1 Introduction

3 Since March 1990, the Japanese JOY company sold titanium golf heads for the first time in the world, and it kicked off the prelude of titanium golf clubs. Only when JOY cooperated with Sichuan Railway and Mizuno and Mitsubishi Materials was it possible to commercialize titanium golf clubs. The head of Sichuan Iron uses Ti-6Al-4V titanium alloy. The upper and hitting surfaces of Mitsubishi material heads use Ti-6Al-4V titanium alloy, and the bottom and neck use pure titanium.

This article briefly introduces the use of titanium and titanium alloys in golf clubs currently on the market.

2, the development and change of golf club head material

There are also wooden golf clubs, which is specifically referred to as # 1 wooden bats (commonly referred to as bats) in this article, because in addition to this, there are bats and iron bats used on flat golf courses, which does not mean that there will be bound to be Use expensive titanium alloy bats. In order to know which of the 14 bats used on a golf course has the largest flight range, it is natural to increase the speed of the ball, while the bat is longer and lighter, preferably the head of the club has a larger volume. Specifically, if the weight of the club 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. Below this specific gravity, the impact force when colliding with the ball is close to 1t Many times, such tests have been conducted to clarify the extremely harsh conditions, but the materials used for club heads have their own qualitative characteristics.

The cypress wood bat has been using a persimmon tree since ancient times, because it is the lightest of all woods and has high strength. The bottom of the ball head uses an Al plate, and the hitting surface uses resin. In order to adjust the weight of the bottom, lead is added to the ball head. The weight of the ball head has reached 200g, and the maximum volume is limited to 190ml. between.

Japan first developed metal golf club heads (dangan) in 1981. The volume is 150ml, which is smaller than the persimmon ball, but the hit rate is extremely high. This is because they fly faster than the persimmon club head. The volume is 150ml. Although it is not as small as the persimmon wood bat, it is very popular in the market. Since then, it has entered the era of metal ball heads. The bat head was originally made of high-strength stainless steel-SUS431 precision casting. At that time, the precision castings of iron ball heads were mainly SUS304 and SUS431, but the high-strength SUS431 was a success. However, it didn't take long for a claim to arise due to the dent of the ball striking surface. As the developer 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, so this is the reason for the change. Soon the SUS431 ball head disappeared, 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 ball head has good strength, corrosion resistance, castability, cost and so on. What is important is the depth of mirror polishing and the high-level sense of its color, and its surface hardness High, even with minor scratches, its gloss can be maintained for a long time, so it is very suitable for golf heads. From this point of view, SUS630, as a golf ball, has good comprehensive properties and is worthy of being an advanced stainless steel alloy.

In spite of this, SUS630 has not been maintained as a golf club head for a long time. The biggest reason is that it is small in size. It is replaced by a carbon ball head, which uses graphite fibers as a matrix and is then thermoformed with epoxy resin, the so-called CFRP, which has a hollow structure inside the ball head. As we all know, graphite fiber is very strong and lightweight, so it is very suitable for bat materials. The volume may be more than 200ml, and the production methods are also different. The surface also has horizontal stripes of graphite fibers, both long fibers and short fibers. In the fierce price competition, because of its excellent performance, combined with the short fiber of ABS resin, and can be produced by injection molding, its price is naturally surprisingly cheap. However, carbon rod heads have not become mainstream, mainly because the standards for displaying CFRP performance 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 respects, the durability of the surface and the cost of the mold in manufacturing caused the material not to become popular.

From metal to carbon, and from metal to titanium, this is a course of development for golf clubs. The new bat is used because of its higher hit rate. At the same time, if the function of the bat using new materials is improved, the cost will naturally increase. But it gives people the illusion that the performance of expensive golf clubs is just fine. Aluminum, in the mid-1990s, was the heyday of aluminum that won the volume competition. Among the aluminum alloys, Dura Aluminum (7075) was used as the ball head material. The tensile strength of 7075 T6 material is about 600 MPa, so it can be considered a bat with higher specific strength, but due to the presence of titanium, it is unknown when it will disappear. In fact, aluminum alloy ball heads have come and gone on the market. The main reason why aluminum cannot be classified as a ball head material is because of corrosion resistance, and it must be surface treated. The most suitable surface treatment is anodizing, but because its surface hardness is not high, the problem of long-term performance is difficult to solve.

Finally, I will introduce a good example of the use of titanium on the iron ball head. That is, an iron ball head with only a 3mm thick titanium plate embedded in the ball striking surface, because a small amount of titanium is used, the performance of the ball head is greatly improved, and its cost performance is also better.

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

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

But in the spring of 1997, in the "Titan Titanium" by Maluman, the thickness of the ball hitting surface was reduced, the ball hitting surface was bent, the deformation of the ball was controlled to prevent energy loss, and the flight range was increased by using SP -700 titanium alloy. The next year another company also published the theory of impedance matching that brought the same rebound force to the ball striking surface, and the closer the natural vibration number of the ball striking surface was to the ball surface. The energy of the ball head can be effectively transferred to the ball, the flight range is improved, and this product sold well in the market at that time.

 One of the rules of golf stipulated by R & A and USGA is: "Design should avoid the elastic effect that adversely affects the ball's movement at the point of impact on the striking surface."

But the fact is that the ball hitting surface is thickened, so the elasticity caused by the increase of the flight range, and the wall thickness of most clubs hitting the ball surface has caused big problems in the world golf industry.

USGA published the clauses that violated the golf rules before April 2000, and in June notified the clubs that violated the rebound coefficient above 0.830.

On the other hand, the R & A representing the Japanese golf industry no longer had any hope for the elastic effect rule in September, and published "the results of the study. The current bat has a higher rebound coefficient than the original metal bat, but the flight range The increase has no impact on golf games. "

The current state of the golf industry in the world is the coexistence of dual standards.

