Steel Manufacturing Blog: Keeping it Steel

ASTM F1554 Anchor Bolt Manufacturing Step-By-Step Process

Posted on Thu, Jul 18, 2019 @ 01:58 PM

 

 

The Steel Supply Company stocks round bar from only the best U.S. manufacturers like Nucor, CMC and Steel Dynamics. Steel round bar is stocked in F1554 grades A36, grade 55, and A-105. While not included in the ASTM F1554, round bar grade A449 is sometimes called out on DOT or transportation projects. The Steel Supply Company carries an ample amount of A449 bar, as well.

Manufacturing starts by cutting the round bar to length. Chamfering then adds the beveled edge to the round bar, which allows for an easy nut fit on the final bolt. Threading is the most critical step of the manufacturing process. ASTM F1554 clearly states that construction grade anchor bolts be made with a 2A tolerance. This assures the bolt's strength while allowing for proper nut fit.

Galvanized-Anchor-Bolt-Grade-55

The Steel Supply Company then uses a powerful rotary draw bender that applies even pressure to the round bar while bending it around a mandrel. This creates a hook with no indentations that could compromise the bolt's strength. Or, the embedded end is threaded to accept an embed nut; often a plate washer is included and welding is required.

Hot dip galvanizing increases the diameter of the bolt. Careful coordination between the thread pitch and zinc coating is required to assure the finished bolt threads correctly.

The finished bolts are then packaged for shipment with the hardware. Steel Supply offers a full range of nuts and washers both plain finished and hot dip galvanized. Regardless of the size of the bolts, packaging is done uniformly and carefully to assure your order is delivered accurately and on time.

Controlling the entire process and keeping ample stock of raw supplies provides the ability to produce excellent quality anchor bolts with quick turn around times.

For more information on The Steel Supply Company's Anchor Bolt Manufacturing Process Click Here.

Tags: S-1 supplement, Anchor Bolts, Bent Anchor Bolts, Cut Thread, Galvanized Anchor Bolts

Slotted Channel Comparison

Posted on Wed, Nov 01, 2017 @ 09:54 AM

Often, we get inquiries from customers asking us to quote on a quantity or series of items. Slide bearings, slotted steel shims, masonry anchors turnbuckle assemblies, etc. While we are always happy to do so, and appreciate the opportunity, it is sometimes difficult to get the customer to focus on the product as well as the cost.

Slotted Channel ComparisonFor this case, we will use the example of the masonry anchor called a slotted channel, also known in the industry as a channel slot, weld-on channel slot, Gripstay® Anchor or Gripstay® Channel Slot.      

Slotted Channel

Looking at the #300 slotted channel (fig. 1) it is a relatively simple masonry anchor. When welded to a column or beam, it provides an anchor for many variations of masonry insert that will secure brick or block to the steel structure. Note, it also has two holes for shooting it onto the columns in the field. Although they almost never do, most of our steel fabricating customers actually have the equipment to make this item themselves.

A closer look at the slotted channel shows, like any manufactured product, that there are details that can be done well or poorly, resulting in a finished product that satisfies its intent 100%, or quite often, much less.

The slotted channel shown in fig. 1 is manufactured by The Steel Supply Company. It is produced from coil steel using a 240-ton progressive die stamping machine. This is important because the correct tooling and machinery allows for a very accurate, endlessly repeatable product.  For example, the width of the slot in fig. 1 is a consistent 0.5625” (9/16”), as it is supposed to be. This allows the insert maximum strength while still allowing for free travel up and down the slot.

Slotted Channel Comparison

Fig. 2 is a competitive brand submitted to us by one of our structural steel fabricating customers.

Highlighting some of the differences;

  • Obvious to the eye, the slot in the alternate brand slotted channel is not the same width from top to bottom. Starting at either end, it measures 0.670” wide. In the center, it is 0.750” wide. The tab of the Insert measures 0.45” wide. This leaves too much gap between the point where the insert makes contact with the slotted channel and the body of the insert. The result is the insert is substantially weakened.
  • The slotted channel in fig. 2 and 3 is contorted so the legs are uneven. Looking at fig. 3, when one end (not shown) makes contact with the surface, the other end contorts as much as 1/4” off the surface.Slotted Channel Comparison
  • Lastly, the slotted channel in fig. 2 is hot dip galvanized. To function, this product has to be welded to an I-Beam, creating noxious gases that the welder will have to deal with. For this reason, The Steel Supply Company offers the slotted channel with a plain carbon steel finish, as well as mill galvanized and stainless steel. We do stock the hot dip galvanized slotted channel because occasionally, the shop drawings will call for it and the ability to make changes is not available, however fabricators will only use this when absolutely required.

To summarize the quality steps that are inherent in slotted channel made on the correct machines with proper and well-maintained tooling;

  • All dimensions on the slot (the most critical part of the slotted channel) are uniform and correct. The slot is 0.5625” wide from top to bottom, and 5.450” long.
  • The legs are of even height on both sides for the full length of the channel. This allows the channel to sit on the I-Beam without any gaps.
  • Because it is stamped and folded on a continuous progressive die, pressure during the striking and bending is even and uniform. This produces a channel that is flat, end to end. There is no contortion.

