What is Keystock?

In the steel industry and in the most general terms, anytime you see the word “stock” attached to another word; think, “stock used to make”. Barstock, Bushing Stock, Rifle Barrel Stock, Pump Shaft Stock, etc. would be stock that you can use to make those items. All details need to be clarified; is it pre-drilled, pre-hardened? What is the finish allowance? The term “stock” just means “may be used for”. Facetiously, a tree might be “Home Construction Stock”. i.e. not the finished product.

Keystock is generally a square or flat shaped lower to mid strength metal, either alloy or carbon steel, that is used to make keys. Those keys are inserted into shafts. A drive motor chuck will engage with the protruding key, and rotate the shaft. The idea is that this key is of less strength than the expensive shaft, so that if something interrupts the motion and causes failure, it will be the cheap little key that fails not the bin expensive shaft. Clear the obstruction, put a new key in, and you’re good to go, hopefully with an undamaged shaft.

The perfect piece of keystock would have less mechanical strength than the shaft, tuned to the actual application, but close enough that the shaft didn’t fail prematurely, contributing to expensive downtime. It would also be a cold drawn bar with good cross-sectional accuracy and a close oversize tolerance. The ideal oversize tolerance for many years was considered to be +.002″/-.000″. That tolerance would allow you to machine a standard keyway, in which the key would fit it in nice and snug. Undersized tolerance resulted in sloppy, loose keys. Too much oversize required un-welcomed machining.

My first experience with keystock was when I was about 10 years old. My uncle took me fishing in Canada. We were in a small aluminum boat with a little outboard motor. We were trolling at a very slow speed and he let me captain the “ship” for awhile. His only caution; stay away from the shallows and weeds; the only things I seemed to have a talent for. Every few minutes we snapped a key when the prop would strike something. We went through an entire little metal pill box of keys. That experience, and his humorous disapproval, stayed with me. The solutions were; chuck me out of the boat, or get somewhat stronger keys.

There is the conundrum. Too soft of a key and you have frequent expensive delays. Too hard of a key and you risk damaging an expensive shaft. (Goldilocks and the porridge issue).

Decades ago, Moltrup Steel, Pennsylvania, was considered the benchmark for keystock tolerance and cross-sectional accuracy. Having failed to secure the quality sufficient to satisfy their own needs, they embarked on producing the finest grade of keystock available. “Moltrup Quality” actually became a legitimate descriptor. I still see reference to Moltrup Keystock today, but am unfamiliar with the exact specifications, or how closely it follows the original “Moltrup Quality” of the past. Moltrup closed in 2002 and it has been my experience that the exacting tolerances disappeared with it. (Associated Steel always maintained a substantial inventory of Moltrup Quality material. It is a diminishing commodity but worth checking). When Moltrup closed, the potential market did not seem sufficient to justify the additional die work and drawing that would insure that high degree of accuracy. The tolerance on keystock gradually opened up to +/-.004″ to .007″ (that’s plus or minus). Even with sources that promote “Keystock”, or Moltrup Quality, pay close attention to the actual tolerance that you will most likely get.

The hardness (through multi-pass cold drawing/strain hardening), tolerance, and cross-sectional accuracy are all doable. Expensive, but doable. Requires a lot of fiddling in production for an item that does not represent any significant tonnage. Until something changes, keystock that is fine-tuned to allow maximum performance of the esoteric shaft application you are dealing with, will have to be made. Your choice, either make it, or chuck the kid out of the boat.

 

-Howard Thomas, April 3rd 2020

 

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Metrics. Why So Difficult?

We have been actively pursuing adopting the metric system in the US roughly since the latter part of the 1700’s. Its been dubbed “Mandatory” in 1809. The success of those efforts has only been eclipsed by Y2K and the great reveal of the contents of Al Capone’s safe. In fact, for a quick chuckle, if you can still find a veteran businessman, mention you heard we are going to be exclusively adopting the Metric System in the USA next year.

At best we can say today that we have had success adopting the metric system in some of, but not all areas of measurement. Wikipedia does a nice job delineating areas where metric measurement has successfully been adopted in the US, (science, military, medicine). The only example of metric measurement that came to mind, however, was the 2 Liter bottles of soft drinks are now illegal in New York. At best we can say Americans are not keen on jumping quickly into metric measurement and saying goodbye to “foot-long” hot dogs and jokes about the inability of men to measure correctly.

