JPS63157816A - Manufacture of carburizing steel material - Google Patents
Manufacture of carburizing steel materialInfo
- Publication number
- JPS63157816A JPS63157816A JP30391486A JP30391486A JPS63157816A JP S63157816 A JPS63157816 A JP S63157816A JP 30391486 A JP30391486 A JP 30391486A JP 30391486 A JP30391486 A JP 30391486A JP S63157816 A JPS63157816 A JP S63157816A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- carburizing
- grains
- rolling
- ferrite
- 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 19
- 238000005255 carburizing Methods 0.000 title claims abstract description 19
- 239000010959 steel Substances 0.000 title claims abstract description 19
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 7
- 239000000463 material Substances 0.000 title abstract description 13
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 26
- 238000005096 rolling process Methods 0.000 claims abstract description 13
- 238000001816 cooling Methods 0.000 claims abstract description 11
- 238000005098 hot rolling Methods 0.000 claims abstract description 11
- 229910001562 pearlite Inorganic materials 0.000 claims abstract description 11
- 238000010583 slow cooling Methods 0.000 claims abstract description 7
- 229910000975 Carbon steel Inorganic materials 0.000 claims abstract description 6
- 239000010962 carbon steel Substances 0.000 claims abstract description 5
- 229910000851 Alloy steel Inorganic materials 0.000 claims abstract description 4
- 230000002401 inhibitory effect Effects 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 14
- 238000010438 heat treatment Methods 0.000 abstract description 11
- 238000000137 annealing Methods 0.000 abstract description 10
- 230000006866 deterioration Effects 0.000 abstract description 3
- 230000008030 elimination Effects 0.000 abstract 1
- 238000003379 elimination reaction Methods 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 11
- 150000004767 nitrides Chemical class 0.000 description 7
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- 238000010273 cold forging Methods 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 238000005482 strain hardening Methods 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 101100492787 Caenorhabditis elegans mai-1 gene Proteins 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000012669 compression test Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、浸炭′用銅材の製造方法に関するものであっ
て、特に冷間加工性にすぐれ、浸炭処理時にオーステナ
イト粒の部分的粗大化による不均一な焼入歪の発生や疲
労などによる機械的性質の劣化を防止でき、さらに軟化
焼鈍省略の可能な浸炭用鋼材の有利な製造方法を提案す
る。Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing a copper material for carburizing, which has particularly excellent cold workability and is capable of partially coarsening austenite grains during carburizing. We propose an advantageous manufacturing method for carburizing steel materials that can prevent the occurrence of uneven quenching distortion and deterioration of mechanical properties due to fatigue, etc., and can also omit softening annealing.
（従来の技術）
鋼材の浸炭処理は、歯車やシャフト等の機械構造用部品
の耐摩耗性、耐疲労性の向上を目的として広〈実施され
ているが、高温かつ長時間の処理を要するため、生産性
及び省エネルギーの点で問題が多い。また、この浸炭処
理は、処理コストが高価であるという以外にも品質上の
問題点として、浸炭処理による鋼材のオーステナイト粒
の混粒粗大化が挙げられる。この粗大オーステナイト粒
が発生すると、焼入性不均一による部品形状の歪の発生
により、歯車等では歯当りが悪化し寿命が低下したり、
はめ合い不良により部品の矯正加工が必要となり、いわ
ゆる部品の歩留りを著しく劣化させる。さらに、オース
テ、ナイト粒粗大化により機械的性質の劣化や浸炭硬化
深さのバラツキ等の問題も惹起する。(Prior art) Carburizing of steel materials is widely carried out for the purpose of improving the wear resistance and fatigue resistance of mechanical structural parts such as gears and shafts. , there are many problems in terms of productivity and energy conservation. In addition to the high processing cost, this carburizing treatment also has a quality problem in that the austenite grains of the steel material become coarser due to the carburizing treatment. When these coarse austenite grains occur, the shape of the part is distorted due to non-uniform hardenability, resulting in poor tooth contact and shortened life in gears, etc.
Poor fitting requires corrective processing of the parts, which significantly reduces the so-called yield of parts. Furthermore, coarsening of auste and night grains causes problems such as deterioration of mechanical properties and variation in carburization depth.