Looking back at the original question of cost vs. product, it appears if the person being quoted had both items to look at while making a decision it may cast the prices quoted in a different light.

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Tags: Anchor Bolts, Slotted Channel, Channel Slot

Anchor Bolt: Threading Logic

Posted on Mon, May 16, 2016 @ 04:15 PM

We have recently seen an increased focus on the topic of anchor bolts and threading. In a previous blog entry, we discussed considering the thread length of Anchor Bolts with excess thread on the exposed end. Based on the intentions and needs of particular steel fabricators, this topic may or may not be applicable to your business (of course, we’ll manufacture the Anchor Bolts to any specification required.)

However, there is also a situation under the “anchor bolt umbrella” that we run into frequently, and it always leads to follow-up questions and further exploration: a straight Anchor Bolt with excess thread on the embedded end and the hardware welded in place.

Anchor Bolt: Threading Logic

The photo example  above shows the embedded end of two Anchor Bolts. The Anchor Bolts in this case are 1” diameter. The drawing calls for:

  • Heavy Hex Nut on the upward side
  • Plate Washer 1/2” thick
  • Another Heavy Hex Nut on the downward side

The plan requires the nuts to be wrench tightened. Then, both nuts need to be welded to the round bar, and both nuts welded to the plate washer. So, once either nut is welded into place, the extra thread above the upward nut cannot be used.

The extra thread raises two issues. The obvious one is the extra time that the threading takes. While it could be a minimal 10 seconds, orders are often for significant quantities. If this order was for 200 Anchor Bolts, the extra thread adds over 30 minutes of machine time.

Anchor Bolt: Threading Logic 

The second issue is plate washer placement. All plans should come with a specific location (depth) for the plate washer. This is important for two reasons:

  1. The deeper the plate washer, the greater it expands the area of concrete that will resist any uplift. This is known as the “Pull-Out Cone.”
  1. The Anchor Bolt and Plate Washer have to co-exist with a rebar plan. It is important to stay within the space the designer allocated.

Anchor Bolt: Threading Logic 

By including an extra length of thread, the designer has created a variable that appears unnecessary. All the Heavy Hex Nuts shown in both photos are wound on by hand. With the extra thread, the installer takes time to position the upward nut so it will hold the Plate Washer at the correct depth. 

The photo above shows how the position of the upward nut impacts the Plate washer positioning. The plate washer can be set at a specific depth by coordinating the thread to a length that will consistently provide that depth with no attention by the installer.

Often, our instruction for our Steel Fabricating customers is to follow the plan as shown. Of course, we will always adhere to our customers’ instruction. When possible, threading as shown in this blog will save threading time, placement time and removed the possibility for error.

One noteworthy point is the Plate Washer dimensions in the first photo – both thickness and length x width. The 1/2” thickness is heavy for a 1” diameter Anchor Bolt. They are usually specified at 1/4” or 3/8” thick. Also, at 2” x 2” the Plate Washer is smaller than we usually see. Its span only exceeds the Heavy Hex Nut by 3/16” flat to flat, and 1/16” from corner to corner. This could be for a variety of reasons. This plan called for F1554 Grade 55 S-1 Round Bar, instead of the typical A-36. That indicates a desire for greater tensile and yield strength. That may explain the 1/2” thickness. The 2” length x 2” width could indicate the need to fit into a tight rebar plan that did not allow for a lot of clearance.

Again, as the Anchor Bolt manufacturer our role is to produce bolts in whatever configuration the plan calls for.

Ordering Anchor Bolts 

If you are in request of anchor bolts, connect with The Steel Supply Company. Our anchor bolts are manufactured at our West Babylon, NY facility, and our extensive round bar stock allows for fast delivery to keep all of your projects on schedule. To get a quote, call 631-385-7273 or click the link below for more information. 

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Tags: Anchor Bolts

Anchor Bolts: Consider Thread Length

Posted on Mon, Apr 18, 2016 @ 03:36 PM

The Steel Supply Company manufactures Anchor Bolts and Turnbuckle Rods every day… and that’s also how often we see Anchor Bolt Drawings calling for threads that appear unnecessarily long. With regards to the exposed end, extra thread length is requested so the fabricator can be sure there will be sufficient thread for the washer and nut to “bottom out” regardless of any problems with positioning.

Typical Size and Grade Bolts

This would hold especially true on typical size and grade bolts – for example, F1554-07a Grade 36 anchor bolts with a diameter of 1”. For production of this bolt, the threading machine would be set at approximately 75 rpm and cut the full thread on one pass. Standard UNC threading for 1” diameter is 8 threads per inch. So the bolt threading time is: 

75 rpm ÷ 8 threads per inch = 9.375 inches of thread per minute.

This can be expressed as one inch of thread every 6.4 seconds.

