JPH0483849A - Soft nitriding steel - Google Patents
Soft nitriding steelInfo
- Publication number
- JPH0483849A JPH0483849A JP19987490A JP19987490A JPH0483849A JP H0483849 A JPH0483849 A JP H0483849A JP 19987490 A JP19987490 A JP 19987490A JP 19987490 A JP19987490 A JP 19987490A JP H0483849 A JPH0483849 A JP H0483849A
- Authority
- JP
- Japan
- Prior art keywords
- weight
- steel
- soft nitriding
- less
- soft
- 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
- 238000005121 nitriding Methods 0.000 title claims abstract description 44
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 42
- 239000010959 steel Substances 0.000 title claims abstract description 42
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 229910052742 iron Inorganic materials 0.000 claims abstract description 4
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 3
- 238000005452 bending Methods 0.000 abstract description 20
- 229910052799 carbon Inorganic materials 0.000 abstract description 4
- 229910052748 manganese Inorganic materials 0.000 abstract description 4
- 229910052804 chromium Inorganic materials 0.000 abstract description 3
- 229910052802 copper Inorganic materials 0.000 abstract description 3
- 229910052745 lead Inorganic materials 0.000 abstract description 3
- 229910052750 molybdenum Inorganic materials 0.000 abstract description 3
- 229910052710 silicon Inorganic materials 0.000 abstract description 3
- 229910052782 aluminium Inorganic materials 0.000 abstract 2
- 230000007423 decrease Effects 0.000 description 10
- 239000010410 layer Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 229910000975 Carbon steel Inorganic materials 0.000 description 3
- 239000010962 carbon steel Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005242 forging Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000009661 fatigue test Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007730 finishing process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Landscapes
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、特に自動車のクランクシャフト用材料として
好適な軟窒化用鋼に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a steel for soft nitriding, which is particularly suitable as a material for automobile crankshafts.
（従来の技術）
自動車のクランクシャフトは、機械構造用炭素鋼を鍛造
などの方法により所定形状に加工した後、主に疲労強度
の向上を目的として軟窒化処理により表面を硬化させて
製造されることも多い。(Conventional technology) Automotive crankshafts are manufactured by processing carbon steel for mechanical structures into a predetermined shape using methods such as forging, and then hardening the surface through nitrocarburizing treatment, primarily to improve fatigue strength. Often.
従来、このような用途には、ＪＩＳ−３４５Ｃ（０，４
５Ｃ−０，７５Ｍｎ）やＪ Ｉ Ｓ−８４８Ｃ（０，４
８ＣＯ，７５Ｍｎ）などの機械構造用炭素鋼が用いられ
ていた。Conventionally, JIS-345C (0,4
5C-0,75Mn) and JIS-848C (0,4
Carbon steel for mechanical structures such as 8CO, 75Mn) was used.
しかし、これらの鋼は、軟窒化処理後の有効硬化深度（
微小ビッカース硬さＨｖ＝３００に対応する表面からの
距離）が０．１０ｍｍ程度と浅く、表面硬さ（表面下２
５μｍでの微小ビッカース硬さ）もＨｖ＝４００程度と
硬くないためにクランクシャフトとして適用した場合に
は疲労強度の点て十分ではなく、高出力のエンジンには
利用できなかった。However, these steels have a low effective hardening depth (
The distance from the surface corresponding to minute Vickers hardness Hv = 300) is shallow at about 0.10 mm, and the surface hardness (distance from the surface corresponding to the
The microscopic Vickers hardness at 5 μm) is not so hard as Hv=400, so when used as a crankshaft, the fatigue strength was insufficient, and it could not be used for high-output engines.
そこで、より高い疲労強度が要求される場合には、窒化
物形成元素であるＡＩ及びＣｒを多量に添加したＪＩＳ
−ＳＡＣＭ ６４５（０，４５ＣＯ，４Ｓｉ−１，５
０ｒ−０，２Ｍｏ−１，０Ａｌ）や炭素鋼にＶを添加し
た鋼（０，４５Ｃ−０，７５Ｍｎ０．ｌ０Ｖ）か用いら
れていた。Therefore, when higher fatigue strength is required, JIS
-SACM 645 (0,45CO,4Si-1,5
0r-0,2Mo-1,0Al) and carbon steel with V added (0,45C-0,75Mn0.10V) were used.
