Patents
Info
- Publication number
- JPS648073B2 JPS648073B2 JP10563779A JP10563779A JPS648073B2 JP S648073 B2 JPS648073 B2 JP S648073B2 JP 10563779 A JP10563779 A JP 10563779A JP 10563779 A JP10563779 A JP 10563779A JP S648073 B2 JPS648073 B2 JP S648073B2
- Authority
- JP
- Japan
- Prior art keywords
- amount
- gas
- carbon concentration
- target
- carburizing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 39
- 229910052799 carbon Inorganic materials 0.000 claims description 39
- 238000000034 method Methods 0.000 claims description 29
- 238000005255 carburizing Methods 0.000 claims description 24
- 239000013256 coordination polymer Substances 0.000 claims description 15
- 238000004458 analytical method Methods 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 7
- 150000001721 carbon Chemical class 0.000 claims description 3
- 230000003247 decreasing effect Effects 0.000 claims description 3
- 239000007789 gas Substances 0.000 description 54
- 229910000831 Steel Inorganic materials 0.000 description 13
- 239000010959 steel Substances 0.000 description 13
- 239000000463 material Substances 0.000 description 12
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- 238000004364 calculation method Methods 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000012159 carrier gas Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- QMQXDJATSGGYDR-UHFFFAOYSA-N methylidyneiron Chemical compound [C].[Fe] QMQXDJATSGGYDR-UHFFFAOYSA-N 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/20—Carburising
- C23C8/22—Carburising of ferrous surfaces
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Description
【発明の詳細な説明】
この発明は、浸炭雰囲気の炭素濃度制御方法に
関し、特に、雰囲気ガス中のCO量と炉内温度と
鋼材表面の目標炭素濃度とから所望の平衡炭素濃
度に相応するCO2量を演算してCO2量の目標値を
設定し、この目標CO2量と雰囲気ガス中のCO2量
との偏差に基づいて炉内に供給されるエンリツチ
ガス量を制御することにより、雰囲気ガス中の
CO量が変動するような場合においても、浸炭雰
囲気の平衡炭素濃度を所望値に保持させるように
したものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling carbon concentration in a carburizing atmosphere, and in particular, the present invention relates to a method for controlling carbon concentration in a carburizing atmosphere, and in particular, a carbon concentration control method that corresponds to a desired equilibrium carbon concentration based on the amount of CO in the atmosphere gas, the temperature inside the furnace, and the target carbon concentration on the surface of the steel material. By calculating the amount of CO 2 and setting the target value of the amount of CO 2 , and controlling the amount of enrichment gas supplied to the furnace based on the deviation between the target amount of CO 2 and the amount of CO 2 in the atmosphere gas, in gas
Even when the amount of CO changes, the equilibrium carbon concentration of the carburizing atmosphere is maintained at a desired value.
一般に、鋼材を浸炭雰囲気中で熱処理する場合
の浸炭機構は、たとえば雰囲気ガスとしてCO＋
CO2混合ガスを例にとると、次の反応式によつて
与えられる。 Generally, when heat treating steel materials in a carburizing atmosphere, the carburizing mechanism uses, for example, CO+ as the atmospheric gas.
Taking CO 2 mixed gas as an example, it is given by the following reaction formula.
2CO〔Ｃ〕＋CO2 ……(1)
上式から浸炭雰囲気の炭素濃度は、雰囲気ガス
成分の中のCO2の分圧を測定することによつて制
御する方法が、従来から行なわれている。しかし
ながら、この制御方法はCO量が一定であること
を前提とするものであるため、必ずしも精密な制
御を望み得ないという難点がある。すなわち、変
成炉方式による雰囲気ガスでは、変成に用いられ
る炭化水素ガスの種類および炭化水素ガスと空気
との混合比によつて、それぞれガス組成が変動
し、また、省資源を目的として、真空炉のような
完全密閉容器に被処理鋼材とともに雰囲気ガスを
パツクして行なう浸炭方式では、エンリツチガス
の供給量に応じてガス組成が変動するため、これ
によるCOの分圧の変動を免れず、したがつて、
CO2のみを測定して行なう従来の制御方法では、
鋼材表面の炭素濃度を所望値に制御するのは、き
わめて困難なこととされていた。 2CO[C]+CO 2 ...(1) From the above equation, the carbon concentration in the carburizing atmosphere has traditionally been controlled by measuring the partial pressure of CO 2 in the atmospheric gas components. . However, since this control method is based on the premise that the amount of CO is constant, there is a drawback that precise control cannot necessarily be expected. In other words, the gas composition of the atmospheric gas produced by the shift furnace method varies depending on the type of hydrocarbon gas used for shift conversion and the mixing ratio of hydrocarbon gas and air. In the carburizing method, in which atmospheric gas is packed together with the steel material to be treated in a completely sealed container, the gas composition fluctuates depending on the amount of enrichment gas supplied, which inevitably causes variations in the partial pressure of CO. Then,
With conventional control methods that measure only CO 2 ,
It has been considered extremely difficult to control the carbon concentration on the surface of steel materials to a desired value.
