JPH02147148A - Production of case hardening steel product - Google Patents
Production of case hardening steel productInfo
- Publication number
- JPH02147148A JPH02147148A JP30015888A JP30015888A JPH02147148A JP H02147148 A JPH02147148 A JP H02147148A JP 30015888 A JP30015888 A JP 30015888A JP 30015888 A JP30015888 A JP 30015888A JP H02147148 A JPH02147148 A JP H02147148A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- case hardening
- case
- hardening steel
- cast
- 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 23
- 239000010959 steel Substances 0.000 title claims abstract description 23
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 238000001816 cooling Methods 0.000 claims abstract description 13
- 239000000203 mixture Substances 0.000 claims abstract description 12
- 238000009749 continuous casting Methods 0.000 claims abstract description 10
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 9
- 239000000956 alloy Substances 0.000 claims abstract description 9
- 238000007711 solidification Methods 0.000 claims abstract description 9
- 230000008023 solidification Effects 0.000 claims abstract description 9
- 238000005096 rolling process Methods 0.000 claims abstract description 8
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 3
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 19
- 229910000760 Hardened steel Inorganic materials 0.000 claims description 12
- 229910052750 molybdenum Inorganic materials 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 229910052797 bismuth Inorganic materials 0.000 claims 2
- 229910052745 lead Inorganic materials 0.000 claims 1
- 238000005255 carburizing Methods 0.000 abstract description 15
- 238000005266 casting Methods 0.000 abstract description 4
- 230000008018 melting Effects 0.000 abstract 1
- 238000002844 melting Methods 0.000 abstract 1
- 239000000047 product Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 7
- 239000013078 crystal Substances 0.000 description 6
- 239000002245 particle Substances 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000005242 forging Methods 0.000 description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 150000001247 metal acetylides Chemical class 0.000 description 2
- 229910001208 Crucible steel Inorganic materials 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000003359 percent control normalization Methods 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
Landscapes
- Continuous Casting (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
本発明は、機械構造部品とする肌焼ｕＡ製品の製造方法
に関し、浸炭時の結晶粒粗大化を防止した製品を提供す
る。The present invention relates to a method for manufacturing case-hardened uA products used as mechanical structural parts, and provides a product that prevents grain coarsening during carburization.
歯車、アウターレースあるいは軸受のような機械構造部
品の製造は、肌焼鋼の棒材や線材を鍛造や機械加工した
のち、浸炭処理をする工程に従って行なうことが多い。
浸炭のための熱処理は、高温に長時間保持する作業であ
って多大のエネルギーを必要とするから、多少は温度を
高めても短時間で完了させたい。
ところが、浸炭時の高温は結晶粒の急激な粗大化をひき
おこしやすい。 それによって、粗粒、混粒の組織がで
きると、焼き歪の増大や靭性の低下という好ましくない
結果を招く。
最近、この問題に対するひとつの解決策として、Ｔｉお
よびＮを特定量かつ特定の比率で含有する肌焼鋼を溶製
し、連続鋳造により、凝固点から１０００℃の温度範囲
を２０℃／ｍｉｎ以上の冷却速度で冷却して鋳片とし、
これを分塊圧延を行なうことなく直ちに棒鋼、線Ｈに圧
延することが提案された（特開昭６３−１６２８１２Ｍ
）。
鋳造時の冷却速度を高くすることは、鋳片の組織を微細
にする点で好ましく、また分塊圧延を行なわずに直接線
材圧延に向けることは、結晶粒粗大の機会を増さないか
ら、原理的に有利なことはたしかである。 分塊圧延を
要しない鋳片サイズは当然に小さいものであって、これ
はまた、高い冷却速度の実現を容易にする。
一方、寸法精度の高い圧延製品を得るために、鋳片の圧
延を冷間ないし温間の温度領域で行なうことがある。
この場合は、後の浸炭のための加熱時に結晶粒が粗大化
する駆動力が、熱間圧延の場合よりむしろ大きいから、
