Application of titanium and titanium alloy in golf head

Application of titanium and titanium alloy in golf head

 

1. Preface

Since March 1990, Japan's JOY Company has sold titanium golf clubs in the world for the first time, which has opened the prelude of titanium golf clubs. The cooperation between JOY Company and Sichuan Railway, and the cooperation between Shuiye and Mitsubishi Materials enabled the commercialization of titanium golf clubs. The rod head of Sichuan Iron is made of Ti-6Al-4V titanium alloy, the top and hitting surface of Mitsubishi material rod head are made of Ti-6Al-4V titanium alloy, and the bottom and neck are made of pure titanium.

This paper briefly introduces the use of titanium and titanium alloy for golf clubs sold in the market at present.

2. Development and change of golf club head material

Golf clubs are also made of wood. In this article, they refer to # 1 wooden clubs (commonly referred to as clubs), because in addition, there are also clubs and iron clubs used in the flat course, which does not mean that high price titanium alloy clubs will inevitably be used. In order to know which of the 14 clubs used in the golf course has the largest flight range, it is natural to improve the ball speed. The clubs are long and light at the same time. It is better that the volume of the club head is also large. Specifically, if the weight of the ball head is about 190g and the volume of the ball head is more than 300ml, the specific gravity can be simply calculated as 190 ÷ 300=0.63. When the specific gravity is below this, the impact force when the ball collides with the ball is close to 1t. Such tests have been carried out many times to clarify the extremely harsh conditions, but the material used for the ball head has its own characteristics.

Persimmon trees have been used for wooden bat since ancient times, because it is the lightest of all wood, but its strength is very high. Al plate is used at the bottom of the ball head, and resin is used at the hitting surface. In order to adjust the weight of the bottom, lead is added into it. The weight of the ball head reaches 200g, the volume is limited to 190ml at most, and the common type is between 170 and 180.

Japan first developed the metal golf club head (dangan) in 1981. The volume is 150ml, smaller than the persimmon ball head, but the hitting rate is very high. This is because it flies faster than the persimmon ball bat. The volume is 150ml, which is not as small as the persimmon bat, but it is very popular in the market. Since then, the era of metal ball head has entered. High strength stainless steel - SUS431 precision casting was initially used for the head material of the ball rod. At that time, the precision castings of iron ball joints were mainly SUS304 and SUS431, but the high-strength SUS431 was successful. However, it didn't take long for a claim to be made due to the concave impact sphere. As the responsible person for the development of Dangan, it was decided to replace the material used with SUS630 (17-4PH). The tensile strength of SUS431 is 840MPa, while the tensile strength of SUS630 is only increased by 1.070 MPa, but the corrosion resistance is better than that of SUS630, so this is the reason for replacement. Soon the SUS431 ball head disappeared from the market, and the SUS304 ball head also had the same fate. Only the SUS630 ball head has been popular for a short time. This is because the strength, corrosion resistance, castability and cost of the ball head are good. The important thing is that the depth of its mirror polishing, the advanced sense of its color, and its surface hardness are high. Even if there is a small scratch, its luster can be maintained for a long time, so it is very suitable for golf head. From this point of view, SUS630, as a golf ball material, has good comprehensive properties and is worthy of being an advanced stainless steel alloy.

However, SUS630 material as a golf club head has not been maintained for a long time. The biggest reason is its small size. Instead, carbon ball head, which is based on graphite fiber and then hot formed with epoxy resin, is called CFRP, and its internal structure is hollow. As we all know, graphite fiber is extremely strong and lightweight, so it is very suitable for ball rod material. The volume may be more than 200ml, and the preparation methods are also different. There are also horizontal lines of graphite fibers floating on the surface, both long fibers and short fibers. In the fierce competition for price, because of its excellent performance, combined with the ABS resin short fiber, and can be produced by injection molding, its price is naturally surprisingly cheap. However, the carbon rod head has not become the mainstream, mainly because the standards for displaying the performance of CFRP are not uniform, and it is difficult to see the performance of the product from the appearance. The most important thing for consumers is the reliability of the product. In other aspects, the durability of the surface and the cost of the mold in the manufacturing have led to the material not becoming popular.

