Ask a corrosion technician anything...

Originally Posted by Bemwe_03i

I got couple of rust spots (< than 1mm) from rock chips in the a pillar, will cleaning these the applying paint over it solve the problem?
Also when i wash my car i apply a coat of spray on wax does this do anything good? Usually in the areas where its in contact with water.

If you do a thorough job of cleaning the areas and make sure you remove all traces of what you used to prep the surface, then you will be good. The tricky part is when you only treat the obvious area of exposed metal and fail to realize the paint that exist around the chip a bit has delaminated out a little further (even on a microscopic level) and you don't clean out the contaminants well enough...and then reseal it all...you will wonder why it is rusting again (not knowing you missed some). Best bet is to take back the paint a little way away from the initial chip and then fix.

Originally Posted by farmdog

Great answers.....you really know your chit.
Well done.

The theory of basic corrosion is really a simply concept (makes me wonder how I get away with the paycheck I do). Your hot water heater has an anode in the center that protects it from corroding...they base the warranty of the expected life span of that anode. A battery is a corrosion cell: A high energy source coupled with a nuetral/low energy source creates a driving force aka power. It is everywhere, in more places than most realize.

Is that a steel that is extremely resistant to rust out there that could have a future?





I know there is a cutlery grade steel coming out from Japan with Carbon replaced with Nitrogen, thus it has an uncanny resistance to rust

Originally Posted by k2pilot

Figured as much... I guess all main components would have to be galvanized, and maybe make all the "rusted" panels purely cosmetic and interchangeable.


What would you advise as the best metal for a main housing structure that would be low maintenance and long life-span, in terms of corrosion?

Something plumbers and others deal with is that fact that two different metals contacting eachother can cause corrosion. Different metals have different energy levels. Think of how one metal takes a much higher temperature to melt than another, this is because they are different compositions. So, if you couple steel with copper...the copper (?...haha, have to look at my metallurgy charts to refresh) will corrode and the steel will stay intact. Remember that science class in high school where they took a penny and plated it with silver from a nickel using a battery? That is corrosion happening due to the different energy levels of the copper penny and silver nickel....albeit a little influence to react faster by the presence of the battery.

As far as what material is best: I'd have to look into that one for you, I'd be bullshitting if I said I knew off hand.

I think the best bet would be to do as you say. Make a strong metal core with a exterior layer of rusted panels, designed in a way that they could be replaced relatively easy (remember though, they will still have a decent life span so it wouldn't need to be the primary focus when designing...just not impossible). Put non-metallic spacers in between the two (insulation even) and you can prolong the life.

Originally Posted by xtestifyx

Is that a steel that is extremely resistant to rust out there that could have a future?





I know there is a cutlery grade steel coming out from Japan with Carbon replaced with Nitrogen, thus it has an uncanny resistance to rust

The more pure the steel the better resistant to corrosion it is due to lack of contaminants. That said, it cost a lot of money to produce that quality of metal and it is often seen as uneconomical to invest that much into the product because:

- Most buyers will not understand/appreciate the elevated price for the quality steel
- You can produce two/three/four times the amount of "normal" grade steel for the cost of one unit of top tier grade steel. Why make a structure last 200 years when made of expensive steel...then we would being paying a much higher cost for things upfront and loose work in the long run when nothing needs repaired/replaced.
- I would be out of a job....FU

That said, there is a small demand for very high quality metals. Think the metal they put in someones hip....that needs to be good enough to last the entire span of projected use and more. They actually reuse metal parts that were once inside a person who is cremated...quality stuff made to last a long time...also why metal hips are pricey!

Nitrogen is a noble gas and not very reactive, thus can help resist a corrosion reaction in the metal...so yea, makes sense to me that they'd use it.

Awesome. Great response!

I'm not squeezing the metallurgist out of you, but can you tell me what these elements do to steels? I know what some of them do, but I'd like to hear from you

Chromium
Cobalt
Copper
Manganese
MolybdenumNickel
Phosphorus
Silicon
Sulfur
Tungsten
Vanadium

Thanks in advance

Originally Posted by Jmanscotch

That said, there is a small demand for very high quality medals. Think the metal they put in someones hip....that needs to be good enough to last the entire span of projected use and more. They actually reuse metal parts that were once inside a person who is cremated...quality stuff made to last a long time...also why metal hips are pricey!

Nitrogen is a noble gas and not very reactive, thus can help resist a corrosion reaction in the metal...so yea, makes sense to me that they'd use it.

I agree with the minimal demand of High grade metals. I think they're using Titanium to make Bolts and such to put into people's spines

I am coming from Cutlery, where only a very small portion of people go for the best available since it's cost is high in comparison. While the difference in performance is quite drastic, most people look at Cutlery as if it didn't matter much

Originally Posted by xtestifyx

Awesome. Great response!