極端に高い浸炭温度を採用しなくてもなお、混粒や巨大
粒が生成する危険が大きい。 上記した、ＴｉおよびＮ
を特定量かつ特定の比率で使用する肌焼鋼の製造方法に
よっても、この問題は対処しきれない。Manufacturing of mechanical structural parts such as gears, outer races, and bearings is often carried out by forging or machining case-hardened steel rods or wires, and then carburizing them. Heat treatment for carburizing requires a large amount of energy as it involves maintaining the product at high temperature for a long period of time, so it is desirable to complete the process in a short time even if the temperature is raised a little. However, the high temperatures during carburizing tend to cause rapid coarsening of crystal grains. As a result, if a structure of coarse grains or mixed grains is formed, undesirable results such as an increase in baking strain and a decrease in toughness occur. Recently, as a solution to this problem, case-hardening steel containing Ti and N in specific amounts and ratios has been produced, and by continuous casting, the temperature range from the freezing point to 1000℃ can be controlled at a rate of 20℃/min or more. Cooled at a cooling rate to form slabs,
It was proposed to immediately roll this into steel bars and wire H without blooming (Japanese Patent Application Laid-Open No. 63-162812M
). Increasing the cooling rate during casting is preferable in terms of making the structure of the slab finer, and direct wire rod rolling without blooming does not increase the chance of grain coarsening. It is certainly advantageous in principle. The slab size that does not require blooming is naturally small, which also facilitates achieving high cooling rates. On the other hand, in order to obtain rolled products with high dimensional accuracy, slabs are sometimes rolled in a cold or warm temperature range.
In this case, the driving force for coarsening the crystal grains during heating for later carburizing is larger than in the case of hot rolling.
Even if extremely high carburizing temperatures are not adopted, there is still a great risk of mixed grains and giant grains being generated. Ti and N mentioned above
This problem cannot be fully addressed by methods of manufacturing case hardened steel that use a specific amount and a specific ratio of .
本発明の目的は、機械構造部品を製造するための肌焼鋼
において、浸炭に先立つ鍛造や圧延の加工工程を冷間な
いし温間で実施しても、浸炭時の熱処理によって結晶粒
の粗大化が生じることのない肌焼鋼製品の製造方法を提
供することにある。
１課題を解決するための手段】
本発明の肌焼鋼製品の製造方法は、Ｃ：０．１０−０．
３０％、Ｓｉ ：０．０２〜０．３５％、Ｍｎ ：０
．２〜２．０％、Ｓｏｎ、ＡＮ ：０．００３〜０．０
６０％、ならびに、Ｎｂ ：０．０１〜０．２０％お
よびＴｉ ：０．０１〜０．１５％の１種または２種を
含有し、Ｎ：０．０２５％以下であって、残部が実質上
Ｆｅからなる合金組成の肌焼鋼を溶製し、連続鋳造法に
よって分塊圧延を必要としないサイズの鋳片に鋳造し、
その際に凝固開始点から凝固終了点に至る温度範囲を２
０℃／ｌｌｌ１ｎ以上の冷却速度をもって急速に冷却し
、得られた鋳片をそのまま棒鋼または線材に圧延するこ
とからなる。
肌焼鋼の合金組成は、上記の各成分に加えて、下記の成
分グループのいずれか一方または両方を添加したもので
あってもよい。
イ） Ｃｒ ：０．３〜２．０％、Ｍｏ ：０．０５
〜０．５％およびＮｉ：０．３〜３．０％の１種または
２種以上。
口） Ｐｂ ：０．０３〜０．１５％、１Ｓｉ：Ｑ。
０３〜０．１５％、Ｃａ ：０．０００３〜０゜００５
０％、およびＴｅ：００ＯＯ５〜０．１０％の１種また
は２種以上。The purpose of the present invention is to provide a case hardening steel for manufacturing mechanical structural parts, in which even if the forging and rolling processes prior to carburizing are performed cold or warm, the heat treatment during carburizing causes grain coarsening. An object of the present invention is to provide a method for manufacturing case hardened steel products that does not cause the occurrence of. 1. Means for Solving the Problems] The method for manufacturing a case hardened steel product of the present invention includes C: 0.10-0.