（発明が解決しようとする課題）
このようにＪＩＳ−３ＡＣＭ ６４５等の従来の軟窒
化用鋼は、ＡＣＣｒ、Ｖ等の窒化物形成元素を含んでお
り、表層の硬化が顕著であるため疲労強度の向上の要請
にはある程度満足できるものの、クランクシャフト用材
料として適用する場合には、次のような新たな問題かあ
る。(Problems to be Solved by the Invention) As described above, conventional steels for soft nitriding such as JIS-3ACM 645 contain nitride-forming elements such as ACCr and V, and the hardening of the surface layer is significant, resulting in fatigue strength. Although it satisfies the demand for improvement to some extent, when applied as a material for crankshafts, the following new problems arise.
軟窒化用鋼によりクランクシャフトを製造する場合には
、通常、クランクシャフト形状に加工し、軟窒化処理し
た後、仕上げ工程において途中の製造工程で生した曲が
りを矯正処理する。しかし、上記したような従来の軟窒
化用鋼では、窒化層か高硬度であるため曲げ矯正処理時
にクランクシャフト表面の窒化層に割れが生しる（即ち
、曲げ矯正性か悪い）という問題かある。When manufacturing a crankshaft using steel for nitrocarburizing, the crankshaft is usually processed into a shape, subjected to nitrocarburizing treatment, and then, in a finishing process, the bending caused during the manufacturing process is corrected. However, with the conventional steel for soft nitriding as described above, since the nitrided layer is highly hard, there is a problem that cracks occur in the nitrided layer on the crankshaft surface during bending straightening treatment (i.e., the bending straightening properties are poor). be.
このように従来の軟窒化用鋼には、疲労強度向上のため
に軟窒化処理をした場合に曲げ矯正性か低下してしまい
、自動車のクランクシャフト材料として不適当であると
いう問題がある。As described above, conventional steel for nitrocarburizing has a problem in that when subjected to nitrocarburizing treatment to improve fatigue strength, the bending straightening property deteriorates, making it unsuitable as a material for automobile crankshafts.
そこで本発明は上記問題点を解決し、疲労強度向上の目
的で軟窒化処理した場合であっても、曲げ矯正が容易で
、かつ曲げ矯正時に窒化層に割れ等が生じることかない
（即ち、曲げ矯正性が優れている）軟窒化用鋼を提供す
ることを目的とする。Therefore, the present invention solves the above problems, and even when soft nitriding is performed for the purpose of improving fatigue strength, bending straightening is easy, and cracks do not occur in the nitrided layer during bending straightening (i.e., bending The purpose of the present invention is to provide a steel for nitrocarburizing (with excellent straightening properties).
（課題を解決するための手段及び作用）上記の問題点を
解決するため鋭意検討を行った結果、Ｓｉの増加は軟窒
化処理後の表面硬さや硬化深さを低下させることが分か
った。従って、Ｓｉは、疲労強度は若干低下させるもの
の、曲げ矯正性の改善には非常に有効な元素であるとい
える。(Means and effects for solving the problem) As a result of intensive studies to solve the above problems, it was found that an increase in Si reduces the surface hardness and hardening depth after soft-nitriding treatment. Therefore, it can be said that Si is a very effective element for improving bending straightening properties, although it slightly reduces fatigue strength.
そして、このようなＳｉの増加による疲労強度の低下は
、Ｃ及び窒化物を形成しない元素であるＭｎの増加によ
る小部硬さの向上により、補完できることか判明した。It has also been found that such a decrease in fatigue strength due to an increase in Si can be compensated for by improving small part hardness due to an increase in C and Mn, which is an element that does not form nitrides.
