【発明の詳細な説明】
この発明は伸線性及びゴムとの接着性特に耐水
接着性の優れたブラスめつき鋼線に関するもので
ある。
ブラスめつきを施した鋼線は、ゴムとの接着性
及び伸線性の優秀さから、直径0.15mm〜0.40mmの
細線に伸線され、このような細線を複数本撚り合
わせてタイヤの骨格を形成する所謂スチールコー
ド、或は高圧ゴムホースの補強用線、その他のゴ
ム、プラスチツク、コンクリート等の補強用材と
して近年大量に使用されて来ている。
この様なブラスめつき鋼線には、従来亜鉛成分
20〜35重量％、従つて、銅成分80〜65重量％（以
下％は総て重量％とする）の、即ち、高銅組成側
に属する、厚みが0.5〜2.0μのブラスを使用して
いるが、このブラスめつき鋼線をスチールコード
として使用したタイヤを、特に高温多湿地域、或
は凍結防止のため道路上に食塩や塩化カルシウム
等を散布する寒冷地域で使用する場合はブラスめ
つき鋼線の耐水、耐塩接着性が問題となつてい
る。
ところで、このブラスめつき鋼線の耐水接着性
を良くする為には、ブラス組成を低銅側（好まし
くは銅％60％以下）に設定すると良いと云うこと
は既に知られていたが、唯、低銅組成では、βブ
ラスが出現して来て、そのため伸線加工が極めて
困難になると云う事態を生じ、耐水接着性を生か
したくとも叙上の伸線困難の点で行詰つていた。
即ち、ブラス層中の銅％とβブラス率((ここで
はαブラスとβブラスとのＸ線回析強度ピークを
夫々I〓、I〓とすると、（I〓×100／I〓＋I〓）％をβ
ブ
ラス率と定義する))と伸線性との関係は第１図に
示すように、銅％が下がるとβブラス率が上が
り、その結果伸線性が落ちると云う関係にあつ
た。
そこでこの発明は、伸線加工が十分に、即ち、
引抜き時、断線の発生が少く、且つダイス摩耗が
少い状態でなされ、而し、例えばタイヤのスチー
ルコードに使用した場合、満足できる程度の、ゴ
ムとの接着性特に耐水接着性を得られる、伸線性
及びゴムとの接着性の優れたブラスつき鋼線を提
供するのをその目的とする。
今この発明の基になつた知見について述べる
と、第１図はCu％−βブラス率線図であり、第
１図中Ａ線は本来のブラス合金（なお合金めつき
ブラスも含む）のβブラス率を示すものである
が、Cu％＝62％程度以下の低Cu側において急激
にβブラス率の増加するのが認められる。
ここで、ブラスめつき鋼線のβブラス率はＸ線
回析装置（機種：理学電機製ミニフレツクス）を
用い、Co−Kd線を２次電圧30KV、電流10ｍＡ
で試料に照射し、スケールレンジ4000Cpsでのα
ブラス（111）とβブラス（110）とのＸ光線回析
ピーク高さを用いて下記のように定義した値であ
る。
記
ブラスめつき鋼線のβブラス率（％）
＝I〓×100／I〓＋I〓
上式にてI〓：βブラス（110）のＸ線回析ピー
ク高さ
I〓：αブラス（111）のＸ線回析ピーク高さ
又第１図において曲線ａ，ｂ，ｃは何れも、鋼
線に銅めつき後、亜鉛めつきを行い、熱拡散処理
を温度を変へて行つたブラスめつき鋼線（但しブ
ラスの組成はＡ線を示すブラス合金と同じ）にお
けるβブラス率を示すもので、何れも加熱時間は
同じであつて、唯ａよりｂ、ｂよりｃの方が加熱
温度が高くなつているものである。
次に上掲の本来のブラス合金、及び熱拡散処理
法でめつきしたブラスめつき鋼線の伸線性を評価
するのに「断線」と云う現象を取上げることに
し、その「断線」に関する種類を分類して置くと
(i) 細まり：伸線完了時の測定で鋼線径が直前の
ダイス径よりも1/100（mm）以上小さくなるこ
と。
(ii) 細まり断線：絞り切れ。
(iii) 摩耗断線：断線部の鋼線径がダイス径よりも
太目で断線した場合及び断線しないが摩耗のた
めダイスを交換した場合。
(iv) その他の断線：疵原因及びその他の原因によ
る場合。
であり、先づ「細まり断線」の点から見るのに先
だち、更に下記の用語の意味を明らかにして置く
と、
Γ細まり発生率……上記「細まり」発生の有無を
計10箇のボビン毎に調べ、10箇のボビン中５箇
あれば50％とするもの。
Γ細まり断線発生率……仕上素線ボビン単位に
「細まり断線」の発生の有無を計10箇のボビン
毎に調べ、10箇のボビン中５箇あれば50％とす
