JPH04308059A - Tool steel for hot working - Google Patents
Tool steel for hot workingInfo
- Publication number
- JPH04308059A JPH04308059A JP9942991A JP9942991A JPH04308059A JP H04308059 A JPH04308059 A JP H04308059A JP 9942991 A JP9942991 A JP 9942991A JP 9942991 A JP9942991 A JP 9942991A JP H04308059 A JPH04308059 A JP H04308059A
- Authority
- JP
- Japan
- Prior art keywords
- hardness
- steel
- less
- quenching
- 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
- 229910001315 Tool steel Inorganic materials 0.000 title claims abstract description 14
- 238000005496 tempering Methods 0.000 claims abstract description 24
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 22
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 22
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 10
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 9
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 6
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 5
- 229910000831 Steel Inorganic materials 0.000 claims description 58
- 239000010959 steel Substances 0.000 claims description 58
- 238000010791 quenching Methods 0.000 claims description 25
- 230000000171 quenching effect Effects 0.000 claims description 25
- 229910052750 molybdenum Inorganic materials 0.000 claims description 11
- 239000012535 impurity Substances 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 abstract description 2
- 235000019589 hardness Nutrition 0.000 description 40
- 230000000052 comparative effect Effects 0.000 description 25
- 230000000694 effects Effects 0.000 description 18
- 230000007423 decrease Effects 0.000 description 12
- 238000001816 cooling Methods 0.000 description 11
- 150000001247 metal acetylides Chemical class 0.000 description 11
- 238000012360 testing method Methods 0.000 description 11
- 239000000463 material Substances 0.000 description 7
- 238000004512 die casting Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 238000009826 distribution Methods 0.000 description 5
- 238000005242 forging Methods 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 238000005336 cracking Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 229910001567 cementite Inorganic materials 0.000 description 2
- -1 cementite carbides Chemical class 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000009497 press forging Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000007788 roughening Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- 238000005495 investment casting Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Heat Treatment Of Articles (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、ダイカストや熱間プレ
ス鍛造等に用いられる熱間金型用の熱間工具鋼に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot work tool steel for hot molds used in die casting, hot press forging, and the like.
【０００２】0002
【従来の技術】ダイカストや熱間プレス鍛造用の金型材
としては、一部の温間鍛造や精密鋳造用の金型、比較的
小寸法の金型、特殊な金型部品等を除いては、従来、Ｓ
ＫＤ６やＳＫＤ６１などを熱処理硬さ ＨＲＣ５０未満
で用いるのが通常のやり方であった。[Prior art] Mold materials for die casting and hot press forging are available, except for some molds for warm forging and precision casting, relatively small-sized molds, special mold parts, etc. , conventionally, S
The usual practice was to use materials such as KD6 and SKD61 with a heat treatment hardness of less than HRC50.
【０００３】0003
【発明が解決しようとする課題】近年の熱間加工技術の
進歩、例えばダイカストの分野では、高圧ダイカスト法
、鍛造技術の分野では、密閉鍛造や高速鍛造の適用が進
み、金型表面に作用する熱的または機械的な負荷が増し
、金型表面にヒートクラックが生成したり、あるいは摩
耗したりして早期に使用不可能となる場合が多くなった
。このうち、損耗現象を改善するために最も効果的であ
るのは、熱処理硬さを高めることであるが、従来の金型
材では、硬さを高めると靭性値が低下するため、割れや
チッピングが生じやすく、熱処理硬さ ＨＲＣ５０程度
以上で使用できる金型の用途は限定されていた。本発明
は、高硬度範囲で高靭性を有し、耐ヒートクラック性に
優れた熱間工具鋼を提供することを目的とする。[Problem to be solved by the invention] Recent advances in hot working technology, for example, in the field of die casting, high-pressure die casting methods, and in the field of forging technology, closed forging and high-speed forging have been applied, which affects the surface of the mold. Thermal or mechanical loads have increased, and in many cases, heat cracks have formed on the mold surface or the mold has worn out, making it unusable at an early stage. Among these, the most effective way to improve the wear phenomenon is to increase the heat treatment hardness, but with conventional mold materials, increasing the hardness lowers the toughness value, resulting in cracking and chipping. This easily occurs, and the applications of molds that can be used with heat treatment hardness of HRC 50 or higher have been limited. An object of the present invention is to provide a hot work tool steel that has high toughness in a high hardness range and has excellent heat crack resistance.
【０００４】0004
【課題を解決するための手段】ＳＫＤ６、ＳＫＤ６１を
始めとする従来の熱間工具鋼では、焼入れ焼もどし硬さ
をＨＲＣ５０以上とするとき、焼もどし温度が６００℃
以下となる。このとき焼もどしで微細に析出する炭化物
の分布密度が極めて大となり靭性が低下するが、この炭
化物の析出挙動に、Ｓｉ，Ｃｒの含有量の関与が極めて
大きいことを発見した。ところで、Ｓｉ含有量を限定し
て合金鋼の靭性を高める効果については、特開昭６０−
５６０５５号、同６０−５９０５３号、同６１−２１３
３４８号、同６１−２１３３４９号でも開示されている
。しかし、これらには、本発明で特定した塑性範囲でＨ
ＲＣ５０以上としたときの特性値等についての記述はな
く、またＣｒ量との関係でＳｉ量を限定する記述もない
。本発明は、前記提案に開示されていない熱間工具鋼の
靭性値に関するＳｉ，Ｃｒ量の関与を詳しく調査し、■
Ｓｉ量の低減による靭性値向上効果は、従来の使用硬さ
であったＨＲＣ ４２〜４８前後のＨＲＣ５０未満より
むしろ、焼もどし温度が低めとなるＨＲＣ５０以上の硬
さのとき大きいこと、■Ｓｉ量の低減による靭性値向上
効果は、含有Ｃｒ量との関係で決定され、Ｃｒ量の低い
合金鋼では、過度の低減は必要でなく、一方金型の焼入
性などを考慮してＣｒ量を高めに設定する場合は、Ｓｉ
量を低めに抑える必要があること、■さらに、本願の第
１，３発明の鋼において、単にＳｉを低減した場合、金
型表面の肌あれをまねき、金型寿命が低下することがし
ばしば認められているが、適量のＣｏを添加することに
よって、Ｓｉを低減した金型材についても、酸化スケー
ルの成長を抑え、肌あれを防止する効果があること、を
発見したことに基づくものである。以上のことから、熱
処理硬さを高目にすることにより、苛酷な熱間加工条件
の金型に使用しても、ヒートクラックや摩耗等の金型表
面の損耗が生じにくく、かつ割れやチッピングが起こり
にくいため、従来より大寸法や複雑形状など広い用途に
適用できる熱間工具鋼の提供が可能となった。[Means for solving the problem] In conventional hot work tool steels such as SKD6 and SKD61, when the quenching and tempering hardness is set to HRC50 or higher, the tempering temperature is 600°C.
