JPH0243319A - Production of case hardening cr-mo steel - Google Patents
Production of case hardening cr-mo steelInfo
- Publication number
- JPH0243319A JPH0243319A JP19226388A JP19226388A JPH0243319A JP H0243319 A JPH0243319 A JP H0243319A JP 19226388 A JP19226388 A JP 19226388A JP 19226388 A JP19226388 A JP 19226388A JP H0243319 A JPH0243319 A JP H0243319A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- rolling
- temperature
- crystal grains
- amount
- 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.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 39
- 239000010959 steel Substances 0.000 title claims abstract description 39
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 238000010438 heat treatment Methods 0.000 claims abstract description 25
- 238000005096 rolling process Methods 0.000 claims abstract description 18
- 238000005098 hot rolling Methods 0.000 claims abstract description 15
- 238000001816 cooling Methods 0.000 claims abstract description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000012535 impurity Substances 0.000 claims abstract description 4
- 229910052742 iron Inorganic materials 0.000 claims abstract description 4
- 239000013078 crystal Substances 0.000 abstract description 19
- 229910001566 austenite Inorganic materials 0.000 abstract description 10
- 230000001105 regulatory effect Effects 0.000 abstract description 4
- 229910052748 manganese Inorganic materials 0.000 abstract description 3
- 229910052710 silicon Inorganic materials 0.000 abstract description 3
- 229910052799 carbon Inorganic materials 0.000 abstract 2
- 229910052804 chromium Inorganic materials 0.000 abstract 2
- 229910052750 molybdenum Inorganic materials 0.000 abstract 2
- 229910052758 niobium Inorganic materials 0.000 abstract 1
- 238000005255 carburizing Methods 0.000 description 18
- 238000000034 method Methods 0.000 description 13
- 239000000463 material Substances 0.000 description 10
- 229910001562 pearlite Inorganic materials 0.000 description 9
- 229910000760 Hardened steel Inorganic materials 0.000 description 8
- 238000005482 strain hardening Methods 0.000 description 8
- 238000010791 quenching Methods 0.000 description 5
- 230000000171 quenching effect Effects 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 238000010583 slow cooling Methods 0.000 description 3
- 238000000137 annealing Methods 0.000 description 2
- 229910001563 bainite Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000010273 cold forging Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
奮栗上■丑朋分國
本発明は、Ｃｒ’−Ｍｏ肌焼鋼の製造方法に関し、詳し
くは、フェライト・パーライト組織を有し、浸炭時の結
晶粒の粗大化を防止したＣｒ−Ｍｏ肌焼鋼の製造方法に
関する。[Detailed description of the invention] The present invention relates to a method for manufacturing Cr'-Mo case hardened steel, and more specifically, it has a ferrite-pearlite structure and coarsening of crystal grains during carburization. The present invention relates to a method for manufacturing Cr-Mo case hardened steel that prevents the above.
従来■伎街
例えば、ボルトやシャフトに多く用いられる従来の肌焼
鋼は、熱間圧延後に冷間加工を要する場合には、鋼組織
を改善するために、例えば、切削加工の前の焼きならし
処理や、冷間鍛造前の球状化焼きなまし処理がなされ、
このようにして、冷間加工性を良好にした後、所要の冷
間加工を施し、次いで、浸炭熱処理される。For example, when conventional case hardening steel, which is often used for bolts and shafts, requires cold working after hot rolling, it is necessary to apply hardening before cutting to improve the steel structure. processing and spheroidizing annealing processing before cold forging.
After the cold workability is improved in this manner, the required cold working is performed, and then carburizing heat treatment is performed.
このように、従来の肌焼鋼によれば、冷間加工前に熱処
理が必要とされるが、省エネルギーや工程簡略化による
コスト節減の要求が厳しい折から、このような熱処理工
程を省略又は簡略化するためには、圧延組織を微細化す
るために、圧延温度を低くする必要がある。他方、肌焼
鋼の場合、浸炭は、通常、９２５℃以上の高温で行なわ
れるので、浸炭加熱時にオーステナイト粒が粗大化し、
浸炭品の内部硬さを高め、また、焼入れ歪や靭性の低下
をもたらす。As described above, conventional case-hardened steel requires heat treatment before cold working, but due to the severe demand for cost reduction through energy conservation and process simplification, such heat treatment steps have been omitted or simplified. In order to make the rolling structure finer, it is necessary to lower the rolling temperature. On the other hand, in the case of case hardening steel, carburizing is usually carried out at a high temperature of 925°C or higher, so austenite grains become coarse during carburizing heating.