From metal to carbon, and from metal to titanium heat, this is a development process of golf clubs. The bat made of new materials is used because of its high hitting rate. At the same time, if the function of the bat made of new materials is to be improved, its cost will naturally rise. But it also gives people the illusion that the performance of golf clubs with high prices is naturally good. Aluminum, in the mid-1990s, was the heyday of aluminum that won the competition for volume. Dula aluminum (7075) is used as ball joint material in the initial stage of aluminum alloy. The tensile strength of 7075 T6 is about 600MPa, so it can be considered as a ball rod with higher specific strength. However, due to the existence of titanium, it does not know when it will disappear. As a matter of fact, aluminum alloy ball joints have experienced several ups and downs in the market. The main reason why aluminum can not be classified as ball joint material is because of corrosion resistance. Surface treatment must be carried out. The most suitable surface treatment is anodizing. However, due to its low surface hardness, the durability problem is difficult to solve.

Finally, a good use example of titanium on iron ball head is introduced. That is, the performance of the iron ball head embedded with only 3mm thick titanium plate on the hitting surface has been greatly improved due to the use of a small amount of titanium, and its performance-price ratio is also good.

3. The relationship between the function and material of golf club head

The higher the rigidity of the ball head, the better the flying range of the bat. This is the common sense of the persimmon bat era. The hitting surface of persimmon is embedded with a table-shaped resin called spherical insert. In order to improve the reinforcement and durability of the ball impact part, the material has gradually evolved into paper fiber, ABS resin and CFRP. In the era of high hardness and rigidity of CFRP embedding, the flight range has been greatly improved. In the era of wooden ball heads, there were examples of 3 or 4 reinforcements in the longitudinal direction in the hitting surface. This is also to improve the rigidity of the hitting surface.

But in the spring of 1997, Maluman Company used SP-700 titanium alloy in "Titan Titanium" to make the wall thickness of the hitting sphere thinner, bend the hitting sphere, control the deformation of the ball, prevent energy loss and increase the flight range. The next year, another company also published the impedance matching theory, which brings the same rebound force to the hitting surface, and the natural vibration number of the hitting surface is closer to the spherical surface. The energy of the ball head can be effectively transferred to the ball, and the flight range can be improved. This product sold well in the market at that time.

One of the golf rules stipulated by R&A and USGA is: "The design should avoid the elastic effect that has a negative impact on the ball's movement at the impact point of the hitting surface."

However, the fact is that the hitting sphere is thinned, which increases the flying range of the elasticity. The thinning of the hitting sphere of most clubs causes major problems in the world golf industry.

Before April 2000, USGA published a violation of golf rules, and in June, it reported a violation of clubs with a rebound coefficient of more than 0.830.

On the other hand, R&A, the representative of the Japanese golf industry, no longer expressed hope for the elastic effect rule in September, and published "The research results show that the current golf clubs have a higher rebound coefficient than the initial metal golf clubs, but the improvement of flight distance has no impact on the golf game."

At present, the situation of the golf industry in the world is that two standards coexist.

In the United States, golf clubs that violate the rules are not used, but in Europe and Japan, such clubs can also be used. In this way, today's golf clubs in Japan are still thin on the hitting surface, which has led to a high rebound hit heat. In the well-known era of titanium's heyday, many new titanium alloys have emerged in such a high-rebound spherical competition.

But in May 2002, USGA and R&A suddenly issued a unified declaration on the rebound coefficient. The main points of the content are: "In the five years after 2003, the rebound coefficient is more variable, ranging from 0.830 to 0.860, and has recovered to below 0.830 since 2008". The sudden announcement made the golf manufacturers fall into a cloud.