30%, Si: 0.02-0.35%, Mn: 0
．． 2-2.0%, Son, AN: 0.003-0.0
60% and one or both of Nb: 0.01-0.20% and Ti: 0.01-0.15%, N: 0.025% or less, and the remainder is substantially A case-hardened steel with an alloy composition consisting of upper Fe is melted and cast into a slab of a size that does not require blooming using a continuous casting method,
At that time, the temperature range from the solidification start point to the solidification end point is
It consists of rapidly cooling at a cooling rate of 0° C./llln or more and rolling the obtained slab as it is into a steel bar or wire rod. The alloy composition of the case hardening steel may include, in addition to the above-mentioned components, one or both of the following component groups. b) Cr: 0.3-2.0%, Mo: 0.05
~0.5% and Ni: 0.3 to 3.0%, one or more. mouth) Pb: 0.03-0.15%, 1Si:Q. 03-0.15%, Ca: 0.0003-0°005
0%, and one or more of Te:00OO5 to 0.10%.
肌焼鋼の結晶粒粗大化を防止する手段として、ＴｉやＮ
ｂの微細炭窒化物を析出させて、そのピンニング効果を
利用することが行なわれている。
従来は、インゴットに鋳造する場合はもちろん、連続鋳
造を行なってもその鋳片は比較的大型で必って分塊圧延
を行なうことを前提にしていたから、Ｔｉ （Ｃ，Ｎ
＞やＮｂ （Ｃ，Ｎ＞は、インゴットにせよ鋳片にせよ
、比較的大きな形で析出し、続く加熱によりいったんマ
トリクス中に溶は込み、再度微細に析出するという過程
を通って、ピンニング効果を発揮する。
前記した、ｌｉおよびＮを特定量かつ特定の比率で存在
させ、急冷鋳造する肌焼鋼の製造方法は、従来技術にお
ける大型炭窒化物の析出−溶解−微細析出という過程を
通らず、溶鋼から一挙に微細なＴｉＮを析出させて利用
するという技術思想に立脚している。 この方法は、前
記したように、高温浸炭への対策としては有用であるが
、冷間ないし温間の加工を行なう場合に効果が乏しかっ
た。
本発明者らの解明したところでは、ＴｉＮは比較的大き
な粒子として析出しやすく、いったん析出した後は析出
物の粒径をコントロールすることは困難であるから、結
晶粒粗大化の駆動力がとくに大きくなる冷間ないし温間
加工を伴う条件下では、ピンニング効果を発揮させるの
に適しないわけである。 そこで、微細に析出してピン
ニング効果を発揮させヤすいＴｉＣ，ＮｂＣ１とくに俊
者を利用すべきである、という結論を発明者らは１ｑだ
。
上記した合金組成の選択、分塊圧延を要しないサイズの
鋳片への連続鋳造、および鋳造の際の高い冷却速度の組
み合わせは、上述の知見にもとづいて導き出した結論で
ある。
本発明で材料とする合金の組成について、任意に添加す
る元素を含めて限定理由を簡単に述べれば、つぎのとお
りである。
Ｃ：０．１０−０．３０％
機械構造部品としての強度の確保のために、ある程度の
Ｃ含有量が必要であり、一方、過大になると合部の靭性
も低下する。 上記の範囲は、その調和をはかって定め
た。
Ｓ＋ ：０．０２〜０．３５％
脱酸剤として上記下限値以上の量を添加するが、冷間な
いし温間の加工性にとっては好ましくないから、上限値
止まりとする。
Ｍｎ ：０．２〜２．０％
介在物とくに硫化物系介在物の形態を制御して、圧延や
鍛造により極度に延伸されないようにすることと、焼入
性を高めるため０．２％以上添加する。 多量にすぎる
と冷温間加工性と機械加工性を損うから、２．０％を限
界とする。
Ｓｏ、ｌ！、 Ａ！Ｊ：０．００３〜０．０６０強力な
脱酸性能を期待して添加するが、あまり多いとアルミナ
系介在物の但が増えて製品の瓢械的性質が劣ってくるか
ら、上記範囲内にコントロールする。
Ｎ ：０．０２５％以下
本発明ではＮの作用には期待せず、むしろ巨大炭窒化物
の生成による強度と靭性の低下を避けるため、上記限度
内で微量に止める。
Ｎｂ ：０．０１〜０．２０％、Ｔｉ：０．０１〜０．
１５％
前記したように、微細な炭化物の生成による結晶粒粗大
化防止の効果を得る。 多すぎると加工性を引き下げる
ばかりでなく、巨大炭窒化物が生成する原因となるから
、上記の限界を超えて添加してはならない。
Ｃｒ ：０．３〜２．０％、Ｍｏ ：０．０５〜Ｏ。
５％
ともに強度と靭性を高めたい場合に、一方または両方を
加える。 Ｃｒが多くなると加工性を低くし、Ｍｏは熱
間加工の妨げとなるほか、コストを高くするから、それ
ぞれ上記限度内の添加に止める。
Ｐｂ ：０．０３〜０．１５％、Ｓｉ ：０．０３〜
０．１５％、Ｃａ ：０．０００３〜０．００５０％、
Ｔｅ ：０．００５〜０．１０％
いずれも被削性改善元素として知られている。
加工性を損わない限度で、１種または２種以上を適量添
加する。
凝固開始点および凝固終了点は、それぞれ、連続鋳造の
ため水冷モールドに注入された溶鋼の、モールドと接触
した部分が凝固をはじめる位置、および鋳片の横断面内
に未凝固の部分がなくなる点をいう。 この２点間を２
０’Ｃ／ｍｉｎ以上の速度で冷却するのは、微細な（Ｎ
ｂ、Ｔｉ）Ｃを均一に析出させて、結晶粒粗大化の防止
に役立てようとするからにほかならない。Ti and N are used as a means to prevent grain coarsening in case hardening steel.
