Forged vs. Cast Irons

In the manufacture of golf irons and wedges, there are two main methods that clubmakers employ to transform raw metal into clubheads – forging and casting.

CASTING

The majority of today's irons feature cast clubheads. In casting, molten metal is poured into a mold to achieve the desired design shape. Iron heads are typically cast using 431 or 17-4 grade stainless steel, strong and durable alloys that are able to withstand long periods of usage and exposure to the elements. Both 431 and 17-4 stainless steel include significant amounts of Chromium and Nickel, elements that increase the tensile strength and hardness of the steel while preventing the material from becoming brittle.

Liquid stainless steel will assume the shape of any container it occupies, which gives club manufacturers great flexibility in their cast design choices. Complex arrays of geometries can be molded that incorporate intricate channels, ribs, and undercuts.

By distributing material (and mass) to the outer edges of the club head, designers are able to increase the club's MOI (Moment of Inertia). Irons that feature this kind of perimeter weighting reduce the tendency of the club to twist on off-center hits. This increased stability effectively creates a larger "sweet spot", and results in a more forgiving iron and tighter dispersion patterns on iron shots.

The precise perimeter weighting made possible by casting also allows club designers to customize each club within an iron set. Long irons will incorporate more mass in the sole and low in the head to raise launch angle and help golfers get the ball up in the air. Short irons will distribute more weight higher in the head, raising the center of gravity in order to achieve lower flight and more predictable distance control.

Cavity back designs also allow for thinner club faces. Coupled with the strength of stainless steel, a thinner iron face can often impart more energy into the golf ball, resulting in longer distance. 

FORGING

In forging, a solid billet of steel is heated, placed in a tool and pressed under tremendous pressure to transform the steel into a desired shape. A relatively soft steel is required in this process and irons are typically forged using a carbon steel alloy. The forging process removes impurities and squeezes the porosity out of the steel, which results in a dense, compact grain structure. Forged irons are very consistent in composition, and they provide golfers with exceptional feel and feedback.

In contrast to casting, the forging process is more time- and labor-intensive, and thus more costly. Forging is also more limited than casting in terms of design flexibility and the ability to distribute weight around the clubhead. Because of this, forged irons tend to assume simpler "traditional blade" shapes, with minimal perimeter weighting. This means that muscle-back forged irons tend to have smaller effective sweet spots. With less MOI, forged irons are less forgiving on off-center strikes. However, for many golfers, this characteristic can be an advantage, as it makes it easier to shape shots and alter trajectory.

FEEL AND PERFORMANCE

A critical consideration when golfers consider a set of irons is feel, and historically, soft carbon steel has reigned supreme in this respect. Many golfers have been willing to accept a trade-off in distance and forgiveness to experience the soft, responsive feel of a forged club on a well-struck iron shot.

However, today, club designers can engineer feel through structure. They can adjust how each component resonates on its own, as well as together with the other components in the design.

Furthermore, recent advances in technology and club design have made it possible to manufacture irons that incorporate advantages from both cast and forging processes. The rise of computer aided design (CAD) and multi-component technology has allowed club makers to fuse cast iron chassis with forged faces, combining the stability and high MOI of cast technology with the buttery feel of forged steel at impact.

And a newer technology, Metal Injection Molding (MIM), has taken the concept of weight distribution to an entirely new level. By placing precise amounts of dense, heavy metals like tungsten in strategic locations, designers can not only increase MOI, but fine-tune flight and optimize performance for each iron in the set.

Modern irons like Titleist T100, T150, T200 and T350 blend the best aspects of all these available technologies, offering golfers a wide range of options without compromising on performance, forgiveness or feel.