JPH03285050A - Exhaust valve steel excellent in high temperature characteristic - Google Patents
Exhaust valve steel excellent in high temperature characteristicInfo
- Publication number
- JPH03285050A JPH03285050A JP8668390A JP8668390A JPH03285050A JP H03285050 A JPH03285050 A JP H03285050A JP 8668390 A JP8668390 A JP 8668390A JP 8668390 A JP8668390 A JP 8668390A JP H03285050 A JPH03285050 A JP H03285050A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- strength
- high temperature
- exhaust valve
- oxidation resistance
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 61
- 239000010959 steel Substances 0.000 title claims abstract description 61
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 12
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 10
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 10
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 7
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 7
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 7
- 229910052796 boron Inorganic materials 0.000 claims abstract description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 6
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 5
- 239000012535 impurity Substances 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims 4
- 230000003647 oxidation Effects 0.000 abstract description 19
- 238000007254 oxidation reaction Methods 0.000 abstract description 19
- 239000000203 mixture Substances 0.000 abstract description 9
- 229910052759 nickel Inorganic materials 0.000 abstract description 5
- 238000002485 combustion reaction Methods 0.000 abstract description 4
- 229910052799 carbon Inorganic materials 0.000 abstract description 3
- 229910000851 Alloy steel Inorganic materials 0.000 abstract 1
- 229910000677 High-carbon steel Inorganic materials 0.000 abstract 1
- 229910000954 Medium-carbon steel Inorganic materials 0.000 abstract 1
- 238000000034 method Methods 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 12
- 230000000694 effects Effects 0.000 description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 8
- 239000000463 material Substances 0.000 description 6
- 230000007797 corrosion Effects 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 3
- 150000001247 metal acetylides Chemical class 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910001347 Stellite Inorganic materials 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- AHICWQREWHDHHF-UHFFFAOYSA-N chromium;cobalt;iron;manganese;methane;molybdenum;nickel;silicon;tungsten Chemical compound C.[Si].[Cr].[Mn].[Fe].[Co].[Ni].[Mo].[W] AHICWQREWHDHHF-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- -1 o 3% or less Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 230000004584 weight gain Effects 0.000 description 1
- 235000019786 weight gain Nutrition 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野〕
本発明は内燃機関の排気バルブ材料として用いられる高
温特性の優れた排気バルブ用鋼に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a steel for exhaust valves having excellent high-temperature properties and used as an exhaust valve material for internal combustion engines.
［従来の技術］
ガソリンエンジンおよびディーゼルエンジン用の排気バ
ルブ材料としては、２１−４Ｎ（ＳＵＨ３５ ０、５
Ｃ−９Ｍｎ−２１Ｃｒ−４Ｎ＋−０．４Ｎ》が広く使用
されていた．しかし近年になってガソリンエンジンの高
出力化に伴い、従来よりバルブ作動温度が上昇し、８５
０℃を越すものもあり、排気バルブ材料としては高温に
おける強度、耐食性が要求されるようになってきた。[Prior Art] Exhaust valve materials for gasoline engines and diesel engines include 21-4N (SUH350, 5
C-9Mn-21Cr-4N+-0.4N] was widely used. However, in recent years, with the increase in the output of gasoline engines, the valve operating temperature has increased to 85%.
In some cases, the temperature exceeds 0°C, and exhaust valve materials are now required to have strength and corrosion resistance at high temperatures.
かかる事情に鑑み、排気バルブ用鋼としては、ＳＵＨ３
５よりも高温疲労強度の大きな材料を用いる必要がある
．そのため、ＳＵＨ３５系弁用鋼使用に際しては、高Ｃ
ｏ−Ｃｒ含有のステライト肉盛りを施した高価な加工弁
を用いるか、または高温強度およびクリープ特性の優れ
たニッケル基合金、例えばＪＩＳ ＮＣＦ７５１等を
用いて対処している。In view of these circumstances, SUH3 is selected as the steel for exhaust valves.
It is necessary to use a material with higher high temperature fatigue strength than 5. Therefore, when using SUH35 series valve steel, high C
This problem is dealt with by using an expensive processed valve with o-Cr-containing stellite overlay, or by using a nickel-based alloy with excellent high-temperature strength and creep properties, such as JIS NCF751.
しかし、上記のＳＵＨ３５系合金では８５０℃程度の疲
労強度が１５ｋｇｆ／ａｍ２以下であり、またＮＣＦ７
５１でも大差なく、逆に硫化物に対する腐食性が劣るほ
か、Ｎｉが主成分であるためコスト高の問題がある。However, the fatigue strength of the above SUH35 series alloy at about 850℃ is less than 15 kgf/am2, and the NCF7
51 is not much different, on the contrary, it has poor corrosiveness against sulfides, and has the problem of high cost since Ni is the main component.
