This texture takes me back quit a few years, when I had to imitate
horse skin in bronze.
To achieve this type of texture, you are going to have to make a
special punch. Prepare a metal rod, like you always do when making
punches. Take a coarse file. If you look at file pattern closely, you
would see that it is made of intersecting lines, however close to the
tang, there is an area where lines do not intersect.
Bring you punch to orange heat ( just a tip ), quickly position tip
on non-intersecting area, and give it a sharp blow. The tip will
acquire negative impression of the area. File the tip to the shape
desired and temper it to dark straw color.
Different textures can be obtained with this tool by using different
shapes and imparting twisting motion with the left hand, and at the
same time when punch is struck with with the hammer.
The texture, you have shown, probably was produced by square or
rectangular punch, but more interesting effects can be had by using
round, triangular, and even crescent shapes. Of course, do not expect
miracles until you practice with the punch for a while.