No offending bats are used in golf in the United States, but they can also be used in European and Japanese games. So, today's golf clubs in Japan are still wall-thinning the surface of the ball, which has caused a high rebound of the ball. In the well-known titanium heyday, many new titanium alloys appeared in the competition of such high rebound batting surfaces.

But in May 2002, the 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 variable rebound coefficient is more than 0.830 ~ 0.860, and it has returned to less than 0.830 after 2008." Sudden announcements made golf manufacturers fall into the mist.

Operator Ball name Spherical material Spherical material 体积 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 Times Golf Studio Lyooma 320 15-5-3 6-4 320 68000O

Willson Diepred 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

Yamato onofu Trave 15-5-4-4 6-4 320 72000

Yamato onofu Tour 15-5-4-4 6-4 320,350 77000

Danlof New Zegushio SP-700 6-4 350 80000

Danlof ElidusonW201 SP-700 6-4 303 OP

Leisure Time 光 360RS SP-700 6-4 360 70000

Leisure items 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

Honma Golf 15-5-3 SP-700 6-4 450 120,000

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

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

Mizuno 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

 The table shows:

(1) In the era of high rebound force, the main alloys used for ball materials and ball striking surface materials are completely different, especially high-strength high-grade titanium alloys for automotive use.

(2) Forging surface materials are mostly forged or rolled materials. The sphere materials are mainly 6-4, which are basically all precision castings, and the others are forging materials.

(3) Most of the hitting surface materials are SP-700, accounting for 41%; followed by 15-5-3, accounting for 22%.

(4) There are three samples of the relatively new alloy SAT-2041 which use this alloy, and the future market prospect is optimistic.

5.New alloys suitable for ball head materials

 In Japan, the new titanium alloys being proposed by various titanium manufacturers for ball head materials are as follows:

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%, which is similar to pure titanium, low in cost, and equivalent in strength to 6-4 alloy, so its high performance-price ratio is its biggest feature. Suitable for warm and hot processing, which is comparable to pure titanium, the neck and bottom of the ball head can be forged.

(2) KSELF (Ti-4.5Al-4Cr-0.5Fe-0.2Cα β alloy)

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

(3) KSTi-9 (Ti-2Mo-1.6V-0.5Fe-4.5Al-0.3Siα β alloy)

Is similar to KSELF, has similar strength characteristics to 6-4, and has high hot and cold ductility and good weldability. Can be used as batting face, bottom and neck.

(4) TVC (KS13-11-3Ti-13V-11Cr-3Alβ alloy)

Because it is a β-type titanium alloy, its workability is excellent, its momentum is above the super high strength alloy 15-5-3-3, and its tensile strength can reach 1550 MPa.

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

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

Datong Special Steel

(1) DAT51 (Ti-22V-4Alβ alloy)

 Excellent workability, high strength can be obtained through aging treatment, and its elasticity is also high, which is most suitable for hitting surface materials.

(2) Bakula titanium (DAT55GTi-15V-6Cr-4Alβ alloy)

Rhenium is the latest alloy developed especially as a wall material for ball striking surfaces. Its strength and toughness are not inferior to those of 15-5-3 alloys. It is expected to increase the rebound coefficient.

NKK

(1) SP-700 (Ti-4.5Al-3V-2Mo-2Feα β alloy)

As mentioned earlier, this year's new products are the most used hitting surface material. This alloy can be compared with the 15-3-3-3 alloy widely used in forged titanium bats. Rest assured alloy. Workability, strength, toughness, playing feel, and cost are titanium alloys with excellent balance for ball heads.

Sumitomo Metal

(1) SAT2041 (Ti-20V-3.5Al-1Sn β alloy)

Recently, more new alloys have been used on ball striking surface materials, which have excellent cold workability. After appropriate aging treatment, high strength and toughness can be obtained, and the ball feel is good.

New Japan Steel Works

(1) β21S (Ti-15Mo-3Al-2.7Nb-0.25Siβ alloy)

 It is needless to say that the workability is good. The balance between strength and toughness is very good. The strength can reach 1500MPa after aging treatment, and it is hoped that it can be used as a new alloy for wall thickness.

Aichi Steel

(1) porous pure titanium

It has been well-received in the existing use of putter heads and wedge-shaped iron heads. The former has a soft playing feel, and the latter is aimed at its rotation. The application of bats is a future issue.

6. Future needs and new materials

The future replacement materials are as follows:

(1) Amorphous metal

Is already in ruins, probably due to technical immaturity. Basic amorphous metal is characterized by high strength, good viscosity, not easy to rust, and light weight. The lighter weight is exactly what golf clubs want. At present, research on Al-, Mg-, and Ti-based amorphous metals with light specific gravity is underway, and the prospect is optimistic.

(2) Intermetallic compounds

中 Among the intermetallic compounds studied as a durable thermal material, Ni3Al has successfully processed 90u foil, and TiAl is also expected to become the body or engine valve material of spacecraft.

(3) Shape memory alloy, super elastic alloy

 The elastic coefficient is small, but the strength is high, the corrosion resistance is excellent, the ball surface with high rebound has a full possibility.

(4) Nanotechnology

Research on improving the strength and toughness of metals has been a part of success, and it goes without saying that it must not be a noteworthy area.

The last thing to mention is that Japan ’s golf club market size is 123 billion yen, of which wooden bats are 65.5 billion yen, about 2.4 million (2001 estimate), and bats account for about 70%.

Previous: Excellent Characteristics And Applications Of Titanium Alloy Materials

Next: The National Grand Theater Is Also Made Of Titanium!