JPH04176563A - Shot peening method for titanium alloy - Google Patents
Shot peening method for titanium alloyInfo
- Publication number
- JPH04176563A JPH04176563A JP30465490A JP30465490A JPH04176563A JP H04176563 A JPH04176563 A JP H04176563A JP 30465490 A JP30465490 A JP 30465490A JP 30465490 A JP30465490 A JP 30465490A JP H04176563 A JPH04176563 A JP H04176563A
- Authority
- JP
- Japan
- Prior art keywords
- shot
- hardness
- workpiece
- worked
- peening
- 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
- 238000005480 shot peening Methods 0.000 title claims abstract description 24
- 229910001069 Ti alloy Inorganic materials 0.000 title claims abstract description 12
- 238000000034 method Methods 0.000 title claims description 10
- 239000002245 particle Substances 0.000 claims description 16
- 229910000975 Carbon steel Inorganic materials 0.000 description 6
- 239000010962 carbon steel Substances 0.000 description 6
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 239000011324 bead Substances 0.000 description 4
- 238000009661 fatigue test Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 230000003746 surface roughness Effects 0.000 description 3
- 238000005422 blasting Methods 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229920000426 Microplastic Polymers 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000376 effect on fatigue Effects 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 238000007373 indentation Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- JVJQPDTXIALXOG-UHFFFAOYSA-N nitryl fluoride Chemical compound [O-][N+](F)=O JVJQPDTXIALXOG-UHFFFAOYSA-N 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
Landscapes
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明はチタン合金のショットピーニング加工方法に
関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a shot peening method for titanium alloy.
（発明の背景）
従来より、疲労寿命を延ばす等の目的で浸炭焼入れした
鋼材等に対してショットピーニング加工を施すことが行
われている。このショットピーニング加工は、ショット
粒を被加工物表面に勢い良く衝突させて表層を微小塑性
変形させ、以て圧縮残留応力を生せしめるとともに加工
硬化を起させる等により、耐疲労性を高めるものである
。(Background of the Invention) Conventionally, shot peening has been performed on carburized and quenched steel materials for the purpose of extending fatigue life and the like. This shot peening process causes shot particles to collide with the surface of the workpiece, causing microplastic deformation of the surface layer, creating compressive residual stress and work hardening, thereby increasing fatigue resistance. be.
ところてチタン合金の場合、一般にはこのようなショッ
トピーニング加工は行われていないか、特に耐疲労性か
要求される場合に限って、かかるショットピーニング加
工か採用されている。However, in the case of titanium alloys, such shot peening is generally not performed, or is only used when fatigue resistance is particularly required.
チタン合金に対してショットピーニング加工を施した場
合、第１図に示しているように硬さ、圧縮残留応力か増
大し、また表面粗さも粗くなる。When shot peening is applied to a titanium alloy, the hardness and compressive residual stress increase, and the surface roughness also increases, as shown in FIG.
但しそれらの増大の程度は一様でなく、例えば圧縮残留
応力についてはピーニングの強さが強くなるにつれてほ
ぼ連続的に増大するが、硬さはある働域を境に飽和した
感じとなる。However, the extent of these increases is not uniform; for example, compressive residual stress increases almost continuously as the peening intensity increases, but hardness seems to be saturated after a certain working range.
このようなシ、ットピーニング加工によるチタン合金の
疲労寿命の向上度合は、それら硬さ、残留応力、粗さ等
の増大の程度によって左右されるが、それら因子は複雑
に絡まりあった形で疲労寿命に影響を及ぼす、従ってそ
れらをどの程度に抑え、制御したら疲労寿命が最も効果
的に向上するかといったことについては明らかでない。The degree to which the fatigue life of titanium alloys is improved by sheet peening depends on the degree of increase in hardness, residual stress, roughness, etc., and these factors are intricately intertwined and affect fatigue life. Therefore, it is not clear to what extent these can be suppressed and controlled to most effectively improve fatigue life.