I'm not squeezing the metallurgist out of you, but can you tell me what these elements do to steels? I know what some of them do, but I'd like to hear from you

Chromium
Cobalt
Copper
Manganese
MolybdenumNickel
Phosphorus
Silicon
Sulfur
Tungsten
Vanadium

Thanks in advance

Definitely a good bit out of my league as most of those are things we do not deal with.

That said, I know sulfur is very bad with any metal!

You seem to have an interest in details. This website offers some resources on metals and corrosion...may not cover a lot of what you are interested in but it is a starting place to browse for some stuff - NACE-National Association of Corrosion Engineers: http://events.nace.org/library/libraryindex.asp

Originally Posted by Bemwe_03i

I got couple of rust spots (< than 1mm) from rock chips in the a pillar, will cleaning these the applying paint over it solve the problem?
Also when i wash my car i apply a coat of spray on wax does this do anything good? Usually in the areas where its in contact with water.

Here is a quote from the above linked website that outlines the inportance of surface prep better than I did:

"Surface preparation is the essential first stage treatment of a substrate before the application of any coating. The performance of a coating is significantly influenced by its ability to adhere properly to the substrate material. It is generally well established that correct surface preparation is the most important factor affecting the total success of surface treatment. The presence of even small amounts of surface contaminants, oil, grease, oxides etc. can physically impair and reduce coating adhesion to the substrate. (reference)

Chemical contaminants that are not readily visible, such as chlorides and sulfates, attract moisture through coating systems resulting in premature failure. In summary, the importance of a chemically clean substrate to provide the best possible contact surface for the applied coating cannot be over-emphasized."

More:

Edit: Maybe I should just prove the link: http://events.nace.org/library/corro...el-surface.asp

Originally Posted by Breyton-BMW

I got some type on zinc anode in there already.

Some more material for you if interested: http://events.nace.org/library/corro...troduction.asp

Originally Posted by xtestifyx

Awesome. Great response!

I'm not squeezing the metallurgist out of you, but can you tell me what these elements do to steels? I know what some of them do, but I'd like to hear from you

Chromium
Cobalt
Copper
Manganese
MolybdenumNickel
Phosphorus
Silicon
Sulfur
Tungsten
Vanadium

Thanks in advance

lol... all of those metals are in my chef knives

http://dl.dropbox.com/u/20861315/IMG_0482.JPG

picture is very large.. it is of my car.
what should i do to fix it that isn't very expensive and something I can do?

this is in front of the front passenger door..

what are some of the worst plants you've been to? The cleanest? Have you ever tested a running line and found that it was beyond its corrosion allowance? Did you have to shut it down?

Found the galvanic chart listing some of those metals. Basically, the higher up on the scale you find something that is paired with steel, the bigger the potential difference is and the more likely it is to create a corrosion cell.

Active (Anodic)

1. Magnesium
2. Mg alloy AZ-31B
3. Mg alloy HK-31A
4. Zinc (hot-dip, die cast, or plated)
5. Beryllium (hot pressed)
6. Al 7072 clad on 7075
7. Al 2014-T3
8. Al 1160-H14
9. Al 7079-T6
10. Cadmium (plated)
11. Uranium
12. Al 218 (die cast)
13. Al 5052-0
14. Al 5052-H12
15. Al 5456-0, H353
16. Al 5052-H32
17. Al 1100-0
18. Al 3003-H25
19. Al 6061-T6
20. Al A360 (die cast)
21. Al 7075-T6
22. Al 6061-0
23. Indium
24. Al 2014-0
25. Al 2024-T4
26. Al 5052-H16
27. Tin (plated)
28. Stainless steel 430 (active)
29. Lead
30. Steel 1010
31. Iron (cast)
32. Stainless steel 410 (active)
33. Copper (plated, cast, or wrought)
34. Nickel (plated)
35. Chromium (Plated) 36. Tantalum
37. AM350 (active)
38. Stainless steel 310 (active)
39. Stainless steel 301 (active)
40. Stainless steel 304 (active)
41. Stainless steel 430 (active)
42. Stainless steel 410 (active)
43. Stainless steel 17-7PH (active)
44. Tungsten
45. Niobium (columbium) 1% Zr
46. Brass, Yellow, 268
47. Uranium 8% Mo
48. Brass, Naval, 464
49. Yellow Brass
50. Muntz Metal 280
51. Brass (plated)
52. Nickel-silver (18% Ni)
53. Stainless steel 316L (active)
54. Bronze 220
55. Copper 110
56. Red Brass
57. Stainless steel 347 (active)
58. Molybdenum, Commercial pure
59. Copper-nickel 715
60. Admiralty brass
61. Stainless steel 202 (active)
62. Bronze, Phosphor 534 (B-1)
63. Monel 400
64. Stainless steel 201 (active)
65. Carpenter 20 (active)
66. Stainless steel 321 (active)
67. Stainless steel 316 (active)
68. Stainless steel 309 (active)
69. Stainless steel 17-7PH (passive)
70. Silicone Bronze 655
71. Stainless steel 304 (passive)
72. Stainless steel 301 (passive)
73. Stainless steel 321 (passive)
74. Stainless steel 201 (passive)
75. Stainless steel 286 (passive)
76. Stainless steel 316L (passive)
77. AM355 (active)
78. Stainless steel 202 (passive)
79. Carpenter 20 (passive)
80. AM355 (passive)
81. A286 (passive)
82. Titanium 5A1, 2.5 Sn
83. Titanium 13V, 11Cr, 3Al (annealed)
84. Titanium 6Al, 4V (solution treated and aged)
85. Titanium 6Al, 4V (anneal)
86. Titanium 8Mn
87. Titanium 13V, 11Cr 3Al (solution heat treated and aged)
88. Titanium 75A
89. AM350 (passive)
90. Silver
91. Gold
92. Graphite