こうした問題点を防止する方法として、従来、かかるオ
ーステナイト組織の粗大化を抑制するために、ＹやΔ４
２． Ｎｂ、 Ｔｉなど結晶粒微細化元素を鋼に含有さ
せる方法が提案され実施されている。Conventionally, as a method to prevent these problems, Y or Δ4
2. A method of incorporating grain refining elements such as Nb and Ti into steel has been proposed and implemented.
例えば、特公昭５４−１６４７号においては、加熱温度
を１１５０°Ｃ以上とし、浸炭処理時に微細に析出して
オーステナイト結晶粒が混粒になるのを抑制する作用を
有するＮｂ、Ａｎ化合物（窒化物、炭化物）を添加して
できるだけ多量にオーステナイト中に分散固溶せしめ、
次いで熱間圧延、熱間鍛造等の熱間加工を施す。なお、
この熱間加工は１０００℃以上の高温で終了させ、オー
ステナイト結晶粒度を粒度番号Ｎｏ、 ５以下の粗粒に
して冷却する方法であり、浸炭時のオーステナイト粒粗
大化防止には極めて有効な方法である。For example, in Japanese Patent Publication No. 54-1647, the heating temperature is set to 1150°C or higher, and Nb, An compound (nitride , carbide) is added and dispersed as a solid solution in the austenite as much as possible,
Next, hot processing such as hot rolling and hot forging is performed. In addition,
This hot working is completed at a high temperature of 1000°C or higher, and the austenite crystal grain size is reduced to coarse grains with grain size number No. 5 or less and cooled. This is an extremely effective method for preventing austenite grain coarsening during carburizing. be.
（発明が解決しようとする問題点）
しかしながら、近年、歯車等は加工コスト低減の目的で
冷間鍛造により加工されることが多くなり、素材の変形
能向上の観点から軟化焼鈍や球状化焼鈍が施される。と
ころが、こういった熱処理が施されると、上述の特公昭
５４−１６４７号で開示される方法では、オーステナイ
ト粒の粗大化を防止する析出物（Ｎｂ、 ＡＩ！、炭窒
化物）が熱処理により大半析出してしまい、その効果が
ほとんど失なわれてしまう。さらに、冷間鍛造による塑
性歪がより粗大化を助長することから十分な効果が上げ
られないのが実状であった。また、冷間鍛造に先立って
熱処理を施す必要からコスト・アップも招いていた。(Problem to be solved by the invention) However, in recent years, gears, etc. are often processed by cold forging for the purpose of reducing processing costs, and from the viewpoint of improving the deformability of the material, softening annealing and spheroidizing annealing are used. administered. However, when such heat treatment is performed, in the method disclosed in the above-mentioned Japanese Patent Publication No. 54-1647, precipitates (Nb, AI!, carbonitrides) that prevent the coarsening of austenite grains are removed by heat treatment. Most of it precipitates out, and its effect is almost completely lost. Furthermore, the plastic strain caused by cold forging promotes coarsening, so that sufficient effects cannot be achieved. Furthermore, the need for heat treatment prior to cold forging also increased costs.
本発明の目的は、オーステナイト粒の粗大化阻止が実現
できると共に軟化焼鈍省略の可能な技術を提案するとこ
ろにある。An object of the present invention is to propose a technique that can prevent coarsening of austenite grains and omit softening annealing.
（問題点を解決するための手段）
上掲の目的は、次の事項を要旨構成とする方法、すなわ
ちオーステナイト粒成長抑制元素としてのＡＩ！、を０
．００５〜０．０７ｗｔ％およびＮを０．００３〜０．
０３１％少なくとも含有している炭素鋼または低合金鋼
を、１０５０°Ｃ以上の温度に加熱し、仕上圧延温度９
５０°Ｃ以上の熱間圧延を行い、次いでｏ、ｏｏｉ〜１
”Ｃ／ｓｅｃの冷却速度に当る徐冷却を行い、フェライ
ト・パーライト組織とすることを特徴とする浸炭用鋼材
の製造方法の採用によって有利に実現される。(Means for solving the problem) The purpose of the above is a method that has the following points as a summary, namely, AI as an austenite grain growth inhibiting element! , to 0
．． 005-0.07 wt% and N 0.003-0.
Carbon steel or low alloy steel containing at least 031% is heated to a temperature of 1050°C or higher, and the finish rolling temperature is 9.