［発明が解決しようとする課題］
かかる従来の排気バルブ用鋼の高温特性に関する問題点
を解決するため提案されたのが、特開昭６０−７７９６
４号公報の発明であって、ＳＵＨ３５を基本成分とし、
ＭｎおよびＮｉの含有量を増加すると共に、Ｍｎ．Ｎｂ
，ＣｕおよびＢを添加することにより、８５０℃におけ
る熱間疲労強度が１ ７ ｋｇｆ／ ａｍ”以上である
排気バルブ用鋼を得ている。[Problems to be Solved by the Invention] In order to solve the problems regarding the high temperature characteristics of the conventional steel for exhaust valves, a proposal was made in JP-A-60-7796.
The invention of Publication No. 4, which uses SUH35 as a basic component,
While increasing the Mn and Ni contents, Mn. Nb
By adding .
しかしながら、排気バルブ用鋼としては、さらに高温引
張強さ、クリープ強度、高温疲労強度等の高温特性が優
れるとともに、熱間加工性および耐酸化性に優れた材料
の出現が望まれている．本発明は内燃機関に用いられる
排気バルブ用鋼の前記のごとき問題点に鑑みてなされた
ものであって、従来の排気バルブ用鋼よりも高温強度お
よび耐酸化性の優れた排気バルブ用鋼を提供することを
目的とする。However, as steel for exhaust valves, there is a desire for materials with even better high-temperature properties such as high-temperature tensile strength, creep strength, and high-temperature fatigue strength, as well as excellent hot workability and oxidation resistance. The present invention was made in view of the above-mentioned problems with steel for exhaust valves used in internal combustion engines. The purpose is to provide.
［課題を解決するための手段］
発明者等は排気バルブ用鋼の高温強度を向上させること
について鋭意研究を重ねた結果、Ｃ含有・量を増量する
こと、およびＮｂとＴｉの複合添加により炭化物析出強
化することが効果的であることを新たに知見した．さら
に、耐酸化性の改善にはＮ；およびＣｒの増量により達
成さること、■、Ｗ、Ｔａの添加によりさらに高温強度
が向上し、Ｂ、ＣＩＩ．Ｍｇの複合添加により熱間加工
性の改善が達成されることを新たに見出だすことにより
、本発明を完成した。[Means for solving the problem] As a result of extensive research into improving the high-temperature strength of steel for exhaust valves, the inventors have found that by increasing the C content and amount and by adding a combination of Nb and Ti, carbide We have newly discovered that precipitation strengthening is effective. Furthermore, the oxidation resistance can be improved by increasing the amount of N; and Cr, and the high temperature strength can be further improved by adding W, Ta, and B, CII. The present invention was completed by newly discovering that hot workability can be improved by the combined addition of Mg.
すなわち、本発明の高温特性の優れた排気バルブ用鋼は
、第１発明として、重量比でＣ ；０ 、３ ０〜０
６０％、Ｓｉ；０．５５％以下、Ｍｎ；５ 、０〜１５
０％、Ｓ ：Ｏ 、ｏ ３％以下、Ｎ ｉ；８ 、０
〜１５。That is, the steel for exhaust valves having excellent high-temperature properties of the present invention has a weight ratio of C;0,30 to 0 as the first invention.
60%, Si; 0.55% or less, Mn; 5, 0-15
0%, S: O, o 3% or less, N i; 8, 0
~15.
０％、Ｃｒ；２０．０−２５．０％、Ｍｏ；１．０〜４
。0%, Cr; 20.0-25.0%, Mo; 1.0-4
.
０％、Ｎｂ．０．１〜０．５５％、Ｔ ｉ ； ０ 、
１〜０．５５％、Ｎ・０．３０〜０ ５５％を含有し
、残部がＦｅおよび不純物元素からなることを要旨とす
る。0%, Nb. 0.1-0.55%, Ti; 0,
1 to 0.55%, N. 0.30 to 0.55%, and the remainder consists of Fe and impurity elements.