特に、Ｍｎは、窒化層の靭性を向上させることにより、
曲げ矯正性の改善にも有効であることも分かった。以上
の知見に基づき、従来にはない高Ｓｉ−高Ｍｎタイプの
軟窒化用鋼を開発するに至った。In particular, Mn improves the toughness of the nitride layer,
It was also found to be effective in improving bend straightening properties. Based on the above findings, we have developed an unprecedented high-Si-high-Mn type steel for soft nitriding.
本発明は、Ｃ：０．３５〜０．６５重量％、ｓｌ：０、
３５〜２． Ｏ０重量％、Ｍｎ ： ０．８０〜２．５
０重量％、Ｃｒ：０．２０重量％以下及びＡ Ｉ！ ：
０．０３５重量％以下を含有し、残部がＦｅ及び不可
避的不純物からなることを特徴とする軟窒化用鋼（以下
「第１の軟窒化用鋼」という）を提供する。The present invention has C: 0.35 to 0.65% by weight, sl: 0,
35-2. O0% by weight, Mn: 0.80-2.5
0% by weight, Cr: 0.20% by weight or less and AI! :
Provided is a steel for soft nitriding (hereinafter referred to as "first steel for soft nitriding") characterized in that it contains 0.035% by weight or less, and the remainder consists of Fe and unavoidable impurities.
また、本発明は、第１の軟窒化用鋼に、更にＮｉ：３．
０重量％以下、Ｃｕ：１．０重量％以下及びＭ。Further, the present invention further provides the first steel for soft nitriding with Ni: 3.
0% by weight or less, Cu: 1.0% by weight or less, and M.
０．５重量％以下からなる群より選ばれる１種以上を含
有させた軟窒化用鋼（以下「第２の軟窒化用鋼」という
）
第１の軟窒化用鋼に、更にＰｂ：０．０３〜０．３５重
量％、Ｃａ ： ０．００１０〜０．０１００重量％及
びＳ：０．０４〜０．１３重量％からなる群より選ばれ
る１種以上を含有させた軟窒化用鋼：第１の軟窒化用鋼
に、更にＢをｏ、 ｏ ｏ ｓ ｏ重量％以下含有させ
た軟窒化用鋼：
第２の軟窒化用鋼に、更にＢを０．００８０重量％以下
含有させた軟窒化用鋼
第２の軟窒化用鋼に、更にＰｂ：０．０３〜０．３５重
量％、Ｃａ：Ｏ，０Ｏ１０〜０．０１００重量％及びＳ
： ０．０４〜０．１３重量％からなる群より選ばれ
る１種以上を含有させた軟窒化用鋼（以下「第３の軟窒
化用鋼」という）：並びに
第３の軟窒化用鋼に、更にＢを０．００８０重量％以下
含有させた軟窒化用鋼、を提供する。A steel for soft nitriding containing one or more types selected from the group consisting of 0.5% by weight or less (hereinafter referred to as "second steel for soft nitriding"). Steel for soft nitriding containing one or more selected from the group consisting of 03 to 0.35% by weight, Ca: 0.0010 to 0.0100% by weight, and S: 0.04 to 0.13% by weight: No. A steel for soft nitriding in which the first steel for soft nitriding further contains not more than 0.0080% by weight of B in the second steel for soft nitriding. Nitriding steel The second soft nitriding steel further contains Pb: 0.03 to 0.35% by weight, Ca: O, 0O10 to 0.0100% by weight, and S.
: Steel for soft nitriding containing one or more types selected from the group consisting of 0.04 to 0.13% by weight (hereinafter referred to as "third steel for soft nitriding"): and the third steel for soft nitriding The present invention also provides a steel for soft nitriding which further contains 0.0080% by weight or less of B.
本発明の軟窒化用鋼を構成する元素の組成を、上記の範
囲内に限定した理由は以下のとおりである。The reason why the composition of the elements constituting the steel for nitrocarburizing of the present invention is limited to within the above range is as follows.
Ｃは、Ｓｉの増加により低下した疲労強度を補うために
重要な元素である。Ｃの含有量を０．３５〜０．６５重
量％としたのは、０．３５重量％未満であると芯部硬さ
が低下し、全体の強度が低下するためてあり、０．６５
重量％を超えると靭性や加工性か低下するためである。C is an important element for compensating for fatigue strength decreased due to increase in Si. The reason for setting the C content to 0.35 to 0.65% by weight is that if it is less than 0.35% by weight, the core hardness will decrease and the overall strength will decrease.