A word of caution; while we are “actively” transitioning between metrics (written in decimal notation)

and “fractions”. Make sure both parties understand the exact point of accuracy that is being discussed. If you purchase a bar of 3-1/4″ Diameter, is your supplier visualizing the same 3-1/4″ Diameter bar (in fractional context?). Or are you really expecting a 3-1/4″ Diameter bar that is 3.250″ Diameter, accurate to the third decimal? What about 3-15/16″ Dia. (3.9375″ Dia. Are you expecting accuracy to the fourth decimal?). True, one topic is diameter size, while the subsequent text refers to accuracy or diameter tolerance. Normally, that would not be an issue. The two would be understood to be separate considerations. However, when you are ping-ponging two different measurement systems as interchangeable, there is a potential for surprise. Mishaps of this nature occur more often than should be the case.

For now, in the United States, think of any changeover of our measurement system sort of like METRXIT. It will likely still take a while. Over time, you will likely see dual notation on things like automobile speedometers, etc. But when it comes to steel bar sizes, fractional annotation may be here for a while. The “fractional” system, sometimes referred to as: The English System, or Imperial Units, has served us well. Change is inevitable. We know that. We’re workin’ on it.

-Howard Thomas, March 5th 2020

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Light Gage

Every once in a while, I have to engage in something that smacks of shameless sales dialog. This is one of those times. So, grit your teeth, send small children out of the room and just get through it.

If you are involved with heavy plate fabrication, and more specifically, if you occasionally handle hardened wear plate, you may want to give some thought to a product we carry that seems to be useful to fabrication and equipment repair facilities; Light Gage (1/8″) real 400bhn Q&T alloy wear plate. Forms well, 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, and that are lighter and therefore increase payload.

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 a nice alternative to 3/8″ and 1/2″ thick A36 liners. That’s a big reduction in weight! You may even find you benefit on the competitiveness of your bids. Depends on what the other guys are quoting.

We stock it in full sheets, 1/8″ x 60″ x 120″ long. We also cut pieces to order; simple rectangles and strips, but also configurations per sketch. Our sheet is cut on a Hi-Def Plasma, and our machine operator has been working with plate for 30  years. The cuts we get look almost like laser-quality with very little heat effected zone along the cut; even with alloy products.

NO SUCH THING AS WEAR RESISTANT STRUCTURALS? (Other than low-hardness A588). Think about tac-welding some clean-plasma-cut flat strips into the wear surfaces of channel and angle or beam.

CAUTIONARY NOTE; Working with hardened steel, anyone’s hardened steel, involves risks. Be sure to use appropriate safety gear (hot-mill gloves, hard had, safety glasses, etc.), Utilize persons experienced in handling hardened steels, to include 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 that you are not absolutely sure of; ask your vendor!

-Howard Thomas, February 5th, 2020

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Inventory Turns – Somebody Pays

Recently we touched upon blanket orders. Today, we are going to look at them specifically as to how they might relate to inventory management.

So, my favorite cautionary snippet warns about “Not shooting pool with anyone who’s first name is the name of a major city.” To an extent, there is wisdom in that. Unless of course you’re THAT GOOD! And, most of us are not.

When it comes to the idea of keeping steel in inventory, there is another snippet that suggests; “Better that you be stuck in an elevator with 50 first graders with fevers, ice cream cones, and intestinal flu, than hold steel bars as inventory.” Doesn’t seem to leave much room for any discussion. Just don’t do it, at any time, for any reason. That used to refer to slow-moving inventory. Today, however, it seams to refer to any inventory, no matter who you are; service center, end-user, manufacturer.

In a nutshell, no one is to maintain any inventory, but everyone is expected to ship their products next day. In reality, that philosophy results in what I refer to as “kick the can”. Someone has the inventory somewhere; we just want it to be someone else’s expense. Inventory is a necessary evil then, so long as someone else is carrying it. Or, as an old and dear friend of mine would always say; “Somebody pays!” Just move the actual mass of hard steel down the line until it is not so visible. BUT, how many decision makers do you want to be between your “Just-in-Time” company and availability of the actual goods? There is no avoidance; to deliver products with the speed expected today, most of us should actually maintain some inventory (that includes end users, manufacturers, and even service operations). We just need to insure we are capable of managing that inventory with a competence that approaches an art-form level.