また、第１発明の高温強度を改善するため、第２発明は
第１発明にさらに■：０ １〜０．５５％、Ｗ；０．１
〜．０．５５％、Ｔａ；Ｏ 、 １ 〜１ 、０％のう
ち１種以上を含有し、第３発明は第１発明の熱間加工性
を改善するためにさらにＢ ；Ｏ 、ｏ Ｏ Ｏ ５〜
０．０２００％、Ｃａ；０．０００５〜０．０２００％
、Ｍｇ：０ 、０ ０ ０ ５〜０．０２００２；のう
ち１種以上を含有し、第４発明は第１発明の高温強度お
よび熱間加工性を改善するためにさらに、Ｖ．０．１〜
１、０％、Ｗ；０．１ 〜０．５５％、Ｔａ；０ 、
１ 〜１ 、０％のうち１種以上、および１３ ；ｏ
、ｏ Ｏ ０ ５〜０．０２００％、Ｃａ；０．０ ０
０ ５〜０．０ ２ ０ ０％、Ｍｇ：０ 、０ ０
．０ ５〜０．０２００％のうちＩＦ１以上を含有する
ことを要旨とする。In addition, in order to improve the high temperature strength of the first invention, the second invention further adds ■: 0 1 to 0.55%, W; 0.1 to the first invention.
~． 0.55%, Ta; O, 1 to 1, and 0%, and the third invention further contains B; ~
0.0200%, Ca; 0.0005-0.0200%
, Mg: 0, 0 0 0 5 to 0.02002; and the fourth invention further contains V. to improve the high temperature strength and hot workability of the first invention. 0.1~
1, 0%, W; 0.1 to 0.55%, Ta; 0,
1 to 1, one or more of 0%, and 13;o
, o O 0 5-0.0200%, Ca; 0.0 0
05-0.0200%, Mg:0,00
．． The gist is to contain IF1 or more in the range of 0.05 to 0.0200%.
本発明の排気バルブ用鋼では、Ｃ含有量を０゜３０〜０
．６０％に増量し、ＮｂおよびＴｉを０．１〜０．５５
％複合添加したので、これらの炭化物が析出され、高温
強度が向上する。また、Ｎ；およびＣｒの含有量を増加
したので、耐酸化性が改善されている。さらに、■、Ｗ
、Ｔａのうち１種以上を含有することによりさらに高温
強度が改善され、Ｂ、Ｃａ、Ｍ、のうち１種以上を含有
することにより熱間加工性を向上せしめた。In the steel for exhaust valves of the present invention, the C content is 0°30 to 0.
．． Increased amount to 60%, Nb and Ti 0.1 to 0.55
% composite addition, these carbides are precipitated and high temperature strength is improved. Furthermore, since the contents of N; and Cr were increased, oxidation resistance was improved. Furthermore, ■, W
, Ta, the high-temperature strength is further improved, and the inclusion of one or more of B, Ca, and M improves hot workability.
次に本発明の高温特性の優れた排気バルブ用鋼の化学成
分の組成限定の理由について説明する。Next, the reason for limiting the chemical composition of the steel for exhaust valves having excellent high-temperature properties according to the present invention will be explained.
Ｃ；ｏ 、３０〜０．６０％
Ｃは炭化物を形成し鋼の高温強度を確保するために必要
な元素であり、この効果を得るためには少なくとも０．
３０％以上を含有する必要がある。C;o, 30-0.60% C is an element necessary to form carbides and ensure high-temperature strength of steel, and in order to obtain this effect, it must be at least 0.60%.
It is necessary to contain 30% or more.
しかし、０．６０％を越えて含有すると、靭延性を低下
するので、上限を０．６０％とした。However, if the content exceeds 0.60%, the toughness and ductility decreases, so the upper limit was set at 0.60%.
Ｓｉ；０．５５％以下
Ｓｉは製鋼時の脱酸元素として添加されるものであるが
、同時にマトリクスを強化し、耐酸化性にも寄与する。Si: 0.55% or less Si is added as a deoxidizing element during steel manufacturing, but it also strengthens the matrix and contributes to oxidation resistance.
しかし、０．５５％を越えて含有されると、靭性および
延性を低下するので、上限を０．５５％とした。However, if the content exceeds 0.55%, the toughness and ductility decrease, so the upper limit was set at 0.55%.
Ｍｎ；５．０〜１５．０％
ＦＬｎはオーステナイト組織を安定化し、Ｎｉの代替と
なる元素である。また、硫化物系環境での耐食性改善に
必要であり、前記効果を得るためには少なくとも５％以
上含有する必要がある。しかし、１５％以上含有すると
、靭性および延性が低下し、耐酸化性が劣化するので、
上限を１５．０％とした。Mn: 5.0 to 15.0% FLn is an element that stabilizes the austenite structure and serves as a substitute for Ni. Further, it is necessary for improving corrosion resistance in a sulfide-based environment, and in order to obtain the above effect, it is necessary to contain at least 5% or more. However, if the content exceeds 15%, the toughness and ductility will decrease, and the oxidation resistance will deteriorate.
The upper limit was set at 15.0%.