そこで、このような難点を排除する技術として
CO2以外の組成ガスを計測する方法も提案される
に至り、たとえば、特開昭51−149135号および特
開昭51−149136号各公報では、CO，CO2，CH4
およびH2を、特開昭52−14539号および特開昭52
−14540号公報では、CO，H2およびH2Oをそれ
ぞれ計測し、これらの分析値で算出した雰囲気中
の炭素濃度を所望の平衡炭素濃度設定値と比較し
て、その偏差に応じてエンリツチガスの添加量を
制御するようにしている。これらの方法は従来よ
りも高精度の制御が可能となる点において効果を
有するものの、分析される組成ガスが少くとも３
種類を必要とするため、却つて分析装置や演算装
置の構造と配置が大型かつ複雑となり、その管理
も容易ではないという難点がある。 Therefore, as a technology to eliminate such difficulties,
Methods for measuring compositional gases other than CO 2 have also been proposed; for example, in JP-A-51-149135 and JP-A-51-149136, CO, CO 2 , CH 4
and H 2 , JP-A-52-14539 and JP-A-52
In Publication No. 14540, CO, H 2 and H 2 O are each measured, and the carbon concentration in the atmosphere calculated from these analysis values is compared with the desired equilibrium carbon concentration set value, and the enrichment gas is adjusted according to the deviation. The amount of addition is controlled. Although these methods are effective in allowing more precise control than conventional methods, they
Since different types are required, the structure and arrangement of the analysis device and the arithmetic device become large and complicated, and their management is difficult.
この発明は、かかる観点に鑑み、従来の制御方
法の欠点を解消するためになされたものであり、
この発明の目的は、CO2とCOの２種類の組成ガ
スを測定することによつて浸炭雰囲気の炭素濃度
を簡易に、かつ精密に制御し得る方法を提供する
ことにあり、また、この発明の目的は、雰囲気ガ
スの組成とくにCOの変動や炉内温度の変化に応
じて所望の平衡炭素濃度に相応するCO2量を修正
することによつて浸炭雰囲気の平衡炭素濃度を一
定に制御する方法を提供することにあり、さら
に、この発明の目的は、熱処理炉の種類、および
浸炭方式の種別を問わず、鋼材の品質を均一かつ
高精度にすることにあり、さらにまた、この発明
の目的はガス浸炭におけるキヤリアガスおよびエ
ンリツチガスの消費量を節減して省資源化を実現
することにある。 In view of this point of view, this invention was made in order to eliminate the drawbacks of conventional control methods,
An object of the present invention is to provide a method for easily and precisely controlling the carbon concentration in a carburizing atmosphere by measuring two types of composition gases, CO 2 and CO. The purpose of this is to control the equilibrium carbon concentration of the carburizing atmosphere at a constant level by modifying the amount of CO 2 corresponding to the desired equilibrium carbon concentration in accordance with the composition of the atmosphere gas, especially the fluctuations in CO and the changes in the furnace temperature. A further object of the present invention is to provide a uniform and highly accurate quality of steel material regardless of the type of heat treatment furnace and the type of carburizing method. The purpose is to save resources by reducing the consumption of carrier gas and enrichment gas in gas carburizing.
