Availability of Carpenter electrical iron and various stainelss alloys 1

[winflex]

I am in the process of prototyping a constant-force solenoid for a valving application. I used 1018 steel for the flux guide and 416SS for the armature until now, but would like to improve performance by using either a Carpenter electrical iron or 1002 steel for the flux guide as well as 430FR or Carpenter Chrome Core13 for the armature.

I called Carpenter and was told that I would have to buy several thousand pounds of electrical iron / Chrome Core13.

Two questions:

- Are there third party distributors that can supply these materials in smaller prototype quantities?
- Will I even get an appreciable increase in performance? I'm currently observing problems with residual magnetism, so a lower coercivity material may help. Also, more force with less MMF would be nice.

Thank you,

- Felix

 

[MagMike]

For prototype quantities of those materials, I would suggest Goodfellow:

http://www.goodfellow.com

They may not carry all of those, but they have a wide offering.

The reduced coercivity of those materials will likely help you, but I'd recommend annealing the parts after machining.

 

[remetaper]

About reduction of Hc , I fully agree with MagMike even if you could find bars ready to use (special mill annealing )
Which kind of shape are you looking for ? And which kind of execution ( ground bar, flat bar, Hex bar, special shape and so on ) There is no difficulties about round bar ( centerless ground ,peeled... ) of 430FR , 430F, 18.2FM and FeSi alloy as well.
I knew tha mainly Valbruna (Italy ) or Valbruna Stainlesss ( Huston and Fort Wayne ) have a large warehouse of these alloys and had a good Customer's Support in case of prototype project thank to his capaity to supply little quantity of bars.
The most important steelmakers of soft magnetic stainless steel are Cartech, Valbruna, Daido, Ugine talking about long products. The smaller steelmaker , the bigger capacity to find a little help.
Let me know what will happen ( obviously, if you like !)
Good luck !

 

[EdStainless]

Who are the guys in Connecticut that do low residual iron?

You could take your 1018 parts and give them a good long anneal in pure hydrogen and the performance would improve significantly. The bigger question is 'do you need to build tow of these that work the same?' If so then go to the trouble to buy the good stuff.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[israelkk]

I do not believe that changing the 1018 will help much. The "bottle neck" is the 416 or the 430 (the stainless plunger). Pure (solenoid quality) 430 is better than 430FR and 416 but the stainless plunger will always be the "bottle neck". If you can not achieve the force you require with 416 the 430 will not give you enough factor of safety anyway. Solenoid should have a minimum safety of factor of 1.5 for commercial use and 2 for aerospace and military use.

 

[davidmoul]

I was (I am actually but I lost hope...) looking for some 430FR in large dimensions to make large electromagnet, but it was impossible someone that can provide quantities for testing... The only way to get some would have been to order a complete batch (20 tons!).

If you find some, I would be really interested into it to! But for the time being, I spent a long time looking for such an alloy and the answer was always that it is only available in other forms than what I was looking for...

 

[winflex]

Thanks for all the feedback.

To answer davidmoul's question, I just received a .75" diameter piece of annealed 430FR round bar 12' in length from Schmolz & Bickenbach, a German steel manufacturer that does business in the states. They will sell prototype quantities, I paid $120 including shipping:

http://www.schmolz-bickenbach.us/index.php?id=5251

Israelkk, I agree that the most critical component is the armature, as the flux densities there are the highest. However, I am concerned with the high coercivity of 1018 and any residual magnetism this may imply.

I will have the 430FR pieces annealed in a hydrogen atmosphere after machining for optimal properties - will keep you posted on results.

- Felix

 

[dgallup]

Smoltz-Bickenbach bought Ugine to get their stainless lines. I've had free samples from them & Carpenter but we buy a lot of steel from both.

You have to do a flux density analysis to know what is the limiting factor. The 416 armature may not be the limiting factor if the sectional area is sufficient.

We have been letting LCS carbon content creep up over the years in our products with no detriment in performance. I'm sure there are other applications that need the very low carbon. There are a lot of grades between 1018 & 1002 that are very commonly used in magnetic devices, readily available and easy to form & machine. A lot of times it's the manufacturing process that dictates the grade.