The following is true. At this time, the distribution density of finely precipitated carbides during tempering becomes extremely large, resulting in a decrease in toughness, and it has been discovered that the content of Si and Cr has a very large influence on the precipitation behavior of these carbides. By the way, the effect of increasing the toughness of alloy steel by limiting the Si content is disclosed in Japanese Patent Application Laid-open No. 1986-
No. 56055, No. 60-59053, No. 61-213
It is also disclosed in No. 348 and No. 61-213349. However, these have H within the plasticity range specified in the present invention.
There is no description of characteristic values when the RC is set to 50 or more, and there is no description of limiting the amount of Si in relation to the amount of Cr. The present invention investigates in detail the involvement of Si and Cr contents in the toughness value of hot work tool steel, which is not disclosed in the above proposal, and
The effect of improving toughness by reducing the amount of Si is greater when the hardness is HRC50 or higher, where the tempering temperature is lower, rather than when the hardness is less than HRC50, which is around HRC42 to 48, which is the conventional hardness used. The effect of improving toughness by reducing the amount of Cr is determined in relation to the amount of Cr contained, and in alloy steels with a low amount of Cr, excessive reduction is not necessary. If you want to set it higher,
■Furthermore, in the steels of the first and third inventions of the present application, it is often recognized that simply reducing Si leads to roughening of the mold surface and shortens the mold life. However, this is based on the discovery that by adding an appropriate amount of Co, mold materials with reduced Si can also be effective in suppressing the growth of oxide scale and preventing rough skin. From the above, by increasing the heat treatment hardness, even when used in molds under severe hot processing conditions, damage to the mold surface such as heat cracks and abrasion is less likely to occur, and cracking and chipping are less likely to occur. Because this is less likely to occur, it has become possible to provide hot work tool steel that can be used in a wider range of applications, including those with larger dimensions and more complex shapes than before.
【０００５】すなわち、本発明は具体的には、重量％で
、Ｃ ０．３５％を越え０．４５％未満、Ｓｉ １．０
０％以下、Ｍｎ ０．１〜１．５％、Ｎｉ ０．１〜１
．５％、Ｃｒ ４．３５〜５．６５％、ＷとＭｏを１種
または２種で１／２Ｗ＋Ｍｏ １．５〜３．５％、Ｖ
０．５〜１．５％で、かつＳｉ，Ｃｒ量がＳｉ＜（１８
．７／Ｃｒ）−３．３の関係式を満たし、残部Ｆｅおよ
び不可避的不純物からなり、焼入れ焼もどし硬さ ＨＲ
Ｃ５０以上で使用することを特徴とする熱間工具鋼、上
記添加元素にさらに重量％で、Ｃｏ ０．３〜５．０％
を添加したもの、および上記それぞれにおいて、Ｓｉを
０．１％越えるごとく制限した熱間工具鋼である。[0005] That is, the present invention specifically focuses on C more than 0.35% and less than 0.45%, Si 1.0% by weight.
0% or less, Mn 0.1-1.5%, Ni 0.1-1
．． 5%, Cr 4.35-5.65%, 1/2 W + Mo 1.5-3.5% with one or two types of W and Mo, V
0.5 to 1.5%, and the amount of Si and Cr is Si<(18
．． 7/Cr)-3.3, the remainder consists of Fe and unavoidable impurities, and the hardness after quenching and tempering is HR
Hot work tool steel characterized by being used at C50 or higher, further containing Co 0.3 to 5.0% by weight in addition to the above additive elements.
and in each of the above hot work tool steels, the Si content is limited to exceed 0.1%.
【０００６】[0006]
【作用】次に本発明の成分範囲の限定理由について述べ
る。Ｃは、本発明鋼のすぐれた焼入性、焼もどし硬さ、
および高温硬さを維持し、またＷ、Ｍｏ、Ｖ、Ｃｒなど
の炭化物形成元素と結合して炭化物を形成し、結晶粒の
微細化効果、耐摩耗性、焼もどし軟化抵抗、高温硬さを
与えるために添加するものである。多すぎると過度の炭
化物の析出をまねき靭性を低下させるので０．４５％未
満とし、本発明鋼の特徴の一つであるＨＲＣ５０以上の
焼入れ焼もどし硬さを保持するため等上記目的の達成の
ために含有量を０．３５％を越えるものとする。Ｓｉは
、本発明鋼の特徴であるＨＲＣ５０以上の高い硬さで高
い靭性値を得るために１．０％以下添加する。詳細には
Ｃｒの項でまとめて述べる。Ｍｎは、焼入性を向上させ
るが、多すぎるとＡ１変態点を過度に低下させ、焼なま
し硬さを過度に高くし、被切削性を低下させるので０．
１〜１．５０％以下とする。ＮｉはＣ， Ｃｒ， Ｍｎ
， Ｍｏ， Ｗなどとともに本発明鋼に優れた焼入性を
付与し、緩やかな焼入冷却速度の場合にも、マルテンサ
イト主体の組織を形成させ、靭性の低下を防ぐために重
要な添加元素であり、また基地の本質的な靭性改善効果
を与えるため、０．１％以上添加する。Ｎｉは上記効果
を得るために添加されるが、多すぎるとＡ１変態点を過
度に低下させ、へたり寿命の低下をまねき、焼なまし硬
さを過度に高くして機械加工性を低下させたので、１．
５０％以下とする。[Operation] Next, the reasons for limiting the range of components of the present invention will be described. C represents the excellent hardenability and tempering hardness of the steel of the present invention;
It also maintains high-temperature hardness and combines with carbide-forming elements such as W, Mo, V, and Cr to form carbides, improving grain refinement, wear resistance, tempering softening resistance, and high-temperature hardness. It is added to give. If the amount is too high, excessive carbide precipitation will occur and reduce toughness, so it should be less than 0.45%, and in order to maintain the quenching and tempering hardness of HRC50 or higher, which is one of the characteristics of the steel of the present invention, it is necessary to achieve the above objectives. For this purpose, the content should exceed 0.35%. Si is added in an amount of 1.0% or less in order to obtain a high toughness value with a high hardness of HRC50 or more, which is a characteristic of the steel of the present invention. The details will be summarized in the section on Cr. Mn improves hardenability, but if it is too large, it excessively lowers the A1 transformation point, increases annealing hardness excessively, and reduces machinability.
