Density  The ratio of the mass of a substance to its volume, expressed, for example, in units of grams per cubic centimeter or pounds per cubic foot. The density of a pure substance varies little from sample to sample and is often considered a characteristic property of the substance. Density often is taken as an indication of how "heavy" a substance is. Iron is denser than cork, since a given volume of iron is more massive (and weighs more) than the same volume of cork. It is often said that iron is "heavier" than cork, although a large volume of cork obviously can be more massive and thus be heavier (i.e., weigh more) than a small volume of iron.  This is a property that is very important in all parts of the club head as we like as light, low density, a club head as possible.

Tensile Strength The measure of a material's ability to resist rupture.  In other words, how much force is required to fracture the material. Tensile strength is also defined in PSI or KSI. This too is also important for the manufacture of the face and body parts of a wood head.

Hardness A comparative scale measurement of the ability of a material to resist surface deformation.  In other words, how much does one material resist permanent denting of its surface. While there are several scales of comparison for hardness, the one most commonly used in conjunction with golf club head design is the Rockwell Scale of Hardness. Hardness is important for all parts of a wood head, though more important for the face.

Elongation A comparison of the ductility of different materials.  In other words, how easy is one material to stretch than another before it breaks such that the higher the number the easier to stretch the material before breaking. Elongation is defined as a per-cent of the dimension of the test piece, such that a higher per-cent value represents greater ductility of the material. Elongation is an important property for both the face and the body parts of the wood head because it will offer an indication of the ability of the face or top crown to flex before permanent damage could occur.

Titanium is a metallic element which in its pure form, possesses very low strength and would be quite unsuitable for the moderate to high stress requirements of the parts of a wood head. While some grades of pure titanium (referred to as commercially pure (CP grades) are used in the manufacture of the crown, sole and skirt parts of a wood head, most of the Titanium materials known by clubmakers are titanium alloys. An alloy is a metal that is a combination of different chemical elements mixed with the base metal for the purpose of intentionally creating different but very specific mechanical properties. Thus, titanium metals known to clubmakers by names such as 6-4, 10-2-3, SP700, etc are all titanium alloys.

One of the most confusing parts of evaluating the quality of a titanium wood head concerns the various grades and alloys used in their manufacture. It is very common for 2 or 3 different grades or alloys of titanium to be used in the manufacture of the various parts of the head. The names or numerical designations of the various titanium alloys are commonly used in the marketing of the heads to try to associate levels of quality with one specific Ti alloy over another. Is a 10-2-3 titanium alloy better than an SP700?  Does 22-4 titanium allow a wood head to perform better than 15-3-3-3 titanium?  Why are different alloys of titanium used in the manufacture of a wood head?  Because companies that sell titanium wood heads do attempt to make performance oriented claims with regard to the various alloys, questions like this swim around in the minds of clubmakers and more technically oriented golfers.

The truth? For one, no single titanium material on its own makes a better performing club head. There are titanium alloys that afford the potential to make a better performing wood head, but how that alloy is used and how its final properties are controlled in the manufacture of the wood head are the real points about whether a specific titanium material has any bearing on the performance of the head.

10-2-3 Beta Titanium. 6-4 Alpha/Beta Titanium. 15-3-3-3 Beta Titanium. SP700 Beta Titanium. DAT51 Titanium. CP Grade Titanium. The names of the different alloys and grades of titanium go on and on and each one supposedly different in its performance when used in the making of a wood head.

The most common method of naming Titanium alloys involves the use of a hyphenated numbering system that identifies the chief chemical element properties of the material. Present in addition to these important elements that set each alloy apart from the next are trace amounts of Carbon, Nitrogen, Oxygen, to name a few, with of course the balance of the alloy being titanium itself. A number of examples that use the numerical system to denote chemical composition of the alloy that are common to wood head manufacture are listed as follows:

1. 6-4 Titanium 6% Aluminum, 4% Vanadium
2. 3-2.5 Titanium 3% Aluminum, 2.5% Vanadium
3. 10-2-3 Titanium 10% Vanadium, 2% Iron, 3% Aluminum
4. 15-3-3-3 Titanium 15% Vanadium, 3% Chromium, 3% Aluminum, 3% Tin
5. 15-5-3 Titanium 15% Molybdenum, 5% Zirconium, 3% Aluminum

Clubmakers have also heard of titanium alloy and material names such as SP700, DAT51, CP grade that do not use this hyphenated number system. Such designations are usually created by companies in foreign countries that do not choose to subscribe to the hyphenated number system. For example, SP700 and DAT51 are titanium alloys made by Japanese companies and represent a 'trade name' for the alloy created by the company that makes the alloy. The same practice occurs in the US, where companies who process the alloys sometimes choose a trade name for the alloy instead of choosing to label the material by a numerical designation of its chief chemical components. Because all alloys are a combination of different amounts of different metallic elements, every Titanium alloy can be expressed by a chemical designation as well. But for purposes of this discussion, when a titanium alloy is identified by a designation other than a hyphenated series of numbers, that designation is a trade name for the alloy.

