Magnetising Iron

A YouTube video showing the process of making iron magnets can be seen here:

To roughly summarize the stages:

Casting iron using time honored techniques; Clean up the casts, repack and reheat (this is something to do with a Curie temperature), then subject the ingots to a magnetic field. When cooled these are only weakly magnetic, but primed for the next step; Subject to a strong electric current that aligns the crystal structure.

It looks possible to abbreviate the process -  a magnetic field could be applied after the initial casting stage while cooling down. This should be straightforward for rectangular block shapes, and there is the advantage of casts being small, reducing overall equipment overheads. 

Magnetizing iron should be done after projection to L1, since it would be expedient to charge them just before fixing, otherwise it will create unnecessary handling problems beforehand during any bulk storage stages. 

Diagram: Magnetic Cast Iron Bricks

Constructing with magnetic bricks completely sidesteps quotidian things like nuts and bolts. No scaffolding required either. The solutions for practical building with this material are not trivial: this will make demands of future robot constructors, but drone technology has developed enormously in recent years. The adaptation for space should be a sideways growth, not a radical step forward.

How thick should an iron wall be? This depends on: the size of the construction; the forces upon it. In the weightlessness of space, it might seem that very little is needed. And actually, we could get by with just enough iron to form an outer shell* if we use high tensile strength ribbons as structural reinforcement, especially if a rotating station is desired. Iron is better in compression that tension, and rotation, combined with internal atmospheric pressure (if any), will apply tensile forces to our structure. So, we can wrap it up with ribbons to reinforce. 

The bricks do not necessarily have to be solid; I have considered box sections that might be sandwiched between an outer and inner layer. The cavity can be usefully employed; in my imaginative forays I have considered the consequences of a significant meteoroid impact, like a fist sized rock punching a hole. Balloons that expand automatically, perhaps, coupled with fast setting foams to plug the hole. Anyway, digressing. 

The bricks can be magnetized in one of three possible orientations. each resulting in different tiling patterns as shown below:

There are 3 types. 1 and 3 give the same result, superficially, by providing the same thickness, but 3 wins because of the overlapping. Cold welding is a factor. Type 2 gives best surface area at the cost of thickness, which I assume to be less desirable in space. An unknown parameter is the protective effect of magnetic iron to space radiation. 

*How big is an outer shell? Frankly, it could be huge. I will be positing my ideas for iron space constructs in future posts, and I think the first will be a design for an LSE counterweight. 

The Next Iron Age

This new Blog was created to support my website 'The Next Iron Age'. Although there are tools for blogging, they didn't work when posts were published. The webpage would just hang and do nothing. So this is to get around the hassle of editing a whole page of entries whenever I want to post something, anything new will be added here instead.