1 to 1.50% or less. Ni is C, Cr, Mn
, Mo, W, etc., it is an important additive element that imparts excellent hardenability to the steel of the present invention, forms a martensite-based structure even at a slow quenching cooling rate, and prevents a decrease in toughness. In addition, it is added in an amount of 0.1% or more in order to provide the essential toughness improvement effect of the matrix. Ni is added to obtain the above effects, but if it is too large, it will excessively lower the A1 transformation point, leading to a decrease in the fatigue life, and excessively increasing the annealing hardness, reducing machinability. Therefore, 1.
50% or less.
【０００７】Ｃｒは、適正な添加量の設定により、焼も
どし軟化抵抗および高温強度の向上、Ｃと結合して炭化
物を形成することによる耐摩耗性の向上、焼入性の向上
および迅速窒化性付与の効果を有するものであり、４．
３５％以上添加する。ただし、Ｃｒは本発明鋼のように
ＨＲＣ５０以上の高い焼入れ焼もどし硬さの金型として
使用される場合、本発明鋼の高い靭性値を確保するため
にはその含有量を制限する必要がある。これは以下に述
べる作用に基づくものである。本発明鋼のようにＨＲＣ
５０以上の高い焼入焼もどし硬さの金型として使用され
る場合、焼もどし温度は６００℃前後またはさらに低く
なるが、この温度域では焼もどしによって基地中に極く
微細に析出する特殊炭化物の分布密度が極めて大きく、
基地の靭性が著しく低下する。一方、Ｃｒ，Ｓｉはその
前段階で析出するセメンタイト炭化物の析出を抑える作
用があるので、逆にＣｒ，Ｓｉの含有量を抑えることに
よってセメンタイト炭化物を適量析出させることにより
基地の靭性を低下させる特殊炭化物の分布密度を抑える
ことができる。このため、Ｓｉ量は１．０％以下、Ｃｒ
は５．６５％以下とするが、ＣｒとＳｉは上記の作用に
複合的に作用するため、金型用として必要な靭性値を得
るべく、Ｓｉ＜（１８．７／Ｃｒ）−３．３％の関係式
を満たすように添加する。この関係式からも判るように
Ｃｒ含有量を多くしたい場合（例えばＣｒ＞５．５％）
には、Ｓｉ量を０．１％以下が必要である。ただし、Ｓ
ｉはＣｏの項で述べるように、これが低すぎると酸化皮
膜が厚くなり過ぎ易いので０．１％を越えることが望ま
しい。Ｃｏを添加で補う場合も同様である。By setting an appropriate amount of addition, Cr can improve tempering softening resistance and high-temperature strength, combine with C to form carbides, thereby improving wear resistance, hardenability, and rapid nitriding properties. 4.
Add 35% or more. However, when Cr is used as a mold with high quenching and tempering hardness of HRC50 or higher like the steel of the present invention, it is necessary to limit the content in order to ensure the high toughness value of the steel of the present invention. . This is based on the effect described below. Inventive steel like HRC
When used as a mold with a high quenching and tempering hardness of 50 or higher, the tempering temperature will be around 600℃ or even lower, but in this temperature range, special carbides that are extremely finely precipitated in the matrix due to tempering. The distribution density of is extremely large,
The toughness of the base is significantly reduced. On the other hand, since Cr and Si have the effect of suppressing the precipitation of cementite carbides that precipitate in the previous stage, conversely, by suppressing the content of Cr and Si, an appropriate amount of cementite carbides can be precipitated, thereby reducing the toughness of the matrix. The distribution density of carbides can be suppressed. Therefore, the amount of Si is 1.0% or less, and the amount of Cr is 1.0% or less.
is 5.65% or less, but since Cr and Si act in combination with the above effects, in order to obtain the necessary toughness value for molds, Si<(18.7/Cr)-3.3. Add so as to satisfy the relational expression of %. As can be seen from this relational expression, when you want to increase the Cr content (for example, Cr > 5.5%)
For this purpose, the amount of Si must be 0.1% or less. However, S
As described in the section on Co, if i is too low, the oxide film tends to become too thick, so it is desirable that it exceeds 0.1%. The same applies to the case where Co is supplemented by addition.