るもの。
であり、第２図イは、第１図中の曲線ｂの特性を
示す熱拡散処理法で作つたブラスめつき鋼線を伸
線したときの細まり発生率とCu％との関係を見
た線図であり、第２図ロは同じく曲線ｂの特性を
示す熱拡散処理法で作つたブラスめつき鋼線を伸
線したときの細まり断線発生率とCu％との関係
を見た線図で、何れも横軸Cu％の下の（ ）内
には第１図より読み取つたβブラス率を附したも
のである。
ところでこれらの線図を見ると、Cu％が62％
以下、即ち、βブラス率が略30％以上において
「細まり発生率」及び「細まり断線発生率」が何
れも急激に増加していることが明らかに看取でき
るる。
即ち、βブラスの現出が多くなると伸線し難い
と云う現象は既に知られているが、ダイス間での
素線の異常な細まり現象に着目すると、第３図に
示すように、βブラス率30％を境にして30％以上
で細まり発生率、細まり断線発生率が、又βブラ
ス率10％以上で総断線頻度比（βブラス率０の場
合の素線長106ｍ当り総断線発生回数を1.0として
任意のβブラス率の場合のその指数を示すもの。）
が急激に増加しているのが明瞭に認められるの
で、βブラス率により伸線し難さを定量化できる
ことがわかる。
なお第３図は種々のCu％のCu−Zn2層めつき
に対し、種々の温度で熱拡散処理を行い、０〜
100％の範囲のβブラス率を現出させた線材を、
通常の湿式伸線を行つて、その場合の細まり発生
率、細まり断線発生率及び総断線頻度比とβブラ
ス率との関係を見た線図であるが、この線図を見
れば鋼線の表面に銅と亜鉛とのめつきを層状に別
個に行つた後、合金化したブラスのめつき層を作
るめつき方法によつて形成したブラスめつき鋼線
の伸線加工性はめつきの銅成分よりもβブラス率
で一義的に関係づけられること、即ち細まり発生
率と細まり断線発生率とはβブラス率が30％を越
えると急増すること、又総断線頻度比はβブラス
率が10％を超えると急増すると云う知見が得られ
る。
なお、又第３図においてＢ，Ｃ線間のギヤツプ
はその殆んどがダイス摩耗発生に起因する。又細
まり断線は通常16〜20枚のダイスの内、前半のダ
イスで発生するが、断線はロスタイムが非常に大
きく、全く発生させない様にすることが望まし
い。
種々実験の結果、ブラスめつき鋼線の伸線加工
性は本質的にはブラス自身の加工性に左右され、
各ダイス毎の落し率を16％とする通常の伸線条件
では、βブラス率が30％を超えると許容し難い伸
線トラブル、例えば断線とダイス摩耗等を生じる
ことが今回これ等の実験により明らかにされた。
蓋し潤滑剤の改良等で伸線条件を改善しても、大
体βブラス率30％を境にしてそれより以上の範囲
で伸線加工性が急激に劣化する現象は避けること
は困難である。
次に、タイヤコードを入れたゴムを加硫後高湿
潤雰囲気中で７日間放置し、約15時間大気中に保
管した後タイヤコードを引抜きその付着性をゴム
付着率（引抜後、ゴムで被覆されている部分の、
ゴムで被覆されておるべき部分に対するコード表
面積率％）で見ると、同様にCu％とは無関係に
βブラス率と一義的な関係があり、その状況は第
３図に示したようにβブラス率が10％以下になる
と急激に低下すると云う知見が得られた。
従来、Cu％が低い程ゴムとの接着性が良好で
あると、漠然と云われて来ていたが、発明者の行
つた実験により、ゴムとブラスめつき鋼線との耐
水接着性はめつき層のβブラス率と関係があり、
βブラス率10％を境として10％未満ではβブラス
率の低下と共にゴムに対する耐水接着性が急激に
低下し、βブラス率10％以上ではβブラス率の上
昇と共に耐水接着性が漸増することが明らかとな
つた。従つて銅と亜鉛との二元素のみの合金に関
する限りでは、ブラスはβブラス率を10〜30％の
範囲に選択することにより、伸線加工性において
はα固溶体単相のブラスに比して殆んど損色のな
いものが得られ、而も更にゴムとの優れた耐水接
着性を有するものが得られると云う知見を得た。
そこで、これらの知見に基づきこの発明に係
る、伸線性及びゴムとの耐水接着性の優れたブラ
スめつき鋼線が着想されるに至り、その構成を説
明すると、鋼線の表面に、銅と亜鉛とのめつきを
層状に別個に行つた後、合金化してブラスのめつ
