"Wear It's At"
Volume 2 Issue 6
Friday, November 3, 2000
In This Issue
1. Welcome and Thanks
|Microhardness in Vickers (Approximate Values)|
|Iron Carbide (Fe3C)||1100|
|Chromium Carbide (Cr7C3)||1800|
|Molybdenum Carbide (Mo2C)||1800|
|Tungsten Carbide (WC)||2100|
|Tungsten Carbide (W2C)||2500|
|Columbium Carbide (CbC)||2400|
|Vanadium Carbide (VC)||2800|
|Titanium Carbide (TiC)||3200|
Judging from the hardness of all the reported carbides above, one might ask why don't we use more Titanium in Chromium Carbide alloys or other alloys for that matter? Well, the answer is quite simple. Titanium also loves Oxygen and Nitrogen, almost as much as it does Carbon and therefore forms very tenacious slags on weld deposits. It is simply to active to be a strong contender for serious wear resistant materials. But we are always working on it. (In another life I co-published a paper on Titanium
Carbide weld deposits and is available by simply emailing me at email@example.com . Be glad to send you a copy.
Judging from the hardness of all the reported carbides above, one might ask why don't we use more Titanium in Chromium Carbide alloys or other alloys for that matter? Well, the answer is quite simple. Titanium also loves Oxygen and Nitrogen, almost as much as it does Carbon and therefore forms very tenacious slags on weld deposits. It is simply to active to be a strong contender for serious wear resistant materials. But we are always working on it. (In another life I co-published a paper on Titanium Carbide weld deposits and is available by simply emailing me at firstname.lastname@example.org . Be glad to send you a copy.
Aside from forming hard Carbides, Carbide forming elements as mentioned above, also have a contributory effect upon the matrix. It has been observed that various amounts of austenite will be transformed to martensite in Iron base Complex Chromium Carbide weld deposits. The extent to which martensite formation occurs is not known to this writer, but observations with a Ferrite Gage in which magnetism is measured in Austenitic Stainless Steels, suggests that martensite formation is significant.
In addition to the above effects on weld deposits, it has been observed microscopically, that Complex Chromium Carbide alloy deposits exhibit a finer Chromium Carbide structure. From an abrasion viewpoint this appears to be advantageous. It is known that large blocky Chromium Carbides or Primary Carbides have a tendency to fracture and fall out under stress and therefore contribute to the overall wear of the component. This can be observed in the wear scars of some ASTM G 65 test results. We also know that many of the Carbide formers such as Molybdenum, Vanadium, and Titanium for example, act as nucleation sites for Chromium Carbides. This theory suggests that because there are more sites for Chromium Carbide formation, the resulting deposit structures have a greater volume of Carbides, but much smaller in actual size. It then follows that the smaller Carbides inherently have a greater total perimeter to be held in place by the matrix. Extending this theory further, one would assume that wear resistance would increase simply because these Carbides will not fracture as easy as large blocky Carbides. Field results appear to confirm this theory.
Our discussion could go on even further to include theories regarding Carbide shape and orientation, but I feel that these topics are well outside the scope of this newsletter.
Suffice it to say that "Complex Carbides Are Complex". Everything about them appears to be complex. One thing for sure though; they are the wave of the future for extreme wear conditions. Postle Industries Inc., Cleveland, Ohio has a number of these alloys for applications involving extreme abrasion and high temperature.
Postalloy 2836 SPL & Postalloy 2839 SPL
These are small diameter wires suitably formulated for out-of-position welding. An excellent product for field and shop applications.
Since we have covered the topic of Chromium Carbide deposits it would only be natural to follow up our understanding of other Carbide systems. Our next issue will therefore deal with TUNGSTEN CARBIDES. These are powerful wear resistant deposits and have some unique properties. Hope you will enjoy the discussion.
Aviation History Month
Epilepsy Awareness Month
International Drum Month
National American Indian Heritage Month
National Author's Day
National Diabetes Month
National Hospice Month
National Sleep Comfort Month
Peanut Butter Lovers Month
Nov 1-Jan 1 - Tie One on for Safety
Special Weeks in November:
1-7 - World Communication Week, Vegan Awareness Week
6-12 - Random Acts of Kindness Week
7-13 - National Chemistry Week, National Split Pea Soup Week
8-14 - Pursuit of Happiness Week, Shallow Persons Awareness Week
12-18 - American Education Week
14-20 - National Geography Awareness Week
15-21 - Nat Children's Book Week
21-28 - National Bible Week
Special Days in November:
1-2 - Day of the Dead
2 - Plan Your Epitaph Day, National Men Make Dinner Day
4 - Will Rogers Day
6 - Sadie Hawkins Day
8 - Abet and Aid Punsters Day
11 - Martinmas, Vox Populi Day
12 - America Recycles Day
13 - World Kindness Day
14 - National American Teddy Bear Day
15 - George Spelvin Day
17 - World Peace Day, Homemade Bread Day
19 - Have a Bad Day Day
20 - United Nations: Universal Children's Day
21 - World Hello Day
22 - National Stop the Violence Day, Feast of Saint Cecilia (Patron Saint of Music)
23 - Thanksgiving Day
30 - Computer Security Day, Stay Home Because You're Well Day
If it weren't for our sponsors, this newsletter would not be possible. Please consider their products and services in all your future wear related needs. Thank You.
Postle Industries Inc. http://www.postle.com . Postle offers a complete range of hardface welding alloys to protect equipment from all types of wear.
Sure Alloy Steel Corporation (http://www.surealloy.com) Wear Control - Design, engineering, and fabrication with over 40 years experience.