【０００８】Ｗ，Ｍｏ量の設定は本発明鋼の用途に必要
とされる高温強度、軟化抵抗を保つ上で重要である。
Ｗ，Ｍｏは、焼もどし処理時に微細な特殊炭化物を析出
して、軟化抵抗、高温強度を高める。ただし過度の添加
は過度の炭化物の析出をまねき靭性を低下させるので、
金型、工具の使用条件に応じた強度、高温強度に基づい
て、１種または２種を１／２Ｗ＋Ｍｏで１．５〜３．５
％添加する。Ｖは、固溶しにくい炭化物を形成して耐摩
耗性および耐焼付性の向上に効果を有するものであり、
焼入加熱時基地に固溶し焼もどし時微細な凝集しにくい
炭化物を析出し、高い温度域における軟化抵抗を大とし
、大きな高温耐力を与えるための重要な元素である。ま
た、結晶粒を微細化して靭性を向上させるとともに、Ａ
１変態点を上げ、優れた高温耐力とあいまって、耐ヒー
トクラック性を向上させる効果をもたらすものである。
本発明鋼の特徴である優れた靭性と高温強度の兼備のた
めにＶ量の設定は非常に重要である。多すぎると巨大な
炭化物を生成し、熱間加工方向に沿う紐状炭化物の分布
傾向を増大させ、その方向に沿うクラックの進展を助長
するため、１．５０％以下とし、低すぎると型表面部の
早期軟化をまねくなど、上記添加の効果が得られないの
で０．５０％以上とする。Setting the amounts of W and Mo is important in maintaining the high temperature strength and softening resistance required for the use of the steel of the present invention. W and Mo precipitate fine special carbides during tempering treatment, increasing softening resistance and high-temperature strength. However, excessive addition leads to excessive carbide precipitation and reduces toughness.
Based on the strength and high temperature strength according to the usage conditions of the mold and tool, type 1 or 2 with 1/2W + Mo is 1.5 to 3.5
%Added. V forms a carbide that is difficult to form a solid solution and is effective in improving wear resistance and seizure resistance,
It is an important element that dissolves into the base during quenching and heats and precipitates fine carbides that are difficult to agglomerate during tempering, increasing softening resistance in high temperature ranges and providing large high-temperature yield strength. In addition, it refines the crystal grains to improve toughness, and
It raises the transformation point by 1 and, together with excellent high-temperature yield strength, has the effect of improving heat crack resistance. The setting of the V content is very important for the steel of the present invention to have both excellent toughness and high-temperature strength. If it is too high, it will generate huge carbides, increase the distribution tendency of string-like carbides along the hot working direction, and encourage the growth of cracks along that direction. The above-mentioned effects of addition cannot be obtained, such as premature softening of the parts, so the content should be 0.50% or more.
【０００９】Ｃｏは、使用中の昇温時、きわめて緻密で
密着性の良い保護酸化皮膜を形成し、これにより相手材
との間の金属接触を防ぎ、金型表面の温度上昇を防ぐと
ともに優れた耐摩耗性をもたらすものである。ただし、
この酸化皮膜は厚くなりすぎると金型表面の肌あれをま
ねき逆効果となるが、Ｃｏは酸化皮膜の形成速度や厚み
を抑える効果を持つ。本発明鋼のようにＳｉ量の少ない
鋼の場合酸化皮膜が厚くなり過ぎ易いため、Ｃｏの添加
は、保護酸化皮膜特性の向上に特に有効である。Ｃｏは
上記効果を付与するために添加するが、多すぎると靭性
を低下させるので５．００％以下とし、低すぎると上記
添加の効果が得られないので０．３０％以上とする。[0009] When the temperature rises during use, Co forms an extremely dense and highly adhesive protective oxide film, which prevents metal contact with the other material and prevents the mold surface from rising in temperature. This provides added wear resistance. however,
If this oxide film becomes too thick, it will cause roughness on the surface of the mold and have the opposite effect, but Co has the effect of suppressing the formation speed and thickness of the oxide film. In the case of steel with a small amount of Si, such as the steel of the present invention, the oxide film tends to become too thick, so the addition of Co is particularly effective in improving the properties of the protective oxide film. Co is added to provide the above effects, but if it is too large it will reduce the toughness, so it should be 5.00% or less, and if it is too low, the above effect of addition cannot be obtained, so it should be 0.30% or more.
【００１０】0010
【実施例】以下、本発明を実施例に基づき詳細に説明す
る。表１にテストに供した本発明鋼および比較鋼の化学
組成を示す。表１において、比較鋼１はＪＩＳＳＫＤ６
１であり、比較鋼３は成分的には特開昭６０−５６０５
５号に開示されたその実施例の一つを狙って吹製したも
のであり、同公報の特許請求の範囲に含まれるとともに
、同６０−５９０５３号、同６１−２１３３４８号、同
６１−２１３３４９号の請求範囲にも含まれる熱間工具
鋼である。また、比較鋼５〜８は、Ｓｉ含有量を各レベ
ルとするが、Ｓｉ＜（１７．８／Ｃｒ）−３．３を満足
しないものである。図１は、表１の各試料を１０２０℃
加熱後、油焼入れまたは半冷１５ｍｉｎ焼入後、焼もど
し温度を変えて、ＨＲＣ４６からＨＲＣ５４の各硬さと
なるごとく焼もどしを行なった場合の硬さとシャルピー
衝撃値の関係を示す。なお、半冷 １５ｍｉｎ焼入とは
、焼入温度（１０２０℃）と室温（２０℃）との中間温
度５２０℃までを１５ｍｉｎで降温する処理を意味する
。
なお、試験片は２ｍｍ深さのＵノッチ試験片である。半
冷１５ｍｉｎ焼入で、衝撃試験を行なう理由は、実際の
金型を冷却する場合、寸法が比較的大きい場合、実際の
焼入冷却速度は、同じように処理した試験片より小さく
なり、また、熱間工具鋼の靭性値は、焼入冷却速度に影
響を受けやすいためである。ＳＫＤ６１の油焼入れの衝
撃値は、ＨＲＣ５０を越える硬さで、急激な低下をまね
き、また半冷１５ｍｉｎ、焼入れの衝撃値は、完全焼入
状態である油焼入れに比べて大幅に低い。比較鋼２は、
油焼入れの衝撃値がＳＫＤ６１に比べ高く、かつ焼入冷
却速度が小さくなったときも（半冷１５ｍｉｎ）靭性値
の低下が大幅に少ない。これは主にＮｉの添加の焼入性
向上効果によるものである。しかし、該比較鋼１の場合
も、ＨＲＣ５０以上の硬さで急激な衝撃値の低下が見ら
れる。比較鋼３の油焼入れの衝撃値は、比較鋼１（ＳＫ
Ｄ６１）のそれと比較して高い。比較鋼３は比較鋼１（
ＳＫＤ６１）の含有Ｓｉ量を低減させたものであり、Ｓ
ＫＤ６１に比べ靭性値が高い。またＨＲＣ５０を越えた
硬さでの衝撃値の低下が緩やかである。なお、該鋼は前
述のように、特開昭６０−５６０５５号の実施例の一つ
を狙成分として吹製したものであるが、該公報には、Ｈ
ＲＣ４６での衝撃値の記載はあるが、ＨＲＣ５０以上の
衝撃値の記載はない。EXAMPLES The present invention will be explained in detail below based on examples. Table 1 shows the chemical compositions of the inventive steel and comparative steel that were tested. In Table 1, comparative steel 1 is JISSKD6
1, and Comparative Steel 3 is JP-A-60-5605 in terms of composition.