Hot rolling at 50°C or higher, then o, ooi~1
This can be advantageously achieved by adopting a method for manufacturing carburizing steel materials, which is characterized by performing slow cooling at a cooling rate of C/sec to form a ferrite-pearlite structure.
（作 用）
上述した課題解決手段として整理した本発明思想の主旨
とするところは、熱間圧延に先立って、１０５０°Ｃ以
上の高温加熱をすることにより、浸炭処理時のオーステ
ナイト粒粗大化防止に有効に働ら＜ ＡＩ窒化物を極力
固溶させ、引続いてへβ窒化物の析出の起こらない９５
０°Ｃ以上で熱間圧延を行い、オーステナイト粒を微細
化した後、１°Ｃ／ｓｅｃ以下、０．００１°（：／ｓ
ｅｃ以上の冷却速度である徐冷を行うことにより、その
ままでも冷間加工可能な軟らかいフェライト・パーライ
ト組織とすることにある。これは添加されたＡＩ！、及
びＮを浸炭処理時までＡＩＮとして析出することを防止
し、浸炭時にその寄与を最大限利用することにある。(Function) The gist of the idea of the present invention organized as a means to solve the problems described above is to prevent coarsening of austenite grains during carburizing treatment by heating at a high temperature of 1050°C or more prior to hot rolling. It works effectively to make AI nitrides into solid solution as much as possible and prevent subsequent precipitation of β-nitrides.95
After hot rolling at 0°C or higher to refine austenite grains, rolling at 1°C/sec or lower and 0.001° (:/s
By performing slow cooling at a cooling rate of EC or higher, it is possible to obtain a soft ferrite-pearlite structure that can be cold-worked as it is. This is added AI! , and N are prevented from being precipitated as AIN until the time of carburizing, and the contribution thereof is utilized to the maximum extent during carburizing.
以上のごとく本発明では、Ａｎ窒化物のオーステナイト
粒成長抑制効果とミクロ組織のフェライト・パーライト
化及び直接軟化による中間焼鈍等の省略により、浸炭時
のオーステナイト粒細粒化を最大限に利用するものであ
ることから、所期の目的を達成するには、Ａｆｆｉ及び
Ｎの含有量を制御する必要がある。以下にかかるＡＩ！
、、Ｎ含有量限定の理由について述べる。As described above, the present invention makes maximum use of the austenite grain refinement during carburizing by eliminating the intermediate annealing, etc. due to the austenite grain growth suppressing effect of An nitride, changing the microstructure to ferrite/pearlite, and direct softening. Therefore, in order to achieve the intended purpose, it is necessary to control the contents of Affi and N. AI for the following!
,,The reason for limiting the N content will be explained.
ＡＩ！、は、熱間圧延前のオーステナイト粒の成長を抑
制する上で有効であることから添加する。AI! is added because it is effective in suppressing the growth of austenite grains before hot rolling.
０．００５ ｗｔ％（以下は「％」で略記する）未満で
はこの効果が十分に現われない、一方、０．０７％を超
えるとＡ（ｌｚｏｚなどの非金属介在物が増加し、冷間
加工性を低下させることから、０．０７％を上限とした
。If it is less than 0.005 wt% (hereinafter abbreviated as "%"), this effect will not be sufficiently exhibited, while if it exceeds 0.07%, nonmetallic inclusions such as A (lzoz) will increase, and cold working The upper limit was set at 0.07% since it lowers the properties.
Ｎは、鋼中のＡＩ！、と結合し、Ａｎ窒化物として析出
することによりオーステナイト粒成長抑制効果を示す。N is AI in steel! , and precipitates as An nitride, which exhibits the effect of suppressing austenite grain growth.
この効果を顕著にするには、０．００３％以上の含有が
必要である。添加量は多いほど効果が大きく、また焼入
性も向上するため好ましいが、０．０３％を超えると効
果が飽和することと、コストアップを招くことから上限
を０．０３％とした。In order to make this effect noticeable, the content must be 0.003% or more. The larger the amount added, the greater the effect and the better the hardenability, so it is preferable, but if it exceeds 0.03%, the effect is saturated and the cost increases, so the upper limit was set at 0.03%.