This is because if it exceeds the weight percentage, toughness and workability will deteriorate.
好ましいＣの含有量は０．４５〜０．５８重量％である
。The preferred C content is 0.45 to 0.58% by weight.
Ｓｉは曲げ矯正性を確保するために重要な元素である。Si is an important element for ensuring bending straightening properties.
Ｓｌの含有量を０．３５〜２．００重量％としたのは、
０．３５重量％未満であると軟窒化処理後の曲げ矯正性
が悪く、２．００重量％を超えると疲労強度の低下が著
しく、また、靭性や加工性も低下するためである。好ま
しいＳｉの含有量は０．３５〜１．００重量％である。The reason for setting the Sl content to 0.35 to 2.00% by weight is because
If it is less than 0.35% by weight, the bending straightening properties after soft-nitriding treatment will be poor, and if it exceeds 2.00% by weight, the fatigue strength will be significantly lowered, and the toughness and workability will also be lowered. The preferred Si content is 0.35 to 1.00% by weight.
ＭｎはＳｉの増加により低下した疲労強度を補うために
重要な元素である。Ｍｎの含有量を０．８０〜２．５０
重量％とじたのは、０．８０重量％未満であると芯部硬
度や靭性が低下するためであり、２．５０重量％を超
えると加工性か低下するためである。Mn is an important element for compensating for fatigue strength decreased due to increase in Si. Mn content 0.80-2.50
The reason for limiting the weight percentage is that if it is less than 0.80 weight%, the core hardness and toughness will decrease, and if it exceeds 2.50 weight%.
This is because processability decreases if the temperature is increased.
好ましいＭｎの含有量は１．２０〜１．６０重量％であ
る。The preferred Mn content is 1.20 to 1.60% by weight.
Ｃｒの含有量を０．２０重量％以下としたのは、Ｃｒは
軟窒化処理時において侵入Ｎと結合し、表面硬さを高め
、硬化深さを大きくし疲労強度を向上させるという利点
かあるものの、０．２０重量♀６を超えて添加すると曲
げ矯正性の低下か著しいためである。好ましいＣｒの含
有量は０．１５重量％以下である。The reason why the Cr content is set to 0.20% by weight or less is that Cr combines with intruding N during soft-nitriding treatment, increases surface hardness, increases hardening depth, and improves fatigue strength. However, if it is added in an amount exceeding 0.20 wt.♀6, the bending straightening properties will be significantly reduced. The preferred Cr content is 0.15% by weight or less.
Ａｊ２の含有量を０．０３５重量％以下としたのはＣｒ
と同様の理由である。なお、Ａｌは溶融時において脱酸
剤としても作用する成分である。好ましいＡｌの含有量
は０．０２０重量％以下である。The content of Aj2 was set to 0.035% by weight or less because of Cr.
This is for the same reason. Note that Al is a component that also acts as a deoxidizing agent during melting. The preferred Al content is 0.020% by weight or less.
Ｎｉ、Ｃｕ及びＭｏは、軟窒化処理時において侵入Ｎと
結合することがないため、その添加により曲げ矯正性が
低下することはなく、一方で固溶強化により強度を向上
させる。Since Ni, Cu, and Mo do not combine with intruding N during the soft-nitriding treatment, their addition does not reduce bending straightening properties, and on the other hand, improves strength through solid solution strengthening.
Ｎｉの含有量を３．０重量％以下とし、Ｃｕの含有量を
１．０重量％以下とし、Ｍｏの含有量を０．５重量％以
下としたのは、いずれの元素も含有量の上限を超えると
加工性が低下するためである。好ましい含有量はＮｉが
１．５０重量％以下、Ｃｕか０．５０重量％以下、％ｉ
ｏか０．５０重量％以下である。The reason why the Ni content is 3.0% by weight or less, the Cu content is 1.0% by weight or less, and the Mo content is 0.5% by weight or less is because all of the elements have the upper limit of content. This is because if it exceeds this, workability will decrease. The preferable content is Ni: 1.50% by weight or less, Cu: 0.50% by weight or less, %i
0.50% by weight or less.