き層を作るめつき方法によつて形成したブラスめ
つき層を有するブラスめつき鋼線であつて、更
に、αブラスとβブラスとのＸ線回析強度ピーク
を夫々I〓、I〓とし、（I〓×100／I〓＋I〓）％をβブ
ラ
ス率と定義した時、該βブラス率が10〜30％の範
囲にあることを特徴とするものである。
このブラスめつき鋼線は叙上のような構成を有
するから、タイヤのスチールコードに使用するた
め、直径0.15mm〜0.40mmの細線に伸線する時、
「細まり断線」（絞り切れ）の発生が殆んどなく、
「ダイス摩耗」も殆んどなく行え、而も伸線素線
を撚り合わせて作つたスチールコードをコムに埋
め込んで加硫したゴム板は苛酷な湿潤雰囲気中に
放置しても充分に高いゴム付着率80％を確保でき
る鋼線が得られ、高圧ゴムホースの補強用線、そ
の他ゴム、プラスチツク、コンクリート等の補強
用材として一層細く伸線する場も容易に冷間伸線
が行える。
実施例
直径0.90mmの線材をパーライト変態後、銅と亜
鉛とのめつきを層状に別個に行つた後、合金化し
てブラスのめつき層を作るめつき方法、例えば熱
拡散処理法で、ブラスめつき層を作る時、ブラス
の銅組成が銅65〜70％レベル、総めつき厚が1.5μ
と、選ぶβブラス率が０、10、15、30、50％にな
るように、直接通電加熱により鋼線温度を種々変
えて熱拡散処理を行い、メツキ層表面のZnO膜を
化学処理し、後該線材をダイス19枚で直径0.175
mmまで、又引抜線速1000ｍ／minで湿式伸線し、
この素線によつて１×３、＋９、＋15と順次撚り合
わせて加工し、最後に直径0.15mmの素線でラツピ
ング仕上げでタイヤコード〔コード構成３＋９＋
15（0.175φ）＋1.（0.15φ）〕を作つた。
このものにつき耐水接着性試験を行い、そのゴ
ム引抜力とゴム付着率を見ると、第１表に示す通
りとなつた。なお伸線前の線材のCu％、βブラ
ス率及び伸線での細まり断線発生率、総断線頻度
比は第１表中に示した通りであつた。
即ち、Cu％（65.1〜70.2％）でβブラス率が10
〜30％の範囲にあるこの発明に係る鋼線は細まり
断線発生率は1.5〜4.3％の間にあつて十分小さ
く、総断線頻度比も総て1.0〜1.8内にありゴム付
着率比は3.1以上であるのに、Cu％はこの発明鋼
線と同じである65〜69.7％のものでもβブラス率
が０〜２％の比較鋼線は伸線断線状況はこの発明
鋼線と同じでもゴム付着率比は1.00〜1.18と極端
に低いし、又βブラス率45.5〜49.7％の比較鋼線
はゴム付着率比は3.77〜3.85と極めて優れている
が、反面、総断線頻度比は3.9〜5.2と全く許容出
来ない水準となつている。
【表】DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brass-plated steel wire with excellent wire drawability and adhesion to rubber, particularly water-resistant adhesion. Brass-plated steel wire is drawn into thin wires with a diameter of 0.15mm to 0.40mm due to its excellent adhesion to rubber and drawability.Multiple such thin wires are twisted together to form the frame of a tire. In recent years, it has been used in large quantities as a so-called steel cord, a reinforcing wire for high-pressure rubber hoses, and as a reinforcing material for other rubbers, plastics, concrete, etc. Conventionally, such brass-plated steel wires do not contain zinc components.