It is blow-blown aiming at one of the embodiments disclosed in No. 5, and is included in the claims of the same, and is also covered by No. 60-59053, No. 61-213348, No. 61-213349. It is a hot work tool steel that is also included in the scope of the claims of No. Comparative steels 5 to 8 have Si contents at various levels, but do not satisfy Si<(17.8/Cr)-3.3. Figure 1 shows how each sample in Table 1 was heated to 1020°C.
After heating, oil quenching or semi-cooling quenching for 15 minutes, the tempering temperature is changed to give a hardness of HRC46 to HRC54. The relationship between hardness and Charpy impact value is shown below. Note that semi-cold quenching for 15 minutes means a process in which the temperature is lowered to an intermediate temperature of 520° C. between the quenching temperature (1020° C.) and room temperature (20° C.) in 15 minutes. Note that the test piece is a U-notch test piece with a depth of 2 mm. The reason for conducting an impact test with half-cooled quenching for 15 minutes is that when cooling an actual mold, if the dimensions are relatively large, the actual quenching cooling rate will be smaller than that of a similarly treated specimen. This is because the toughness value of hot work tool steel is easily affected by the quenching cooling rate. The impact value of SKD61 when oil quenched has a hardness that exceeds HRC50, causing a sudden drop, and the impact value when semi-cooled for 15 minutes and quenched is significantly lower than that of oil quenching, which is a completely quenched state. Comparative steel 2 is
The impact value of oil quenching is higher than that of SKD61, and even when the quenching cooling rate is reduced (half-cooling 15 min), the decrease in toughness value is significantly smaller. This is mainly due to the hardenability improving effect of adding Ni. However, in the case of Comparative Steel 1 as well, a sharp drop in impact value is observed when the hardness exceeds HRC50. The oil quenching impact value of Comparative Steel 3 is the same as that of Comparative Steel 1 (SK
D61) is higher than that of D61). Comparative steel 3 is compared to comparative steel 1 (
SKD61) with reduced Si content, S
Higher toughness than KD61. Furthermore, the impact value decreases slowly when the hardness exceeds HRC50. As mentioned above, this steel was made by blowing using one of the examples in JP-A No. 60-56055 as the target component, but the publication does not include H.
Although there is a description of the impact value at RC46, there is no description of the impact value at HRC50 or higher.
【００１１】図２に、本発明鋼１，２，３，４の半冷１
５ｍｉｎ焼入れの衝撃値を、比較例２，４のそれと比較
して示す。比較鋼２は同４に比し、前述のようにＮｉ添
加による焼入性向上により半冷１５ｍｉｎの衝撃値向上
が図られているが、Ｓｉ＜（１８．７／Ｃｒ）−３．３
を満足していないため、ＨＲＣ５０またはそれ以上の高
硬度での衝撃値低下が急峻である。これに対し、本発明
鋼１，２，３，４および比較鋼４は、上記ＳｉとＣｒと
の関係式を満足するからこの低下が緩やかである。なお
、本発明鋼３は高温強度付与のため、ＭｏやＶの添加量
を多めとしたため衝撃値が比較鋼４と同程度であるが、
後に述べるヒートクラック発生寿命が大きいことに特徴
を持つ。特に、被加工材の溶湯温度の高いダイカスト金
型や、被加工材との接触時間の長い鍛造金型など、型面
の昇温温度が高い用途の場合、高温強度を付与するＷ，
Ｍｏ， Ｖ量を多めとする。
これに応じて、衝撃値の絶対値は低下する傾向を示すが
、硬さの上昇にともなう急激な衝撃値の低下は認められ
ない。FIG. 2 shows semi-cooled steels 1, 2, 3, and 4 of the present invention.
The impact values after quenching for 5 minutes are shown in comparison with those of Comparative Examples 2 and 4. Compared to Comparative Steel 4, Comparative Steel 2 has an improved impact value after 15 minutes of semi-cooling due to the improvement in hardenability due to Ni addition as described above, but Si<(18.7/Cr)-3.3
Therefore, the impact value decreases sharply at high hardness of HRC50 or higher. On the other hand, inventive steels 1, 2, 3, and 4 and comparative steel 4 satisfy the above relational expression between Si and Cr, so this decrease is gradual. In addition, in order to impart high-temperature strength, the present invention steel 3 has a relatively large amount of Mo and V added, so its impact value is about the same as that of comparative steel 4.
It is characterized by a long heat crack generation life, which will be described later. In particular, in applications where the temperature of the die surface is high, such as die casting molds where the temperature of the molten metal of the workpiece is high, or forging molds where the contact time with the workpiece is long, W, which imparts high-temperature strength,
Increase the amounts of Mo and V. Correspondingly, the absolute value of the impact value tends to decrease, but no rapid decrease in the impact value is observed as the hardness increases.
