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"Wear It's At"
Volume 2 Issue 4
Thursday, May 25, 2000
In This Issue
2. Love Bug Virus
3. Carbides - Part II Chromium Carbide
4. Beer Swill
Welcome aboard to all the new subscribers. Our list is growing by the day. Please feel free to contribute articles, topics, or just plain questions. I encourage your participation as I'm sure all who receive this newsletter do.
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2. Love Bug Virus
Hope you haven't been hit by the Love Bug virus. There are many strains, so it still pays to be very cautious about attachments to your emails. Tip: when sending emails with an attachment, be sure to identify yourself somehow to your intended reader, explaining the attachment, etc. Anything that will give your reader confidence that the email is truly from you and that opening the email is OK.
The love bug was termed a " vbs" virus. Microsoft has suggested a disarming of your system to prevent a vbs virus from harming your hard drive. Simply go to Control Panel/Add/Remove Programs/Windows Setup/Accessories/Details and uncheck the "Windows Scripting Host" feature. I have done that in addition to making sure my virus protection is up to date.
3. Carbides - Part II
In the last issue we discussed the role of carbon and touched briefly on Iron Carbide. In this issue we want to take a look at Chromium Carbides. Chromium Carbides represent the largest use of carbides in hardfacing. There are many alloys that utilize this family of carbides. Why are they so popular? Ferro Chrome, a powder form of (Iron + Chromium + Carbon), from which Chromium Carbides are formed, is relatively inexpensive and readily available to electrode manufacturers. Carbon
loves Chromium and forms various marriage combinations, depending upon the amount of each in the molten state. The various forms are very hard ( about 1700HV ), large and unlike Tungsten Carbide (WC) which sinks to the bottom of the melt, is evenly dispersed throughout the thickness of the deposit.
Chromium Carbide alloys can be broken down into 3 distinct categories and vary in abrasion resistance.
1. Medium Chromium Carbide (Moderate Abrasion - Good Impact)
2. High Chromium Carbide (Good Abrasion - Moderate Impact)
3. Complex Chromium Carbide .(Excellent Abrasion - Poor Impact)
Medium Chromium Carbide:
Typically these alloys are about 15% Chromium - 3.25% Carbon. Small additions of Manganese and Silicon are added to cleanse the steel. The remainder is Iron. As the weld deposit cools form the molten state down to room temperature, Chromium performs a dual role. First it forms a non-magnetic mixed form of iron, known as Austenite. This phase of Iron is tough and acts as the glue, so to speak, that holds the carbides together. Second it forms Chromium Carbides that often are dispersed
along grain boundaries in the Austenite grains. The resulting deposit is rich in both components and lends itself to applications that require moderate abrasion resistance and good impact resistance. Rock crushing components are ideally served with these alloys. Deposits check crack easily and are limited to about 2 layers (1/4" thick).
Suggested Products: POSTLE INDUSTRIES: 2820-SPL www.postle.com
BTWUSA - UTP: OA 2010, 711B www.btwusa.com
BTWUSA - SOUDOKAY: 500-O www.btwusa.com
High Chromium Carbide:
Typically these alloys are about 28% Chromium - 4.25% Carbon. Small additions of Manganese and Silicon are added to cleanse the steel. The remainder is Iron. From the molten state, because of the high amounts of Chromium and Carbon the, Primary Chromium Carbide is formed first and later followed by Austenite and other forms of Chromium Carbide as it cools to room temperature. The Primary Chromium Carbide is hexagonal in shape, large, and quite numerous. This is what gives these alloys such
great abrasion resistance. Unfortunately these alloys do not stand up well to impact and applications are limited to low impact situations such as ground engaging implements (plow shares, rippers, etc.). Deposits check crack easily and are limited to about 2 layers (1/4" thick).
Suggested Products: POSTLE INDUSTRIES: 2832-SPL, 2834-SPL www.postle.com
BTWUSA - UTP: OA 2030, 7100 www.btwusa.com
BTWUSA - SOUDOKAY: A38-O www.btwusa.com
Complex Chromium Carbide:
Typically these alloys are about 28% Chromium - 5% Carbon + (Other Carbide Formers), such as Vanadium, Columbium, Tungsten, and/or Molybdenum. The "Other Carbide Formers" add greater abrasion resistance at room temperature or high temperature abrasion resistance, depending upon which alloy elements are used. Their deposits are similar to other Chromium Carbide alloys, in that they also check crack and are limited to about 2 layers. Impact resistance is poor. Typical applications usually
involve heat such as found in Steel Mill components; chutes, liners, guides, etc.
Suggested Products: POSTLE INDUSTRIES: 2836-SPL www.postle.com
BTWUSA - UTP: AF Ledurit 68, AF Ledurit 70, OA2040 www.btwusa.com
BTWUSA - SOUDOKAY: A43-O, A45-O www.btwusa.com
The above outlines of the major Chromium Carbide alloys is by far not the extent of this diverse family. There are many hybrids, each with it's own characteristics. Contact our sponsors of hardfacing materials to get a more in-depth look at them.
In the next newsletter we will cover some of the specific characteristics of Chromium Carbide deposits, such as deposition methods, bead shape, abrasion resistance, check cracking, and non-check cracking techniques. I will be looking forward to visiting with you.
4. SCIENTISTS SAY BEER IS SWILL
http://www.briefme.com/a/article.cgi?id=20585&uid=199215 The New Scientist reports in its latest issue that swilling beer provides drinkers one unexpected health benefit: vitamin B6, which can help the heart. In a recent Dutch study appearing in the British medical journal The Lancet, researchers found beer drinkers had 30 percent more of this vitamin in their systems than non-drinkers, and 15 percent more than drinkers of
red wine or the Dutch version of gin. Click on the link above to find out why itís just swill to have a brew.
William L. Smith, http://home.earthlink.net/~micromegas/index.html
Bohler Thyssen Welding USA Inc. (http://www.btwusa.com) is a single source supplier for practical high quality electrodes, wires, and fluxes.
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.