Ｐｂ、Ｃａ及びＳは、軟窒化処理時において侵入Ｎと結
合することかないため、その添加により曲げ矯正性が低
下することはなく、一方で軟窒化処理前の鋼に快削性を
付与する。また、Ｐｂは、軟窒化特性を低下させ、曲げ
矯正性を向上させる。Since Pb, Ca, and S do not combine with intruding N during soft-nitriding, their addition does not reduce bend straightening properties, and on the other hand, imparts free machinability to the steel before soft-nitriding. Furthermore, Pb reduces soft-nitriding properties and improves bend straightening properties.
Ｐｂの含有量を０．０３〜０．３５重量％としたのは、
０．０３重量％未満であると快削性が低下し、０．３５
重量％を超えると強度及び靭性か低下するためである。The Pb content was set to 0.03 to 0.35% by weight because
If it is less than 0.03% by weight, free machinability will decrease, and 0.35
This is because if the content exceeds % by weight, the strength and toughness will decrease.
好ましいＰｂの含有量は０．１５〜０．３０重量％であ
る。The preferred Pb content is 0.15 to 0.30% by weight.
Ｃａの含有量を０．００１０〜０．０１００重量％とじ
たのは、０．００１０重量％未満であると快削性が低下
し、０．０１００重量％を超えて添加することは鋼の溶
製上困難だからである。好ましいＣａの含有量は０．０
００５〜０．００２５重量％である。The reason why the Ca content is set at 0.0010 to 0.0100% by weight is that if it is less than 0.0010% by weight, the free machinability will deteriorate, and if it is added in excess of 0.0100% by weight, it will cause the steel to melt. This is because it is difficult to manufacture. The preferred Ca content is 0.0
005 to 0.0025% by weight.
Ｓの含有量を０．０４〜０．１３重量％とじたのは、０
．０４重量％未満であると快削性が低下し、０．１３重
量％を超えると強度及び靭性が低下するためである。好
ましいＳの含有量は０．０４〜０．０７重量％である。The content of S is 0.04 to 0.13% by weight.
．． This is because if it is less than 0.04% by weight, free machinability will decrease, and if it exceeds 0.13% by weight, strength and toughness will decrease. The preferred S content is 0.04 to 0.07% by weight.
Ｂは、軟窒化処理時に侵入Ｎと結合してＢＮとなるが、
ＢＮは硬度が低いので却って軟窒化特性か向上し、曲げ
矯正性が低下することはない。また、Ｂを所定量含有さ
せると焼入後の芯部硬さを向上させることかでき、特に
太物部品にした場合の強度向上に有効である。B combines with intruded N during soft-nitriding treatment to form BN,
Since BN has low hardness, the nitrocarburizing properties are improved, and the bend straightening properties are not deteriorated. Furthermore, by containing a predetermined amount of B, the core hardness after quenching can be improved, and this is particularly effective in improving the strength of thick parts.
Ｂの含有量を０．０ Ｏ８０重量％以下としたのは、０
、００８０重量％を超えて添加しても、増量したことに
よる効果の向上はなく、製造コストの上昇を招（だけだ
からである。好ましいＢの含有量は０、００４０重量％
以下である。The reason why the content of B is 0.0 O is 80% by weight or less.
, 0.0080% by weight or more, the increased amount does not improve the effect and only increases the manufacturing cost. The preferred content of B is 0.0040% by weight.
It is as follows.
（実施例）
実施例１〜１９及び比較例１〜８
第１表に示す組成の各元素を含有し、残部が鉄と不可避
的不純物からなる軟窒゛化用鋼材料（比較例１はＪＩＳ
−８４８Ｃ，比較例２はＪＩＳ−３ＡＣＭ６４５である
）を、小型真空溶解炉により溶製して、各々５０ｋｇの
棒状のインゴットを得た。(Example) Examples 1 to 19 and Comparative Examples 1 to 8 A steel material for soft nitriding containing each element of the composition shown in Table 1, with the balance being iron and unavoidable impurities (Comparative Example 1 is a JIS
-848C and JIS-3ACM645 in Comparative Example 2) were melted in a small vacuum melting furnace to obtain rod-shaped ingots each weighing 50 kg.