For example, SP700 Titanium, which is an alpha/beta grade alloy (not a beta grade like some companies advertise), could also referred to as 4.5-3-2-2 Titanium (4.5% Aluminum, 3% Vanadium, 2% Molybdenum, 2% Iron). Same for DAT51, a trade name created by Kobe Steel of Japan for their version of a 22-4 Titanium alloy.

Titanium’s 15-3-3-3 and SP700 offer tradeoffs when considering which may be better to seek when making your next purchase. 15-3-3-3 has the highest tensile strength of the 2 but a smaller elongation percentage. Meanwhile, SP700 still possesses considerable tensile strength but does add a few percentage points in the category of elongation. How does this translate? SP700, through its’ higher elongation figure, can impart more spring upon impact, and thus deliver more energy to the golf ball increasing distance.

So what are the trade off’s? Cost. Though this figure varies widely, the SP700 titanium is typically a bit more expensive than the 15-3-3-3, usually on the order of $20 - $40. This amount is oftentimes minimized by using SP700 strictly in the face of the driver head. Also, the higher one’s club head speed, the more realized benefit that could be realized from the increased spring effect of SP700. Golfers with a lower swing speed may not notice substantial yardage gains when comparing the two and therefore may not wish to pay this premium. Truly though, it is hard to go wrong with using either titanium as both offer such incredible playing characteristics, such vast improvements over stainless steel

Ideally you would want to use the Beta Titanium alloy with 210,000 psi strength AND 14 million psi Modulus of Elasticity. But the higher the strength, the higher the modulus will be. Therefore, any Beta Titanium alloy selected involves making a judgment of the balance of the two properties and how that will translate into the performance of the finished face design of the Driver.

10-2-3, SP700 and 22-4/DAT51 Titanium all have a very good balance of high strength to low modulus and therefore are very good to use to make Driver faces. 15-3-3-3 if process properly is very good as well, although there is a little more tendency for 15-3-3-3 to become brittle than the others mentioned here. 6-4 Titanium has the best elasticity of any titanium used in club head design, but its strength is much lower than 10-2-3/SP700/22-4/DAT51 so it is better for use in fairway woods with smaller faces, or for Drivers designed for much slower swing speed players.

6-4 Titanium    Titanium is used in wood heads manufactured with the formula 6Al-4V: these are 90% Titanium, 6% Aluminum and 4% Vanadium. Titanium is often used in oversize and larger heads. This alloy of titanium is primarily used in the construction of the shell the head is constructed of and not the face.  Unless stated specifically titanium heads advertised as Beta-Titanium use this alloy(6-4 Titanium) for the shell of the head and Beta-Titanium(15-3-3-3 Beta-Ti) in the face.

Mechanical Properties VS REAL Mechanical Properties of Titanium

Metals can be subjected to a process of precise heating over specific amounts of time to ordain the FINAL REAL mechanical properties of the metal in the specific part being made. While the science of heat treatment or post-forming treatment is very detailed, in short, the post-forming treatment of the metal is intended to cause the molecular structure of the metal to be changed in specific and predictable ways to achieve a variety of final mechanical and structural properties that may be more desired for the performance of the part.

For example, depending on the heat treatment followed, the tensile strength of 6-4 Titanium will range from 120,000 psi up to 170,000!! Or as another example, depending on the heat treatment process, 10-2-3 beta Titanium will range in tensile strength from 135,000 psi to 210,000 psi! Most clubmakers assume that 10-2-3 Beta Titanium will always have a much higher strength than 6-4 Titanium. This is not true unless you know the post-forming heat treatment process used. The same is true for all of the Titanium alloys used in the manufacture of wood heads. Therefore, it is IMPOSSIBLE without knowing the heat treatment procedure to know what any mechanical property of any Titanium alloy will be in the end product. As a result, heat treatment or post-forming treatment procedures are a CRITICAL part of the designer's and the foundry's responsibility to ensure the performance of the wood head's parts are properly created.

Heat Treatment of a Titanium wood head will affect each and every mechanical property in addition to the one example mentioned in the previous paragraph. Because each of the properties plays its own important role in the manufacture and ultimate performance of a Titanium wood head, a high quality head not only requires a good design but excellent control on the processing of the materials used in its creation.  This is one reason you can see the price of titanium club heads constructed of the same alloys vary considerably.  Heat treating is as much or more important than using a specific titanium alloy.

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