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

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

 

 

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

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

 

 

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

 

Hardening Steel With Heat

We have touched on the topic of the effects of heat on steel in the past. These little reminders are directed at those of us who are not accomplished thermal treaters of steel. And, that is based on the assumption that you wouldn’t be reading this article if you are already proficient in hardening steel. NOT INSTRUCTIONAL! “Random thoughts on hardening steel” in his article are strictly for information purposes only.

To a large part the carbon content of steel determines its hardenability. More carbon/higher hardness. Low carbon (below .26), virtually means no hardenability. Although some people will argue that, and that’s fine, it makes for a nice bet in a bar. A very general guide for a novice is; “through-hardening” alloy or carbon steel yields a maximum hardness equal to carbon times one hundred, i.e. .30 carbon = 30RC, .40 carbon = 40RC, etc. For general reference, most pre-hardened steels offered to the public, will be roughly 30RC. At that hardness, they have good “toughness”, which is a combination of hardness and strength. Surface hardness (skin hardness, flame hardness), is somewhere around ten points over the above shown numbers, so, you can get approximately a 50RC surface hardness on a piece of 4140. It’s actually a little harder but that will give you a ballpark idea.

Through hardened steel has many advantages. One potential disadvantage might be that it could be a bit brittle. Surface hardening is generally preferred when the application may have impact or flex. In that case you would want to retain some core “flex” (ductility) in the steel you are working with. In general terms; strength goes up when hardness goes up. Too hard and brittleness (potential for abrupt fracture) becomes a factor.

The speed at which you cool the steel from the hardening temperature will affect the resultant hardness. Like baking bread or deserts; think ingredients, time and temperature. Get them worked out correctly and you have a pleasant result.

Other elements added to steel (inside the steel) or added to the furnace as a gas, will also affect the overall hardenability. There is no substitute for knowing the grade of the steel and its current hardness.

ALL IS NOT LOST! If at first you don’t succeed, try, try, again. Steel is generally very forgiving. You can repeat the thermal treatment over and over without damaging the material provided you have not exceeded the hardening temperature. If you end up with a lot of surface decarb (the powdery grey skin and scale that forms on the surface of the heated steel due to the carbon burning off), you will have to remove that so that it doesn’t act as a “heat sink” and inhibit subsequent hardening attempts. You will also have to research the thermal treatment procedure of “annealing”, as that may be required prior to your subsequent hardening attempts.

It will be necessary to remove the decarb anyway if you intend to accurately determine the hardness of the steel. The old rule used to be; “Grind to bright metal.” Decarb can still be present in bright metal. So, grind to remove all decarb. It is a safe bet, with almost any carbon or alloy steel; if you are getting a Rockwell “C” hardness reading under 22RC, you are probably still in decarb, since most carbon and alloy steels will pick up some hardness following a thermal procedure unless you just happened to accidentally perform a  perfect anneal.

-Howard Thomas, August 6th 2019

 

Cut To Length Steel And Random Bar Lengths

Some time ago we posted an article about random bar lengths. The attention from that blog contributed to this follow-up about cut-to-length bars. More importantly, how that term differs from random (rdm) bar lengths.

Random bar lengths can be anything the distributor deems beneficial to his selling of the steel bars in  his, or her, inventory. It is most common in the general steel marketplace to see random bar lengths listed as 10/12ft rdm, stainless bars were often listed as 11 to 14ft rdm. You might say that is more less the default in the industry. However, even that category does not define exactly what might be shipped to you. You may get a 13ft bar, or even a 16ft bar; depending on what the distributor has on the floor at the time. In rare instances you may get an 8ft bar or 9ft bar, although shipping a shorter bar is not all that common. The practice of offering random bar lengths can be a very good thing. You should be able to save money on the purchase, less than the higher cost of requiring a bar to be cut to a specific length. Just make sure you and the seller are on the same page at the point of inquiry.

Cut-to-length bars are just that; bars are cut to the exact length you require. You just need to be clear in expressing your requirements; and include a length tolerance that works for both parties. For many decades “plus 1/8″, minus 0” was quite common, and the default if nothing was specified. It pays to be sure both parties understand the same requirement. Especially if it is a first time order or a new vendor or customer. Your expectations understood by one supplier may be lost on the new supplier.

There are other concerns that may affect your order regarding cut-to-length. You may want to specify “No Mill Ends”, or, “Trim Mill Ends”. Mill ends (the original ends of the bars as they were shipped to the distributor from the steel mill), may have been trimmed at the mill, and just fine. They may also be sheared, in which case there may be a slight taper to the end of the bar. The diameter at the bar end may be a bit undersize. It may not be a square cut. It may be slightly dished, it may have identification stamped into the end. If you have not allowed some trim stock to the length you ordered, this may be an issue. It is not a major issue on most orders, but it is worth mentioning if it could be.