It has been carried out to precipitate fine carbonitrides (b) and utilize their pinning effect. Conventionally, when casting into ingots, or even when continuous casting was performed, it was assumed that the slabs were relatively large and had to be subjected to blooming.
> and Nb (C,N>) precipitate in a relatively large form, whether in an ingot or a slab, melt into the matrix by subsequent heating, and precipitate finely again, resulting in a pinning effect. The above-mentioned method for manufacturing case-hardened steel in which Li and N are present in specific amounts and in a specific ratio and is rapidly cooled and cast eliminates the process of precipitation-dissolution-fine precipitation of large carbonitrides in the conventional technology. This method is based on the technical concept of precipitating and utilizing fine TiN from molten steel all at once.As mentioned above, this method is useful as a countermeasure against high-temperature carburization, but it According to the present inventors, TiN tends to precipitate as relatively large particles, and once precipitated, it is difficult to control the particle size of the precipitates. Therefore, it is not suitable for exerting the pinning effect under conditions involving cold or warm working, where the driving force for grain coarsening is particularly large. The inventors have come to the conclusion that it is necessary to use high-quality materials such as TiC and NbC1. The combination of particularly high cooling rates is a conclusion drawn based on the above-mentioned findings.The reasons for limiting the composition of the alloy used as the material of the present invention, including optionally added elements, are as follows. C: 0.10-0.30% A certain amount of C content is necessary to ensure strength as a mechanical structural component, but if it is too large, the toughness of the joint will also decrease. The range of S+: 0.02 to 0.35% is added as a deoxidizing agent in an amount exceeding the above lower limit, but it is not preferable for cold or warm processability. Mn: 0.2 to 2.0% Control the form of inclusions, especially sulfide inclusions, to prevent them from being excessively elongated by rolling or forging, and to improve hardenability. Add 0.2% or more to increase the content. If the amount is too large, cold workability and machinability will be impaired, so 2.0% is the limit. So, l!, A!J: 0.003 to 0. 060 is added with the expectation of strong deoxidizing performance, but if it is too large, alumina-based inclusions will increase and the mechanical properties of the product will deteriorate, so it should be controlled within the above range.N: 0.025 % or less In the present invention, the effect of N is not expected, but rather the amount is kept within the above-mentioned limit in order to avoid deterioration of strength and toughness due to the formation of giant carbonitrides. Nb: 0.01-0.20%, Ti: 0.01-0.