本発明法に適用される鋼としては炭素鋼及び低合金鋼で
、特に制約されるものではないが、一般的に肌焼鋼と呼
称され、浸炭される鋼であればよい。成分組成は、例え
ば、Ｃ：０．０５〜０．３％、ＳＩ：０．４０％以下、
Ｍｎ ： ０．３〜１．８％を含む炭素鋼、あるいは必
要に応じてＮｉ ： ４．５％以下、Ｃｒ：２％以下、
Ｍａｉ１％以下、Ｎｂ ： ０．１％以下、■＝０．２
％以下およびＢ ： ０．００５％以下の１種又は２種
以上を含む低合金鋼が好適である。Steels that can be applied to the method of the present invention include carbon steels and low alloy steels, and are not particularly limited, but any steel that is generally called case hardening steel and can be carburized may be used. The component composition is, for example, C: 0.05 to 0.3%, SI: 0.40% or less,
Carbon steel containing Mn: 0.3 to 1.8%, or as necessary Ni: 4.5% or less, Cr: 2% or less,
Mai 1% or less, Nb: 0.1% or less, ■=0.2
% or less and B: 0.005% or less, low alloy steel containing one or more types is suitable.
以上の鋼を常法にて溶製し、１０５０°Ｃ以上の温度域
において加熱する。ＡＩ！、窒化物は１０５０°Ｃを超
えるとほぼ完全に固溶することから下限を１０５０℃と
した。The above steel is melted by a conventional method and heated in a temperature range of 1050°C or higher. AI! The lower limit was set at 1050°C since nitrides almost completely dissolve in solid solution at temperatures exceeding 1050°C.
次いで熱間圧延を９５０°Ｃ以上で行う。この工程は、
熱間圧延後の除冷により軟化したフェライト・パーライ
ト組織を得るための前段階として重要である。構造用鋼
の直接軟化処理方法としては、例えば、「特開昭５８−
５８２３５号」で開示されているような圧延温度を７５
０〜１０００°Ｃの低温で行ういわゆる制御圧延（コン
ドロールド・ローリング）法を適用後制御冷却にて製造
されることが多い。Then, hot rolling is performed at 950°C or higher. This process is
It is important as a preliminary step to obtain a softened ferrite-pearlite structure by slow cooling after hot rolling. As a direct softening treatment method for structural steel, for example, ``Japanese Patent Application Laid-Open No. 1986-
No. 58235, the rolling temperature was set to 75.
It is often manufactured by applying the so-called controlled rolling method, which is carried out at a low temperature of 0 to 1000°C, followed by controlled cooling.
要するに、本発明ではこういった制御圧延法を採用しな
いことが特徴である。制御圧延法では、低温圧延により
オーステナイト粒は再結晶を十分に起すことなく伸長す
るので粒内に加工歪が蓄積する。フェライト・パーライ
ト変態の促進にはこの状態は極めて有利である。しかし
、浸炭処理時のオーステナイト粒の粗大化抑制作用のあ
るＡＩ窒化物の析出も著しく促進されるので抑制効果が
低下してしまう。また、熱間圧延時のオーステナイト粒
も非常に微細化されるため得られるフェライト・パーラ
イト組織は微細となることから、冷間加工時の変形抵抗
の上昇をまねく。In short, the present invention is characterized in that such a controlled rolling method is not employed. In the controlled rolling method, austenite grains are elongated due to low-temperature rolling without sufficient recrystallization, so that work strain accumulates within the grains. This condition is extremely advantageous for promoting ferrite-pearlite transformation. However, the precipitation of AI nitride, which has the effect of suppressing coarsening of austenite grains during carburizing, is also significantly promoted, resulting in a reduction in the suppressive effect. In addition, since the austenite grains during hot rolling are also made extremely fine, the resulting ferrite/pearlite structure becomes fine, leading to an increase in deformation resistance during cold working.
このような理由により本発明では、熱間圧延の圧延仕上
温度の下限を９５０°Ｃとし、ＡＩ！、窒化物析出の心
配のない温度域でオーステナイト粒の微細化を再結晶を
利用して行うのである。For these reasons, in the present invention, the lower limit of the finishing temperature of hot rolling is set to 950°C, and AI! The refinement of austenite grains is carried out using recrystallization in a temperature range where there is no fear of nitride precipitation.