It increases the internal hardness of carburized products, and also causes quenching distortion and a decrease in toughness.
そこで、本発明者らは、既に、Ｃｒ鋼については、特開
昭５９−１２３７１４号公報や特開昭６１−６２１２号
公報に記載さているように、ＡＮ及びＮ量を規制すると
共に、熱間圧延前の加熱温度を規制することによって、
熱間圧延ままにて冷間加工することができ、しかも、冷
間加工後の浸炭処理においても、結晶粒が細粒に保持さ
れる肌焼鋼を見出している。Therefore, the present inventors have already regulated the amounts of AN and N for Cr steel, as described in JP-A-59-123714 and JP-A-61-6212, and also By regulating the heating temperature before rolling,
We have discovered a case-hardened steel that can be cold-worked as hot-rolled and whose crystal grains remain fine even during carburizing treatment after cold working.
しかしながら、Ｃｒ −Ｍ ｏ肌焼鋼の場合は、熱間圧
延ままでは、Ｃｒ−Ｍｏ鋼が焼入性が高いために、空冷
条件でも、ヘイナイトの圧延組織が形成される。本発明
者らの研究によれば、圧延ままでの組織がベイナイトで
あるときは、浸炭加熱時に結晶粒の粗大化が起こること
が見出された。However, in the case of Cr-Mo case-hardened steel, a haynite rolling structure is formed even under air cooling conditions because Cr-Mo steel has high hardenability when hot rolled. According to research conducted by the present inventors, it has been found that when the as-rolled structure is bainite, coarsening of crystal grains occurs during carburizing heating.
が ゛ しようとする課
本発明者らは、Ｃｒ −Ｍ ｏ肌焼鋼における上記した
問題を解決するために鋭意研究した結果、鋼中における
ＡＮとＮの含有量をＡ６／Ｎ重量比と共に（Ａｌ＋２Ｎ
）、即ち、Ａｌ量とＮ量の２倍量とで規定し、かかる鋼
を熱間圧延前に所定の温度に加熱すると共に、圧延終了
温度及びその後の冷却速度を規制して、圧延材の組織を
フェライト・パーライト組織とすることによって、浸炭
加熱時の結晶粒の粗大化を防止し得ることを見出して、
本発明に至ったものである。As a result of intensive research in order to solve the above-mentioned problems in Cr-Mo case-hardened steel, the present inventors have determined that the contents of AN and N in the steel as well as the A6/N weight ratio (Al+2N
), that is, the amount of Al and twice the amount of N are specified, and the steel is heated to a predetermined temperature before hot rolling, and the rolling end temperature and subsequent cooling rate are regulated to improve the temperature of the rolled material. It was discovered that coarsening of crystal grains during carburizing heating can be prevented by creating a ferrite-pearlite structure.
This led to the present invention.
従って、本発明は、冷間加工前の熱処理を省略又は簡略
化して、圧延ままで冷間加工することができ、更に、浸
炭熱処理時にオーステナイト結晶粒が粗大化しないＣｒ
−Ｍ ｏ肌焼鋼の製造方法を提供することを目的とす
る。Therefore, the present invention can omit or simplify the heat treatment before cold working and cold work as rolled, and furthermore, the austenite crystal grains do not become coarse during carburizing heat treatment.
- An object of the present invention is to provide a method for producing Mo case hardening steel.