Ｓ、０．０３０％以下
Ｓは鋼の熱同加工性を劣化させる元素であり、０．０３
０％を越えて含有させると、熱間加工性が著しく劣化す
るので、上限を０．０３％とした。S, 0.030% or less S is an element that deteriorates the thermal workability of steel, and 0.03%
If the content exceeds 0%, hot workability will be significantly deteriorated, so the upper limit was set at 0.03%.
なお、良好なる熱同加工性を得るためには、０゜０１５
％以下とすることが望ましい。In addition, in order to obtain good thermal processability, 0°015
% or less.
Ｎ ｉ；８．０〜１５．０％
Ｎｉはオーステナイト相を安定化するために必須の成分
であり、また耐熱性および耐酸化性を確保するために必
要な元素である。前記効果を確保するためには少なくと
も８．０％以上を含有する必要がある。しかし、１５．
０％を越えて含有させてら前記効果が飽和すると共に、
原価が高くなるので、上限を１５．０％とした。Ni; 8.0 to 15.0% Ni is an essential component for stabilizing the austenite phase, and is also an element necessary for ensuring heat resistance and oxidation resistance. In order to ensure the above effect, it is necessary to contain at least 8.0% or more. However, 15.
If the content exceeds 0%, the above effect is saturated, and
Since the cost would be high, the upper limit was set at 15.0%.
Ｃｒ：２０．０〜２５．０％
Ｃ「は耐酸化性を確保するため必要な元素であり、この
効果を得るためには２０．０％以上含有する必要がある
。しかし、２５．０％を越えて含有させると、σ相を生
成し、靭性および延性を低下し、クリープ強度を劣化す
るため、上限を２５゜０％とした。Cr: 20.0-25.0% C is a necessary element to ensure oxidation resistance, and in order to obtain this effect it is necessary to contain 20.0% or more. However, 25.0% If the content exceeds 25%, the σ phase will be generated, the toughness and ductility will be reduced, and the creep strength will be degraded. Therefore, the upper limit was set at 25°0%.
Ｍｏ；０．５５〜４．０％
ＭＯは基地に固溶して固溶強化をもたらすので、強度改
善のため必要な元素である。前記効果を得るためには、
０．５５％以上の含有が必要である。Mo; 0.55 to 4.0% MO is a necessary element for improving strength because it forms a solid solution in the matrix and brings about solid solution strengthening. In order to obtain the above effect,
The content must be 0.55% or more.
しかし、４．０％を越えて含有させても、前記効果が飽
和すると共に、原僅高となり、σ相を生成し易くなるの
で、上限を４．０％とした。However, even if the content exceeds 4.0%, the above-mentioned effect will be saturated, the base will be slightly higher, and the σ phase will be more likely to be generated, so the upper limit was set at 4.0%.
Ｎｂ、０．１〜０．５５％
Ｎｂは炭窒化物を形成し、クリープ強度を向上する元素
であり、０．１％以上含有する必要がある。しかし、０
．５５％を越えて含有させると、靭性および延性を劣化
するので、上限を０．５５％とした。Nb, 0.1 to 0.55% Nb is an element that forms carbonitrides and improves creep strength, and must be contained in an amount of 0.1% or more. However, 0
．． If the content exceeds 55%, toughness and ductility deteriorate, so the upper limit was set at 0.55%.
Ｔｉ；０．１〜１，０％
Ｔ１は炭窒化物を生成し、クリープ強度を向上させるた
め必要な元素であり、前記効果を得るためには０．１％
以上含有させる必要がある。しかし、０．５５％を越え
て含有させると、靭性および延性を低下するので、上限
を０．５５％とした。Ti: 0.1-1.0% T1 is an element necessary to generate carbonitrides and improve creep strength, and in order to obtain the above effect, 0.1% is required.
It is necessary to contain the above amount. However, if the content exceeds 0.55%, the toughness and ductility decrease, so the upper limit was set at 0.55%.
Ｎ ；ｏ 、３０〜０．５５％
Ｎは窒化物を生成し、鋼の強度を確保する元素であり、
この効果を得るためには少なくとも０゜３０％以上を含
有する必要がある。しかし、Ｎのオーステナイト合金に
対する固溶限が０．５５％であるので、上限を０．５５
％とした。N;o, 30-0.55% N is an element that generates nitrides and ensures the strength of steel,
In order to obtain this effect, it is necessary to contain at least 0.30% or more. However, since the solid solubility limit of N in austenite alloy is 0.55%, the upper limit should be set to 0.55%.
%.