次いで、こうして得られた熱延材を０．００１°Ｃ／ｓ
ｅｅ〜１°Ｃ／ｓｅｃの冷却速度で徐冷し、材ミクロ組
織をフェライト・パーライト組織とする。この場合冷却
速度の上限を１°（：／ｓｅｅ以下に限定した理由は、
本発明の対象とする鋼及び圧延条件の範囲では１°Ｃ／
ｓｅｃを超えるとマルテンサイト、またはベイナイトの
混入が起り、軟化したフェライト・パーライト組織が得
られないためである。一方、下限を０．００１°Ｉ：、
／ｓｅｅとした理由は、十分に軟化したフェライト・
パーライト組織が得られるものの、長時間の徐冷のため
に加熱設備の強化や生産性の低下を招き、却ってコスト
・アップとなって好ましくないからである。Next, the hot-rolled material thus obtained was heated at 0.001°C/s.
The material is gradually cooled at a cooling rate of ee to 1°C/sec to make the material microstructure a ferrite/pearlite structure. In this case, the reason why the upper limit of the cooling rate was limited to 1° (:/see) is as follows:
In the range of steel and rolling conditions targeted by the present invention, 1°C/
This is because if it exceeds sec, martensite or bainite will be mixed in, making it impossible to obtain a softened ferrite-pearlite structure. On the other hand, the lower limit is 0.001°I:,
/see is because the ferrite is sufficiently softened.
This is because although a pearlite structure can be obtained, the slow cooling over a long period of time requires reinforcement of heating equipment and a decrease in productivity, which is undesirable as it increases costs.
（実施例） 以下、本発明の実施例について詳細に説明する。(Example) Examples of the present invention will be described in detail below.
第１表に示した成分組成の鋼Ｎｏ、 １〜２を常法にて
溶製し、１５０ｍｍ角ビレツトに分塊圧延し、２０ｍｍ
φの棒鋼に仕上げるのに際して、第２表に示す加熱、圧
延及び冷却条件にて製造した。その後、ミクロ組織観察
、圧縮試験における限界圧縮（据込）率を求めた。また
浸炭時のオーステナイト粒の粗大化状況を調査する目的
でガス浸炭（９３０°ＣＸ４ｈｒ−＋ ８５０°Ｃ×３
０分→１００°Ｃ油冷、カーボン・ポテンシャル＝０．
８５％）処理を行い、オーステナイト粒度及び混粒発生
率を調査した。なお、混粒発生率は試験片のオーステナ
イト粒を現出させた後、光学顕微鏡にて５０視野観察し
、全視野面積に対する混粒の合計面積の割合で求めた。Steel Nos. 1 and 2 having the composition shown in Table 1 were melted by a conventional method, and then bloomed into a 150 mm square billet, and then rolled into a 20 mm square billet.
When finishing a steel bar of φ, it was manufactured under the heating, rolling and cooling conditions shown in Table 2. Thereafter, the microstructure was observed and the critical compression (upset) rate in the compression test was determined. In addition, gas carburizing (930°C
0 minutes → 100°C oil cooling, carbon potential = 0.
85%) treatment, and the austenite grain size and mixed grain generation rate were investigated. Incidentally, the generation rate of mixed grains was determined by observing 50 fields of view using an optical microscope after exposing the austenite grains of the test piece, and determining the ratio of the total area of mixed grains to the total field area.
その結果を同じく第２表に示す。The results are also shown in Table 2.
第２表において、供試Ｎｏ、 ３は、加熱温度が本発明
の限定範囲外にあり、限界圧縮率は高いものの地のオー
ステナイト粒も粗ぐ、混粒の発生率が高い。これに対し
、供試Ｎｏ、１．２及び１６はオーステナイト粒も細か
く、かつ混粒の発生がない。In Table 2, in sample No. 3, the heating temperature was outside the limited range of the present invention, and although the critical compressibility was high, the underlying austenite grains were coarse and the incidence of mixed grains was high. On the other hand, in sample Nos. 1.2 and 16, the austenite grains were fine and no mixed grains were generated.