量 を”パするための手段
本発明によるＣｒ−Ｍｏ肌焼鋼の製造方法は、重量％に
て
Ｃ０．１２〜０．３０％、
Ｓｉ０．４０％以下、
Ｍｎ ０．５０〜２．００％、
Ｃｒ ０．７０〜１．５０％、
ＭＯ０．ｌＯ〜０．５０％、
残部鉄及び不可避的不純物よりなり、
（Ａ Ｉ！＋ ２ Ｎ）量カ０．０４５〜０．０６５％
であり、且つ、Ａｌｌ／Ｎ重量比が２．１〜３．５の範
囲にある鋼を、その熱間圧延前に上記（Ａ Ｉ ＋２
Ｎ）量によって規定される温度Ｔ（”Ｃ）
Ｔ≧３７５０ （Ａｌ＋２Ｎ）＋９５０に加熱し、この
後に熱間圧延を行なない、８５０〜９５０℃の範囲の温
度で圧延を終了し、次いで、３０℃／分よりも遅い冷却
速度にて冷却することを特徴とする。Means for reducing the amount of Cr-Mo case hardened steel according to the present invention includes, in weight percent, C: 0.12 to 0.30%, Si: 0.40% or less, Mn: 0.50 to 2.00%. , Cr 0.70-1.50%, MO 0.1O-0.50%, balance consisting of iron and inevitable impurities, (AI!+2N) amount 0.045-0.065%
The above (A I +2
N) is heated to a temperature defined by the amount T(''C) T≧3750 (Al+2N)+950, followed by hot rolling, and the rolling is completed at a temperature in the range of 850 to 950°C, then, It is characterized by cooling at a cooling rate slower than 30° C./min.
先ず、本発明において用いる鋼における化学成分を限定
した理由について説明する。First, the reason for limiting the chemical components of the steel used in the present invention will be explained.
Ｃは、浸炭後に鋼材を焼入れして、中心部の強度を高く
するために、少なくとも０．１２％を添加することが必
要であるが、余りに多量に添加するときは、浸炭焼入後
の靭性を劣化させるので、上限は０．３０％とする。It is necessary to add at least 0.12% of C in order to harden the steel material after carburizing and increase the strength of the central part, but if it is added in too large a quantity, it will reduce the toughness after carburizing and quenching. The upper limit is set at 0.30%.
Ｓｔは、脱酸剤として添加されるが、余りに多いときは
冷間加工性を著しく阻害するので、上限を０．４０％と
する。St is added as a deoxidizing agent, but if it is too large, it will significantly impede cold workability, so the upper limit is set to 0.40%.
Ｍｎは、焼入性を増し、強度を高くするために必要な元
素であるが、多ずぎるときは靭性を低下させるので、そ
の添加量は０．５０〜２．００％の範囲とする。Mn is an element necessary to increase hardenability and strength, but if too much Mn decreases toughness, the amount added is in the range of 0.50 to 2.00%.
Ｃｒば、焼入れ性を改善する元素として、Ｍｎと同様に
有用であるが、添加量が多ずぎると、焼入れ強度を高く
しずぎて、靭性を悪くするので、その添加量は０．７０
〜１．５０％の範囲％とする。Cr is useful as an element for improving hardenability, like Mn, but if the amount added is too large, the hardening strength will be lowered and the toughness will be deteriorated, so the amount added is 0.70.
~1.50% range%.
Ｍｏも、焼入性を改善する効果を有するが、この効果を
有効に得るには、少なくとも０．１０％の添加を必要と
する。しかし、０．５０％を越えて過多に添加するとき
は、強度が過度に高くなると同時に、圧延後の冷却を制
御しても、結晶粒の粗大化が起こるので、添加量は０．
５０〜２．００％の範囲とする。Mo also has the effect of improving hardenability, but in order to effectively obtain this effect, it is necessary to add at least 0.10%. However, if it is added in excess of 0.50%, the strength will become excessively high and at the same time the crystal grains will become coarser even if cooling after rolling is controlled.
The range is 50% to 2.00%.
本発明の方法においては、用いる鋼は、上記した元素に
加えて、Ｎｂを含有していてもよい。In the method of the present invention, the steel used may contain Nb in addition to the above-mentioned elements.
Ｎｂは、浸炭焼入時の結晶粒を微細に保持する効果を有
する。しかし、過多に添加するときは、上記効果が飽和
すると共に、Ｎｂの炭窒化物等の析出が多くなり、加工
性を阻害するので、添加量は０．１０％以下とする。Nb has the effect of keeping crystal grains fine during carburizing and quenching. However, when adding too much, the above effects are saturated and precipitation of Nb carbonitrides and the like increases, which impairs workability, so the amount added is limited to 0.10% or less.