Using brass with a thickness of 0.5 to 2.0μ, which has a copper content of 20 to 35% by weight, therefore, a copper content of 80 to 65% by weight (hereinafter, all percentages are by weight), that is, belongs to the high copper composition side. However, if tires using this brass-plated steel wire as the steel cord are used in particularly hot and humid regions, or in cold regions where salt, calcium chloride, etc. are sprayed on roads to prevent freezing, brass-plated steel wire may be used as the steel cord. Water resistance and salt resistance adhesion of steel wire have become problems. By the way, it has already been known that in order to improve the water-resistant adhesion of this brass-plated steel wire, it is better to set the brass composition to a low-copper side (preferably 60% copper or less). In low-copper compositions, β-brass appeared, which made wire drawing extremely difficult, and even if we wanted to take advantage of water-resistant adhesion, we were stuck with the above-mentioned difficulty in wire drawing. . That is, the copper % in the brass layer and the β brass ratio ((Here, if the X-ray diffraction intensity peaks of α brass and β brass are I〓 and I〓, respectively, (I〓 × 100 / I〓 + I〓) % β
As shown in Figure 1, the relationship between the brass ratio (defined as the brass ratio)) and the wire drawability was such that as the copper percentage decreased, the β brass ratio increased, and as a result, the wire drawability decreased. Therefore, in this invention, the wire drawing process is sufficient, that is,
During drawing, wire breakage is minimized and die wear is minimized, and when used, for example, in steel cords for tires, satisfactory adhesion to rubber, particularly water-resistant adhesion, can be obtained. The purpose is to provide a brassed steel wire with excellent wire drawability and adhesion to rubber. Now, to describe the knowledge that is the basis of this invention, Fig. 1 is a Cu%-β brass ratio diagram, and line A in Fig. 1 is the β of the original brass alloy (including alloy-plated brass). This shows the brass ratio, and it is observed that the β brass ratio increases rapidly on the low Cu side, where Cu% is about 62% or less. Here, the β-brass ratio of the brass-plated steel wire is measured using an X-ray diffraction device (model: Rigaku Corporation Miniflex).
irradiate the sample with α at a scale range of 4000Cps.
This is a value defined as below using the X-ray diffraction peak heights of brass (111) and β brass (110). Note: β brass ratio (%) of brass-plated steel wire = I〓×100/I〓+I〓 In the above formula, I〓: X-ray diffraction peak height of β brass (110) I〓: α brass (111) ) In Fig. 1, curves a, b, and c are all brass wires that were copper-plated, then zinc-plated, and then heat-diffused at different temperatures. It shows the β brass ratio in galvanized steel wire (however, the brass composition is the same as the brass alloy showing A wire), and the heating time is the same for both, only b is heated more than a, and c is heated more than b. The temperature is rising. Next, in order to evaluate the drawability of the original brass alloy listed above and the brass-plated steel wire plated using the thermal diffusion treatment method, we will take up the phenomenon of "wire breakage", and we will discuss the types of "wire breakage". The classification is as follows: (i) Thinning: When the steel wire diameter is measured at the completion of wire drawing, it is 1/100 (mm) or more smaller than the previous die diameter. (ii) Narrowing and breakage: A break in the diaphragm. (iii) Wire breakage due to wear: When the steel wire diameter at the breakage part is thicker than the die diameter and the wire breaks, or when the die is replaced due to wear although the wire does not break. (iv) Other disconnections: due to defects or other causes. Before looking at it from the point of view of "thinning and breaking," let us further clarify the meanings of the following terms: Γ Thinning occurrence rate...The presence or absence of the above-mentioned "thinning" is determined by a total of 10 cases. Each bobbin is examined, and if there are 5 out of 10 bobbins, the percentage is 50%. Γ Thinning and wire breakage occurrence rate: The presence or absence of "thinning and wire breakage" is checked for each bobbin of finished strands, and if there are 5 out of 10 bobbins, it is considered 50%. Figure 2 A shows the relationship between the thinning occurrence rate and Cu% when a brass-plated steel wire made by the thermal diffusion treatment method showing the characteristics of curve b in Figure 1 is drawn. Figure 2 (b) shows the relationship between the occurrence rate of thinning and wire breakage and Cu% when a brass-plated steel wire made by the thermal diffusion treatment method exhibiting the characteristics of curve b is drawn. In each diagram, the β brass ratio read from Figure 1 is added in parentheses below the horizontal axis Cu%. By the way, looking at these diagrams, Cu% is 62%
It can be clearly seen that both the "thinning occurrence rate" and the "thinning occurrence rate" increase rapidly when the β brass ratio is approximately 30% or higher. In other words, it is already known that the more β brass appears, the more difficult it is to draw the wire, but if we focus on the abnormal thinning of the wire between the dies, as shown in Figure 3, When the brass rate is 30% or more, the occurrence rate of thinning and the occurrence rate of thinning and breakage are 30% or more, and when the β brass rate is 10% or more, the total breakage frequency ratio (wire length 10 6 m when the β brass rate is 0) This shows the index for an arbitrary β brass rate, assuming that the total number of wire breaks per hit is 1.0.)