【００１２】次にＣｒとＳｉ量の設定のために行なった
実験結果を図３に示す。該図は表１の比較鋼、本発明鋼
数例ずつについて、Ｓｉ，Ｃｒ含有量をプロットすると
ともに、その半冷１５ｍｉｎ焼入れ後焼もどしにより硬
さＨＲＣ５２としたときのシャルピー衝撃値を添字で表
したものである。なお、図中で本７は本発明鋼７を、同
様に比１は比較鋼１を示す。前述のようにＣｒは焼入性
を向上させる元素であるので、焼入性が問題となる大寸
法の金型材については、多めに添加する。しかし、この
場合、「作用」の項に述べたような焼もどし炭化物の析
出分布、挙動に影響するため、これに応じてＳｉ量を設
定する必要が生じる。図３に示す通り、半冷１５ｍｉｎ
焼入れで、焼もどし硬さＨＲＣ５２とした場合、Ｃｒ，
Ｓｉ量がともに高い場合の衝撃値は低い（例；比較鋼８
）。またＣｒ量が高い場合、Ｓｉ量が低めであっても衝
撃値の低下をまねく（例；比較鋼５）のに対し、Ｃｒ量
が比較的低い場合は、ある程度のＳｉを含有しても衝撃
値は比較的高い（例；本発明鋼７）。
過度のＳｉ量の低減は、耐酸化性不足にともなう金型表
面の肌あれや金型の切削工具などによる被加工性の低下
をまねくため、上記靭性の影響を配慮して必要とされる
Ｃｒ量に応じて、重量％でＳｉ＜（１８．７／Ｃｒ）−
３．３を満たす程度に設定する。Next, FIG. 3 shows the results of an experiment conducted to set the amounts of Cr and Si. This figure plots the Si and Cr contents for the comparison steel in Table 1 and several examples of the invention steel, and also shows the Charpy impact value when the hardness is HRC52 by semi-cooling quenching for 15 minutes and tempering. This is what I did. In addition, in the figure, Book 7 indicates Invention Steel 7, and Ratio 1 indicates Comparative Steel 1. As mentioned above, Cr is an element that improves hardenability, so it is added in a large amount for large mold materials where hardenability is a problem. However, in this case, since it affects the precipitation distribution and behavior of tempered carbides as described in the "effect" section, it is necessary to set the amount of Si accordingly. As shown in Figure 3, semi-cooling for 15 minutes
When hardened and tempered to a hardness of HRC52, Cr,
The impact value is low when both amounts of Si are high (e.g. Comparative Steel 8
). In addition, when the Cr content is high, the impact value decreases even if the Si content is low (e.g. Comparative Steel 5), whereas when the Cr content is relatively low, the impact value decreases even if a certain amount of Si is contained. The value is relatively high (eg, invention steel 7). Excessive reduction in the amount of Si will lead to roughening of the mold surface due to insufficient oxidation resistance and a decrease in machinability with mold cutting tools. Depending on the amount, in weight %, Si<(18.7/Cr)-
Set to the extent that 3.3 is satisfied.
【００１３】次に、熱間工具鋼において、実用性能上、
最も重要な耐ヒートクラック性のテストについて確認を
行なった結果を述べる。耐ヒートクラック性のテストに
ついては、ヒートクラック発生までの熱サイクル数Ｎと
、このテストを前記熱サイクルの数Ｎの２倍まで継続し
た時のクラックの最大深さＤについて評価した。テスト
仕様は、６０ｍｍφ×４０ｍｍの試験片の表面を６００
℃に急熱した後、表面を２０℃の水で急冷する操作を繰
り返すものである。ヒートクラック発生までの熱サイク
ル数Ｎには、主に高温強度が、ヒートクラックの内部へ
の進展性、つまりクラック最大深さＤに対しては、おも
に靭性値がそれぞれ関与するが、このほか工具表面の特
性、とくに耐酸化性が、酸化被膜の生成や成長のし易さ
の点で、それぞれ耐ヒートクラック性に影響する。図４
に、本発明鋼、比較鋼の耐ヒートクラック性試験の結果
を示す。各データから、硬さを高めることにより、ヒー
トクラック発生までのサイクル数Ｎが明らかに増大する
ことがわかる。また、比較鋼７は比較鋼１に比しＭｏを
増量して高温強度を高めたものであるが、これによって
サイクル数Ｎが増大し、金型のヒートクラック寿命向上
につながることが伺われる。しかし、これは一面で硬さ
をＨＲＣ５２と高くした場合、ヒートクラックの進展深
さが大きくなることがわかる。アルミダイカスト型のよ
うな実用金型で、ＳＫＤ６１をＨＲＣ５２程度に調質し
、鋳造を行なった場合、熱サイクルによる熱応力の他に
、型締め力等の機械的応力が金型に作用するため、深く
進展したヒートクラックを起点とした割損が起きやすい
。このため、小寸法の金型の例を除き、ＳＫＤ６１では
ＨＲＣ５０以下の硬さで使用されているのが現状である
。これに対し、図４に示すように、本発明鋼では、ＨＲ
Ｃ５２まで硬さを高めた場合でも、ヒートクラックの進
展深さが小さい。本発明鋼は、前記のようにＨＲＣ５２
の高い硬さでも、高い靭性値を保持するため、実用金型
に適用した例で、割損をまねいていない。Next, regarding hot work tool steel, in terms of practical performance,
We will describe the results of the most important heat crack resistance test. Regarding the heat crack resistance test, the number N of thermal cycles until the occurrence of heat cracks and the maximum depth D of cracks when this test was continued up to twice the number N of thermal cycles were evaluated. The test specifications are that the surface of a 60mmφ x 40mm test piece is
After rapidly heating the surface to 20°C, the surface is rapidly cooled with water at 20°C, which is repeated. The number of thermal cycles N until heat cracks occur is mainly affected by high-temperature strength, and the propagation of heat cracks into the interior, that is, the maximum crack depth D, is mainly affected by the toughness value. Surface characteristics, particularly oxidation resistance, affect heat crack resistance in terms of the ease with which oxide films form and grow. Figure 4
2 shows the results of a heat crack resistance test of the inventive steel and comparative steel. It can be seen from each data that increasing the hardness clearly increases the number of cycles N until heat cracks occur. Furthermore, Comparative Steel 7 has increased Mo content to enhance high-temperature strength compared to Comparative Steel 1, and it can be seen that this increases the number of cycles N, leading to an improvement in the heat crack life of the mold. However, this means that when the hardness is increased to HRC52, the depth of heat crack development increases. When using a practical mold such as an aluminum die-casting mold, when SKD61 is tempered to about HRC52 and cast, mechanical stress such as mold clamping force acts on the mold in addition to thermal stress due to thermal cycles. , breakage is likely to occur due to deeply developed heat cracks. For this reason, except for small-sized molds, SKD61 is currently used with a hardness of HRC50 or less. On the other hand, as shown in Fig. 4, in the steel of the present invention, HR
Even when the hardness is increased to C52, the depth of heat crack development is small. As mentioned above, the steel of the present invention has a HRC52
Even with high hardness, it maintains a high toughness value, so it has not caused breakage when applied to practical molds.