Heavy industry is alive and well. Globally, there is a big need for digging, busting, breaking, grinding and pushing; dirt, rocks, yogurt, whatever. Service centers are tasked with anticipating the needs of that industry months or years ahead of potential orders. No easy task. End users, however, may witness repetitive usage of materials within somewhat predictable cycles. They enjoy a level of “forecast insight” that steel service centers would love to have, no matter how slight it might be. Yet fewer than you would imagine utilize the benefits of a useful and available inventory management tool; “Blanket Orders”.

Committing “forward”, to a dedicated source of supply, for a dedicated quantity of material, may be facilitated by using a blanket order. Not a bad compromise that protects continuance of supply and improves cash flow.

-Howard Thomas, January 21st, 2020

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Partnering

The “partnering” discussed here, in the steel industry, will refer to a working relationship between supplier and end-user, where benefit is derived by both parties.

One specific example that has been very effective is the blanket order, or blanket contract. Both parties need the potential advantages of a well-constructed blanket contract.

The vendor gets a bit of predictable inventory usage and potential predictable cash flow. The customer will benefit from: continuance of supply, firm pricing, cash flow (often a major concern in smaller mom and pop service centers), time and space savings, etc. When one of these “Partnering Contracts” is done well (fairly), there may even be cost savings to the customer, and increased profit to the supplier. Other benefits do not necessarily relate solely to purchase cost.

At risk for the vendor is default from the customer who’s needs may change during the tenure of the contract. A smaller service center may be concerned with exactly the same thing; a change to their customer’s needs mid-stream.

If you have never been party to a blanket contract for materials, you should be aware that there are certain predictable cautions and time proven verbiage common to most blanket contracts. The text will address standard issues like duration of contract, types of releases (fixed or “as-needed”), etc. Persons with limited familiarity, or who have never entered into a Blanket Order will likely have many concerns relative to over-committing, potential exit clauses, etc.  You should know, that similar to any type of contract there must be benefit for both parties. There is no “one-size fits all” contract.

Working with a familiar and trusted vendor and extensive COMMUNICATION will only improve the quality of any joint agreement. Formulate a rough draft of contract terms that express, and address, your concerns. There are no predetermined constraints or requirements that you will be bound to. Ensure the contract terms fit both parties.

In an earlier post, we discussed the definition of, Random Bar Lengths. Many people in this industry assume there is a fixed length spread. Not so. Bar length variances are basically determined by each supplier based on length variances that offer advantages. In appreciation for selling lengths that are the easiest and most economical to ship, a cost advantage is passed along to the customer. Look at a blanket contract in the same way. In your particular situation, what issues provide advantage? Would a good “escape clause” ease your concerns? What about an extended contract period, or releases on demand?

Blanket Contracts for Materials are an excellent form of “Partnering”. They should be viewed as opportunities, not restraints. When discussing “Partnering” be open to compromising on terms that will assist you in perhaps obtaining some “non-standard” terms that you feel strongly about.

The beginning of a new year is a great time to get dialog started.

-Howard Thomas, Jan 2nd, 2020

 

 

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Are There Different Types of 4140 Alloy Steel?

Is all 4140 alloy steel the same?
It is common for 4140 alloy steel to be supplied in either the annealed (soft) condition, or Quench & Tempered (Q & T), the hardened condition. The hardened condition is used where added strength or resistance to wear is desired. The softer condition is used where considerable machining may be required, or where more ductility is required. And then of course there are different surface conditions, shapes, etc. What we will be addressing here will be something a bit less obvious.

Quality varies from mill to mill, and within even one mill, quality will depend on the specification the customer is having it made to. The number one cause of shaft failure in heavy industry is fatigue related failure. “Toughness” resists fatigue, and “cleanliness” increases toughness. Cleanliness in steel is a result of refinement process incorporated in the melting of the steel. (electric furnace melt, vacuum degassing, small grain refinement, etc.). Each process may contribute to the quality of the steel. Each has a cost to the service center requesting it. When all of the available cleanliness processes are incorporated, the collective cost of those extras could be near, or may even exceed the base cost of the steel grade.

I have always considered the steel making process to be more of an art form than merely a manufacturing effort. Very much the same as; there are certified welders, and then there are certified welders. There is often a big difference from one to another. Or, as the age old adage points out; “What do you call a doctor who graduates last in his/her class? The answer is still Doctor. It is the same with steel; who makes it and how is it made?