15% As mentioned above, the effect of preventing coarsening of crystal grains due to the formation of fine carbides is obtained. If the amount is too large, it not only reduces workability but also causes formation of giant carbonitrides, so it must not be added in excess of the above limit. Cr: 0.3-2.0%, Mo: 0.05-O. 5% Add one or both if you want to increase strength and toughness. When Cr increases, workability decreases, and Mo impedes hot working and increases cost, so each addition is limited to within the above-mentioned limits. Pb: 0.03~0.15%, Si: 0.03~
0.15%, Ca: 0.0003-0.0050%,
Te: 0.005 to 0.10% All are known as elements that improve machinability. One or more of these may be added in appropriate amounts within the limits that do not impair processability. The solidification start point and solidification end point are respectively the point at which the part of molten steel injected into a water-cooled mold for continuous casting that comes into contact with the mold begins to solidify, and the point at which there is no unsolidified part within the cross section of the slab. means. 2 between these two points
Cooling at a rate of 0'C/min or higher
b, Ti) This is because the purpose is to uniformly precipitate C and to help prevent crystal grain coarsening.
表に示す組成の合金組成の肌焼鋼を溶製し、−部は大き
さ４００Ｋｓのインゴットに鋳造し、一部は５００Ｘ４
００ｍの大断面の鋳片へ、そして残りは１５０Ｘ１５０
ｍの小断面の鋳片へ、いずれも連続鋳造により鋳造した
。
凝固開始点から終了点まで（インゴット鋳造では注湯か
ら未凝固部分がなくなると推定される時点まで）の冷却
速度は、それぞれ５℃／ｍｉｎ （インゴット）、１
０℃／ｍｉｎ （大断面連鋳）および５０℃／ｌ１１
ｉｎ （小断面連鋳）である。 従って、第三の場合
だけが本発明に従う実施例であり、他は比較例である。
インゴットおよび大断面鋳片は分塊圧延したのち、小断
面鋳片はそのまま、いずれも圧延して直径３２ｍの棒材
にした。
各試料の半分を、７６０’Ｃに８時間保持し、ついで１
０℃／ｍｉ口の速度で６５０°Ｃまで降温したのち空冷
する球状化焼鈍処理をしてから、機械加工により、直径
２５履×高さ３７．５Ｍの試験片にした。 これを冷間
で据え込み、高さを１２＃まで減らした。 据込率は７
３％である。
残り半分の試料は、直ちに機械加工して上記寸法の試験
片にしてから、９００℃に加熱した温間加工条件下に、
上記と同じ据込率の据え込みを行なった。
それぞれの試験片を、９２０℃×６時間の加熱条件でガ
ス浸炭したのち、ＪＩＳ−ＧＯ５５１にもとづいて結晶
粒度を測定した。 その結果、比較例すなわち冷却速度
の遅いインゴット鋳造の鋼塊および大断面連続鋳造の鋳
片から出発したものは、冷間加工の場合も温間加工の場
合も、粗粒ないし混粒の組織ばかりであったが、実施例
の小断面鋳片から出発したものは、冷間加工、温間加工
の両方とも、すべての試料が細粒の組織であった。
別に、０．２Ｃ−０，８Ｍｎ−１，２Ｏｒ −（０，０
１〜０．２）Ｎｌ）の組成（このほか、Ｓｉ ：０．
０２％およびＳｏｎ 、ｌ！ ： ０．０３％を含有し
、残部が実質上Ｆｅからなる）の合金の溶湯を、種々の
冷却速度で冷却して凝固させ、析出した炭化物の粒径を
しらべた。 プロットは、添付図面に示すような、両対
数グラフで２本のほぼ平行な直線にはさまれる領域（図
に斜線で示した）に入っていた。Case-hardened steel with the alloy composition shown in the table is melted, the - part is cast into an ingot of size 400Ks, and the part is 500X4.