供試Ｎｏ、５．６．７及び１２は、圧延仕上温度が本発
明の限定範囲外にあり、いずれも混粒の発生がある。こ
れに対して同じ加熱温度、冷却速度でも供試Ｎｏ、 ４
では圧延仕上温度が合格しているとこのようなことは無
い。Sample Nos. 5, 6, 7, and 12 had rolling finishing temperatures outside the limited range of the present invention, and mixed grains were generated in all of them. On the other hand, even with the same heating temperature and cooling rate, sample No. 4
If the rolling finishing temperature is acceptable, this will not happen.
供試Ｎｏ、 ８及び１１は、冷却速度が本発明の限定範
囲外であるが、Ｎｏ、 ８では混粒の発生が認められる
。Samples Nos. 8 and 11 had cooling rates outside the scope of the present invention, but in samples Nos. 8 and 8, the occurrence of mixed grains was observed.
Ｎｏ、１１はいずれもすぐれた特性を示し問題ないが、
徐冷時間が長大となり過ぎ、生産、性、コストの点で難
があった。No. 11 both show excellent characteristics and have no problems,
The slow cooling time was too long, which caused problems in terms of production, efficiency, and cost.
供試Ｎｏ、１３は、供試Ｎ０１８に軟化焼鈍処理を施こ
す従来技術例であるが、オーステナイト粒の粗大化及び
混粒の発生が認められる。Sample No. 13 is a prior art example in which sample No. 18 is subjected to a softening annealing treatment, but coarsening of austenite grains and generation of mixed grains are observed.
供試Ｎｏ、１４は、加熱温度、仕上温度が低く、本発明
の限定範囲外である。これでは限界圧縮率は著しく高く
なるなるが、混粒の発生が著しい。Sample No. 14 had a low heating temperature and a low finishing temperature, and was outside the scope of the present invention. In this case, the critical compression ratio becomes extremely high, but the occurrence of mixed grains is significant.
供試Ｎｏ、１５及び１７は、Ａ／！、Ｈのいずれかが本
発明の限定範囲外にあり、いずれも混粒の発生があった
。Sample Nos. 15 and 17 are A/! , H were outside the scope of the present invention, and mixed grains occurred in both cases.
（発明の効果）
以上の説明および実施例の結果から明らかなごとく、従
来法で製造された浸炭用鋼では混粒の発生がさけ難くか
つ冷間加工に際しては前もって軟化焼鈍や球状化焼鈍を
要していたのに対し、本発明によれば、混粒の発生がな
く耐粗粒化に優れる他、軟化焼鈍を省略して直接冷間加
工の可能な一材の製造が可能である。(Effects of the invention) As is clear from the above explanation and the results of the examples, it is difficult to avoid the generation of mixed grains in steel for carburizing produced by the conventional method, and softening annealing or spheroidizing annealing is required before cold working. On the other hand, according to the present invention, there is no generation of mixed grains, which is excellent in grain coarsening resistance, and it is also possible to produce a material that can be directly cold-worked without softening annealing.
Claims (1)
００５〜０．０７ｗｔ％およびＮを０．００３〜０．０
３ｗｔ％少なくとも含有している炭素鋼または低合金鋼
を、１０５０℃以上の温度に加熱し、仕上圧延温度９５
０℃以上の熱間圧延を行い、次いで０．００１〜１℃／
ｓｅｃの冷却速度に当る徐冷却を行い、フェライト・パ
ーライト組織とすることを特徴とする浸炭用鋼材の製造
方法。1. Al as an austenite grain growth inhibiting element is added to 0.
005-0.07wt% and N 0.003-0.0
Carbon steel or low alloy steel containing at least 3wt% is heated to a temperature of 1050°C or higher, and the finish rolling temperature is 95°C.
