The BH curve is very helpful and should suffice. My problem is basically as follows: I have built magnetic circuits using solid material, i.e. 1018 or equivalent. Now we have a box type geometry and we need to weld. Someone brought up the concern about the welded joints not being a sufficient path and possibly causing ~ 1% change in the field at the point of interest (about 300mm away from the joint). I am debating that the welded joint only causes very local(to the joint) changes to the field probably on the order of 0.01% or less. The magnetic inductance of the circuit is virtually unchanged although local permeability may vary due to the heat affected zone of the weld. Post annealing may eliminate this altogether.
His argument might be that at the joint there could be a gap between the welded parts so that most of the flux is forced to go through the small area of the weld.
What is the flux density of the steel circuit at that point now. A gap will not help you but if your geometry overlaps with out a gap and you are below saturation than a weld is not much of an issue. Subtract the area effected by the weld and see what the effect is in an FEA solution. That would be worst case. If the circuit is corner to corner with a fillet weld it is a bad design.
Going back to the original question about the BH curve for 1018, I was also looking for this information and got the information from the link. The software I use only has 1008 and 1010 low-carbon steel values in its standard material library. Now I'm a little confused. From my software, at H=318310, B=2.485 for 1008 and B=2.4 for 1010. From the information on 1018, B=2.43 at this H. Shouldn't the B for 1018 be lower than 2.4 Tesla, because of the higher carbon content? I'm working on a solenoid that operates in saturation and trying to correlate the model which I designed in 1008 and the sample I had made with 1018 steel.
The heat treatment and/or mechanical working of the steel play significant roles in magnetic output. That's probably why you see different numbers.
Most 10XX series steels are not processed with magnetic properties in mind, so you're going to see a lot of variation.
One should only consider published BH curves as approximate (same goes for that supplied by your software). Going from 1008 to 1018 (assuming the heat treat and mechanical work is similar) is only going to cause 2 to 3% change in output.