【００１４】上記のヒートクラック試験片に発生したヒ
ートクラックの断面形態を観察したところ、試験片の表
面およびクラックの開口部にも表面酸化が進行しており
、本発明鋼５は、酸化被膜が特に厚く０．１ｍｍであっ
た。これに対してＣｏを添加し、耐酸化性が改善された
本発明鋼１１，１２は、酸化被膜の厚みが０．０４ｍｍ
であり、クラック進展深さも小さく、耐ヒートクラック
進展性の改善効果が大きかった。[0014] When we observed the cross-sectional form of the heat crack that occurred in the above heat crack test piece, we found that surface oxidation had progressed on the surface of the test piece and also at the opening of the crack. It was especially thick, 0.1 mm. On the other hand, inventive steels 11 and 12 with improved oxidation resistance by adding Co, the thickness of the oxide film was 0.04 mm.
, the crack growth depth was small, and the effect of improving heat crack growth resistance was large.
【００１５】[0015]
【発明の効果】以上に記述したように、本発明鋼は、熱
間用の金型として従来材料より高い硬さ、具体的にはＨ
ＲＣ５０以上の硬さで割損をまねくことなく使用でき、
ヒートクラック発生や摩耗の点で優れた使用寿命を与え
る金型を製造することができる。しかも金型の使用中の
金型表面の酸化被膜の成長速度を抑え、肌あれやヒート
クラックの金型内部への進展が抑制され、この面からも
優れた使用寿命を与えることができる。Effects of the Invention As described above, the steel of the present invention has higher hardness than conventional materials, specifically H
With a hardness of RC50 or higher, it can be used without causing breakage.
It is possible to manufacture a mold that has an excellent service life in terms of heat cracking and wear. Moreover, the growth rate of the oxide film on the mold surface during use of the mold is suppressed, and the propagation of rough skin and heat cracks into the mold interior is suppressed, and from this point of view as well, it is possible to provide an excellent service life.
【図１】比較鋼１〜３の油焼入れと半冷 １５ｍｉｎ焼
入れ後、各硬さに焼もどしした場合の、シャルピー衝撃
値の焼もどし硬さに対する変化の挙動を示した図である
。FIG. 1 is a diagram showing the behavior of changes in Charpy impact value with respect to tempering hardness when Comparative Steels 1 to 3 were oil-quenched and semi-cooled for 15 minutes and then tempered to various hardnesses.
【図２】本発明鋼１，２，３，４および比較鋼２，４の
半冷１５ｍｉｎ焼入れ後、各硬さに焼もどしした場合の
、シャルピー衝撃値を示す図である。FIG. 2 is a diagram showing the Charpy impact values of Inventive Steels 1, 2, 3, and 4 and Comparative Steels 2 and 4 when they are tempered to various hardnesses after being semi-cooled and quenched for 15 minutes.
【図３】本発明鋼１，４，５，６，８，９，１０と比較
鋼１，２，５，６，７，８のそれぞれの半冷１５ｍｉｎ
焼入れ後、焼もどし硬さＨＲＣ５２としたときのシャル
ピー衝撃値を、各鋼の含有Ｓｉ，Ｃｒ量で整理した図で
ある。[Fig. 3] Half-cooling for 15 min for each of the inventive steels 1, 4, 5, 6, 8, 9, and 10 and comparative steels 1, 2, 5, 6, 7, and 8.
It is a graph in which the Charpy impact value when the tempering hardness is HRC52 after quenching is arranged by the amount of Si and Cr contained in each steel.
【図４】本発明鋼１，２，５，６，１１，１２および比
較鋼１，７についての耐ヒートクラック性試験結果を示
す図である。FIG. 4 is a diagram showing the results of a heat crack resistance test for Invention Steels 1, 2, 5, 6, 11, and 12 and Comparative Steels 1 and 7.
【表１】[Table 1]
Claims (4)
４５％未満、Ｓｉ １．００％以下、Ｍｎ０．１〜１．
５％、Ｎｉ ０．１〜１．５％、Ｃｒ ４．３５〜５．
６５％、ＷとＭｏを１種または２種で１／２Ｗ＋Ｍｏ
１．５〜３．５％、Ｖ ０．５〜１．５％で、かつＳｉ
，Ｃｒ量がＳｉ＜（１８．７／Ｃｒ）−３．３の関係式
を満たし、残部Ｆｅおよび不可避的不純物からなり、焼
入れ焼もどし硬さＨＲＣ５０以上で使用することを特徴
とする熱間工具鋼。Claim 1: C exceeds 0.35% and 0.35% by weight.
less than 45%, Si 1.00% or less, Mn 0.1-1.
5%, Ni 0.1-1.5%, Cr 4.35-5.
65%, 1/2W + Mo with one or two types of W and Mo
1.5-3.5%, V 0.5-1.5%, and Si
, the amount of Cr satisfies the relational expression Si<(18.7/Cr)-3.3, the remainder consists of Fe and unavoidable impurities, and the tool is used with a quenching and tempering hardness of HRC50 or more. steel.