特にチタン合金の場合、柔らかい割には変形能が小さく
て傷が付き易く、従ってショットピーニング加工の条件
によっては、加工を施すことによって却って疲労寿命が
低下してしまうことも有り得る。特に従来のピニーング
においてガラスピーズを使用した場合、ヘアークラック
の発生が著しく、また破壊したビーズが表面に打ち込ま
れる場合もあり、疲労強度の安定的向上を望めなかった
。Particularly in the case of titanium alloys, although they are soft, their deformability is small and they are easily scratched. Therefore, depending on the shot peening conditions, the fatigue life may actually be reduced by performing the shot peening process. In particular, when glass beads are used in conventional pinning, hair cracks occur significantly, and broken beads may sometimes be driven into the surface, making it impossible to expect a stable improvement in fatigue strength.
（課題を解決するための手段）
本発明はかかるチタン合金に対するンコットビーニング
加工の条件を確立し、適正に加工を施し得る方法を提供
すべくなされたもので、その要旨は、チタン合金から成
る被加工物に対してソヨトトピーニング加工を施すに際
し、ショット粒の硬さ、ショット粒の大きさ、投射速度
、投射量の各条件を下記条件に設定することにある。(Means for Solving the Problems) The present invention has been made in order to establish the conditions for the cotto beaning process on titanium alloys and to provide a method for appropriately processing the titanium alloys. When subjecting the workpiece to the soft peening process, the following conditions are set for the hardness of the shot grains, the size of the shot grains, the blasting speed, and the blasting amount.
（イ）ショット粒の硬さ：被加工物の硬さ以上で且つ該
被加工物の硬さにビッカース硬さで３００を加えた値以
下。(a) Hardness of shot grains: greater than or equal to the hardness of the workpiece and less than the value obtained by adding 300 Vickers hardness to the hardness of the workpiece.
（ロ）ショット粒の大きさ：平均粒径で０ 、０４〜０
、４層重。(b) Size of shot grains: average grain size of 0, 04 to 0
, 4 layers heavy.
（ハ）投射速度二投射速度を秒速でＶｍとし、ンヨット
粒の平均粒径をＤ■ｌとしたとき、Ｄｒ−Ｖｍ ０ 、
５〜４ 、 Ｏ、！−ナルｍＪ！。(c) Projection speed 2 When the projection speed is Vm in seconds and the average particle size of the Nyoyot grains is Dl, Dr-Vm 0 ,
5~4, O,! -Naru mJ! .
（ニ）投射量：被加工物全面にショット粒が当った時点
をカバレージ１００％としたとき、該カバレージ値が２
００％以上となる量。(d) Amount of shot: When the coverage is 100% when the shot particles hit the entire surface of the workpiece, the coverage value is 2
00% or more.
（作用及び発明の効果）
本発明においてシ厘ット粒の硬さを被加工物の硬さ以上
とするのは、これよりもショット粒の硬さが低いとショ
ットピーニング加工の効果が生しないからであり、また
硬さの上限値を被加工物の硬さにビルカース硬ざで３０
０を加えた値としているのは、これよりもショット粒の
硬さが硬くなると、シ、ット粒の靭性、寿命が低下して
割れや欠けを生じ易くなること、ショト粒の割れや欠け
によってエツジの鋭いショット粒の破片が発生し、これ
が被加工物の表面に当って傷付けるようになり、被加工
物の疲労寿命を低下させるようになることによる。(Operation and Effect of the Invention) In the present invention, the hardness of shot peening is set to be higher than the hardness of the workpiece because if the hardness of shot peening is lower than this, the shot peening process will not be effective. , and the upper limit of hardness is 30 on the Birkers hardness scale depending on the hardness of the workpiece.
The reason for adding 0 to the value is that if the hardness of the shot grains becomes harder than this, the toughness and life of the shot grains will decrease, making them more likely to crack or chip. This is because fragments of shot particles with sharp edges are generated, which hit and damage the surface of the workpiece, reducing the fatigue life of the workpiece.
尚本発明においては、ショット粒として各種材質のもの
を使用することが可能であるが、好適なのは炭素鋼系、
オーステナイトステンレス鋼系のものであり、ガラスピ
ーズやセラミックス粒等は望ましくない、理由は、それ
ら粒子は靭性に乏しくて割れ易く１発生した鋭い破片が
被加工物の表面に食い込んで被加工物表面に介在物が埋
まったような状態となるからである。In the present invention, shot particles made of various materials can be used, but carbon steel, carbon steel, etc. are preferable.
