From January 2020 post: NOTE: These are tips and guidelines/suggestions, acquired over the years. Not instructions.
There are steel grades (Mild Steel) that pretty much won’t harden by heat treatment. There are steel grades that are hardenable by thermal treatment. And there are steel grades that won’t harden during heat treatment but will harden if you whack em’ around; known as Work Hardening, Strain Hardening, or Cold Working steels. The most common of the work hardening grades (Austenitic) are the stainless grades 304L or 316L. They belong to a group of steel, categorized by grain type, as the austenitic stainless grades (typically 300 series, and the less common 200 series).
However, there is a non-stainless alloy steel that also work hardens; Hadfield Manganese Steel (or 11 to 14% Manganese, Austenitic Manganese Steel, or simply Manganese). It is a somewhat unique product that has found a home in heavy industrial applications where a combination of impact and abrasion tear up perfectly good steel. The railroad industry and the shot-blast industry are two of the prime venues for this product. As good as Manganese is in brutal service, it can also be somewhat “user adverse”; difficult to fabricate pretty much in every operation you might consider. It wants to work harden. During machining, it will harden ahead of your tooling, it will harden in the forming process, and it will be unforgiving of any misadventures in the welding process. Lack of attention to some simple details during welding, and you will be rewarded with embrittlement and fracture.
WELDING MANGANESE STEEL is not exotic or complex. The steel is just big and ugly, has a hard time making friends, and you need to respect some simple precautions. Think of everything you know about welding hard alloys, and pretty much reverse most of it. Don’t preheat Manganese Steel. Keep it cool, keep the interpass temp cool. Assist the welded unit to cool quickly; even if you have to spray some water to cool it. Employ techniques that tend to minimize welding temperature i.e short arc, minimize puddling, skip and backstep.
Don’t use carbon or low-alloy rods. Use Manganese Electrodes
If welding Manganese to Manganese:
Use Covered Electrodes (AWS A5.13, EFeMn-A) E-FeMnA
If welding Manganese to carbon or alloy
Use Covered Stainless Electrodes (AWS A5.4, E309) E-FeMn B
Use High Speed GMAW and FCAW not SMAW
If the Manganese has work-hardened in service (such as may likely be encountered in repair jobs),
cut away the hardened surface. Then apply a “butter-coat” of 307 stainless. The hardened surface, if not removed, will contribute to embrittlement and eventual fracture at the welded area.
Peen the welds while hot
Arc Welding is Good Don’t use OxyAcetylene (contributes to embrittlement)
Lean rod into direction of travel – flow the bead, don’t push it
Minimize energy input (65,000 joules max).
So, when welding hardened alloy steel, you are trying to get sound welds and maintain the hardness.
When welding Manganese, you’re trying to get sound welds period. Not protect any pre- hardened condition. Hardness will occur (or reoccur) when placed or placed back into service.
-Howard Thomas, December 7th 2021
Over the years we have looked at the nuisance of galling in several separate blogs.
That is because, every year galling makes it to the leader’s group of “Heavy Maintenance Royal Pains”, alongside, magnetism, barber pole-ing, and cupping or oil-canning.
So, let’s begin with this for anyone absent those days; Galling is the seizing of mating parts. A sort of Cold-Welding as it were.
When it is time to disassemble for inspection or repair, often the parts (hubs, casings, flanges), won’t come apart. That leads to hours of lost time and materials, often to find internal parts were savable, had you not destroyed the case. One industry I occasioned to visit finally gave up and inspections switched to mandatory replacements. Ouch!
Galling is a special thrill with the stainless assemblies often found in industries that prohibit the use of lubricants (food service and production).
Parts tend to gall as a response to friction and low-yield strength deformation. Eliminate the friction, eliminate the deformation, minimize galling. Not so fast. Can’t use most lubes in food service due to contamination.
If you’re using stainless shafts, you are most likely accustomed to a certain amount of gumminess in machining; a product of reduced strength that also contributes to deformation.