Operator's bat name Spherical material Spherical material Volume (ml) Price (yen)

Akilaprigutac Akilavintedge model SP-700 6-4 415 OP

Accinet Japan Tight List 975J-VS 15-3-3-3 6-4 312 58000

Accinet Japan King Copra SS370 SAT-2041 6-4 370 OP

E-era Golf Studio Lyoma 320 15-5-3 6-4 320 68000O

Wilson Diered PF400 Bakula Titanium 6-4 400 0P

Catana Golf TM320Ti 15-5-3 KS-100 320 88000

Casca DD4 SP-700 6-4 400 85000

Canon Sales BUMP415 SP-700 6-4 415 98000

Sightseeing Group Wave C bat 390 SP-700 6-4 390 70000

Salomon &Tela made 320Ti Tour SP-700 6-4 340 OP

Salomon &Tela made XR-03 SP-700 6-4 410 OP

Dio Tech Golf HSW Heavy 360 15-3-3-3 6-4 360 OP

Sybo Japan Sybo compression bat SP-700 6-4 410 OP

Seiko es yard T-9FA 0.5 15-5-3 15-3-3-3 320 95000

Seiko es yard T-9BL 15-3-3-3 KS 100 360 88000

Daiwa Onofu Trave 15-5-4-4 6-4 320 72000

Dahe Onofu Tour 15-5-4-4 6-4 320350 77000

Danlof New Zegushio SP-700 6-4 350 80000

Danlof ElidusonW201 SP-700 6-4 303 OP

Leisure time 360RS SP-700 6-4 360 70000

Leisure project 380ED 10-2-3 6-4 380 8000

つるゃ PG Ver.02 SP-700 6-4 350 70000

つるゃ RX-400MM SAT-2041 6-4 400 80000

Naiki Ti350X SAT-2041 6-4 350 OP

Naiki Ti275 450Ti 15-3-3-3 275 OP

Fortyn Deenpwan 15-3-3-3 6-4 348 48000

Britiston Sports RV-10 330 SP-700 15-3-3-3 330 85000

Britiston Sports RX-1 275 15-5-3 15-3-3-3 275 95000

Benjian Golf 15-5-3 SP-700 6-4 450 120000

Magulega Mucktech navvy2 380 Ti-9 6-4 380 55000

Mastar Astlo Tour 380 10-2-3 6-4 385 78000

Maluman Bisonik 350 SP-700 6-4 350 70000

Shuiye 300SII 315 15-5-3 15-3-3-3 315 90000

Shuiye 300SII 330 15-5-3 15-3-3-3 330 90000

Ymaha Mystery 01 DAT51 KS-100 340 75000

Hengbin rubber TR-X 15-5-3 15-3-3-3 350 83000

Yonics 3000 Spec 400 SP-700 6-4 400  70000

It can be seen from the table that:

(1) In the era of high resilience, the main alloy used for the ball material is completely different from that used for the hitting surface material. Especially, the hitting surface material uses high-strength high-grade titanium alloy for vehicles.

(2) The hitting surface materials are mostly forged or rolled materials, while the ball materials are mainly 6-4, which are basically precision castings, and the other are forged materials.

(3) SP-700 is mostly used for hitting surface materials, accounting for 41%; Then 15-5-3, accounting for 22%.

(4) The relatively new alloy SAT-2041 has been used in three samples, and the future market prospect is optimistic.

5. New alloy for ball joint material

In Japan, various titanium manufacturers are proposing the following new titanium alloys for ball joint materials:

Kobe Steel

(1) KS100/KS120(O:0.3--0.35,Fe:0.35--0.5,Si:0--0.6)

The alloy element of this alloy is only 1%, similar to pure titanium, with low cost and strength equivalent to 6-4 alloy, so its high performance-price ratio is its biggest feature. It is suitable for warm and hot processing, which is comparable to pure titanium. It can forge the neck and bottom of the ball head.