00m large section slab, and the rest is 150X150
Both specimens were cast by continuous casting into slabs with a small cross section of m. The cooling rate from the start point to the end point of solidification (in ingot casting, from pouring to the time when the unsolidified portion is estimated to be gone) is 5°C/min (for ingot) and 1°C/min, respectively.
0℃/min (large cross-section continuous casting) and 50℃/l11
in (small cross-section continuous casting). Therefore, only the third case is an example according to the present invention, and the others are comparative examples. After the ingot and the large cross-section slab were subjected to blooming rolling, the small cross-section slab was rolled as it was to form a bar with a diameter of 32 m. Half of each sample was held at 760'C for 8 hours and then
After performing a spheroidizing annealing treatment in which the temperature was lowered to 650°C at a rate of 0°C/mi mouth and then air-cooled, a test piece with a diameter of 25 shoes and a height of 37.5M was made by machining. This was cold-upset and the height was reduced to 12#. The repayment rate is 7
It is 3%. The remaining half of the samples were immediately machined into specimens with the above dimensions, and then heated to 900°C under warm processing conditions.
Upgrading was carried out at the same upsetting rate as above. After gas carburizing each test piece under heating conditions of 920° C. for 6 hours, the grain size was measured based on JIS-GO551. As a result, the comparative examples, that is, those starting from ingot-cast steel ingots with slow cooling rates and large-section continuous casting slabs, had a coarse-grained or mixed-grained structure in both cold-worked and warm-worked cases. However, all samples starting from the small cross-section slabs of Examples had fine-grained structures in both cold working and warm working. Separately, 0.2C-0,8Mn-1,2Or-(0,0
1 to 0.2)Nl) composition (in addition, Si:0.
02% and Son, l! A molten alloy containing 0.03% Fe and the remainder substantially consisting of Fe was cooled and solidified at various cooling rates, and the particle size of the precipitated carbide was examined. The plot fell within the region (indicated by diagonal lines in the figure) between two substantially parallel straight lines on a log-log graph, as shown in the accompanying drawing.
本発明の方法に従って製造した肌焼鋼製品は、極めて微
細な（Ｔｉ、Ｎｂ）Ｃが均一に析出していて、その後の
加工を、冷間ないし温間の結晶粒粗大化の駆動力が熱間
より高くなる方法で行なった場合でも、浸炭時の加熱に
よる粗粒化や巨大品の生成をみることがない。 この結
晶粒粗大化防止の効果は、高温で浸炭処理を行なった場
合にも、明らかに得られる。 従って本発明の方法は、
冷間ないし温間の加工という、加熱工程を省略するかま
たは消費エネルギーを低減して寸法精度の高い浸炭用部
品を用意する加工法を採用し、それを高温に短時間加熱
するという、生産性を高めエネルギーコストを低く抑え
た浸炭処理を行なう最近の肌焼鋼の使用態様にマツチし
た、合理的な製造方法ということができる。The case-hardened steel products manufactured according to the method of the present invention have extremely fine (Ti, Nb)C precipitated uniformly, and the driving force of cold or warm crystal grain coarsening is used for subsequent processing. Even when the carburizing process is carried out using a method that increases the carburizing temperature, coarse grains and large products are not formed due to heating during carburizing. This effect of preventing coarsening of crystal grains is clearly obtained even when carburizing treatment is performed at high temperature. Therefore, the method of the present invention
We adopt a processing method called cold or warm processing, which either eliminates the heating process or reduces energy consumption to prepare parts for carburizing with high dimensional accuracy, and then heats them to high temperatures for a short time to improve productivity. This can be said to be a rational manufacturing method that matches the recent usage of case-hardened steel, which is carburized to increase the carburizing process and keep energy costs low.