すなわち、この発明に係る浸炭雰囲気の炭素濃
度制御方法は、下記の実施例において詳述するよ
うに、熱処理炉内の雰囲気組成ガスからCO2量と
CO量分析値Pcpと炉内温度と鋼材表面の目標炭素
濃度CPeqとにより雰囲気ガスの平衡炭素濃度に
相応する目標CO2量
（Ｓ×Pcp 2／CPeq）を演算して設定し、
ただし、Ｓ（温度係数）＝CPsat（飽和炭素濃度）／
Ｋ（平衡恒数）
この目標CO2量と雰囲気ガス中のCO2量分析値
との偏差に基づいて炉内に供給されるエンリツチ
ガス量を増減し、前記偏差値が零となるように制
御することを特徴とするものである。 That is, the method for controlling carbon concentration in a carburizing atmosphere according to the present invention, as described in detail in the examples below, controls the amount of CO 2 from the atmosphere composition gas in the heat treatment furnace.
Calculate and set the target CO 2 amount (S×P cp 2 /CP eq ) corresponding to the equilibrium carbon concentration of the atmospheric gas using the CO amount analysis value P cp , the furnace temperature, and the target carbon concentration CP eq on the surface of the steel material. , However, S (temperature coefficient) = CP sat (saturated carbon concentration) /
K (equilibrium constant) The amount of enrichment gas supplied to the furnace is increased or decreased based on the deviation between this target amount of CO 2 and the analysis value of the amount of CO 2 in the atmosphere gas, and the amount of enrichment gas is controlled so that the deviation value becomes zero. It is characterized by this.
この発明の制御方法は、次に述べる演算式を用
いて行なわれる。すなわち、前掲の浸炭機構の反
応式(1)における平衡恒数をＫとすると、次の平衡
式が成立する。 The control method of the present invention is performed using the following arithmetic expression. That is, if K is the equilibrium constant in the reaction equation (1) of the carburizing mechanism described above, the following equilibrium equation holds true.
Ｋ＝Pco2／ac・Pco2 ……(2)
ここに、ac；飽和度
Pco、Pco2；それぞれCO、CO2の分圧
ac＝平衡炭素濃度CPeq／飽和炭素濃度CPsat……(3)
いま、式(3)を式(2)に代入して変形すると、
Pco2＝Ｓ×Pcp 2／CPeq ……(4)
ここに、Ｓ＝CPsat／Ｋ
Ｓは処理温度によつて定まる定数（温度係数）
である。 K=Pco 2 /a c・Pco 2 ...(2) Where, a c ; Saturation degree Pco, Pco 2 ; Partial pressure of CO and CO 2 , respectively. a c = Equilibrium carbon concentration CP eq / Saturated carbon concentration CP sat ...(3) Now, substituting equation (3) into equation (2) and transforming it, Pco 2 = S x P cp 2 /CP eq ...(4) Here, S = CP sat /K S is Constant determined by processing temperature (temperature coefficient)
It is.
式(4)から、Pcpの変化分で目標とするPcp2を修
正すればよいことが判る。 From equation (4), it can be seen that the target P cp2 should be corrected by the change in P cp .
以下、この発明の制御方法を図示した実施例に
ついて説明する。第１図は、この発明に用いる制
御装置の実施例を示すブロツク図であり、一定の
処理温度に保持されている熱処理炉１には、鋼材
（図示せず）を装入して浸炭処理が行なわれる。
この熱処理炉１内には、浸炭ガスを発生させる滴
注剤を図示しない供給源から管路２によつて供給
し、また同様にエンリツチガスを図示しない供給
源から制御弁４を介して管路３によつて供給して
所定の平衡炭素濃度の雰囲気ガスを生成させるよ
うになつている。この雰囲気ガスは管路５から該
管路５に接続されたCO分析計６に送られる。該
CO分析計６によつて分析されたCO量はCO分析
信号として演算装置１０に入力する。また、炉内
温度を、熱電対７により測定して温度信号とし
て、同様に演算装置１０に入力する。一方、所望
する鋼材の表面炭素濃度を炭素濃度設定器８に設
定して、これを目標炭素濃度設定信号として同様
に演算装置１０に入力する。 Embodiments illustrating the control method of the present invention will be described below. FIG. 1 is a block diagram showing an embodiment of the control device used in the present invention. A heat treatment furnace 1 maintained at a constant treatment temperature is charged with steel material (not shown) and subjected to carburizing treatment. It is done.