Since it is made of austenitic stainless steel, glass beads and ceramic grains are not desirable because these particles have poor toughness and break easily. This is because the condition appears to be filled with inclusions.
また炭素鋼系、オーステナイトステンレス鋼系のうち、
より望ましいのはオーステナイトステンレス鋼系のもの
である。理由はオーステナイトステンレス鋼系の場合、
炭素鋼系のものと比較して同じ硬さのもとで靭性が高く
、使い勝手も良好であるからである。Also, among carbon steel and austenitic stainless steel,
More desirable is an austenitic stainless steel. The reason is that in the case of austenitic stainless steel,
This is because, compared to carbon steel-based materials, it has higher toughness at the same hardness and is easier to use.
本発明においては、ショット粒として大きさが平均粒径
で０．０４〜０．４ｍ＋ｓのものを用いる。In the present invention, shot grains having an average particle size of 0.04 to 0.4 m+s are used.
０．０４厘厘より小さいとショットピーニングの効果が
表われず、逆に０．４■膳より大きいと、必要以上に大
きい圧痕が生じるようになって、被加工物の表面粗さが
増大し、疲労寿命に悪影響を及ぼすからである。If it is smaller than 0.04 cm, the effect of shot peening will not be apparent, and if it is larger than 0.4 cm, an unnecessarily large indentation will be created and the surface roughness of the workpiece will increase. This is because it has a negative effect on fatigue life.
ショットピーニング加工に際しては、ショット粒の投射
速度も重要な因子であり、本発明ではこの投射速度を所
定速度範囲に制御する。即ち、本発明では投射速度を秒
速でＶｍ、ショット粒の粒径をＤａｍとしたとき、Ｄ√
Ｖが０．５〜４．０の範囲に入るようにする。In shot peening processing, the projection speed of shot grains is also an important factor, and in the present invention, this projection speed is controlled within a predetermined speed range. That is, in the present invention, when the projection speed is Vm per second and the particle size of the shot grain is Dam, D√
Make sure that V falls within the range of 0.5 to 4.0.
１つ１つのショット粒について見た場合、被加上物への
衝突時によるピーニング効果は、ショット粒の硬さの影
響を除いて考えればその大きさＤと速度■の関数となる
。When looking at each shot grain individually, the peening effect caused by the collision with the workpiece becomes a function of its size D and speed (2), excluding the influence of the hardness of the shot grain.
本発明においてはそのピーニング効果がＤＪＶで規定さ
れることを見出し、そこでＤ√Ｖが０．５以上となるよ
うに投射速度を制御する。投射速度がこの速度よりも遅
い場合にはピーニング効果が充分表われず、逆に４，０
よりも大きいと、被加工物の表面粗さが増大すると共に
亀裂が発生し、またショット粒の寿命が低下して上述し
たような不具合を生ずる。In the present invention, it has been found that the peening effect is defined by DJV, and therefore the projection speed is controlled so that D√V is 0.5 or more. If the projection speed is slower than this speed, the peening effect will not be sufficient;
If it is larger than , the surface roughness of the workpiece increases and cracks occur, and the life of the shot particles decreases, causing the above-mentioned problems.
本発明では、更に、ショット粒の投射量をカバレージが
２００％以上となるようにする。ここでカバレージ２０
０％とは、被加工物表面においてショット粒が当ってい
ない部分がなくなったとき、換言すれば加工面の全ての
部位に対してショット粒が当った時点をカバレージ１０
０％とし、その倍量のショット粒が当った時の投射量を
意味する。即ち被加工物表面の何れの部位に対してもシ
ョット粒が少なくとも二回は当るに必要な投射量を意味
する。この投射量は、ノヨ・・ト粒の投射時間をコント
ロールとすることによって制御できる。In the present invention, the amount of shot particles to be projected is further adjusted so that the coverage becomes 200% or more. Coverage 20 here
0% means that there is no part of the surface of the workpiece that is not touched by shot grains, in other words, the point in time when shot grains hit all parts of the machined surface is coverage 10.
