First, notice the terms "maraging steels" (pural) and "these materials" in their reference. Maraging steel is not a single alloy as many people seem to believe, but is actually a description of a group of different, yet related, steel alloys that possess a similar chemical makeup and range of higher-strength mechanical properties.

In fact, most golfers have not even been using the proper pronunciation of this sophisticated classification of steel alloys. The correct pronunciation of this family of high-strength steels is mar-AGE'-ing, not "MARRIAGE-ing" nor "MAR'-ange-ing".

A maraging steel is a steel alloy with a very low percentage of carbon which can form an iron-nickel martensite crystalline structure that can be age-hardened to achieve greater strength, hardness and toughness. Hence the term mar-AGE-ing.

To Golfers, maraging is a term that many are using to reference a single metal; to metallurgists, maraging is simply a description of certain high nickel, high cobalt or chromium content steel alloys that can be specifically heat treated to achieve very high strengths.

When most metals are formed into a product, whether by forging, casting or any other fabrication method, the product can be subjected to a variety of heating and cooling processes which can significantly change their strength, hardness or other mechanical properties. Whatever the heating and cooling methods, these process known as heat treatment are a vital part of the manufacture of most metal parts.

For example, most golfers are familiar with the alloy used to make steel metal and iron heads known as and labeled as 17-4ph. The numbers 17 and 4 refer to the percentage of chromium (15-17.5%) and nickel (3-5%) percent of the steel, but the letters 'ph' refer to the manner in which the steel is heat treated after it is formed into the shape of the head. The 'ph' in the alloy designation stands for precipitive hardening, which means the 17-4 heads are heated to a specific temperature after which they are quench cooled through immersion in water or special composition of oil.

This heating and rapid reduction in temperature allows the 17-4 steel to achieve both the higher level of strength and hardness desired by the foundry. In addition, process creates a specific and advantageous orientation of molecules in the 17-4 alloy to prevent the metal from becoming more brittle than desired.

After conventional heat treatment, the maraging steel is very strong, and hard, but it is very brittle. To restore toughness, the maraging steel is heated again and held at a lower temperature for a period, after which it is slowly cooled. This process slightly reduces the strength and hardness, but more than makes up for it by restoring ductility (ability to stretch) which increases toughness and makes the metal more able to withstand impact with the ball. Because this process of secondary heating and cooling takes a longer time than liquid immersion process, the term used to describe this is aging.

From the standpoint of the metal, there are several types of steel that can be classified as maraging steel in their chemistry. The change in the alloy makeup is dramatic; which range in tensile strength from just under 200.000 psi all the way up to nearly 400,000 psi. It is this change in the steel's chemistry - largely an increase in the nickel and molybdenum along with an increase in the chromium content - that allows maraging steels to be fabricated and processed to be harder and stronger than the traditional steel used for clubhead manufacture such as 17-4 or 431.

But hardness and strength alone are not the key properties which could potentially enhance the performance of clubhead. ONLY IF THE MARAGING STEEL IS ENGINEERED PROPERLY in the clubhead design can it produce a positive improvement in shot making from the standpoint of slight distance increase and a significant change in the impact feel.

The words "engineered properly" are far more important than the words harder and stronger when it comes to using a maraging steel in the manufacture of a clubhead. Golfers cannot be trapped into believing that all clubheads made with a maraging steel in the face are going to be magic clubs. They are not! In fact, it does not really matter if a maraging steel alloy is used to fabricate the clubface; it is only important that the strength and other significant mechanical properties are high enough and matched properly with the design of the striking face.

Regardless as to whether the clubface metal is maraging steel or 17-4ph stainless, if it is matched correctly to the right face thickness and secured properly to the body of the clubhead, the materials can make for better golf clubhead design. In reality, the steel used to fabricate the face of the Orlimar Tri-Metal is a high-strength steel alloy manufactured by the Custom Steel Corporation, USA called Custom 465. Custom 465 contains a significant percentage of titanium which is incorporated in the alloy to boost its strength so that a thinner face construction can used without fear of fracture. The tensile strength of the Custom 465 is well within the range exhibited by maraging steel; In fact, it is much higher than most of the maraging steel used in the manufacture of clubheads today, but it still is not maraging steel in mind of a metallurgist.

The face thickness of a metal clubhead must be designed with both the strength of the clubhead metal and the impact stresses placed on the clubface kept in the forefront of the designer's mind.

It is an established fact that the predominant alloy used in the manufacture of steel metal woods is called 17-4ph stainless steel. But the most popular steel used in the production of investment cast iron is called 431 stainless steel. So what the difference?

The answer is chemistry. The chief difference between 17-4ph stainless steel and 431 stainless steel is that 17-4ph steel contains an average 15 to 17.5 chromium and 3.5 to 5 percent of nickel along with a high percentage of iron and other trace elements. In contrast, 431 steel contains on an average 15 to 17 percent of chromium and 1.25 to 2.5 percent of nickel with its remaining complement of iron and other trace of elements.

Those seemingly subtle differences allow for the 17-4ph steel to be on the average some 20 percent higher in strength than 431 steel. As a result, a club designer knows that the face of 10-degree-lofted driver made from 17-4ph steel will need to be at least 3mm thick in order to withstand impacts from the golfers with swing speeds to up to 140mph. Accordingly, designers also know that if a driver were made from 431 steel, the lower strength of that alloy requires the clubface to be made at least 4mm thick to stand up to the same stress. Obviously, designers reject 431 steel for metal woods because with a face thickness of 4 mm, the maximum size that 431 steel driver could be and still not exceed the normal driver head weight would be 165cc, which would be far smaller than the majority of golfers would buy.

Typically, maraging steel can be sourced which demonstrate strengths from 200,000 psi up to 4000,000 psi. The range in strength between the various alloys of maraging steels is determine by the percentage of the various elements in the steel as well as in the manner in which the steel are processed, or heat treated, after they are formed into the shape of the clubface.

So the trick is not in the metal, its hardness, its strength or its elastic modulus. Instead the secret lies in how that metal and its specific hardness and strength and elasticity is actually utilized within a particular clubhead design.

Philip Ang, 1999-2000 Winner International Clubmaker of the Year
conferred by Golf Clubmakers Association (GCA) - USA compiles this article from Golfsmith Tech Report.