Iron-type golf club head

An iron-type golf club head, comprising:

• a body, comprising a heel portion, a sole portion, a toe portion, a top-line portion, a front portion, and a rear portion, wherein the rear portion comprises a rear opening, the rear opening having a total area of at least 400 square millimeters (mm2), and wherein the front portion comprises a strike face and a back surface opposite the strike face;
• a rear fascia, coupled to the rear portion of the body and covering the rear opening and at least partially enclosing an internal cavity;
• and
• a stiffening material positioned within the internal cavity and in contact with the back surface of the front portion and a forward-facing surface of the rear portion, wherein the stiffening material is insertable, through the rear opening, into the internal cavity before the rear fascia is coupled to the rear portion of the body;
• wherein a characteristic time (CT) at a geometric center of the strike face is at least 250 microseconds;
• wherein a maximum thickness of the front portion, at the strike face, is less than or equal to 3.5 mm;
• wherein the front portion, at the strike face, excluding grooves, has a minimum thickness between, and inclusive of, 1.1 mm and 2.2 mm;
• wherein the rear fascia is made of a material having a density between, and inclusive of, 0.9 grams/cubic-centimeter (g/cc) and 5 g/cc;
• wherein the iron-type golf club head has an external head volume between, and inclusive of, 15 cc and 70 cc, and the internal cavity has a cavity volume between, and inclusive of, 5 cc and 30 cc;
• wherein the stiffening material occupies less than 25% of the back surface of the front portion along the x-axis;
• wherein the front portion further comprises a front opening;
• wherein the strike face comprises a strike plate joined to the front portion to cover the front opening;
• wherein the strike plate comprises a sole wrap portion that defines a portion of the sole portion;
• wherein a portion of the strike plate is welded to the sole portion;
• and
• wherein at least a portion of the rear opening extends from a first region of the rear portion, proximate the sole, to a second region of the rear portion, proximate the top-line portion.

An iron-type golf club head, comprising:

• a body, comprising a heel portion, a sole portion, a toe portion, a top-line portion, a front portion, and a rear portion, wherein the rear portion comprises a rear opening, the rear opening having a total area of at least 400 square millimeters (mm2), and wherein the front portion comprises a strike face and a back surface opposite the strike face;
• a rear fascia, coupled to the rear portion of the body and covering the rear opening and at least partially enclosing an internal cavity;
• and
• a stiffening material positioned within the internal cavity and in contact with the back surface of the front portion and a forward-facing surface of the rear portion, wherein the stiffening material is insertable, through the rear opening, into the internal cavity before the rear fascia is coupled to the rear portion of the body;
• wherein a characteristic time (CT) at a geometric center of the strike face is at least 250 microseconds;
• wherein a maximum thickness of the front portion, at the strike face, is less than or equal to 3.5 mm;
• wherein the front portion, at the strike face, excluding grooves, has a minimum thickness between, and inclusive of, 1.1 mm and 2.2 mm;
• wherein the rear fascia is made of a material having a density between, and inclusive of, 0.9 grams/cubic-centimeter (g/cc) and 5 g/cc;
• wherein the iron-type golf club head has an external head volume between, and inclusive of, 15 cc and 70 cc, and the internal cavity has a cavity volume between, and inclusive of, 5 cc and 30 cc;
• wherein the front portion further comprises a front opening;
• wherein the strike face comprises a strike plate joined to the front portion to cover the front opening;
• wherein the strike plate comprises a sole wrap portion that defines a portion of the sole portion, and a portion of the strike plate is welded to the sole portion;
• wherein the stiffening material contacts less than 25% of a total surface area of a back surface of the strike plate, and the stiffening material has a surface area of at least 50 mm2;
• and
• wherein the stiffening material comprises a polymeric material having a hardness of at least 10 Shore A and no more than 40 Shore D, and a density of no more than 1.75 g/cc.