Resistors With Steel Leads

[dr pepper]

Heres some more confusion:
There are diffrent grades of stainless, the cheaper end 304 rust's, only the higher grade stuff such as 316 marine stainless is guaranteed not to rust.
I would have thought manufacts aiming to cut costs in the first place will use the cheaper grade.

 

[Tony Stewart]

I defer to OEM specs like Kemet who have been around for almost 100-yrs and survived many market shifts.

ROHS Standard: 100% matte tin (Sn) with nickel (Ni) underplate and steel core ( “T” designation).
Alternative 1: 60% tin (Sn)/40% lead (Pb) finish with copper-clad steel core ( “H” designation).

 

[MrAl]

This thread was about ordinary resistors, not some special purpose device for which you don't have any details.

Before we go further down the new tangent, please define what you mean by "qualifies as a stainless steel." That is, is any alloy that contains chromium and iron a "stainless steel" regardless of the relative proportions each metal or the inclusion of other metals and non-metals in the alloy?

John

Hello,

New tangent? What new tangent? We're talking about resistors right? We then started talking about resistors with stainless steel leads rather than just plain steel leads, and you did not believe it would be reasonable to have a resistor with SS leads even though in other places in the thread other members mentioned rusting resistor leads of ordinary resistor leads that must have been made from plain steel. At the very least, i would think that would tell you that it might not be such a bad idea

It makes sense to me that if we had a lot of resistors with plain steel leads and they worked ok to begin with but the leads rusted after a time that we would be able to improve the design with stainless steel leads instead of plain steel leads. That way we'd have the usual resistor but with longer lasting leads.

And i dont see any tangent here because this "new" resistor is just a power resistor that is made to be able to endure in more harsh environments. As i am sure you know, chromium is added in order to improve certain properties of steel. One is hardness, the other is resistance to corrosion. The name "stainless steel" is a friendly name, that helps to recognize the properties of the steel over some other major type of steel. In order for it to qualify as a stainless steel it would have to contain chromium, and the percent to qualify varies depending on who makes the steel. It's usually over 10 percent, but in general the more chromium that is added the better the corrosion resistance.
So we can ask the question, if we want to make a metal with base metal of iron that is corrosion resistant, what should we do? We should add chromium.
We can also ask the question, if someone made a metal from iron and chromium and tout it as being corrosion resistant, what kind of metal is it likely to be?
For this particular product we can also ask, if they made a metal from iron and chromium and wanted it to be able to withstand a harsh sulfer rich environment, then what approximate percentage chromium should we use? We would make the metal some 18 percent chromium or higher. Then we can ask, what would we probably call a metal that contains iron and 18 percent chromium that can be used in a very harsh environment? I'll leave that answer up to the reader


So in short, i dont see any problem talking about a power resistor where the leads and the whole body are made of stainless steel, and i would not have any problem calling that metal stainless steel knowing only two of the metals it contains are iron and at least 18 percent chromium. At the very least it would add to the info we get from the information gathering process when a question comes up.

 

[jpanhalt]

Hello, MrAl

Here is what you said earlier:

For one example, Vishay sells a "Metal Strip" resistor made of a proprietary mix that includes at least iron and chromium which i think qualifies it as a stainless steel...

I was simply reacting to the underlined statement, which is incorrect and am glad you have looked up the definition of stainless steel. As you now know, there are many alloys of steel that contain chromium and are not considered to be "stainless." 4130 "moly" is a common example of one such alloy. Now, if the alloy used by Vishay in the resistor you mentioned is proprietary, are you sure it has at least 18% chromium and qualifies as stainless?

Like you, I have no problem discussing the use of stainless steel in electronic components; however, I don't think this thread was started with that object in mind. I have worked a little with stainless, including welding thin-wall 321 alloy mufflers, and would prefer plated mild steel to any of the stainless steels with which I have worked for ease of soldering and cutting.

Regards, John

 

[MrAl]

Hello, MrAl

Here is what you said earlier:


I was simply reacting to the underlined statement, which is incorrect and am glad you have looked up the definition of stainless steel. As you now know, there are many alloys of steel that contain chromium and are not considered to be "stainless." 4130 "moly" is a common example of one such alloy. Now, if the alloy used by Vishay in the resistor you mentioned is proprietary, are you sure it has at least 18% chromium and qualifies as stainless?

Like you, I have no problem discussing the use of stainless steel in electronic components; however, I don't think this thread was started with that object in mind. I have worked a little with stainless, including welding thin-wall 321 alloy mufflers, and would prefer plated mild steel to any of the stainless steels with which I have worked for ease of soldering and cutting.