Into this heat treatment furnace 1, a dripping agent for generating carburizing gas is supplied from a supply source (not shown) through a pipe line 2, and enrichment gas is similarly supplied from a supply source (not shown) through a pipe line 3 through a control valve 4. The atmosphere gas is supplied with a predetermined equilibrium carbon concentration to produce an atmospheric gas having a predetermined equilibrium carbon concentration. This atmospheric gas is sent from the pipe 5 to a CO analyzer 6 connected to the pipe 5. Applicable
The amount of CO analyzed by the CO analyzer 6 is input to the calculation device 10 as a CO analysis signal. Further, the temperature inside the furnace is measured by the thermocouple 7 and similarly inputted to the calculation device 10 as a temperature signal. On the other hand, a desired surface carbon concentration of the steel material is set in the carbon concentration setting device 8, and this is similarly inputted to the calculation device 10 as a target carbon concentration setting signal.
演算装置１０には、前掲式(4)の演算回路が組み
込まれており、これに入力されたCO分析信号、
温度信号および目標炭素濃度設定信号による演算
を行なつて、雰囲気ガスの平衡炭素濃度に相当す
る目標CO2量を算出する。この目標CO2量はCO2
調節計９の設定値として入力する。 The arithmetic device 10 has a built-in arithmetic circuit of the above formula (4), and the CO analysis signal inputted thereto,
A calculation is performed using the temperature signal and the target carbon concentration setting signal to calculate the target amount of CO 2 corresponding to the equilibrium carbon concentration of the atmospheric gas. This target CO2 amount is CO2
Input as the setting value of the controller 9.
また、炉内の雰囲気ガスは管路５に接続された
CO2分析計１１によつてCO2量が分析され、CO2
分析信号としてCO2調節計９にフイードバツクさ
れる。CO2調節計９は前記演算装置１０から設定
値として入力された目標CO2量の信号とCO2分析
計１１から測定値として入力されたCO2分析信号
とを比較して、これにより生じた偏差信号で管路
３に接続された制御弁４を作動させ、偏差信号の
大小に応じて該制御弁４の開度を調節する。以上
の様子を、炉内雰囲気の化学反応面から考察する
と次のようになる。 In addition, the atmospheric gas in the furnace is connected to pipe 5.
The CO 2 amount is analyzed by the CO 2 analyzer 11, and the CO 2
It is fed back to the CO 2 controller 9 as an analysis signal. The CO 2 controller 9 compares the target CO 2 amount signal input as a set value from the arithmetic unit 10 with the CO 2 analysis signal input as a measured value from the CO 2 analyzer 11, and calculates the amount of CO 2 generated thereby. A control valve 4 connected to the pipe line 3 is actuated by the deviation signal, and the opening degree of the control valve 4 is adjusted depending on the magnitude of the deviation signal. The above situation is considered as follows from the viewpoint of chemical reaction of the atmosphere inside the furnace.
第１図で、管路２から供給されるキヤリアガス
として、たとえば滴注式では、メタノールが使用
されるので、これが分解してCOとH2が生成され
る。 In FIG. 1, methanol is used as the carrier gas supplied from the pipe line 2 in, for example, the dripping method, and this decomposes to produce CO and H 2 .
CH3OHCO＋2H2 ……(5) このうち、浸炭反応にはCOガスが関与する。 CH 3 OHCO + 2H 2 ...(5) Of these, CO gas is involved in the carburizing reaction.
2COCr＋CO2 ……(6)
(6)式で、浸炭が進行するにつれ、反応は右に移
行し、COが減少する反面、CO2が増大する。そ
の結果、外部からCOの供給がなければ、(4)式よ
り雰囲気のカーボンポテンシヤルは低下してい
く。 2COCr+CO 2 ...(6) In equation (6), as carburization progresses, the reaction shifts to the right, and while CO decreases, CO 2 increases. As a result, unless CO is supplied from the outside, the carbon potential of the atmosphere decreases according to equation (4).