It is clearly seen that the ratio increases rapidly, so it can be seen that the difficulty in wire drawing can be quantified by the β brass ratio. Figure 3 shows Cu-Zn double layer plating with various Cu percentages, which were subjected to heat diffusion treatment at various temperatures.
A wire rod with a β brass ratio in the range of 100%,
This is a diagram showing the relationship between the occurrence rate of thinning, the incidence of thinning and wire breakage, the total wire breakage frequency ratio, and the β-brass ratio when performing normal wet wire drawing. The drawability of brass-plated steel wire formed by a plating method in which copper and zinc are plated separately in layers on the surface of the wire, and then a plating layer of alloyed brass is formed. The relationship is uniquely related to the β-brass rate rather than the copper component, that is, the occurrence rate of thinning and the occurrence rate of thinning and breakage increase rapidly when the β-brass rate exceeds 30%, and the total breakage frequency ratio is The findings show that the rate increases rapidly when it exceeds 10%. Furthermore, in FIG. 3, most of the gap between lines B and C is caused by die wear. Also, thinning and wire breakage usually occur in the first half of the 16 to 20 dice, but wire breakage causes a very large amount of loss time, so it is desirable to prevent it from occurring at all. As a result of various experiments, we found that the drawability of brass-plated steel wire essentially depends on the workability of the brass itself.
These experiments have shown that under normal wire drawing conditions where the drop rate for each die is 16%, if the β brass rate exceeds 30%, unacceptable wire drawing problems such as wire breakage and die wear will occur. revealed.
Even if the wire drawing conditions are improved by improving the lid lubricant, etc., it is difficult to avoid the phenomenon in which the wire drawability deteriorates rapidly beyond the β-brass ratio of 30%. . Next, after vulcanization, the rubber containing the tire cord was left in a highly humid atmosphere for 7 days, and after being stored in the air for about 15 hours, the tire cord was pulled out and its adhesion was measured by the rubber adhesion rate (after pulling out, the rubber was covered with rubber). of the part that is
Similarly, when looking at the cord surface area percentage (%) relative to the area that should be covered with rubber, there is a unique relationship with the β-brass ratio, regardless of the Cu%, and this situation is shown in Figure 3. We found that when the rate falls below 10%, it rapidly declines. Conventionally, it has been vaguely said that the lower the Cu%, the better the adhesion with rubber, but the inventor's experiments revealed that the water-resistant adhesive plating layer between rubber and brass-plated steel wire is It is related to the β brass rate of
When the β-brass ratio is less than 10%, the water-resistant adhesion to rubber decreases rapidly as the β-brass ratio decreases, and when the β-brass ratio exceeds 10%, the water-resistant adhesion gradually increases as the β-brass ratio increases. It became clear. Therefore, as far as alloys containing only two elements of copper and zinc are concerned, by selecting the β brass ratio in the range of 10 to 30%, the wire drawability of brass is improved compared to alpha solid solution single phase brass. It has been found that a product with almost no color loss can be obtained and also has excellent water-resistant adhesion to rubber. Based on these findings, we came up with the idea of a brass-plated steel wire with excellent wire drawability and water-resistant adhesion to rubber, according to the present invention. A brass-plated steel wire having a brass-plated layer formed by a plating method in which zinc is plated separately in layers and then alloyed to form a brass-plated layer, further comprising: α When the X-ray diffraction intensity peaks of brass and β brass are respectively I〓 and I〓, and (I〓×100/I〓+I〓)% is defined as the β brass ratio, the β brass ratio is 10 to 30. It is characterized by being in the range of %. Since this brass-plated steel wire has the above-mentioned structure, when drawing it into a fine wire with a diameter of 0.15 mm to 0.40 mm for use in steel cords for tires,
There is almost no occurrence of "thin wire breakage" (diaphragm breakage),
There is almost no die wear, and the rubber plate, which is made by embedding steel cord made by twisting drawn wire strands into a comb and vulcanizing it, has a high enough rubber even if left in a harsh humid atmosphere. Steel wire with an adhesion rate of 80% can be obtained, and cold wire can be easily drawn to thinner wires for reinforcing high-pressure rubber hoses and other reinforcing materials such as rubber, plastic, and concrete. Example After a wire rod with a diameter of 0.90 mm is transformed into pearlite, it is plated with copper and zinc separately in layers, and then alloyed to form a brass plating layer. When creating the plating layer, the copper composition of the brass should be at a level of 65 to 70% copper, and the total plating thickness should be 1.5μ.