Often, we encounter a situation where a grade of steel has failed in service. It is common for the customer to consider changing the grade of steel. In many instances it would be more appropriate to retry the recommended steel again, but perhaps investigate purchasing from a higher quality resource.

If you believe on specific grade of steel has identical attributes to that same grade from any source, you are likely to encounter some surprises along the way. Don’t get bit by an insufficient piece of steel because you misunderstood the situation.

“A man walks up to a woman waiting at the bus stop. Next to her is a large friendly looking dog. The man asks if her dog bites. She smiles and says, “No. He is very friendly and loves people.” The man reaches to pet the dog and is immediately bitten. “I thought your dog didn’t bite!”, he exclaims. “That’s not my dog.”

An old experienced business associate of mine would often comment on something I did that did not come out as planned. He would simply say; “Well kid, you almost had it right.”

Don’t be that kid. Pay attention to the details and make your life easier.

-Howard Thomas, Nov 25th, 2019

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Using 4140 Alloy Steel

Iron ore, found lying around near the surface of the earth, can be heated and primitively refined (a cave man could do it) to become iron. Iron is soft and pliable, great for lots of things and better than a poke in the eye, but begging for improvement. With minimal additional elements and a bit more refining “mild steel” made its debut. Mild steel is the leanest form of carbon steel. It is generally considered non-hardenable and is fairly pliable; stranger than iron and still fairly ductile. From that point you can add and subtract elements (manganese, chromium, nickel, moly, etc.) add heat and then cool and you can pretty much tweak it to be particularly well suited for an infinite variety of specific uses (carbon, alloy, stainless, and tool steel). You could make steel that holds a sharp edge; slices and dices, and could even cut someone’s shoe in half. You can make steel that gets very hard but is also very brittle, steel that gets very hard on the surface but stays softer at the core, and steel that gets very strong and will stand up to impact, shock and gouging. Fortunately for us in the present day, most any type of carbon or alloy steel you would want already has a recipe and a full set of instructions that have been worked out since people have been throwing rocks.

For most of us in the industry who will encounter grades of steel in our work-a-day-lives, we can generally categorize them into two separate camps: steel that is made into parts sold commercially to the general public and manufacturing companies, “production-steel”. And, steel that requires special properties to fix the machines that make those parts, “maintenance-steel”. When working with steel to make things, the steel used for the tooling takes quite a beating. It may have to stand up to bending, or breaking, or abrasive wear. It may be subject to twist, or corrosion.

4140 is pretty much the “Defacto-Standard” for  a good all-around general-purpose maintenance steel for replacement parts. It has been designed to possess high strength (sometimes referred to as ultra-high strength), along with noticeable resistance to gouging, bending, fatigue, wear, and to an extent even corrosion. 4140 may be supplied in several hardness ranges to deliver several levels of strength. In most cases it is considered to be fairly machinable and weldable. You can forge it and bend it with caution.

It is considered to be a “through hardening steel”, but it will also accept surface hardening to maintain a ductile core. While it may on occasion be used in production manufacturing, as the steel that becomes the parts being made, it is generally not used where speed of machining is the requirement. With 4140, you will give up a little bit of machining time to gain strength and toughness.

4140 is a great basic chemistry that is easily modified at the steel mill by use of additional elements to achieve additional, and/or, specific properties for specific industries or jobs. For instance, if you need high hardness that is deeper and more uniform, you could add Nickel to the 4140. The subsequent grade would be an alloy called 4340. Want to increase resistance to softening in higher service temperatures, like a bracket for an exhaust pipe, add Vanadium and increase the carbon a bit; there was a grade for that, 6150. Want easier welding, forging, and maybe a hardened chisel edge but soft core, lower the carbon a bit, and add a bit of Tungsten, and you have 4135 non-tempering steel. And so on. Need to make a high strength shaft with a high surface hardness for wear resistance but a very tough core, increase the carbon a bit. Remember, a rough calculation for potential surface hardness is ten points over carbon content i.e. 4150, potential surface, flame or induction hardness 60RC.

So, when do you use 4140 alloy steel?