一方、制御弁４から供給されるエンリツチガス
として、プロパンガスを使用すると、(6)式のCO2
ガスと反応して、
C3H3＋3CO26CO＋4H4 ……(7)
(7)式により、雰囲気中の脱炭成分であるCO2ガス
が還元成分であるCOとH2ガスにリホーミングさ
れ、再び浸炭能力が高められる。 On the other hand, if propane gas is used as the enrichment gas supplied from the control valve 4, CO 2
By reacting with the gas, C 3 H 3 +3CO 2 6CO + 4H 4 ... (7) According to equation (7), CO 2 gas, which is a decarburizing component in the atmosphere, is reformed into CO and H 2 gas, which are reducing components. , the carburizing capacity is increased again.
したがつて、CO2調節計９の偏差信号に応じた
出力により、制御弁４のプロパンガス量を増減し
て偏差値を零にすることにより、所定の平衡炭素
濃度に制御される。 Therefore, by increasing or decreasing the amount of propane gas in the control valve 4 according to the output of the CO 2 controller 9 in accordance with the deviation signal to make the deviation value zero, the carbon concentration is controlled to a predetermined equilibrium carbon concentration.
なお、CO2調節計は、一般にフイードバツク制
御では、PID調節計が適している。 Note that as a CO 2 controller, a PID controller is generally suitable for feedback control.
前記実施例における雰囲気ガス中のCO2量およ
びCO量の分析方法としては、たとえば赤外線吸
収法またはガスクロマトグラフ法その他適宜の方
法を採用するものとする。またCO2調節計として
は、サーボ設定形式のものが好適である。演算装
置はアナログ式デジタル式の何れでも採用するこ
とができる。第２図は、第１図の実施例において
アナログ式演算装置を用いた場合の目標CO2量の
演算工程を示すブロツク図である。CO分析計６
（第１図）からのCO分析信号Pcpは２乗演算器１
２に入力されて２乗演算が施され、Pcp 2として次
の乗算器１３に送られる。一方、熱電対７からの
温度信号は、関数発生器１４により炉内温度に対
応した温度係数Ｓ（＝CPsat／Ｋ）に変換されて乗算
器１３に送られる。乗算器１３では、Pcp 2とＳと
の信号の乗算が行なわれ、Pcp 2・Ｓとして次の除
算器１５に入力される。除算器１５はこのPcp 2・
Ｓを炭素濃度設定器８からの目標炭素濃度設定信
号CPeqで除して、目標値としてのCO2量である
Pcp 2・Ｓ／CPeqとしてCO2調節計９に出力する。この
ようにして、CO2調節計９には雰囲気ガスの平衡
炭素濃度に相当する目標CO2量が設定値として入
力される。 As a method for analyzing the amount of CO 2 and the amount of CO in the atmospheric gas in the above embodiments, for example, an infrared absorption method, a gas chromatography method, or other appropriate method is employed. Also, as the CO 2 controller, a servo setting type is suitable. The arithmetic unit can be either analog or digital. FIG. 2 is a block diagram showing the process of calculating the target CO 2 amount when an analog calculation device is used in the embodiment shown in FIG. CO analyzer 6
The CO analysis signal P cp from (Fig. 1) is squared by the square calculator 1.
2, where it is subjected to a squaring operation and sent to the next multiplier 13 as P cp 2 . On the other hand, the temperature signal from the thermocouple 7 is converted by the function generator 14 into a temperature coefficient S (=CP sat /K) corresponding to the temperature inside the furnace, and sent to the multiplier 13 . In the multiplier 13, the signals P cp 2 and S are multiplied, and the result is input to the next divider 15 as P cp 2 ·S. The divider 15 uses this P cp 2・
Dividing S by the target carbon concentration setting signal CP eq from the carbon concentration setting device 8 is the amount of CO 2 as the target value.
Output to CO 2 controller 9 as P cp 2・S/CP eq . In this way, the target CO 2 amount corresponding to the equilibrium carbon concentration of the atmospheric gas is input to the CO 2 controller 9 as a set value.