■、Ｗ、 Ｔａ；０．１〜０．５５％
ｖ、ＷおよびＴａは炭窒化物を生成し、高温強度を改善
するため、０．１％以上の含有が必要である、しかし、
０．５５％以上含有させても、前記効果が飽和すると共
に、原価高となるため、上限を０．５５％とした。■, W, Ta; 0.1 to 0.55% V, W and Ta form carbonitrides and improve high temperature strength, so they must be contained at 0.1% or more. However,
Even if the content is 0.55% or more, the above effect is saturated and the cost increases, so the upper limit was set at 0.55%.
Ｂ、Ｃａ、Ｍｇ；０．０００５〜０．０２００％Ｂ、Ｃ
ａおよびＭｇは熱間加工性を改善するため、必要な元素
で、この効果を得るためには０．０００５％以上含有す
る必要がある。しかし、０．０２００％を越えて含有さ
せても、却って熱間加工性を劣化させるので、上限を０
．０２００％とした。B, Ca, Mg; 0.0005-0.0200% B, C
A and Mg are necessary elements to improve hot workability, and in order to obtain this effect, they must be contained in an amount of 0.0005% or more. However, even if the content exceeds 0.0200%, the hot workability will deteriorate, so the upper limit should be set to 0.0200%.
．． 0200%.
［実施例］
本発明の実施例を比較例および従来例と比較しつつ説明
し、本発明の特徴を明らかにする。[Example] Examples of the present invention will be explained while comparing with comparative examples and conventional examples, and the characteristics of the present invention will be clarified.
第１表に示す化学成分からなる本発明鋼、比較鋼および
従来鋼を電気炉にて溶製した。第１表において、Ａ〜Ｐ
鋼は本発明例であって、Ａ〜Ｄ鋼は第１発明、Ｅ〜Ｈ鋼
は第２発明、ｌ〜Ｌ鋼は第３発明、Ｍ−Ｐ鋼は第４発明
である。Ｑ〜Ｔ鋼は比較鋼であって、Ｑ鋼はＣ含有量が
本発明の組成範囲より低い比較鋼、Ｒ鋼はＴｉを含有し
ない比較鋼、Ｓ鋼はＮｂおよびＴｉ含有量が本発明の組
成範囲より多い比較鋼、Ｔ鋼はＳ含有量が本発明の組成
範囲より多い比較鋼である。また、Ｕ鋼は特開昭６０−
７７９６４号公報の発明に相当する成分の従来鋼、■鋼
は５ＵＨ３５に相当する成分の従来鋼である。Steels of the present invention, comparative steels, and conventional steels having the chemical components shown in Table 1 were melted in an electric furnace. In Table 1, A to P
The steels are examples of the present invention, and the A to D steels are the first invention, the E to H steels are the second invention, the L to L steels are the third invention, and the MP steel is the fourth invention. Q to T steels are comparative steels, Q steel is a comparative steel whose C content is lower than the composition range of the present invention, R steel is a comparative steel that does not contain Ti, and S steel is a comparative steel whose Nb and Ti contents are lower than the composition range of the present invention. Comparative steel and T steel are comparative steels in which the S content is higher than the composition range of the present invention. In addition, U steel is JP-A-60-
Conventional steel whose composition corresponds to the invention of Publication No. 77964, (2) Steel is a conventional steel whose composition corresponds to 5UH35.
（以下余白）
第１表に示す各鋼について鍛造後１１００℃で４５分間
固溶化熱処理を施したのち水冷し、ついで７５０℃で４
時間時効処理を施した。続いて、各鋼について、高温引
張強さ、クリープ強度、高温疲労強度、熱間加工性およ
び耐酸化性について測定した。(Left below) For each steel shown in Table 1, after forging, it was subjected to solution heat treatment at 1100℃ for 45 minutes, water-cooled, and then heated to 750℃ for 45 minutes.
Time aging treatment was applied. Subsequently, each steel was measured for high temperature tensile strength, creep strength, high temperature fatigue strength, hot workability, and oxidation resistance.
高温引張強さについては、平行部直径５−転平行部長さ
２５ｍｍの試験片を用いて９００℃において引張強さを
測定した。Regarding high-temperature tensile strength, the tensile strength was measured at 900°C using a test piece with a parallel part diameter of 5 mm and a parallel part length of 25 mm.
クリープ試験は直径６鋤−の試験片を用い試験温度８５
０℃、１００時間のクリープ強度を測定した。The creep test was conducted using a test piece with a diameter of 6 plows at a test temperature of 85
Creep strength was measured at 0°C for 100 hours.
高温疲労強度については、小野式回転曲げ試験機を用い
、８５０℃における疲れ限度を測定した。Regarding high temperature fatigue strength, the fatigue limit at 850° C. was measured using an Ono rotary bending tester.