Pretty much anywhere. It is a great all around general maintenance alloy chrome, moly, manganese steel. A great platform chemistry for many other application specific steel grades. It is fairly resilient in thermal treatment and may be quenched in water, oil, or other mediums. It is readily machinable and weldable (standard low-hydrogen process), forgeable, and with limitations; formable. It is suitable for many various hardening methods including; furnace, flame, induction, carburization, and cryogenic treatment. There are improvements to the basic grade, but, keep in mind that as steel grades get pushed toward higher and higher levels of performance, they become more and more temperamental.

-Howard Thomas, Nov 5th, 2019

 

 

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Steel Mills Are Changing – Take 3

You are here

The producing steel industry that survived looks much different than our grandfather’s steel industry. “Standard Sizes” have taken on a whole new meaning. Bread and butter items that represented the largest tonnage sales require larger and larger purchase orders that are cost prohibitive to only the largest users or resellers. The plethora of smaller, more efficient mini-type-mills have made any return of the old steel business model doubtful. Into this new landscape, you will eventually be impacted by unavailability of grades, shapes, and sizes and lengths, that have forever been “Standards”.

Whatever is a person to do? Get to know your steel supplier. Understand their capabilities, their financial health, their industrial knowledge, their mill relationships. Think outside of the box. Buy smarter. Take another look at machining options that you thought were prohibitive. Using up a bar end-cut even though you have to remove a lot of stock, might not be as costly as you previously thought. The per pound price of a piece of steel is a relative number. Veal Scaloppini may be $18.00/lb, but if two can have a nice meal for $9.00, you can treat yourself now and again.

The specialty steel business is healthy; the heavy industrial maintenance facets of that business are even more healthy. It will remain so because it has always been more artform than mechanical. Because it is on a very low rung of the food chain of steel supply, don’t be disheartened by “Steel News”. Most doesn’t apply to you. Know your options. Get to know your suppliers AND competitors. Understand, that going forward, dead weight will become increasingly costly; whether that means inflated inventories, or an artistically challenged workforce.

On a clear night in the green valleys along the rivers that traverse the country, you can sometimes hear moaning. A frightfully eerie moaning that sounds a lot like… “Feed me Seymour.” That’s not you. You’re a small and lean and specialty maintenance mean! Different set of problems.

-Howard Thomas, Oct 15th, 2019

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Steel Mills Are Changing – Take Two

Shortly following the end of WWII, many special military grades of steel became available to feed the ravenous growth in industries like housing and manufacturing. During that boom, the commercial sector found uses for new steel grades developed by the military, and price was not an object. Existing steel mills previously occupied with feeding into the war effort, misjudged the massive needs of a burgeoning private sector.

Armor Plate became wear plate liners for steel mills and mine trucks. Hardened alloy round bar intended for gun barrels on battleships became mandrels and line shafts. The clamoring public would end up consuming all that was available and that which was not yet available. During the next 30 years or so, even newer grades were developed with special properties needed by big users and big buyers. Automotive, Appliance, Railroad, Mining, and an upgrading military drove invention and innovation. That amalgamation of industry was dubbed “The smoke stack industry”. Steel salesmen were “Smoke stack chasers”. If you were a part of that smoke stack industry, your request for a special modified grade of steel saw it quickly become a standard grade or stock size.

New alloy grades, new production methods, new shapes and sizes would soon become the bread and butter items for steel sellers. In the latter part of the twentieth century, it was hard to imagine a size that was not a stock size in whatever shape. But, the driving forces of heavy industrial activity are cyclical. In time, and on the buying-side of the equation, designs would change, requirements diminished, saturation achieved. On the supply-side, steel mills would react to the cyclical downturns by limiting production or “Hot idling” mills. (Putting them into a short hibernation).

Mills accepted the unavoidable downturns but nothing immediately coordinated industry’s permanent disuse of an item with the mills eagerness to accommodate the needs of those industries. All was viewed as the cyclical behavior; the natural order of things. Nothing specifically identified “gone-forever” items. Right about at this time, the concept of mega-mills was gaining traction. Capabilities of the mills, along with the efficiencies were being improved.

Mills reacted to this ebb and flow by limiting production of certain items to coincide with industrial cycles. Some items would disappear from the menu of available steel, but only until times got better. A signal of economic rebound brought a rebirth of increased production to include not just new demand, but to align production with virtually the same menu of sizes and shapes offered before the “correction”. Important buyers needed only to wait until the next upturn, at which time they could order their new unique items, comfortable in the knowledge that they would also have the ability to order standard, or, stock sizes when and if they needed. Like sugar and bread in a grocery store; there when needed.