When mating parts encounter friction (resistance) they bind. Subsequently, they may deform and “cold-weld” together (gall). You can try minimizing binding during installation by slowing the installation speed; perhaps use a hand feed to detect potential galling areas; then back off pressure and speed. You can make sure the parts fit nicely (snug) to eliminate pulling the part together using the threads like a turnbuckle.
SMOOTHER & STRONGER THREADS would help as they would minimize friction and resist deformation. Using dissimilar steel parts with dissimilar hardness would also help deter galling. Try using “Rolled Threads”. Rolled Threads are smoother than cut threads so they have less surface defects which means less propensity for fatigue failure. But let’s keep the focus on galling. Rolled Threads are stronger because they are compressed or displaced into shape. That work-hardens (strain-hardens, cold-works) the thread; especially if it is a stainless steel.
“Roll-Threaded Rod Minimizes Galling”, may not be headline-making news. But it is a byproduct of that thread production method. Life is short. Be easy on yourself. Take advantage of available benefits before reengineering the whole job.
-Howard Thomas, November 8th 2021
Let me know if this reads a better, changed the order and made it (in my opinion ) a little easier of a flow without altering the message
Are there hardened (400bhn) wear plate angles and channels? November 2021 Blog
NO SUCH THING AS WEAR RESISTANT STRUCTURALS? (Other than low-hardness A588)
It is possible to make your own!
We stock a true 400bhn wear plate (sheet), 1/8” x 60” x 120”. It is clean, flat, and easy (relative to wear plates) to fabricate. We can Hi-def-plasma-cut pieces to order; simple rectangles and strips, or configurations per sketch. The cuts look almost like laser-quality with very little heat effected zone along the edge.
If you are involved with heavy plate maintenance and fabrication; more specifically, if you occasionally handle hardened wear plate, you will have a need for this unique product.
It forms well, is readily weldable (not too rich of a chemistry to cause problems), and it provides weight reduction where installation and handling might be a problem; not to mention you can make wear resistant containers, hoppers, tanks, that are lighter and therefore increase payload.
Where can it be used?
Strip it and tack weld it into the high wear areas of structural (A36) shapes. Tack it into the throat of a “U”, or, on the inside of one or both legs of an angle. You now have wear resistant structural steel.
Is a cart riding on top of a rail wearing down the top surface? Tack on a strip of this to add a 400bhn wear surface.
The material is perfect for emergency temporary patching of blow-outs on job sites until heavier fabricated pieces can be delivered. An installer can get the pieces into hard-to-reach places where a repairman could handle the plate by hand. This is an alternative to 3/8” and ½” thick A36 liners. That’s a big reduction in weight! You may even find you benefit from the competitiveness of your bids.
Cutting: oxy, plasma, band saw (use blades for hardened alloys), abrasive wheel, laser, and water-jet.
Welding: Standard Low Hydrogen Method (7018, 8018)
Form: using standard precautions for working with wear plate. Form against the grain. Leave a large radius at the bend (when wear-lining angles and channels utilize a cut-and-weld operation)
I know this reeks of a sales pitch, but, we have customers who keep this on hand around the plant for; “As Needed by Anyone Needing It” purposes. It is a life-saver for keeping things moving while you are otherwise attempting to resolve the issue.
CAUTIONARY NOTE; Working with hardened steel, anyone’s hardened steel, involves risks. Be sure to use appropriate safety gear (hot-mill gloves, hard hat, safety glasses, etc.), Utilize persons experienced in handling hardened steels, including certified welders, etc. Try to form against the grain, incorporate the largest bend radius the application will handle. And, COMMUNICATE, COMMUNICATE, COMMUNICATE.
If there is something you are not sure of; ask your vendor!
-Howard Thomas, October 27th, 2021
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Howard Thomas
Experience
Sr. Acct. Mgr. (US Southwest) / Metallurgical Consultant
Associated Steel Corporation
Jan 2017 – Present
Past Vice President / General Manager
Associated Steel Corporation
Apr 1998 – Jan 2017
Past Vice President / General Manager
Baldwin International
Apr 1974 – Mar 1997
Education
Cleveland State University
Kent State University
University of Denver