Then, the ZnO film on the surface of the plating layer was chemically treated by heat diffusion treatment by changing the steel wire temperature by direct current heating so that the selected β brass ratio was 0, 10, 15, 30, and 50%. After that, cut the wire into a diameter of 0.175 with 19 dies.
mm, and wet wire drawing at a drawing speed of 1000 m/min.
These wires are twisted and processed in order of 1×3, +9, +15, and finally wrapped with wires with a diameter of 0.15 mm to create a tire cord [cord configuration 3+9+
15 (0.175φ) + 1. (0.15φ)]. A water-resistant adhesion test was conducted on this product, and the rubber pull-out force and rubber adhesion rate were as shown in Table 1. The Cu% of the wire before wire drawing, the β brass ratio, the occurrence rate of thinning and breakage during wire drawing, and the total wire breakage frequency ratio were as shown in Table 1. That is, the β brass rate is 10 at Cu% (65.1-70.2%).
The steel wire according to the present invention, which is in the range of ~30%, has a thinning and wire breakage occurrence rate of 1.5 to 4.3%, which is sufficiently small, and the total wire breakage frequency ratio is all within 1.0 to 1.8, and the rubber adhesion rate ratio is within the range of 1.0 to 1.8. 3.1 or more, the Cu% is 65 to 69.7%, which is the same as this invention steel wire, but the comparison steel wire with a β brass ratio of 0 to 2% has the same drawing breakage as this invention steel wire. The rubber adhesion rate ratio is extremely low at 1.00 to 1.18, and the comparison steel wire with a β brass rate of 45.5 to 49.7% has an extremely excellent rubber adhesion rate ratio of 3.77 to 3.85, but on the other hand, the total wire breakage frequency ratio is 3.9. ~5.2, which is a totally unacceptable level. 【table】
【図面の簡単な説明】[Brief explanation of drawings]
第１図はブラスの組成とβブラス率との関係及
び銅めつき後、亜鉛めつきを行ない、熱拡散温度
を変えてめつき層をブラス化したブラス鋼線のブ
ラス組成とβブラス率との関係を示す線図、第２
図イはブラスにおけるCu％及びβブラス率と細
まり発生率との関係をプロツトした線図、第２図
ロはブラスにおけるCu％及びβブラス率と細ま
り断線発生率との関係をプロツトした線図、第３
図は種々のCu％のものを総合して得られたβブ
ラス率と細まり発生率、細まり断線発生率、総断
線頻度比及び耐水接着性試験におけるゴム附着率
比との関係を示す線図を夫々示す。
Figure 1 shows the relationship between the brass composition and the β-brass ratio, and the relationship between the brass composition and β-brass ratio of a brass steel wire that was copper-plated, then galvanized, and the plated layer was made brass by changing the heat diffusion temperature. Diagram showing the relationship between
Figure A is a diagram plotting the relationship between Cu% and β brass rate in brass and the incidence of thinning, and Figure 2 B plots the relationship between Cu% and β brass rate in brass and the incidence of thinning and breakage. Line diagram, 3rd
The figure shows the relationship between the β-brass ratio obtained by integrating various Cu percentages, the occurrence rate of thinning, the occurrence rate of thinning and breakage, the total breakage frequency ratio, and the rubber adhesion rate ratio in the water resistant adhesion test. Figures are shown respectively.