End - Noble (Less Active, Cathodic)

Originally Posted by scott0482

http://dl.dropbox.com/u/20861315/IMG_0482.JPG

picture is very large.. it is of my car.
what should i do to fix it that isn't very expensive and something I can do?

this is in front of the front passenger door..

If you arn't afraid of giving prep and paint a go, I don't see why you couldn't give it a shot...worse case you end up paying someone to do it right...which you would do anyways if you didn't try.

Take the skirt off to get better access, sand down to bare metal a spot maybe twice the size of what it is now, clean with some cleaning agent (there are good/commonly used items for paint prep out there), dry well, give the surface a good profile for the primer/paint to adhere to, then prime/paint.

Originally Posted by 325max

what are some of the worst plants you've been to? The cleanest? Have you ever tested a running line and found that it was beyond its corrosion allowance? Did you have to shut it down?

Work in refineries eh?

Worst, in terms of infrastructure condition: Tie between Mid Valley Pipeline and Buckeye Pipelines (in regards to petro)....other than that, any natural gas company. NG companies tend to skirt by the law a bit due to their shear size and network of systems. With all of their recent attention due to exploding lines killing people...they are getting cracked down on quickly and are about to be forced to spend MAJOR, aka billions and billions, of greenbacks to get their infrastructure up to regulation.

I was doing an audit for a 20" crude oil line in Lima, Ohio. The local BP-Husky refinery decided since no one was claiming this 50+ year old line that existed (record keeping in the old days was horrible, ofcourse) that they were going to claim it and use it to pipe product to a nearby terminal. The audit showed there was no system in place that was providing corrosion protection to the pipe (duh, no one knew who owned it so who was going to invest money into it?!) but when they saw the six figure price of digging up sections to complete visual inspections of it...they weren't interest and went ahead and started using it. Two months later, they have a nice leaking pipeline with the EPA breathing down their necks over it. They tried to say they were "leasing" the use of the pipeline and therefore not responsible for the spill...but they had no one to point the finger of ownership at

Best upkept systems: Sunoco. Toledo and NY have refineries that I've been in and they stay on top of their ****.

We are a contracting firm, we design, install and audit the industry. EPA and DOT get to play the part of deciding what to due with the information we report.

Originally Posted by JJR4884

lol... all of those metals are in my chef knives

Not all lol. A lot of those are only in the finest.

You won't see anything special in a Shun, just VG 10 and it's nothing special

Hi, I am in the ndt field and work with a corrosion inspector time to time. Do you do any work in boilers or paper mill? Most of the corrosion inspector I encounter are in the storage tank field (jp8 - jet fuel).

Originally Posted by INsXTC

Hi, I am in the ndt field and work with a corrosion inspector time to time. Do you do any work in boilers or paper mill? Most of the corrosion inspector I encounter are in the storage tank field (jp8 - jet fuel).

We do some nondestructive testing, but with the cost of getting everyone certified for that sorta stuff...we pretty much let the other more specialized companies keep that market (we have enough cost regarding certifications as it is and just cannot break into the market enough to justify the expense).

We mainly deal with external corrosion and therefore don't mess with boilers.

The guys you know that work around the storage tanks would be more along the lines of what we do. We mainly deal with the crude and refined oils, gasoline (jet fuel as well), butane, propane, kerosene, natural gas and a few others.

This thread is a lot more interesting then I thought it would be.

Originally Posted by Jmanscotch

Some more material for you if interested: http://events.nace.org/library/corro...troduction.asp

Thanks.

Originally Posted by sneaky

this thread is a lot more interesting then i thought it would be.

+1