更に、本発明において用いる銅は、Ａβ／Ｎβ／Ｎ重量
比１〜３．５の範囲であり、且つ、（ＡＮ−１−２Ｎ）
量が０．０４５〜０．０６５％の範囲となる条件下に、
Ａβ及びＮを含有することが必要である。Furthermore, the copper used in the present invention has an Aβ/Nβ/N weight ratio in the range of 1 to 3.5, and (AN-1-2N)
Under conditions where the amount is in the range of 0.045 to 0.065%,
It is necessary to contain Aβ and N.
（Ａ ４ ＋ ２ Ｎ）量が上記範囲よりも少ないとき
、及びＡβ／Ｎ重量比が上記範囲からはずれているとき
は、熱間圧延前に所定の温度に加熱し、且つ、後述する
所定条件下に熱間圧延しても、このようにして得られる
圧延材は、冷間加工した後、浸炭処理に際して、オース
テナイト結晶粒の粗大化を防ぐに足る量のＡＩＮが析出
せず、オーステナイト結晶粒が粗大化する。一方、（八
β＋２Ｎ）量が上記範囲より多いときは、圧延前の加熱
によって、鋼中にＡｎＮを十分に溶は込ますことができ
ず、やはり浸炭時にオーステナイトが粗大化する。When the amount of (A 4 + 2 N) is less than the above range, and when the Aβ/N weight ratio is outside the above range, it is heated to a predetermined temperature before hot rolling, and under the predetermined conditions described below. Even if it is hot-rolled, the rolled material obtained in this way is not precipitated with sufficient amount of AIN to prevent coarsening of austenite crystal grains during carburizing treatment after cold working, and the austenite crystal grains are becomes coarser. On the other hand, when the amount of (8β+2N) is larger than the above range, AnN cannot be sufficiently infused into the steel by heating before rolling, and austenite becomes coarse during carburization.
即ち、本発明においては、鋼は（Ａｌ＋２Ｎ）量及びＡ
β／Ｎ重量比が共に所定の範囲にあるごとを要する。That is, in the present invention, the steel has an amount of (Al+2N) and an amount of A
Both β/N weight ratios must be within a predetermined range.
更に、本発明の方法においては、上記のような鋼を熱間
圧延した後の圧延材における析出Ａ７！Ｎが４ｏｐｐｍ
以下であることを要する。Furthermore, in the method of the present invention, precipitation A7! in the rolled material after hot rolling the steel as described above! N is 4 oppm
The following must be true.
このように、熱間圧延後の圧延材における析出ＡｆｆＮ
量を４ｏｐｐｍ以下にするには、上記のように、本発明
に従って所定量のＡβ及びＮを含有する鋼を、熱間圧延
前にその（ＡＩ２４−２Ｎ）量によって次式で規定され
る温度Ｔ（℃）以上に加熱することによって達成される
。In this way, the precipitated AffN in the rolled material after hot rolling.
In order to reduce the amount to 4 oppm or less, as described above, the steel containing a predetermined amount of Aβ and N according to the present invention is heated to a temperature T defined by the following formula depending on the amount of (AI24-2N) before hot rolling. This is achieved by heating to a temperature above (°C).
Ｔ≧３７５０ （／’ｌ！−１２Ｎ） ＋９５０本発明
の方法においては、上記所定温度に加熱した後、その鋼
を熱間圧延するに際して、その仕上終了温度を８５０〜
９５０℃とすることが好ましい。仕上終了温度をこのよ
うに９５０℃以下とすることによって、圧延終了時のオ
ーステナイト結晶粒を微細化し、焼入性を低めることが
できる。T≧3750 (/'l!-12N) +950 In the method of the present invention, when hot rolling the steel after heating it to the above-mentioned predetermined temperature, the finishing finishing temperature is set at 850~
The temperature is preferably 950°C. By setting the finishing temperature to 950° C. or lower, the austenite crystal grains at the end of rolling can be made finer and the hardenability can be lowered.