なお、温度係数Ｓ＝CPsat／Ｋにおいて、CPsat
は鉄−炭素系平衡状態図より、
CPsat2.8×10-3t−1.3（ただし、723≦ｔ＜850℃）
3.0×10-3t−1.47（ただし、850≦ｔ＜950℃）
3.4×10-3t−1.85（ただし、950≦ｔ＜1000℃）
ただし、ｔは温度℃
また、Ｋはハリスの式より、
logK＝−15966／Ｔ＋9.06
ただし、Ｔは絶対温度（〓＋460）として計算
される。 In addition, when temperature coefficient S=CP sat /K, CP sat
From the iron-carbon equilibrium diagram, CP sat 2.8×10 -3 t−1.3 (723≦t＜850℃) 3.0×10 -3 t−1.47 (850≦t＜950℃) 3.4× 10 -3 t−1.85 (950≦t<1000℃) However, t is the temperature in degrees Celsius. Also, K is from the Harris equation, logK=−15966/T+9.06 However, T is the absolute temperature (〓+460) calculated.
この発明の制御方法を用いて、浸炭処理を行な
つて得た被処理鋼材の表面炭素濃度の分析結果を
従来の赤外線式CO2分析法による分析結果と対比
してみると第３図に示すとおりである。同図の浸
炭時間は、炉内が浸炭温度（930℃）に達し、雰
囲気制御を開始してから後の経過時間である。同
図におけるこの発明の方法を用いた浸炭処理は、
次の工程にしたがつて行なつたものである。ま
ず、被処理鋼材を炉内に装入したのち、真空ポン
プにて炉内の空気を排出する。その後、大気圧付
近までキヤリアガスを封入して密閉する。次いで
昇温し炉内温度が回復したところで、この発明の
制御方法によつてエンリツチガスを供給し、雰囲
気ガスの平衡炭素濃度を所定値に保持しながら所
定時間浸炭処理を行なう。ここでキヤリアガスに
ついては、RXガスやメタノールあるいはメタノ
ールとN2ガスとの混合ガスが適当である。 Figure 3 shows a comparison of the analysis results of the surface carbon concentration of the treated steel material obtained by carburizing using the control method of this invention with the analysis results using the conventional infrared CO 2 analysis method. That's right. The carburizing time in the figure is the elapsed time after the inside of the furnace reached the carburizing temperature (930°C) and atmospheric control was started. The carburizing treatment using the method of this invention in the same figure is as follows:
This was done according to the following steps. First, after the steel material to be treated is charged into the furnace, the air inside the furnace is exhausted using a vacuum pump. After that, carrier gas is filled to near atmospheric pressure and the chamber is sealed. Then, when the temperature is raised and the furnace temperature has recovered, enrichment gas is supplied according to the control method of the present invention, and carburization is carried out for a predetermined time while maintaining the equilibrium carbon concentration of the atmospheric gas at a predetermined value. Here, as the carrier gas, RX gas, methanol, or a mixed gas of methanol and N 2 gas is suitable.
この発明は、前述したとおり雰囲気ガス中の
CO量と炉内温度と鋼材表面の目標炭素濃度とか
ら所望の平衡炭素濃度に相応する目標CO2量を設
定し、この設定値と雰囲気ガス中のCO2量との偏
差に基づいてエンリツチガスの供給量を制御する
ように構成したものである。したがつて、この発
明によれば雰囲気ガス中のCO量がどのように変
動しても雰囲気ガスの平衡炭素濃度を一定に制御
することが可能となる。しかも、雰囲気ガスのう
ち、CO量とCO2量の２種類の組成ガスを分析し
て、目標CO2量をCO量の変動に応じて修正する
ものであるから、きわめて簡易な手段によつて雰
囲気ガスの精密制御が可能となるだけでなく、熱
処理炉の種類、浸炭方式の種別を問わず適用でき
ることと相まつて、均一かつ高精度のすぐれた品
質の鋼材を得ることができる。また、この発明に
よれば、エンリツチガスはもちろん、キヤリアガ
スの大幅な節減が可能となり、省資源化の要請に
充分応えることができる。 As mentioned above, this invention
A target CO 2 amount corresponding to the desired equilibrium carbon concentration is set from the CO amount, furnace temperature, and target carbon concentration on the surface of the steel material, and the enrichment gas is adjusted based on the deviation between this set value and the CO 2 amount in the atmospheric gas. It is configured to control the supply amount. Therefore, according to the present invention, it is possible to control the equilibrium carbon concentration of the atmospheric gas to be constant no matter how the amount of CO in the atmospheric gas changes. Moreover, the method analyzes two types of composition gases, the amount of CO and the amount of CO 2 in the atmospheric gas, and corrects the target amount of CO 2 according to the fluctuations in the amount of CO, so it is an extremely simple method. Not only is it possible to precisely control the atmospheric gas, but it can also be applied to any type of heat treatment furnace or carburizing method, making it possible to obtain uniform, highly accurate, and excellent quality steel materials. Further, according to the present invention, not only enrichment gas but also carrier gas can be significantly reduced, and the demand for resource saving can be fully met.