If the type of cut required is to a very close tolerance you may want to specify “Square Cut Ends”, and then the tolerance you require. There may be additional charges depending on how specific your needs are.

Very small diameters (those under 5/8″ Dia.) may require special dialogue or instructions if your expectations are exacting. Can the vendor bundle and cut? Once again, there could be additional charges incurred. Very large diameters (over 10″Dia.) usually require a little extra stock be left on the cut. Depending on the size and the intended use, some people will leave 3/8″ or 1/2″ on the cut. Chromed bars often come with “masked areas” at the end of mill length bars. That is an area that has not been chromed. It may be several inches. If you typically purchase full mill random lengths of chrome bars from one supplier, you may want to insure both you and your new supplier understand the specific bar mults of the finished shafts you intend to make. Discuss “trimmed ends” at the point of inquiry.

Newer saws and better saw blades are able to cut phenomenally close these days. There seem to be blades for nearly every metal and hardness. But, just because the saw and the blade can cut close, does not mean that’s what you will be getting. Communication goes a long way to avoid a mishap. Remember; “When it goes bad, who’s wallet comes out?”

-Howard Thomas, June 21st 2019

Bending Steel

There is a famous saying; “A man must know his limitations.” I am sure it is also appropriate for a woman. So it is with this topic. Some steel grades can be bent fairly easily. And, some steel grades in some conditions should never be bent. Before attempting to bend steel you must fully understand its limitations. If you are one of those who never reads instructions and just charges ahead, then there is another appropriate quote from the same person; “Do you feel lucky, kid? Well, do you…?”

The thing is, bending steel is dangerous, even steel listed as “formable”. Ideally, it should be left to experts. But, if you are going to do it anyway, you must know some things about the metal you are contemplating bending. The grade and internal cleanliness are important. But more important is the hardness and the depth and uniformity of that hardness. Soft malleable (ductile) steel in a very light gage may take a nice bend simply by “hand”. Harder (heat treated) heavier gage steel may require high capacity sophisticated equipment that has built-in protections for the machine operator. Very hard steel may not tolerate even the slightest bend, or even pressure for that matter. To put it in perspective, when you think of very hard steel, think of a pane of glass. You wouldn’t push the center of a large pane of glass to see if it bends. At least I hope not. When hard steel fails during a bending process, it literally explodes! As in, loud noise and a section of the roof leaving the building rather quickly.

Before you attempt to bend a piece of steel say this out loud three times; “This is an angry piece of steel that doesn’t want to be played with, and there is a reason why everyone behind me is stepping back.” Then step into your safety gear, study everything you can about the steel, then call a person who bends steel professionally. If that is just not possible and you are required to bend it yourself, do some serious research before you begin and remember, wear appropriate safety gear. Bending steel is not a job for amateurs. Use certified/qualified expert technicians.

Some key words that may help you discover a bit about bending steel are listed below:

Forming, Press Brake, Rolling, Open Air Die, Bottom Die, Bullnose Die, Arc, Degree of Arc, Knife Die (as in; don’t use this type of die), Degree of Bend, Radius of Bend, Hardness HB, Hardness RC, Decarb Removal, Surface Preparation Steel, Brinell, Rockwell, Plasticity, Plastic Deformation, Spring-Back, Work Hardening, Heat Treating, Surface Hardness, Through Hardness, Gushing Head Wound, Depressed Skull Fracture, Life Insurance

4T, 8T, 12T relate to how many times you multiply the thickness of the steel to determine a suggested minimum bend radius. 4T would require a radius of four times the thickness, 12T would be twelve times the thickness, etc.

And, one more famous quote; “Don’t try this at home!”

-Howard Thomas, June 4th 2019

What is Lean Duplex Stainless Steel?

So, what is Lean Duplex Stainless Steel? When and where would you use it? A big topic for a short article. This is merely a brief introduction. Perhaps it will encourage further investigation. Also, we are referring here only to solid round bar, sheet and plate.