しかし、仕上温度が余りに低いときは、適冷Ｍｉ織が形
成されるので、仕上温度の下限を８５０ ｃとする。However, if the finishing temperature is too low, a suitably cooled Mi weave will be formed, so the lower limit of the finishing temperature is set at 850°C.
更に、本発明の方法においては、ヘイナイト組織の発生
を避けると共に、フェライト・パーライト組織を生成さ
せるために、仕上圧延の終了後、３０℃／分以下の速度
にて徐冷することが必要である。冷却速度が３０℃／分
を越えるときは、ヘイナイト組織が生成し、前述したよ
うに、浸炭加熱時に結晶粒の粗大化が起こる。本発明に
従って、圧延材の組織をフェライト・パーライトとする
ことによって、浸炭加熱時の結晶粒の粗大化を有効に防
止することができる。上記徐冷の方法は、特に、限定さ
れるものではないが、通常、徐冷カバー又は徐冷炉中を
通過させるのがよい。Furthermore, in the method of the present invention, in order to avoid the generation of a haynite structure and to generate a ferrite-pearlite structure, it is necessary to slowly cool the material at a rate of 30° C./min or less after finish rolling. . When the cooling rate exceeds 30° C./min, a haynite structure is generated, and as described above, coarsening of crystal grains occurs during carburizing heating. According to the present invention, by making the rolled material have a ferrite-pearlite structure, coarsening of crystal grains during carburizing heating can be effectively prevented. The method of slow cooling is not particularly limited, but it is usually preferable to pass through a slow cooling cover or a slow cooling furnace.
本発明においては、用いる材料は、線材でも棒材でもよ
＜、線材を用いる場合は、コイル状で徐冷しても、リン
グ状で徐冷してもよい。In the present invention, the material used may be a wire or a bar. When a wire is used, it may be slowly cooled in a coil shape or in a ring shape.
光凱傅侠果
本発明の方法によるＣｒ−Ｍｏ肌焼鋼は、以上のように
、（Ａｊｌ！＋２Ｎ）量とＡ６／Ｎ重量比を特定した鋼
材を、熱間圧延前に上記（Ａρ＋２Ｎ）量によって前記
式にて規定される温度以上に加熱すると共に、仕上圧延
を所定の温度で終了し、更に、その後、所定の冷却速度
にて徐冷して、組織をフェライト・パーライトとしたも
のであるので、浸炭加熱時に結晶粒を細粒に保持するこ
とができ、かくして、焼入硬さのばらつきや焼入歪を低
減することができる。As described above, the Cr-Mo case hardened steel produced by the method of the present invention is produced by subjecting the steel material with the specified (Ajl!+2N) amount and A6/N weight ratio to the above (Aρ+2N) amount before hot rolling. The material is heated to a temperature higher than that specified by the above formula, finish rolling is completed at a predetermined temperature, and then slowly cooled at a predetermined cooling rate to change the structure to ferrite/pearlite. The crystal grains can be kept fine during carburizing heating, and thus variations in quenching hardness and quenching distortion can be reduced.
実施班
以下に実施例を挙げて本発明を説明するが、本発明はこ
れら実施例により何ら限定されるものではない。EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way.
実施例１
第１表に示す化学成分組成を有する本発明鋼及び比較鋼
の１５５鶴角鋼片を第２表に示すように、所定の温度に
加熱した後、所定の温度にて仕上圧延を終了し、次いで
、徐冷炉内で徐冷し、又は放冷して、２５ｎ径線材とし
た。Example 1 After heating 155 square steel slabs of the invention steel and comparative steel having the chemical compositions shown in Table 1 to a predetermined temperature as shown in Table 2, finish rolling was completed at a predetermined temperature. Then, it was slowly cooled in an annealing furnace or allowed to cool to obtain a 25n diameter wire rod.
この線材を酸洗し、脱スケールした後、７６０℃で３時
間加熱した後、炉冷し、更に、１０〜５０％の冷間加工
を施し、９２５℃で３時間加熱後、水冷して、オーステ
ナイト結晶粒を測定した。This wire was pickled and descaled, heated at 760°C for 3 hours, cooled in a furnace, further subjected to 10 to 50% cold working, heated at 925°C for 3 hours, cooled with water, Austenite grains were measured.