For decades that symbiotic relationship seemed destined to go on forever. But, in time customers became more educated at recognizing and predicting boom and bust cycles. They began to hate the bust cycles and incorporated inventory management procedures and systems to assist them in limiting purchases to all but critical need items. Steel service centers, the now and again marketing arm of steel mills, subsequently began to make adjustments to their own inventories. Altruistic philosophy be damned. If you’re not going to sell it, don’t stock it! The attractive mill price of big tonnage orders became not so attractive, definitely not sufficient to offset the detrimental effects of maintaining a grossly obese inventory. Now, the monster sized “Feed me Seymour” steel mills had to react. Smaller appetizer orders from industry did not fill the bill. So, into a climate of tonnage resistance from astute service centers and with pragmatic acceptance of the realities of their existence; the mills launched programs requiring even greater tonnage orders. Eventually, they would be required to prune back their offerings (grades, sizes, and shapes), strategically re-align or network with more responsive and efficient mini-mills and processors; or go into a “Cold Shut-Down”. Generally, the state of being a little bit dead.

-Howard Thomas, Sep 27th 2019

 

 

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When Hot Rolled Steel? – When Cold Finished Steel?

Whoever said; “Cuts like butter, or, Machines like butter”, may not have meant that was a good thing. Visualize butter; not cryogenic butter. The thing is, you need a little hardness (read as strength) if you are expecting decent cutting and machining.

Generally, cold finished steel; which takes into consideration both Cold Rolled and Cold Drawn, provides higher hardness and higher strength than Hot Rolled Steel. Hot Rolled Steel here, means Hot Rolled Annealed (softened) Steel. Hot Rolled Q&T (Hardened) Steel, on the other hand, is most often harder than Cold Finished Steel. A ball park assessment of the comparable hardness would be something like this;

Cold Drawn/Cold Rolled = 20RC          Hot Rolled Annealed = 18RC     Hot Rolled Q&T = 30RC

If you want a rough idea of the relative strength of each, convert RC roughly to Brinell (BHN) hardness (RC times 10), and divide by two. So, 20RC = 200bhn = 100,000psi Tensile. 30RC = 300 bhn = 150,000psi Tensile, and so on. Now, don’t be using this for engineering. It is simply a rough comparison for reference sake.

Cold finished steels are worked at room temp. Hot finished steels are worked hot, almost 2000°F. “Cold Rolled” typically refers to flat bar, sheet, and plate. “Cold drawn” generally refers to bar shapes. Cold working steel strain or “work” hardens it. The higher hardness elevates the strength. But, since it is not a thermally hardened material, the cold working process also imparts stress. That stress is retained in the steel. It may cause movement during subsequent machining or grinding. Q&T Hot Rolled Steels respond to thermal treatment, so, they may be stress relieved at some point of their production. That process relieves stress that may have been retained from processing.

With all of the changes that are happening in the world of steel availability, the question may soon be, which one is available in the size you need. More and more hot rolled shapes, that were once considered staples of the industry, are disappearing. There is a far greater variety of bar shapes available in cold finished product that in hot rolled product; especially hot rolled Q&T.

Also, cold finished bars are provided in much more accurate cross sections and closer tolerances than hot rolled. So, Cold Finished bars are more available, better surface condition, greater aesthetics, stronger, and offer greater opportunity to obtain the size and shape you need. That is why Cold rolled squares and rectangles (flats) are ubiquitously used as rails for automation. They are often machined to accept custom wheels, cams, and mounting hardware. Cold finished alloy bars may be surface hardened to minimize greatly extend wear resistance and service life.

Hot Rolled Annealed steels are more malleable. They tend to retain less stress which translates to less movement. Hot Rolled Q&T steels, especially Alloy steels, offer much higher strength, but, they are somewhat less available than the great variety of sizes available in Cold Finished products, have less cross sectional accuracy, and generally are used where accuracy is not critical and/or a portion of the surface will be removed.

High grade cold finished alloy bars are clean and strong. Better service centers will employ subsequent straightening, even with bars from their general stock. They will also provide fabrication services to prep the mill bars for specific automation rail applications. This may involve; further straightening, drilling and countersinking, surface hardening (multiple or single surface), and custom end preparation.

-Howard Thomas, August 19th 2019

 

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