Hi,
Steel tubing is made from regular steel which has low permeability (mu). Maybe if you are lucky you'll get mu=100 but true magnetic materials have mu=1000 or more. The cross sectional areas is a bit skimpy too. A 1.13 inch diameter bar has about 1 square inch cross sectional area, while a 1 inch diameter tube with wall thickness of 0.06 inch has magnetic cross sectional area 0.4 square inches
However, if you dont close the magnetic path then the inductance is more related to the air gap than the permeability of the steel, and although 1/2 the area is not desirable, i would think it would still work to some degree. So you might get it to work good enough for your purpose depending on what the purpose is.
For the purpose of degaussing, it might work. The field would not be as directed as you would like it to be, but could still be good enough even so. It would depend on the amount of wire you use and what voltage you have available to drive this construction. Since the area is less than optimal, that means the wire usage is not optimal so that means you dont get as strong a field as you would with a solid core. Adding steel to the inner core area should improve this.
Degaussing is the task of taking the target material through it's BH curve until it reaches (0,0). Knowing the magnetization level and direction means we can apply a counter force and accomplish the task in one single fairly quick operation. However, it is difficult to tell where the material is on it's BH curve so we end up using an ad hoc method that involves a changing magnetic field that takes the material through it's BH curve repeatedly while at the same time decreasing the amplitude of the field so that eventually when the external field reaches zero the material also reaches zero.
This involves using a constant AC current to generate the field, usually of low frequency like 50 or 60Hz, while at the same time moving the field around a little so it reaches all parts of the material and also at the same time moving the field away from the material so that the material BH area traversed gets smaller and smaller. This simply means moving the coil around while at the same time moving it away from the material slowly.