圧延ままでのＡｆＮ量と組織、及び９２５℃でのオース
テナイト結晶粒粗大化率を第２表に示す。Table 2 shows the AfN content and structure as rolled, and the coarsening rate of austenite grains at 925°C.
本発明による化学成分を有する鋼１及び２をそれぞれ用
いて、本発明の方法Ａ又はＢに従って得たＣｒ−Ｍｏ肌
焼鋼は、いずれも組織がフェライト・パーライトであっ
て、１０％及び５０％冷間加工部のいずれにおいても、
浸炭加熱時に結晶粒の粗大化が起こらない。The Cr-Mo case-hardened steels obtained according to the method A or B of the present invention using Steels 1 and 2 having chemical compositions according to the present invention, respectively, have a ferrite-pearlite structure, and have a structure of 10% and 50%. In any of the cold working parts,
No coarsening of crystal grains occurs during carburizing heating.
これに対して、本発明による化学成分をもたない鋼３及
び４をそれぞれ用いて、方法Ｃ及びＤに示すように、上
記とほぼ同様に処理するとき、組織はフェライト・パー
ライトを得ることができるが、浸炭加熱時に結晶粒が粗
大化する。また、本発明による化学成分を有する鋼２を
用いても、方法Ｅに示すように、圧延後、空冷するとき
は、フェライト及びパーライトと共に、ベイナイト組織
が生じ、浸炭加熱時に著しい結晶粒の粗大化が起こる。On the other hand, when steels 3 and 4, which do not have the chemical components according to the present invention, are treated in substantially the same manner as described above as shown in Methods C and D, the structure becomes ferrite/pearlite. However, the crystal grains become coarse during carburizing heating. Furthermore, even if Steel 2 having the chemical composition according to the present invention is used, as shown in Method E, when air cooling is performed after rolling, a bainite structure is formed together with ferrite and pearlite, and the crystal grains become coarsened significantly during carburizing heating. happens.
また、方法Ｆに示すように、熱間圧延前の加熱温度が低
いときは、Ａ／Ｎが過多に生成し、その結果、組織はフ
ェライト・パーライトであるが、浸炭加熱時に著しい結
晶粒の粗大化が起こる。In addition, as shown in method F, when the heating temperature before hot rolling is low, excessive A/N is generated, and as a result, the structure is ferrite/pearlite, but the crystal grains become coarse during carburizing heating. transformation occurs.
Claims (2)
且つ、Ａｌ／Ｎ重量比が２．１〜３．５の範囲にある鋼
を、その熱間圧延前に上記（Ａｌ＋２Ｎ）量によつて規
定される温度Ｔ（℃） Ｔ≧３７５０（Ａｌ＋２Ｎ）＋９５０ に加熱し、この後に熱間圧延を行なない、８５０〜９５
０℃の範囲の温度で圧延を終了し、次いで、３０℃／分
よりも遅い冷却速度にて冷却することを特徴とするＣｒ
−Ｍｏ肌焼鋼の製造方法。(1) In weight%, C0.12-0.30%, Si0.40% or less, Mn0.50-2.00%, Cr0.70-1.50%, Mo0.10-0.50%, balance It consists of iron and inevitable impurities, and the amount of (Al+2N) is 0.045 to 0.065%,
In addition, the steel having an Al/N weight ratio in the range of 2.1 to 3.5 is heated to a temperature T (°C) defined by the above (Al + 2N) amount before hot rolling: T≧3750 (Al + 2N) +950 and then hot rolling to 850-95
Cr characterized by finishing the rolling at a temperature in the range of 0°C and then cooling at a cooling rate slower than 30°C/min.
- A method for producing Mo case hardening steel.