図面は、本発明で使用する合金組成の肌焼鋼を種々の冷
却速度で鋳造したときの、析出した微細な炭化物（主と
してＮｂＣ）の粒径に冷却速度が及ぼす影響を示したグ
ラフである。
特許出願人 大同特殊鋼株式会社The drawing is a graph showing the effect of cooling rate on the particle size of precipitated fine carbides (mainly NbC) when case hardening steel having the alloy composition used in the present invention is cast at various cooling rates. Patent applicant: Daido Steel Co., Ltd.
Claims (4)
．３５％、Ｍｎ：０．２〜２．０％、Ｓｏｌ．Ａｌ：０
．００３〜０．０６０％、ならびに、Ｎｂ：０．０１〜
０．２０％およびＴｉ：０．０１〜０．１５％の１種ま
たは２種を含有し、Ｎ：０．０２５％以下であつて、残
部が実質上Ｆｅからなる合金組成の肌焼鋼を溶製し、連
続鋳造法によって分塊圧延を必要としないサイズの鋳片
に鋳造し、その際に凝固開始点から凝固終了点に至る温
度範囲を２０℃／ｍｉｎ以上の冷却速度をもって急速に
冷却し、得られた鋳片をそのまま棒鋼または線材に圧延
することからなる肌焼鋼製品の製造方法。(1) C: 0.10-0.30%, Si: 0.02-0
．． 35%, Mn: 0.2-2.0%, Sol. Al: 0
．． 003 to 0.060%, and Nb: 0.01 to
A case hardening steel having an alloy composition containing 0.20% and one or two of Ti: 0.01 to 0.15%, N: 0.025% or less, and the balance substantially consisting of Fe. It is melted and cast into a slab of a size that does not require blooming using a continuous casting method, and at that time, the temperature range from the solidification start point to the solidification end point is rapidly cooled at a cooling rate of 20°C/min or more. A method for manufacturing case-hardened steel products, which comprises rolling the obtained slab as it is into steel bars or wire rods.
Ｃｒ：０．３〜２．０％、Ｍｏ：０．０５〜０．５％お
よびＮｉ：０．３〜３．０％の１種または２種以上を含
有する組成のものを使用する請求項１の肌焼鋼製品の製
造方法。(2) As case hardening steel, in addition to the components described in claim 1,
A claim in which a composition containing one or more of Cr: 0.3 to 2.0%, Mo: 0.05 to 0.5%, and Ni: 0.3 to 3.0% is used. 1. Method for manufacturing case hardened steel products.
Ｐｂ：０．０３〜０．１５％、Ｂｉ：０．０３〜０．１
５％、Ｃａ：０．０００３〜０．００５０％およびＴｅ
：０．００５〜０．１０％の１種または２種以上を含有
する組成のものを使用する請求項１の肌焼鋼製品の製造
方法。(3) As case hardening steel, in addition to the components described in claim 1,
Pb: 0.03-0.15%, Bi: 0.03-0.1
5%, Ca: 0.0003-0.0050% and Te
2. The method for manufacturing a case hardened steel product according to claim 1, wherein a composition containing one or more of: 0.005 to 0.10% is used.