次に、このインゴットを、１２００℃の温度下、第１段
の鍛造で直径７０ｃｍの丸棒にし、更に同温度下、第２
段の鍛造で直径２０ｃｍの丸棒にした。Next, this ingot is forged into a round bar with a diameter of 70 cm at a first stage of forging at a temperature of 1200°C, and then at a second stage at the same temperature.
It was made into a round bar with a diameter of 20 cm by step forging.
その後、前記丸棒を８７０°Ｃで２時間加熱し、空冷す
る焼きならし処理をして、直径１０ｃｍ、長さ１３０ｃ
ｍの供試体（切欠係数 α−１，８４）を調製した。次
に、この供試体に５８０℃、９０分間の条件で軟窒化処
理（タフトライト処理）した。Thereafter, the round bar was normalized by heating it at 870°C for 2 hours and cooling it in air, so that it had a diameter of 10cm and a length of 130cm.
A specimen of m (notch coefficient α-1,84) was prepared. Next, this specimen was subjected to soft nitriding treatment (tuftlite treatment) at 580° C. for 90 minutes.
この軟窒化処理した供試体について、以下の方法により
軟窒化性の評価、回転曲げ疲れ試験及び曲げ矯正試験を
した。結果を第１表に示す。The nitrocarburizing test specimens were evaluated for nitrocarburizability, rotary bending fatigue test, and bend straightening test using the following methods. The results are shown in Table 1.
軟窒化性評価 表面のビッカース硬度、ビッカース硬度
が３００までの表面からの深さ及び内部（供試体の芯部
付近）のビッカース硬度を測定した。Evaluation of Soft-Nitriding Properties The Vickers hardness of the surface, the depth from the surface up to a Vickers hardness of 300, and the Vickers hardness of the inside (near the core of the specimen) were measured.
回転曲げ疲労試験、疲労限度を小野式により測定した。Rotational bending fatigue test and fatigue limit were measured using the Ono method.
曲げ矯正試験・供試体を、ｌｏＯｃｍ間隔の二つの支点
上に水平に置き、供試体の前記支点間の中間部に荷重を
加えた場合（二点支持中央集中荷重）に、シャフト表面
に割れか生じるまでのたわみ量で評価した。Bending straightening test: When the specimen is placed horizontally on two fulcrums spaced apart by loOcm and a load is applied to the intermediate part between the fulcrums of the specimen (two-point support central concentrated load), no cracks appear on the shaft surface. Evaluation was made based on the amount of deflection required to occur.
（以下余白）
（発明の効果）
本発明の軟窒化用鋼は、所定量のＣ，Ｓｉ、Ｍｎ、Ｃｒ
及びＡｌを含有し、残部がＦｅと不可避的不純物からな
るものであり、更に、前記軟窒化用鋼に所定量のＮｉ、
Ｃｕ及びＭｏ ； Ｐｂ、Ｃａ及びＳ並びにＢを適宜組
み合わせて含有させてなるものである。(Left below) (Effects of the invention) The steel for soft nitriding of the present invention has a predetermined amount of C, Si, Mn, and Cr.
and Al, with the remainder consisting of Fe and unavoidable impurities, and furthermore, a predetermined amount of Ni,
Cu and Mo; Pb, Ca, S, and B are contained in an appropriate combination.
本発明の軟窒化用鋼はこのような組成であることから、
従来の軟窒化用鋼と比べて、同程度の芯部硬さを保持し
たまま、表面硬さを低くすることができる。従って、本
発明の軟窒化用鋼は、優れた疲労強度を保持したまま、
曲げ矯正性が向上されており、曲げ矯正時において窒化
層に割れ等が生じることがない。Since the steel for soft nitriding of the present invention has such a composition,
Compared to conventional soft-nitriding steels, the surface hardness can be lowered while maintaining the same core hardness. Therefore, the steel for nitrocarburizing of the present invention maintains excellent fatigue strength and
The bending straightening properties are improved, and no cracks or the like occur in the nitrided layer during bending straightening.