且つ、Ａｌ／Ｎ重量比が２．１〜３．５の範囲にある鋼
を、その熱間圧延前に上記（Ａｌ＋２Ｎ）量によつて規
定される温度Ｔ（℃） Ｔ≧３７５０（Ａｌ＋２Ｎ）＋９５０ に加熱し、熱間圧延において、８５０〜９５０℃の範囲
の温度で圧延を終了し、この後、３０℃／分よりも遅い
冷却速度にて冷却することを特徴とするＣｒ−Ｍｏ肌焼
鋼の製造方法。(2) C0.12-0.30% by weight, Si0.40% or less, Mn0.50-2.00%, Cr0.70-1.50%, Mo0.10-0.50%, Nb0 .10% or less, the balance consists of iron and unavoidable impurities, the amount of (Al + 2N) is 0.045 to 0.065%,
In addition, the steel having an Al/N weight ratio in the range of 2.1 to 3.5 is heated to a temperature T (°C) defined by the above (Al + 2N) amount before hot rolling: T≧3750 (Al + 2N) Cr-Mo case hardening characterized by heating to +950 °C, finishing the rolling at a temperature in the range of 850 to 950 °C during hot rolling, and then cooling at a cooling rate slower than 30 °C / min. Method of manufacturing steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63192263A JP2767254B2 (en) | 1988-08-01 | 1988-08-01 | Method for producing Cr-Mo case hardened steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63192263A JP2767254B2 (en) | 1988-08-01 | 1988-08-01 | Method for producing Cr-Mo case hardened steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0243319A true JPH0243319A (en) | 1990-02-13 |
| JP2767254B2 JP2767254B2 (en) | 1998-06-18 |
Family
ID=16288379
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63192263A Expired - Lifetime JP2767254B2 (en) | 1988-08-01 | 1988-08-01 | Method for producing Cr-Mo case hardened steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2767254B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05125437A (en) * | 1991-10-31 | 1993-05-21 | Sanyo Special Steel Co Ltd | Manufacture of grain size stabilized case hardening steel |
| EP0933440A1 (en) * | 1997-07-22 | 1999-08-04 | Nippon Steel Corporation | Case hardened steel excellent in the prevention of coarsening of particles during carburizing thereof, method of manufacturing the same, and raw shaped material for carburized parts |
| CN108396251A (en) * | 2017-02-05 | 2018-08-14 | 鞍钢股份有限公司 | Aviation alloy structure hot rolled steel plate and production method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57104625A (en) * | 1980-12-19 | 1982-06-29 | Sumitomo Metal Ind Ltd | Manufacture of fine-grain case-hardening steel |
| JPS61261427A (en) * | 1985-05-13 | 1986-11-19 | Kobe Steel Ltd | Production of steel having superior cold workability and preventing coarsening of grain during carburization heating |
| JPS6376815A (en) * | 1986-09-18 | 1988-04-07 | Kobe Steel Ltd | Warm working method of steel for carburizing |
-
1988
- 1988-08-01 JP JP63192263A patent/JP2767254B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57104625A (en) * | 1980-12-19 | 1982-06-29 | Sumitomo Metal Ind Ltd | Manufacture of fine-grain case-hardening steel |
| JPS61261427A (en) * | 1985-05-13 | 1986-11-19 | Kobe Steel Ltd | Production of steel having superior cold workability and preventing coarsening of grain during carburization heating |
| JPS6376815A (en) * | 1986-09-18 | 1988-04-07 | Kobe Steel Ltd | Warm working method of steel for carburizing |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05125437A (en) * | 1991-10-31 | 1993-05-21 | Sanyo Special Steel Co Ltd | Manufacture of grain size stabilized case hardening steel |
| EP0933440A1 (en) * | 1997-07-22 | 1999-08-04 | Nippon Steel Corporation | Case hardened steel excellent in the prevention of coarsening of particles during carburizing thereof, method of manufacturing the same, and raw shaped material for carburized parts |
| EP0933440A4 (en) * | 1997-07-22 | 2001-11-28 | Nippon Steel Corp | Case hardened steel excellent in the prevention of coarsening of particles during carburizing thereof, method of manufacturing the same, and raw shaped material for carburized parts |
| CN108396251A (en) * | 2017-02-05 | 2018-08-14 | 鞍钢股份有限公司 | Aviation alloy structure hot rolled steel plate and production method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2767254B2 (en) | 1998-06-18 |
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