For many decades, Austenitic Stainless Grades dominated the industrial and commercial marketplace. They provided excellent general corrosion resistant properties. Then, hardenable martensitic grades began to see usage where increased strength was required. The successful combination of the grain types (Austenite and Ferrite) into one steel introduced Duplex Stainless Steel. Duplex grain structures allowed the broadest utilization of the properties of each. The initial concept was not terribly new; having been introduced about 80 years ago. LEAN DUPLEX stainless steels were the offspring of that product. Early improvements to the Duplex grade involved the enrichment of chemistry of the initial Duplex grade creating upgrades called; Super Duplex and Hyper Duplex; elevated property products with elevated price tags. A significant nickel shortage in the late 1960’s sent engineers scrambling to reverse the “richer is better” trajectory. They embarked upon a project that would minimize the expensive elements in the steel to lower the cost. Minimizing the content of key elements was expected to likewise minimize effectiveness. That was acceptable provided any new grade was still effective in combatting corrosion (specifically Stress Corrosion Cracking, or SCC) and increasing strength over the levels provided by the Austenitic and Martensitic grades used prior to the inception of Duplex.

The resultant steel was Lean Duplex (LDX). It was leaner and cheaper by a long shot. The great surprise was that the resultant loss in corrosion resistance and strength was not as significant as was anticipated. In fact, it was minimal for most intended service applications.

Fairly quickly, the LDX grades enjoyed overwhelming acceptance in the global manufacturing of various tanks, vessels and tubing. So much so, that it is rare these days to find any of those items that do not contain some percentage of Lean Duplex Stainless Steel. What was not readily apparent was the huge potential for daily use as upgraded replacements for the myriad of mundane, and unheralded daily maintenance wear parts and widgets that represent the lowest rung on the maintenance metals food chain; the gremlin maintenance parts that bend and pit and wear. The parts that won’t disassemble because of galling.

My opinion: Lean Duplex shafting, sheet and plate is under-used as a maintenance material. It needs a publicist, promoter or talent agent. Some gnarly champion that might say; “You can use that sh..t on anything!”

It’s that good. Why, it’s the Ginsu knife, the Veg-O-Matic of stainless shafts.

the lean duplex grades are stronger than the austenitic grades of 304 and 316. In my opinion they are generally better grades than 410 and 416. But wait, there’s more, Lean Duplex resists Stress Corrosion Cracking in Sour Service Applications. Since it will most likely be non-similar to your current stainless grades and because it will most likely have a different hardness, it is not disposed to gall. Plus, it is stronger and easier to machine.

Conclusion & Sales Pitch: Associated Steel is one of the few service centers that carries Lean Duplex (ASC2250® LDX) in long shafts they will cut to size. They also carry IN STOCK two different shaft finishes; Fine Turned Oversize “the size will make the size” resulting in less machining and less wasted material, and a Precision polished finished guaranteed bearing fit. Try it! Inquire on hi-def plasma cut parts from plate. Make maintenance life a little easier. Note: Your particular maintenance application has unique characteristics. Always refer to published material information sheets for qualification. 

-Howard Thomas, May 6th 2019

 

What is Brake Die Steel?

Let’s begin this post with two of my favorite words; Ubiquitous; (everywhere, like raindrops during a storm), and, Esoteric; (known by a select small group of people).

What do these mean? Brake Die, Gun Barrel or Rifle Stock, Pump Shaft Straightness, Boat Shaft, Food Service Grade Stainless, Cold Roll, “Ultrasonic Inspect to 388, (and even FDA approved). While they may have a specific meaning to someone (esoteric), they do not have a defined meaning to everyone (ubiquitous in certain industries). In reality these are generic descriptions without reference to defined requirements and properties, at best they are like answering someone’s question regarding the location of your pending vacation by responding; “Up North.”

From my experience, and from a supplier’s point of view, the only real commonality they have is the suggestion of liability. You cannot hope to avoid potential mishap if you really do not have more information on the chemical and physical requirements of the steel the person is discussing.

Brake Die Steel – Generally, a high quality carbon or alloy, appropriate for dies, that may be, or is, hardened. Often an alloy from the 4000 series. Is it pre-machined? Not necessarily. Is it pre-hardened? Not necessarily. Is it oversized square and shiny? Not necessarily.

Food Service Grade Stainless – Generally means it does not contaminate food with residue from the steel and it maintains a clean finish. Most often some grade of stainless. More information is needed.

Gun Barrel and Rifle Stock – Generally a 4000 series high integrity hardened alloy. But, not a specific grade.

Boat Shaft – You really have no information from that term. Could be anything, carbon, alloy, stainless, monel, bronze, etc. Most customers will require specific properties that conform to some sort of Marine Agency such as ABS, etc.

Cold Roll – Not a steel grade but a production method. Need more information.

FDA Approved – A misnomer. FDA does not grant approvals for metals.

Pump Shaft Straightness – The specifics are different for everyone. There are ASTM specifications but many large companies have their own “esoteric” specifications. You need to know more.

Ultrasonic Test 388 – An ASTM test method to determine the internal integrity of steel. Requires more detail such as acceptability and reject-ability levels.

-Howard Thomas, April 22nd 2019