熱間加工性については、１０５０℃でグリ−プルによっ
て引張試験を行い、その絞り値を測定した。Regarding hot workability, a tensile test was conducted using a Greeple at 1050°C, and the area of area was measured.
耐酸化試験は、試料を大気中で９００℃で１００時間保
持した後の酸化増量を測定するものである。The oxidation resistance test measures the oxidation weight gain after holding the sample at 900° C. for 100 hours in the atmosphere.
得られた結果は第２表に併せて示した。The obtained results are also shown in Table 2.
（以下余白）
第
表
第２表から知られるように、比較例であるＱ鋼はＣ含有
量が本発明の組成範囲より低いので、高温引張強さが１
７ 、７ ｋｇｒ／ ａｍ２、クリープ限度が４．４ｋ
ｇ４／＋ｕｉ’、高温疲労強度が１３．９ｋｇｆ／−輪
部であって、高温強度において劣り、比較例であるＲ鋼
はＴｉを含有しないので、高温引張強さが１７．４ ｋ
ｇｆ／ ｍｕ２、クリープ限度が４．３ｋｇｆ／ｍｓ＋
”、高温疲労強度が１３．８ｋｇｆ／ｍｍ２であって、
同様に高温強度において劣る。また、比較例であるＳ鋼
はＮｂおよびＴｉを本発明の組成範囲より多く含有し、
Ｔ鋼はＳ含有量が多いので、高温特性においては優れて
いるものの、熱間加工性において劣る。(Left below) As is known from Table 2, Q steel, which is a comparative example, has a C content lower than the composition range of the present invention, so its high temperature tensile strength is 1.
7,7 kgr/am2, creep limit 4.4k
g4/+ui', the high-temperature fatigue strength is 13.9 kgf/-ring, which is inferior in high-temperature strength, and the comparative example R steel does not contain Ti, so the high-temperature tensile strength is 17.4 k
gf/mu2, creep limit is 4.3kgf/ms+
”, high temperature fatigue strength is 13.8 kgf/mm2,
Similarly, it is inferior in high temperature strength. In addition, S steel, which is a comparative example, contains more Nb and Ti than the composition range of the present invention,
Since T steel has a high S content, it has excellent high-temperature properties but is inferior in hot workability.
一方、従来鋼であるＵ鋼は、高温引張強さが１９．１に
ビｒ／ｍｍ”、クリープ限度が４．８ｋｇｆ／鶴−２、
高温疲労強度が１７．６ｋｇｆ／１１ｍ２、酸化腐食増
量が０ 、５１１１１１／ ｃｍ”といずれも満足すべ
きものではなく、従来鋼であるｖ鋼は高温引張強さが１
８゜２ｋｇｆ／ａｍ”、り’）−７’ｆｌ１度ｈ’４．
６ｋｇｆ／ａｍ”、高温疲労強度が１４．５ｋｇｆ／ａ
ｍ”、酸化腐食増量が０．６５−ｇ／ａｓ”であり、Ｖ
鋼も同様に満足し得るものでない。On the other hand, U steel, which is a conventional steel, has a high temperature tensile strength of 19.1 Bir/mm", a creep limit of 4.8 kgf/Tsuru-2,
The high temperature fatigue strength is 17.6 kgf/11 m2, the oxidation corrosion increase is 0, 511111/cm'', which are not satisfactory, and the conventional steel V steel has a high temperature tensile strength of 1.
8゜2kgf/am'', ri')-7'fl1 degree h'4.
6kgf/am”, high temperature fatigue strength is 14.5kgf/a
m", the oxidation corrosion increase is 0.65-g/as", and V
Steel is similarly unsatisfactory.