４５％未満、Ｓｉ １．００％以下、Ｍｎ０．１〜１．
５％、Ｎｉ ０．１〜１．５％、Ｃｒ ４．３５〜５．
６５％、ＷとＭｏを１種または２種で１／２Ｗ＋Ｍｏ
１．５〜３．５％、Ｖ ０．５〜１．５％、Ｃｏ ０．
３〜５．０％で、かつＳｉ，Ｃｒ量がＳｉ＜（１８．７
／Ｃｒ）−３．３の関係式を満たし、残部Ｆｅおよび不
可避的不純物からなり、焼入れ焼もどし硬さ ＨＲＣ５
０以上で使用することを特徴とする熱間工具鋼。Claim 2: C exceeds 0.35% and 0.35% by weight.
less than 45%, Si 1.00% or less, Mn 0.1-1.
5%, Ni 0.1-1.5%, Cr 4.35-5.
65%, 1/2W + Mo with one or two types of W and Mo
1.5-3.5%, V 0.5-1.5%, Co 0.
3 to 5.0%, and the amount of Si and Cr is Si<(18.7
/Cr)-3.3, the balance consists of Fe and unavoidable impurities, and the hardness after quenching and tempering is HRC5.
A hot work tool steel characterized by being used at a temperature of 0 or more.
４５％未満、Ｓｉ ０．１％を越え１．００％以下、Ｍ
ｎ ０．１〜１．５％、Ｎｉ ０．１〜１．５％、Ｃｒ
４．３５〜５．５％、ＷとＭｏを１種または２種で１
／２Ｗ＋Ｍｏ １．５〜３．５％、Ｖ ０．５〜１．５
％で、かつＳｉ，Ｃｒ量がＳｉ＜（１８．７／Ｃｒ）−
３．３の関係式を満たし、残部Ｆｅおよび不可避的不純
物からなり、焼入れ焼もどし硬さ ＨＲＣ５０以上で使
用することを特徴とする熱間工具鋼。3. C exceeds 0.35% and 0.35% by weight.
Less than 45%, Si more than 0.1% and less than 1.00%, M
n 0.1-1.5%, Ni 0.1-1.5%, Cr
4.35-5.5%, one or two of W and Mo
/2W+Mo 1.5-3.5%, V 0.5-1.5
%, and the amount of Si and Cr is Si<(18.7/Cr)-
A hot work tool steel that satisfies the relational expression 3.3, is composed of the remainder Fe and unavoidable impurities, and is used with a quenching and tempering hardness of HRC50 or more.
４５％未満、Ｓｉ ０．１％を越え１．００％以下、Ｍ
ｎ ０．１〜１．５％、Ｎｉ ０．１〜１．５％、Ｃｒ
４．３５〜５．５％、ＷとＭｏを１種または２種で１
／２Ｗ＋Ｍｏ １．５〜３．５％、Ｖ ０．５〜１．５
％、Ｃｏ ０．３〜５．０％で、かつＳｉ，Ｃｒ量がＳ
ｉ＜（１８．７／Ｃｒ）−３．３の関係式を満たし、残
部Ｆｅおよび不可避的不純物からなり、焼入れ焼もどし
硬さ ＨＲＣ５０以上で使用することを特徴とする熱間
工具鋼。4. C exceeds 0.35% and 0.35% by weight.
Less than 45%, Si more than 0.1% and less than 1.00%, M
n 0.1-1.5%, Ni 0.1-1.5%, Cr
4.35-5.5%, one or two of W and Mo
/2W+Mo 1.5-3.5%, V 0.5-1.5
%, Co 0.3 to 5.0%, and the amount of Si and Cr is S
A hot work tool steel that satisfies the relational expression i<(18.7/Cr)-3.3, is composed of the remainder Fe and unavoidable impurities, and is used with a quenching and tempering hardness of HRC50 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09942991A JP3191008B2 (en) | 1991-04-04 | 1991-04-04 | Hot tool steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09942991A JP3191008B2 (en) | 1991-04-04 | 1991-04-04 | Hot tool steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04308059A true JPH04308059A (en) | 1992-10-30 |
| JP3191008B2 JP3191008B2 (en) | 2001-07-23 |
Family
ID=14247208
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP09942991A Expired - Lifetime JP3191008B2 (en) | 1991-04-04 | 1991-04-04 | Hot tool steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3191008B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010074017A1 (en) * | 2008-12-25 | 2010-07-01 | 日立金属株式会社 | Steel tempering method |
| JP2010532715A (en) * | 2007-07-10 | 2010-10-14 | ファウ・ウント・エム・ドイチュラント・ゲゼルシャフト・ミット・ベシュレンクテル・ハフツング | Forged mandrel for hot forging metal tubular workpieces |
| KR20230127163A (en) | 2022-02-24 | 2023-08-31 | 다이도 토쿠슈코 카부시키가이샤 | Steel for a mold and mold |
-
1991
- 1991-04-04 JP JP09942991A patent/JP3191008B2/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010532715A (en) * | 2007-07-10 | 2010-10-14 | ファウ・ウント・エム・ドイチュラント・ゲゼルシャフト・ミット・ベシュレンクテル・ハフツング | Forged mandrel for hot forging metal tubular workpieces |
| WO2010074017A1 (en) * | 2008-12-25 | 2010-07-01 | 日立金属株式会社 | Steel tempering method |
| CN102264921A (en) * | 2008-12-25 | 2011-11-30 | 日立金属株式会社 | Steel tempering method |
| JP2014177710A (en) * | 2008-12-25 | 2014-09-25 | Hitachi Metals Ltd | Hardening method for steel |
| JP5815946B2 (en) * | 2008-12-25 | 2015-11-17 | 日立金属株式会社 | Hardening method of steel |
| KR20230127163A (en) | 2022-02-24 | 2023-08-31 | 다이도 토쿠슈코 카부시키가이샤 | Steel for a mold and mold |
| US11952640B2 (en) | 2022-02-24 | 2024-04-09 | Daido Steel Co., Ltd. | Steel for a mold and mold |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3191008B2 (en) | 2001-07-23 |
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