0%, it means the amount of shot when twice the amount of shot particles hits. In other words, it means the amount of shot particles required to hit any part of the surface of the workpiece at least twice. This amount of projection can be controlled by controlling the projection time of the particles.
このように投射量をカバレージ２００％以上に多くする
必要があるのは、ショット粒の投射量が少ないと被加工
物全面が均一にピーニングされず、局部的に硬さ等のば
らつきを生じるからである。The reason why it is necessary to increase the shot amount to cover 200% or more is because if the shot amount is small, the entire surface of the workpiece will not be peened uniformly, causing local variations in hardness etc. be.
（実施例）
次に本発明の特徴を更に明確にすへく、以下に実施例を
詳述する。(Example) Next, in order to further clarify the characteristics of the present invention, examples will be described in detail below.
第１表、化学成分（重量％）・硬さ
第１表に示す組成のチタン合金を次の製造工程、即ちプ
ラズマ溶解、これに統〈真空アーク２次溶解、２５１雪
φへの熱間圧延、歪とり焼なましく７００℃×１時間）
の各工程を経て製造した。The titanium alloy with the composition shown in Table 1, chemical composition (wt%) and hardness is subjected to the following manufacturing process: plasma melting, secondary melting in vacuum arc, hot rolling to 251 mm diameter. , strain relief annealing at 700℃ x 1 hour)
It was manufactured through the following steps.
そして第２図（Ｂ）に示す形状の試験片１０を作成して
酸洗（フッ硝酸）を行い、これに対して下記条件の下に
第２図（Ａ）に示す方法（図中１２はショットピーニン
グ機のインペラを表わす）でショットピーニング加工を
施した上で疲労試験を行った。結果が第２表に示しであ
る。尚第２表中波れ限度向上率の欄の数値は、被加工材
質３ＡＶの場合はＮｏ、Ａに対する比率であり、また６
ＡＶの場合はＮｏ、Ｋに対する比率である。Then, a test piece 10 having the shape shown in FIG. 2(B) was prepared and pickled (with fluoro-nitric acid), and then subjected to the method shown in FIG. 2(A) under the following conditions (12 in the figure is A fatigue test was conducted after shot peening with a shot peening machine (representing the impeller of a shot peening machine). The results are shown in Table 2. In addition, the numerical values in the ripple limit improvement rate column in Table 2 are the ratios to No. and A in the case of workpiece material 3AV, and 6.
In the case of AV, it is the ratio to No and K.
［ショットピーニング方法］
■ショットピーニング機 （第２図（Ａ））炭素鋼
系、ステンレス鋼ショット用として遠心投射式ショット
ピーニング機を用い、セラミック、ガラス系ビーズ用と
して直圧式エアプラス機を用いた。[Shot peening method] ■ Shot peening machine (Figure 2 (A)) A centrifugal projection shot peening machine was used for carbon steel and stainless steel shots, and a direct pressure air plus machine was used for ceramic and glass beads. .
■ピーニング条件
カバレージ １００〜１ｏｏｏ％ 各種投射速度Ｖ
２０〜２００−八ｅＣ各種投射角度 ９００
投射量＠Ｌ ６００膳■
＠）シゴット粒
材質 炭素鋼系。■ Peening condition coverage 100~1ooo% Various projection speeds V
20~200-8eC Various projection angles 900 Projection amount @L 600 servings ■ @) Shigot grain material Carbon steel type.
オーステナイト系ステンレス鋼系
硬さ Ｈｖ ２６８，３００，５５０，７０
０，８３０平均粒径（■薦） ０．０４，０．０６
，０．１０，０．２０゜０．４０，０．８０
［疲労試験方法］
小野式回転曲げ疲れ試験
試験片形状 （第２図（Ｂ））（図中数
値の単位はＩ）
（以下余白）
以上の結果から分かるように、本発明の各条件に従って
ショットピーニング加工を施した場合、疲労寿命が効果
的に向上する。Austenitic stainless steel hardness Hv 268,300,550,70
0,830 Average particle size (■ Recommended) 0.04, 0.06
, 0.10, 0.20゜0.40, 0.80 [Fatigue test method] Ono type rotary bending fatigue test specimen shape (Figure 2 (B)) (The unit of numerical value in the figure is I) (Hereafter, the margin is ) As can be seen from the above results, fatigue life is effectively improved when shot peening is performed according to the conditions of the present invention.