本発明の軟窒化用鋼は、特に自動車のクランクシャフト
用材料として好適である。The steel for nitrocarburizing of the present invention is particularly suitable as a material for automobile crankshafts.
Claims (6)
〜２．００重量％、Ｍｎ：０．８０〜２．５０重量％、
Ｃｒ：０．２０重量％以下及びＡｌ：０．０３５重量％
以下を含有し、残部がＦｅ及び不可避的不純物からなる
ことを特徴とする軟窒化用鋼。(1) C: 0.35-0.65% by weight, Si: 0.35
~2.00% by weight, Mn: 0.80~2.50% by weight,
Cr: 0.20% by weight or less and Al: 0.035% by weight
A steel for soft nitriding, characterized in that it contains the following, with the remainder consisting of Fe and inevitable impurities.
％以下及びＭｏ：０．５重量％以下からなる群より選ば
れる１種以上を含有する請求項１記載の軟窒化用鋼。(2) The soft-nitriding agent according to claim 1, further containing one or more selected from the group consisting of Ni: 3.0% by weight or less, Cu: 1.0% by weight or less, and Mo: 0.5% by weight or less. steel.
．００１０〜０．０１００重量％及びＳ：０．０４〜０
．１３重量％からなる群より選ばれる１種以上を含有す
る請求項１記載の軟窒化用鋼。(3) Furthermore, Pb: 0.03 to 0.35% by weight, Ca: 0
．． 0010-0.0100% by weight and S: 0.04-0
．． The steel for nitrocarburizing according to claim 1, containing one or more selected from the group consisting of 13% by weight.
１又は２記載の軟窒化用鋼。(4) The steel for soft nitriding according to claim 1 or 2, further containing 0.0080% by weight or less of B.
．００１０〜０．０１００重量％及びＳ：０．０４〜０
．１３重量％からなる群より選ばれる１種以上を含有す
る請求項２記載の軟窒化用鋼。(5) Furthermore, Pb: 0.03 to 0.35% by weight, Ca: 0
．． 0010-0.0100% by weight and S: 0.04-0
．． The steel for soft nitriding according to claim 2, containing one or more selected from the group consisting of 13% by weight.
５記載の軟窒化用鋼。(6) The steel for soft nitriding according to claim 5, further containing 0.0080% by weight or less of B.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19987490A JP2854685B2 (en) | 1990-07-27 | 1990-07-27 | Steel for soft nitriding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19987490A JP2854685B2 (en) | 1990-07-27 | 1990-07-27 | Steel for soft nitriding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0483849A true JPH0483849A (en) | 1992-03-17 |
| JP2854685B2 JP2854685B2 (en) | 1999-02-03 |
Family
ID=16415063
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19987490A Expired - Fee Related JP2854685B2 (en) | 1990-07-27 | 1990-07-27 | Steel for soft nitriding |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2854685B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8876988B2 (en) | 2010-11-17 | 2014-11-04 | Nippon Steel & Sumitomo Metal Corporation | Steel for nitriding and nitrided part |
| WO2016035519A1 (en) * | 2014-09-02 | 2016-03-10 | 新日鐵住金株式会社 | Non-tempered soft-nitrided component |
-
1990
- 1990-07-27 JP JP19987490A patent/JP2854685B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8876988B2 (en) | 2010-11-17 | 2014-11-04 | Nippon Steel & Sumitomo Metal Corporation | Steel for nitriding and nitrided part |
| WO2016035519A1 (en) * | 2014-09-02 | 2016-03-10 | 新日鐵住金株式会社 | Non-tempered soft-nitrided component |
| JPWO2016035519A1 (en) * | 2014-09-02 | 2017-07-27 | 新日鐵住金株式会社 | Non-tempered soft nitriding parts |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2854685B2 (en) | 1999-02-03 |
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