第１図は、この発明に用いる制御装置の実施例
を示すブロツク図、第２図は演算工程の実施例を
示すブロツク図、第３図は被処理鋼材の表面炭素
濃度と浸炭時間との関係を示す線図である。
図中、１は熱処理炉、４は制御弁、６はCO分
析計、８は炭素濃度設定器、９はCO2調節計、１
０は演算装置、１１はCO2分析計である。
Fig. 1 is a block diagram showing an embodiment of the control device used in the present invention, Fig. 2 is a block diagram showing an embodiment of the calculation process, and Fig. 3 is the relationship between the surface carbon concentration of the steel to be treated and the carburizing time. FIG. In the figure, 1 is a heat treatment furnace, 4 is a control valve, 6 is a CO analyzer, 8 is a carbon concentration setting device, 9 is a CO 2 controller, 1
0 is a calculation device, and 11 is a CO 2 analyzer.
Claims (1)
CO量とを分析し、CO量分析値Pcpと炉内温度と
鋼材表面の目標炭素濃度CPeqとにより雰囲気ガ
スの平衡炭素濃度に相当する目標CO2量 （Ｓ×Pcp 2／CPeq）を演算して設定し、 ただし、Ｓ（温度係数）＝CPsat（飽和炭素濃度）／
Ｋ（平衡恒数） この目標CO2量と雰囲気ガス中のCO2量分析値
との偏差に基づいて炉内に供給されるエンリツチ
ガス量を増減し、前記偏差値が零となるように制
御することを特徴とする浸炭雰囲気の炭素濃度制
御方法。[Claims] 1. The amount of CO 2 from the atmospheric composition gas in the heat treatment furnace.
The target CO 2 amount corresponding to the equilibrium carbon concentration of the atmospheric gas (S × P cp 2 / CP eq ), where S (temperature coefficient) = CP sat (saturated carbon concentration) /
K (equilibrium constant) The amount of enrichment gas supplied to the furnace is increased or decreased based on the deviation between this target amount of CO 2 and the analysis value of the amount of CO 2 in the atmosphere gas, and the amount of enrichment gas is controlled so that the deviation value becomes zero. A method for controlling carbon concentration in a carburizing atmosphere.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10563779A JPS5629668A (en) | 1979-08-20 | 1979-08-20 | Carbon concn. controlling method of carburizing atmosphere |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10563779A JPS5629668A (en) | 1979-08-20 | 1979-08-20 | Carbon concn. controlling method of carburizing atmosphere |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5629668A JPS5629668A (en) | 1981-03-25 |
| JPS648073B2 true JPS648073B2 (en) | 1989-02-13 |
Family
ID=14412965
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10563779A Granted JPS5629668A (en) | 1979-08-20 | 1979-08-20 | Carbon concn. controlling method of carburizing atmosphere |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5629668A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6029461A (en) * | 1983-07-29 | 1985-02-14 | Tokyo Netsu Shiyori Kogyo Kk | Controlling method of carburizing atmosphere for batch type carburizing furnace |
| US5139584A (en) * | 1989-07-13 | 1992-08-18 | Solo Fours Industriels Sa | Carburization process |
| CN104790006A (en) * | 2015-04-22 | 2015-07-22 | 江汉石油钻头股份有限公司 | Strengthened composite layer on rotor surface of screw drilling tool and machining process thereof |
-
1979
- 1979-08-20 JP JP10563779A patent/JPS5629668A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5629668A (en) | 1981-03-25 |
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