Regards, John

Hello there John,

Now that you mention it i never tried to solder SS i dont think, but i have soldered mild steel and found it to be harder to solder than copper but i was still able to solder it. I even went as far as used mild steel for a soldering iron tip because it lasted longer than copper and i got tired of buying the copper tips.

I reasoned that the choice of SS for sulfer rich environments would contain at least 18 percent chromium in order to properly resist corrosion from such an environment. That led me to believe that *most likely* there is at least 18 percent chromium in the mix. Sure i can not be sure of this percentage, but it makes sense unless the maker did not know enough to use enough chromium. But they do mention iron and chromium, and they do mention resistance in a sulfer rich environment, so i would think it would be some form of SS or at least something like it. I guess the question i might ask is why wouldnt they use SS, and why wouldnt it be reasonable to call it SS given the main metals are iron and chromium.
Since your answer could very well be, "It could be another metal", that's fine, but then you should show that it is a metal that is commonly used in sulfer rich environments. You may find one, although i dont think that necessarily voids the discussion anyway because we might find one that does specifically state that SS is the metal, and at the very least we could actually make a resistor ourselves that uses any type of SS we care to for leads (or body or both), and that way we'd have a resistor with SS leads The main question seemed to be if we did have one, what properties would change. Apparently the permeability would change over that of plain steel. I think that's the main issue.

 

[KeepItSimpleStupid]

FWIW: A copper clad center conductor in RG-6 is common.

 

[Tony Stewart]

I agree K.I.S.S.
Surprising, perhaps, performance is identical for CCS (Copper Clad Steel) and Bare Copper (BC) Center Conductor Honeywell RG-9 as rated from 5 MHz to 3GHz 75Ω. Skin effects dominate the impedance by the ratio of outer radii for outer/inner conductor to define Zo.

 

[KeepItSimpleStupid]

The only performance that degrades is when using the RG-6 for running a rotator like I am. I have a really cool Eagle Aspen RORT100 rotator that isn't made any more.

Aside:
It's quirky, but built really nice. I changed the mounting studs to stainless, but did not powder coat the brackets. I also added a TB-105 support bearing.

It uses the DISEQ-C protocal (think open-source satellite positioning) over coax. I'm using separate control and pre-amp lines. Pre-amp DC injected from an attic supply. I think it uses pic processors and has to store the positions each time it moves, thus I suspect that it may be write cycle-limited. Rotation is > 360 degrees. Reason why I suspect that is, a power failure won't cause movement or re-synchronization.

It does not report the "actual position" when rotating. The lack of substantial current draw tells the box that it's at position.
There are some home-brew controllers for other rotators that use accelerometers for position.

 

[dr pepper]

Hey JP, I worked at Bosal here in the UK, they used to make mufflers, tube and full exhaust systems.
304 lasted longer than aluminized steel, but it still rotted away in the end.

 

[MrAl]

Hi,

Yeah i have read that there are many different grades with higher or lower chromium content, but they seem to need a certain environment in order to maintain their protective outer layer. Without that they have problems too.

Next up: Resistors with uranium leads

 

[spec]

Hey JP, I worked at Bosal here in the UK, they used to make mufflers, tube and full exhaust systems.
304 lasted longer than aluminized steel, but it still rotted away in the end.

This is nothing to do with resistors, but I know Bosal, because I always fit their exhaust systems to my old Peugeot 406. Any other make, although cheaper, are noisey, don't fit properly, and don't last as long.

About stainless steel: there are many types, but in very broad terms, there is engineering SS or 60/40, which does rust to a degree, but it retains the characteristics of mild steel to a degree. Then, at the other extreme, there is bright stainless which kitchen sinks and the like are made. Bright SS is hard, relatively brittle, and awkward to work, but does not rust.

 

[MrAl]

Hi,

Yeah SS products made for the food industry last a very long time. Had an article made like that, stood outside for years but you'd never know it from the appearance. Try cutting it though...good luck

 

[spec]

Hi,

Yeah SS products made for the food industry last a very long time. Had an article made like that, stood outside for years but you'd never know it from the appearance. Try cutting it though...good luck

Too true but, if you don't want to do any sharp bends, you can make some really nice items from bright stainless. I always use SS fittings and fixtures, unless prohibitively expensive. SS is also approximately 4x stronger. A shower control in our bathroom kept comming loose and after being tighened serveral times the thread would go. In the end I got fed up and got a SS replacement bolt- not only does the control work better and feel more solid, but it has never come loose again. The bolt cost a bit though: £0.50

I hate to see gutters down pipes and cladding etc held in place with fixings that rust- with a light coloured finish you get ugly brown staining and ultimate failure. On the last house that I refurbished the SS fittings were like new after 25 years.

It beats me why SS is not used more universally, especially on cars; it can't be on cost grounds. In the UK a typical family car costs around £15K UK, £2K UK of that is spent on advertising.