これに対して、本発明鋼であるＡ−Ｐ鋼は′Ｉ！＆温引
張強さが２５．３ｋｇｆ／ａｍ”以上、クリープ限度が
６．３ｋｇｆ／＋ｕｓ２以上、高温疲労強度が１８．２
に＆ｆ／ａｍ”以上、酸化腐食増量が０．４７ｍＢ／ａ
ｍ’以下であって、高温特性および耐酸化性共に比較鋼
および従来鋼に優り、排気バルブ鋼として所望の優れた
高温特性および耐酸化性を有すると共に、熱間加工性も
従来鋼よりも優れていることが確認された。On the other hand, the A-P steel, which is the steel of the present invention, has 'I! & Warm tensile strength is 25.3 kgf/am” or more, creep limit is 6.3 kgf/+us2 or more, high temperature fatigue strength is 18.2
&f/am” or more, oxidation corrosion increase is 0.47mB/a
m' or less, and is superior to comparative steels and conventional steels in both high temperature properties and oxidation resistance.It has excellent high temperature properties and oxidation resistance desired as an exhaust valve steel, and also has better hot workability than conventional steels. It was confirmed that
［発明の効果］
本発明の排気バルブ用鋼は、以上説明したように、Ｃ含
有量を増量し、ＮｂおよびＴｉを複合添加したので、こ
れらの炭化物が析出され、高温強度が著しく改善された
。また、ＮｉおよびＣｒの含有量を増加により、耐酸化
性が改善され、Ｖ、Ｗ、Ｔａの添加によりさらに高温強
度が改善され、Ｃａ、Ｍ、およびＢの添加に上り熱間加
工性を向上せしめた。そのため、本発明鋼では、９００
℃における引張強度が２５ｋｇｆ／ａｍ”以上、８５０
℃における１００時間のクリープ限度が６ ｋｇｆｌ
ａ−’以上、８５０℃における１０７回疲労強度が１８
ｋｇｆ／−一２以上であって、さらに熱間加工性および
耐酸化性に優れ、内燃機関の排気バルブ用材料として極
めて有用である。[Effects of the Invention] As explained above, in the steel for exhaust valves of the present invention, the C content is increased and Nb and Ti are added in combination, so these carbides are precipitated and the high temperature strength is significantly improved. . In addition, increasing the content of Ni and Cr improves oxidation resistance, adding V, W, and Ta further improves high-temperature strength, and adding Ca, M, and B improves hot workability. I forced it. Therefore, in the steel of the present invention, 900
Tensile strength at °C is 25 kgf/am" or more, 850
100 hour creep limit at ℃ is 6 kgfl
a-' or more, 107 times fatigue strength at 850°C is 18
kgf/-12 or more, has excellent hot workability and oxidation resistance, and is extremely useful as a material for exhaust valves of internal combustion engines.
Claims (4)
０％以下、Ｍｎ；５．０〜１５．０％、Ｓ；０．０３％
以下、Ｎｉ；８．０〜１５．０％、Ｃｒ；２０．０〜２
５．０％、Ｍｏ；１．０〜４．０％、Ｎｂ；０．１〜１
．０％、Ｔｉ；０．１〜１．０％、Ｎ；０．３０〜０．
５５％を含有し、残部がＦｅおよび不純物元素からなる
ことを特徴とする高温特性の優れた排気バルブ用鋼。(1) Weight ratio of C: 0.30 to 0.60%, Si: 1.
0% or less, Mn; 5.0-15.0%, S; 0.03%
Below, Ni; 8.0-15.0%, Cr; 20.0-2
5.0%, Mo; 1.0-4.0%, Nb; 0.1-1
．． 0%, Ti: 0.1-1.0%, N: 0.30-0.
A steel for exhaust valves with excellent high-temperature properties, characterized by containing 55% Fe and the remainder consisting of Fe and impurity elements.
０％以下、Ｍｎ；５．０〜１５．０％、Ｓ；０．０３％
以下、Ｎｉ；８．０〜１５．０％、Ｃｒ；２０．０〜２
５．０％、Ｍｏ；１．０〜４．０％、Ｎｂ；０．１〜１
．０％、Ｔｉ；０．１〜１．０％、Ｎ；０．３０〜０．
５５％と、Ｖ；０．１〜１．０％、Ｗ；０．１〜１．０
％、Ｔａ；０．１〜１．０％のうち１種以上を含有し、
残部がＦｅおよび不純物元素からなることを特徴とする
高温特性の優れた排気バルブ用鋼。(2) Weight ratio of C: 0.30 to 0.60%, Si: 1.
0% or less, Mn; 5.0-15.0%, S; 0.03%
Below, Ni; 8.0-15.0%, Cr; 20.0-2
5.0%, Mo; 1.0-4.0%, Nb; 0.1-1
．． 0%, Ti: 0.1-1.0%, N: 0.30-0.
55%, V; 0.1-1.0%, W; 0.1-1.0
%, Ta; contains one or more of 0.1 to 1.0%,
A steel for exhaust valves with excellent high-temperature properties, characterized in that the remainder consists of Fe and impurity elements.
０％以下、Ｍｎ；５．０〜１５．０％、Ｓ；０．０３％
以下、Ｎｉ；８．０〜１５．０％、Ｃｒ；２０．０〜２
５．０％、Ｍｏ；１．０〜４．０％、Ｎｂ；０．１〜１
．０％、Ｔｉ；０．１〜１．０％、Ｎ；０．３０〜０．
５５％と、Ｂ；０．０００５〜０．０２００％、Ｃａ；
０．０００５〜０．０２００％、Ｍｇ；０．０００５〜
０．０２００％のうち１種以上を含有し、残部がＦｅお
よび不純物元素からなることを特徴とする高温特性の優
れた排気バルブ用鋼。(3) Weight ratio of C: 0.30 to 0.60%, Si: 1.