以上本発明の実施例を詳述したが、これはあくまで本発
明の一例示であって、本発明は、その主旨を逸脱しない
範囲において、当業者の知識に基づき様々な変更を加え
た態様において実施可能である。Although the embodiments of the present invention have been described in detail above, this is merely an illustration of the present invention, and the present invention may be modified in various ways based on the knowledge of those skilled in the art without departing from the spirit thereof. It is possible to implement.
第１図は本発明の背景説明のために示したピーニング強
さと粗さ、硬さ及び残留応力との関係を示す図であり、
第２図は本発明の実施例において採用したショットピー
ニング加工の方法と試験片の説明図である。
ｌＯ：試験片 １２：インペラ
代理人 弁理士 吉 １） 和 失策１図
ピーニングぢ主さFIG. 1 is a diagram showing the relationship between peening strength, roughness, hardness, and residual stress, shown for explaining the background of the present invention.
FIG. 2 is an explanatory diagram of a shot peening method and a test piece employed in an example of the present invention. 1O: Test piece 12: Impeller agent Patent attorney Yoshi 1) Mistake 1 Figure peening is the master
Claims (1)
グ加工を施すに際し、ショット粒の硬さ、ショット粒の
大きさ、投射速度、投射量の各条件を下記条件に設定す
ることを特徴とする、表面にヘアークラックを生ぜしめ
ないチタン合金のショットピーニング加工方法。 （イ）ショット粒の硬さ：被加工物の硬さ以上で且つ該
被加工物の硬さにビッカース硬さで３００を加えた値以
下。 （ロ）ショット粒の大きさ：平均粒径で０．０４〜０．
４ｍｍ。 （ハ）投射速度：投射速度を秒速でＶｍとし、ショット
粒の平均粒径をＤｍｍとしたとき、Ｄ√Ｖ＝０．５〜４
．０となる速度。 （ニ）投射量：被加工物全面にショット粒が当った時点
をカバレージ１００％としたとき、該カバレージ値が２
００％以上となる量。[Claims] When performing shot peening on a workpiece made of a titanium alloy, the conditions of shot grain hardness, shot grain size, shot speed, and shot amount are set to the following conditions. A titanium alloy shot peening method that does not produce hair cracks on the surface. (a) Hardness of shot grains: greater than or equal to the hardness of the workpiece and less than the value obtained by adding 300 Vickers hardness to the hardness of the workpiece. (b) Size of shot grains: average grain size of 0.04-0.
4mm. (c) Projection speed: When the projection speed is Vm in seconds and the average particle diameter of shot grains is Dmm, D√V=0.5 to 4
．． The speed at which it becomes 0. (d) Amount of shot: When the coverage is 100% when the shot particles hit the entire surface of the workpiece, the coverage value is 2
00% or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30465490A JPH04176563A (en) | 1990-11-09 | 1990-11-09 | Shot peening method for titanium alloy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30465490A JPH04176563A (en) | 1990-11-09 | 1990-11-09 | Shot peening method for titanium alloy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04176563A true JPH04176563A (en) | 1992-06-24 |
Family
ID=17935629
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30465490A Pending JPH04176563A (en) | 1990-11-09 | 1990-11-09 | Shot peening method for titanium alloy |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04176563A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004122332A (en) * | 2002-10-04 | 2004-04-22 | Toyota Motor Corp | Shot-peening method |
| JP2004181535A (en) * | 2002-11-29 | 2004-07-02 | Toyota Motor Corp | Shot-peening method |
| JP2007175799A (en) * | 2005-12-27 | 2007-07-12 | Sintokogio Ltd | Shot peening method of precious metal product |
-
1990
- 1990-11-09 JP JP30465490A patent/JPH04176563A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004122332A (en) * | 2002-10-04 | 2004-04-22 | Toyota Motor Corp | Shot-peening method |
| JP2004181535A (en) * | 2002-11-29 | 2004-07-02 | Toyota Motor Corp | Shot-peening method |
| JP2007175799A (en) * | 2005-12-27 | 2007-07-12 | Sintokogio Ltd | Shot peening method of precious metal product |
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