Your forge is running at 2500-2600°F and your wool melts at 2300°F ... what could possibly go wrong? Using Hi-Z wool, which is rated at 2800F°F is a better idea if the forge is to be welded. But there is more to your problem as described - read on:
A forge needs two things -
#1 is a insulating lining. Inswool and kaowool are the normal ones used. 1" of wool works for a small utility forge, 2" of wool is better for larger forges and required for a welding forge.
#2 is a refractory coating to cover and protect the wool lining. The standard coating is Satanite. Other refractories can be used, and some can be cast. The satanite or other refractory is applied over the wool blanket to a thickness of 1/4-1/2". It must be dried for a few days and then slowly fired to attain hardness and refractory properties. The refractory coating is usually rated at 2800-3000°F.
A welding forge (all forges IMHO) should have a final coat of ITC-100 ( or equivalent) to make the forge run more efficient and at a higher temperature. The ITC-100 is applied to the fired refractory coating to a thickness of 1/16" to 1/8". It also is slowly fired to attain its properties.
A floor made from a high temp and flux resistant material is also a god idea. Bubble alumina, Missou, or Castolite -3000 are all good choices. Some folks use kiln slelving or fire brick for the floor. In a vertical welding forge, an inch or two of kitty litter in the bottom will work quite well.
Notes:
A cast liner should be about 1" thick and have at least 2" of wool around it. A sheet metal shell is wrapped around the whole thing very similar to how a HT oven is constructed.
Forge ends can be easily made from 1" Ins-board. This is easy to cut and fit. Some commercial rectangular chamber forges are made entirely from ins-board. Ins-board is very reasonable and can be bought in sizes from 12"X12" up to 4X8 foot sheets.