0% or less, Mn; 5.0-15.0%, S; 0.03%
Below, Ni; 8.0-15.0%, Cr; 20.0-2
5.0%, Mo; 1.0-4.0%, Nb; 0.1-1
．． 0%, Ti: 0.1-1.0%, N: 0.30-0.
55%, B; 0.0005-0.0200%, Ca;
0.0005~0.0200%, Mg; 0.0005~
A steel for exhaust valves with excellent high-temperature properties, characterized by containing one or more of 0.0200% and the remainder consisting of Fe and impurity elements.
０％以下、Ｍｎ；５．０〜１５．０％、Ｓ；０．０３％
以下、Ｎｉ；８．０〜１５．０％、Ｃｒ；２０．０〜２
５．０％、Ｍｏ；１．０〜４．０％、Ｎｂ；０．１〜１
．０％、Ｔｉ；０．１〜１．０％、Ｎ；０．３０〜０．
５５％と、Ｖ；０．１〜１．０％、Ｗ；０．１〜１．０
％、Ｔａ；０．１〜１．０％のうち１種以上を含有し、
さらにＢ；０．０００５〜０．０２００％、Ｃａ；０．
０００５〜０．０２００％、Ｍｇ；０．０００５〜０．
０２００％のうち１種以上を含有し、残部がＦｅおよび
不純物元素からなることを特徴とする高温特性の優れた
排気バルブ用鋼。(4) Weight ratio of C: 0.30 to 0.60%, Si: 1.
0% or less, Mn; 5.0-15.0%, S; 0.03%
Below, Ni; 8.0-15.0%, Cr; 20.0-2
5.0%, Mo; 1.0-4.0%, Nb; 0.1-1
．． 0%, Ti: 0.1-1.0%, N: 0.30-0.
55%, V; 0.1-1.0%, W; 0.1-1.0
%, Ta; contains one or more of 0.1 to 1.0%,
Furthermore, B; 0.0005 to 0.0200%, Ca; 0.
0005-0.0200%, Mg; 0.0005-0.
A steel for exhaust valves having excellent high-temperature properties, characterized in that it contains one or more of 0.0200% and the remainder consisting of Fe and impurity elements.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8668390A JPH03285050A (en) | 1990-03-30 | 1990-03-30 | Exhaust valve steel excellent in high temperature characteristic |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8668390A JPH03285050A (en) | 1990-03-30 | 1990-03-30 | Exhaust valve steel excellent in high temperature characteristic |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03285050A true JPH03285050A (en) | 1991-12-16 |
Family
ID=13893807
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8668390A Pending JPH03285050A (en) | 1990-03-30 | 1990-03-30 | Exhaust valve steel excellent in high temperature characteristic |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03285050A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002294411A (en) * | 2001-03-29 | 2002-10-09 | Tohoku Tokushuko Kk | Steel for exhaust vale high in high-temperature strength and superior in resistances to corrosion and abrasion |
| US20110236247A1 (en) * | 2010-03-25 | 2011-09-29 | Daido Tokushuko Kabushiki Kaisha | Heat resistant steel for exhaust valve |
| WO2013027841A1 (en) * | 2011-08-24 | 2013-02-28 | 大同特殊鋼株式会社 | Heat-resisting steel for exhaust valves |
| JP2022522092A (en) * | 2018-12-20 | 2022-04-14 | フェストアルピネ・ベーラー・エーデルシュタール・ゲー・エム・ベー・ハー・ウント・コー・カー・ゲー | Super austenitic material |
-
1990
- 1990-03-30 JP JP8668390A patent/JPH03285050A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002294411A (en) * | 2001-03-29 | 2002-10-09 | Tohoku Tokushuko Kk | Steel for exhaust vale high in high-temperature strength and superior in resistances to corrosion and abrasion |
| US20110236247A1 (en) * | 2010-03-25 | 2011-09-29 | Daido Tokushuko Kabushiki Kaisha | Heat resistant steel for exhaust valve |
| WO2013027841A1 (en) * | 2011-08-24 | 2013-02-28 | 大同特殊鋼株式会社 | Heat-resisting steel for exhaust valves |
| US9745649B2 (en) | 2011-08-24 | 2017-08-29 | Daido Steel Co., Ltd. | Heat-resisting steel for exhaust valves |
| JP2022522092A (en) * | 2018-12-20 | 2022-04-14 | フェストアルピネ・ベーラー・エーデルシュタール・ゲー・エム・ベー・ハー・ウント・コー・カー・ゲー | Super austenitic material |
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