Ｃｒ：０．３〜２．０％、Ｍｏ：０．０５〜０．５％お
よびＮｉ：０．３〜３．０％の１種または２種以上、な
らびに、Ｐｂ：０．０３〜０．１５％、Ｂｉ：０．０３
〜０．１５％、Ｃａ：０．０００３〜０．００５０％お
よびＴｅ：０．００５〜０．１０％の１種または２種以
上を含有する組成のものを使用する請求項１の肌焼鋼製
品の製造方法。(4) As case hardening steel, in addition to the components described in claim 1,
One or more of Cr: 0.3-2.0%, Mo: 0.05-0.5% and Ni: 0.3-3.0%, and Pb: 0.03-0. 15%, Bi: 0.03
The case hardening steel according to claim 1, wherein the case hardening steel has a composition containing one or more of the following: 0.15% to 0.15%, Ca: 0.0003 to 0.0050%, and Te: 0.005 to 0.10%. How the product is manufactured.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63300158A JP2926725B2 (en) | 1988-11-28 | 1988-11-28 | Manufacturing method of case hardened steel products |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63300158A JP2926725B2 (en) | 1988-11-28 | 1988-11-28 | Manufacturing method of case hardened steel products |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02147148A true JPH02147148A (en) | 1990-06-06 |
| JP2926725B2 JP2926725B2 (en) | 1999-07-28 |
Family
ID=17881444
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63300158A Expired - Lifetime JP2926725B2 (en) | 1988-11-28 | 1988-11-28 | Manufacturing method of case hardened steel products |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2926725B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004238702A (en) * | 2003-02-07 | 2004-08-26 | Sumitomo Metal Ind Ltd | Carburized component excellent in low-cycle impact fatigue resistance |
| JP2007162128A (en) * | 2005-11-15 | 2007-06-28 | Kobe Steel Ltd | Case hardening steel having excellent forgeability and crystal grain-coarsening prevention property, its production method and carburized component |
| JP2011219854A (en) * | 2010-03-26 | 2011-11-04 | Jfe Steel Corp | Case-hardening steel and method for manufacturing the same |
| JP2012062536A (en) * | 2010-09-16 | 2012-03-29 | Jfe Steel Corp | Case-hardening steel and method for producing the same |
| CN105886937A (en) * | 2016-05-31 | 2016-08-24 | 安阳钢铁股份有限公司 | Low-cost and ultrahigh-strength steel wire rod for round-link chain and manufacturing method of low-cost and ultrahigh-strength steel wire rod |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63162812A (en) * | 1986-12-26 | 1988-07-06 | Nippon Steel Corp | Manufacture of case-hardening steel |
-
1988
- 1988-11-28 JP JP63300158A patent/JP2926725B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63162812A (en) * | 1986-12-26 | 1988-07-06 | Nippon Steel Corp | Manufacture of case-hardening steel |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004238702A (en) * | 2003-02-07 | 2004-08-26 | Sumitomo Metal Ind Ltd | Carburized component excellent in low-cycle impact fatigue resistance |
| JP2007162128A (en) * | 2005-11-15 | 2007-06-28 | Kobe Steel Ltd | Case hardening steel having excellent forgeability and crystal grain-coarsening prevention property, its production method and carburized component |
| JP2011219854A (en) * | 2010-03-26 | 2011-11-04 | Jfe Steel Corp | Case-hardening steel and method for manufacturing the same |
| JP2012062536A (en) * | 2010-09-16 | 2012-03-29 | Jfe Steel Corp | Case-hardening steel and method for producing the same |
| CN105886937A (en) * | 2016-05-31 | 2016-08-24 | 安阳钢铁股份有限公司 | Low-cost and ultrahigh-strength steel wire rod for round-link chain and manufacturing method of low-cost and ultrahigh-strength steel wire rod |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2926725B2 (en) | 1999-07-28 |
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