Tie rods

[John C]

I saw on another board some folks asking about HD tie rods.

Just wanted to let you guys know that the tie rods sold by DAP are not stainless steel and they will start to rust very quickly. It happened on mine and other folks (a few of them posted on the other board but they did not admit it).

Just thought you should know. And BTW, we do not sell tie rods so I there is no "conflict of interest" here, just letting you guys know.

[SCSL]

Thanks John that is good to know.
Coincidently,,,,,,,,,,,,,, I've been looking at HD tie rods. Figure it's only a matter of time before I leave a tie, drag, or track in the field & need back-ups.

[jeffreydv]

I have the DAP tie rods and the do rust very quickly. I bought some paint for them but havent gotten around to painting them yet. I am very impressed with how heavy they are and feel they are worth buying.

Jeff
92 RRC

[TerryS]

File this in the 'FWIW' dept. There are many grades of stainless steel (actually, about 60) They are graded for Heat Resistance, Abrasion Resistance, Corrosion Resistance, UTS (Ultimate Tensile Strength) and a variety of combinations of those qualities. The most common , 'garden variety' stainless steels are the Austenitic grades,(like 304, 316) consisting of about 18% Chromium, 8% nickel, molybdenum in the 316s, and generally having a carbon content of .08% or less. Austenitic stainless steels are the grades generally used where corrosion resistance is required, such as in medical applications, and corrosive environments like seawater. These grades of stainless (70,000 psi average) have relitively low tensile strengths as compared to low alloy steels (as low as 90,000 psi, but commonly 105,000 and higher. Ductility is the mechanical property which permits a metal to distort and recover (or not) but not fracture. Ductility is measured in elongation, and reduction of area. Corrosion resistant stainless, the austenitics, are very ductile, but to be this way, they bend easily.
There are grades of stainless steels which posses very high strength, and also good ductility, with excellent corrosion resistance. They are in the Martensitic familie, and the best are the CA6NM (cast spec) and F6NM (forged spec) I have never seen an automotive product produced in these grades, it's too expensive.

For the non techies, what I'm saying here is, track rods, tie rods, things like that are not in my opinion parts which should be made in corrosion resistant alloys. That's what paint is for.

[John C]

Originally Posted by TerryS

File this in the 'FWIW' dept. There are many grades of stainless steel (actually, about 60) They are graded for Heat Resistance, Abrasion Resistance, Corrosion Resistance, UTS (Ultimate Tensile Strength) and a variety of combinations of those qualities. The most common , 'garden variety' stainless steels are the Austenitic grades,(like 304, 316) consisting of about 18% Chromium, 8% nickel, molybdenum in the 316s, and generally having a carbon content of .08% or less. Austenitic stainless steels are the grades generally used where corrosion resistance is required, such as in medical applications, and corrosive environments like seawater. These grades of stainless (70,000 psi average) have relitively low tensile strengths as compared to low alloy steels (as low as 90,000 psi, but commonly 105,000 and higher. Ductility is the mechanical property which permits a metal to distort and recover (or not) but not fracture. Ductility is measured in elongation, and reduction of area. Corrosion resistant stainless, the austenitics, are very ductile, but to be this way, they bend easily.
There are grades of stainless steels which posses very high strength, and also good ductility, with excellent corrosion resistance. They are in the Martensitic familie, and the best are the CA6NM (cast spec) and F6NM (forged spec) I have never seen an automotive product produced in these grades, it's too expensive.

For the non techies, what I'm saying here is, track rods, tie rods, things like that are not in my opinion parts which should be made in corrosion resistant alloys. That's what paint is for.

So Terry, your saying that because the tie rods start to rust very quickly does not mean that they are of inferior quality? Is that right? So we should probably spray paint the tie rods?

[Bogatyr]

John,
Yeah, I think that's the gist of what Terry mentioned...stainless, although corrosion resistant, has a lower tensile strength. So stainless parts that take a lot of stress, like recovery gear etc should be stayed away from.

Bogatyr

[TerryS]

Boggy's got it right, If you want strength, stick with low alloy steel. Anyone that tells you (as stated in certain ads) that their stainless fasteners have a tensile strength of over 100k is full of cackaloochie. 300 series Austenitic stainleass is quite soft, ductile and NG for Steering components. If it's ordinary hardware, that's fine, but not for applications like recovery mounts and that sort.
Most good automotive ball joints wouldn't be supplied in SS. Yes, aircraft Heym joints are, but firstly they are sized to the application, and secondly they may have been given heat treatments to elevate the tensile (at the expence of loosing ductility)
Why can't someone make a good set of Defender Door hinges out of 316? I would except the bank saw fit to shut me down 7 years ago, hence my early retirement and idle time to post nonsense on Lr bbs.
Forgot to add, re the rust issue, All carbon steels will rust (oxidize) except for certain proprietary alloys like Corten, a USS patent, and one by Bethlehem whose name escapes me. In fact they, too, rust, but it is the first layer of oxidation that prevents further oxidation. Actually, that's sort of how stainless works. The chrome levels in SS cause a chrome oxide that protects the base metal.
Good tierod ends will be a forged 8600 series alloy (NiCrMo) Something like 8640, and have a tensile in the 135K range.

[John C]

Originally Posted by Bogatyr

John,
Yeah, I think that's the gist of what Terry mentioned...stainless, although corrosion resistant, has a lower tensile strength. So stainless parts that take a lot of stress, like recovery gear etc should be stayed away from.

Bogatyr

So, a SS Warn Snatch Block is no good? How about parts that are Cad plated? Just curious...

[TerryS]

Originally Posted by John C

So, a SS Warn Snatch Block is no good? How about parts that are Cad plated? Just curious...

No, it's probably OK if it's designed for that material and has been up-sized to give it a cross sectional strength of Low alloy steel. Cad plating is ok for corrosion resistance, as would zinc. Any plateing which involves elevated temperatures (above the material's lower critical temp) should be stress relieved. Galvanizing is actually more a coating, rather than plating process. a fairly low temp treatment, which isn't likely to create induced stresses.
A Warn snatch block probably has a thicker cross section than an equivilant carbon steel block. Keep in mind, that application won't see stresses and loads like a steering component. Loads would be in the approx level as that the winch is pulling, i.e. under 10K

[onslow]

Originally Posted by John C

I saw on another board some folks asking about HD tie rods.

Just wanted to let you guys know that the tie rods sold by DAP are not stainless steel and they will start to rust very quickly. It happened on mine and other folks (a few of them posted on the other board but they did not admit it).

Just thought you should know. And BTW, we do not sell tie rods so I there is no "conflict of interest" here, just letting you guys know.

Im surprised such an item is made from stainless due to the constant change from tension into compression stainless by its nature does not like such forces and has a tendency to work harden and crack not really something you want in a track rod!!

[John C]

Originally Posted by TerryS

No, it's probably OK if it's designed for that material and has been up-sized to give it a cross sectional strength of Low alloy steel. Cad plating is ok for corrosion resistance, as would zinc. Any plateing which involves elevated temperatures (above the material's lower critical temp) should be stress relieved. Galvanizing is actually more a coating, rather than plating process. a fairly low temp treatment, which isn't likely to create induced stresses.
A Warn snatch block probably has a thicker cross section than an equivilant carbon steel block. Keep in mind, that application won't see stresses and loads like a steering component. Loads would be in the approx level as that the winch is pulling, i.e. under 10K

Gotcha!! Thanks alot for the info.