(2) KSELF(Ti-4.5Al-4Cr-0.5Fe-0.2C α+β Alloy)

It has the same strength characteristics as 6-4, and its forging characteristics are comparable to that of pure titanium. Its cutting performance is twice that of 6-4 alloy, and its cost is cheaper than 6-4. It can be used for hitting the face, bottom and neck.

(3) KSTi-9(Ti-2Mo-1.6V-0.5Fe-4.5Al-0.3Si α+β Alloy)

Similar to KSELF, it has similar strength characteristics with 6-4, high hot and cold ductility and good weldability. It can be used for hitting the face, bottom and neck.

(4) TVC(KS13-11-3Ti-13V-11Cr-3Al β Alloy)

because of this β Type B titanium alloy has excellent machinability, its momentum is higher than that of ultra-high strength alloy 15-5-3-3, and its tensile strength is up to 1550MPa, which can be used as the surface material for extremely thin hitting ball.

(5) KS15-5-4-4(Ti-15Mo-5Zr-4Al-4V)

It is a high-grade titanium alloy for automobile, the same as 15-5-3, but its strength is better and matches its elasticity. It is more likely to be used as hitting surface material.

Datong special steel

(1)DAT51(Ti-22V-4Al β Alloy)

It has excellent workability, high strength and high elasticity after aging treatment, and is most suitable for making surface materials for hitting balls.

(2) Bakula Titanium (DAT55GTi-15V-6Cr-4Al β Alloy)

It is the latest alloy developed especially as the thin wall material of the hitting surface. Its strength and toughness are not inferior to 15-5-3 alloy. It is expected to improve the rebound coefficient.

NKK

(1)SP-700(Ti-4.5Al-3V-2Mo-2Fe α+β Alloy)

As mentioned earlier, this alloy is the most widely used surface material in this year's new products. It can be compared with the 15-3-3-3 alloy widely used in forging titanium ball rods. It is the most reassuring alloy for ball head use. Processability, strength, toughness, ball feeling and cost are excellent titanium alloys for ball head.

Sumitomo Metal

(1)SAT2041(Ti-20V-3.5Al-1Sn β Alloy)

Recently, a lot of new alloys have been used on the surface materials of the ball. They have excellent cold workability. After proper aging treatment, they can obtain high strength and high toughness, and have a good sense of hitting.

Nippon Steel

(1) β 21S (Ti-15Mo-3Al-2.7Nb-0.25Si β Alloy)

Needless to say, good workability, excellent balance between strength and toughness, aging treatment strength up to 1500MPa, hope to be used as a new alloy with thin wall on the hitting surface.

Aichi Steel

(1) Porous pure titanium

It has been praised in the use of the existing light bat head and wedge iron bat head. The former has a soft sense of playing ball, and the latter is aimed at its rotatability. The application of the bat is a future topic.

6. Future needs and new materials

Future replacement materials are as follows:

(1) Amorphous metal

It has been in a downfall, which may be caused by immature technology. The basic amorphous metal is characterized by high strength, good viscosity, low rusting and light weight. And the light weight is exactly what golf clubs want. At present, the research of Al, Mg and Ti amorphous metals with light specific gravity is under way, and the prospect is optimistic.

(2) Intermetallic compound

Among the intermetallic compounds studied as durable thermal materials, Ni3Al has successfully processed 90u foil, and TiAl is also expected to become the body or engine valve material of the spacecraft. There are many studies, and the possibility is high.

(3) Shape memory alloy, super elastic alloy

It has small elastic coefficient, high strength, excellent corrosion resistance, high rebound hitting surface, and full possibility.

(4) Nanotechnology

The research on improving the strength and toughness of metals has been partially successful, not to mention noteworthy areas.

Finally, it should be mentioned that the market size of golf clubs in Japan is 123 billion yen, including 65.5 billion yen of wooden clubs, about 2.4 million pieces (estimated in 2001), accounting for about 70%.