yes you are on the right lines here (and you shouldn't be surprised that you can attach things to a physical process as these are generally how the concepts are derived in the first place)
In general though, you should be surprised if you're not annoyed at what seems like an 'overly abstract & detached from material foundation' analysis, in the first three chapters of Capital. It's been mentioned a lot of times before, but in these sections a lot of stuff is just presented as though it's a priori true - with little reasons or even hints as to why Marx thinks these are true
This comes down to a difference between his method of exposition (i.e. starting Capital with some fairly abstract concepts) and method of enquiry (i.e. the real world observations that leads to these concepts developing)
So while in Capital it may looks like the abstract stuff comes before (or in the absence of) the concrete, this is just how it's setout - the method of inquiry, i.e. the way he got to those concepts is very much the real/concrete analysed and then the concepts built around it
This diagram below gives a pretty good overview of Marx's dialectical method of enquiry, which should give you some comfort as to how the things you are reading in those early three chapters actually came around
So briefly:-
Moment 1 is the observation of the concrete and the appropriation of the material in detail
Moment 2 sees that material used to develop first simple abstract concepts and then on to more complex/richer concepts to establish a 'totality of thoughts', it's the logical construction of the essence and the interconnected organic whole, i.e. the understanding of the inner connections and them as a totality
Moment 3 continues the logical process, but not in terms of essence, but in terms of how that essence appears, how to explain that appearance and the various forms in which the essence is manifested, and indeed how that totality of that essence must appear
So Moments 2 & 3 are still theory and conceptual at this stage, Moment 4 then goes on to relate the concepts that have been generated to the real concrete world, the testing stage so to speak. Here is when the 'concept of the real' and the 'concrete in the mind' (i.e. the abstract thought developed in moments 2 & 3) is reconciled to the real objective concrete, which is also a return to the starting point and the point of departure again as the process goes on and on.
As Marx says of this process in the
afterword to volume 1:-
Of course the method of presentation must differ in form from that of inquiry. The latter has to appropriate the material in detail, to analyse its different forms of development, to trace out their inner connexion. Only after this work is done, can the actual movement be adequately described. If this is done successfully, if the life of the subject-matter is ideally reflected as in a mirror, then it may appear as if we had before us a mere a priori construction.
My dialectic method is not only different from the Hegelian, but is its direct opposite. To Hegel, the life process of the human brain, i.e., the process of thinking, which, under the name of “the Idea,” he even transforms into an independent subject, is the demiurgos of the real world, and the real world is only the external, phenomenal form of “the Idea.” With me, on the contrary, the ideal is nothing else than the material world reflected by the human mind, and translated into forms of thought.
This moment 4 in the whole thing is the real test of the results of the power of the abstraction (done in steps 2 & 3) and thus is absolutely critical. An example of this process in action is highlighted by Marx in a
letter to Engels in the year Capital Vol1 was first published
As regards Chapter IV, it was a hard job finding things themselves i.e., their interconnection. But with that once behind me, along came one Blue Book after another just as I was composing the final version and I was delighted to find my theoretical conclusions fully confirmed by the facts. Finally, it was written to the accompaniment of carbuncles and daily dunning by creditors!