Perform hot rolling at 0°C or higher, then 0.001-1°C/
A method for manufacturing steel for carburizing, characterized by performing slow cooling at a cooling rate of sec to obtain a ferrite-pearlite structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30391486A JPS63157816A (en) | 1986-12-22 | 1986-12-22 | Manufacture of carburizing steel material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30391486A JPS63157816A (en) | 1986-12-22 | 1986-12-22 | Manufacture of carburizing steel material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63157816A true JPS63157816A (en) | 1988-06-30 |
| JPH0572442B2 JPH0572442B2 (en) | 1993-10-12 |
Family
ID=17926787
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30391486A Granted JPS63157816A (en) | 1986-12-22 | 1986-12-22 | Manufacture of carburizing steel material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63157816A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05163525A (en) * | 1991-12-09 | 1993-06-29 | Sanyo Special Steel Co Ltd | Manufacture of crystal grain stabilized case hardened steel of fine structure |
| JP2002030339A (en) * | 2000-07-19 | 2002-01-31 | Mitsubishi Seiko Muroran Tokushuko Kk | V-free non-heat-treated steel for hot forging |
| JP2017210656A (en) * | 2016-05-26 | 2017-11-30 | 高周波熱錬株式会社 | Method of manufacturing steel for carburization |
| CN113403527A (en) * | 2020-03-17 | 2021-09-17 | 丰田自动车株式会社 | Blank for vacuum carburization and method for manufacturing same |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS541647A (en) * | 1977-06-06 | 1979-01-08 | Matsushita Electric Ind Co Ltd | Optical fiber connector |
| JPS5529126A (en) * | 1978-08-23 | 1980-03-01 | Hitachi Ltd | Self-protecting type semiconductor controlled rectifying device |
| JPS569326A (en) * | 1979-07-03 | 1981-01-30 | Daido Steel Co Ltd | Manufacture of case hardening steel |
| JPS5789425A (en) * | 1980-11-20 | 1982-06-03 | Daido Steel Co Ltd | Manufacture of steel for carburizing |
| JPS57104626A (en) * | 1980-12-19 | 1982-06-29 | Sumitomo Metal Ind Ltd | Manufacture of fine-grain case-hardening steel |
| JPS5816024A (en) * | 1981-07-21 | 1983-01-29 | Sumitomo Metal Ind Ltd | Production of case hardening steel for high temperature carburization |
| JPS58130269A (en) * | 1982-01-28 | 1983-08-03 | Sumitomo Metal Ind Ltd | Manufacture of soft-nitrided article having large hardening depth |
| JPS59123714A (en) * | 1982-12-30 | 1984-07-17 | Kobe Steel Ltd | Production of steel material where temperature at which coarse grain of austenite crystal is formed is high |
-
1986
- 1986-12-22 JP JP30391486A patent/JPS63157816A/en active Granted
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS541647A (en) * | 1977-06-06 | 1979-01-08 | Matsushita Electric Ind Co Ltd | Optical fiber connector |
| JPS5529126A (en) * | 1978-08-23 | 1980-03-01 | Hitachi Ltd | Self-protecting type semiconductor controlled rectifying device |
| JPS569326A (en) * | 1979-07-03 | 1981-01-30 | Daido Steel Co Ltd | Manufacture of case hardening steel |
| JPS5789425A (en) * | 1980-11-20 | 1982-06-03 | Daido Steel Co Ltd | Manufacture of steel for carburizing |
| JPS57104626A (en) * | 1980-12-19 | 1982-06-29 | Sumitomo Metal Ind Ltd | Manufacture of fine-grain case-hardening steel |
| JPS5816024A (en) * | 1981-07-21 | 1983-01-29 | Sumitomo Metal Ind Ltd | Production of case hardening steel for high temperature carburization |
| JPS58130269A (en) * | 1982-01-28 | 1983-08-03 | Sumitomo Metal Ind Ltd | Manufacture of soft-nitrided article having large hardening depth |
| JPS59123714A (en) * | 1982-12-30 | 1984-07-17 | Kobe Steel Ltd | Production of steel material where temperature at which coarse grain of austenite crystal is formed is high |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05163525A (en) * | 1991-12-09 | 1993-06-29 | Sanyo Special Steel Co Ltd | Manufacture of crystal grain stabilized case hardened steel of fine structure |
| JP2002030339A (en) * | 2000-07-19 | 2002-01-31 | Mitsubishi Seiko Muroran Tokushuko Kk | V-free non-heat-treated steel for hot forging |
| JP2017210656A (en) * | 2016-05-26 | 2017-11-30 | 高周波熱錬株式会社 | Method of manufacturing steel for carburization |
| CN113403527A (en) * | 2020-03-17 | 2021-09-17 | 丰田自动车株式会社 | Blank for vacuum carburization and method for manufacturing same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0572442B2 (en) | 1993-10-12 |
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| LAPS | Cancellation because of no payment of annual fees |