The more pliable Grade A-36 steel does not cause as much wear on the cutting tools, known as “Chasers,” so very little cost is involved there as well.

Extra thread length does not change the bolt’s tensile or yield strength, so requesting extra thread in cases like this may be prudent. Viewing the above equation, the cost of adding a couple of inches of extra thread would be minimal. 

Impact During Different Situations

Now consider the opposite situation. Anchor Bolts made to ASTM F1554-07a specifications calling for Grade A-105 round bar at 2” diameter. Two important changes will greatly effect threading time. Thread depth and material resistance.

  • The yield strength is approximately 2-1/2 to 3 time greater than Grade A-36.
  • The depth of the thread has gone from 0.15” to 0.28” (approx. when adjusting for tolerance range).

To attempt to thread this bolt with the same system as the 1” grade A-36 shown above would result in even the hardest Chasers at 65 Rockwell shattering almost immediately. The first adjustment to accommodate this situation is to step the speed down to the slowest rpm the gearing will enable. Freewheeling that would be 24 rpm. Once the load is applied, that drops down to 16 rpm. 

Anchor Bolts: Consider Thread Length UNC Specs for 2” diameter bolts call for 4-1/2 threads per inch. Using the same calculations as above: 
16 rpm ÷ 4-1/2 threads per inch = 3.55 inches of thread per minute

This can be expressed as one inch of thread every 17 seconds. 

Comparing only threading speed, the 2” Anchor Bolt requires 3 times longer making the thread… but that is only a small part of the added time, tool wear and cost.

Three Passes for Proper Cutting 

Due to the hardness of the A-105 steel, the thread is not cut in one single pass. To cut this bolt properly, considering not only finished product quality but tool longevity and operator safety this thread requires 3 passes as shown below.

Anchor Bolts: Consider Thread LengthEach pass increases the thread penetration with the final pass bringing the thread into UNC tolerance. (Pitch diameter tolerance for 2” diameter bolt = 1.8433 min to 1.8528 max.) 

When threading in multiple passes, all the bolts of a given lot are threaded on each setting. That is, if 100 anchor bolts are being made, all 100 get the first pass. The Chasers are then drawn tighter to cut the second pass and all 100 bolts are threaded again. Finally, the chasers are brought to the pitch diameter that will cut the thread to within the above-mentioned tolerances and all 100 bolts are run again.

Looking back at the original calculation for the 2 different bolts, it shows the 2” Grade A-105 requiring approximately 3 x the threading time as the 1” Grade A-36. When the manufacturing reality described above is included the 2” Grade A-105 requires 3 full passes plus all the loading and re-loading as each bolt is re-threaded. 

Adding in the slower cutting speeds and all the extra steps and cautions required it could take as much 8 to 10 times longer to manufacture the 2” Grade A-105 Anchor Bolt. No one inch of thread would change the cost much, but multiplied by all the inches times all the bolts the cost is significant. 

Anchor Bolts: Consider Thread Length

For this reason when ordering Anchor Bolts or Turnbuckle Assemblies, Clevis Rods, Hanger Rods, etc. it is worth spending a minute considering if what is being specified will actually provide benefit or if it is unnecessarily adding cost.

Ordering Anchor Bolts 

If you are in request of anchor bolts, connect with The Steel Supply Company. Our anchor bolts are manufactured at our West Babylon, NY facility, and our extensive round bar stock allows for fast delivery to keep all of your projects on schedule. To get a quote, call 631-385-7273 or click the link below for more information.

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Tags: Anchor Bolts

The Impact of Temperature and Climate on Steel Fabrication

Posted on Wed, Mar 11, 2015 @ 02:04 PM

To our steel fabricating customers in the south and warmer climates, temperature considerations may not play a major role in scheduling work, but in the north it is a very real consideration. From the obvious limitations on pouring concrete to the much less obvious like hot dip galvanizing steel Shims or threaded rod, the cold changes the plan.

The weather is finally starting to warm up, but during mid-February, on average, the northeast region of the United States experienced bone-chilling temperatures barely pushing 20°F at 2:00 in the afternoon, and near zero or below overnight. During February, most of the country had experienced record low temperatures just before the turn of spring. 

Unfortunately, steel fabricators in less warm climates are used to scheduling problems during the winter. Jobs get delayed due to inability to pour concrete footings and foundations, impossible jobsite conditions, etc. Even beyond that, there are shop and field conditions that can effect production and quality.

A good example is the curing rate of cementitious grout. The main ingredient, Portland cement, requires an endothermic reaction to cure. That is, if it creates and retains heat in the curing process. At temperatures of 50°F and above, cementitious grout cures quickly and with 24 hours, has usually achieved sufficient compressive strength. It will typically continue to cure and get stronger for the next 28 days.

Once the temperature goes below 50°F, the curing process begins to slow down but not appreciably until the temperature goes down to about 35°F. As the cementitious grout is trying to generate the heat it needs to cures, the heat is being dispensed rapidly into the atmosphere.

The curing time curve for epoxy anchors is a good example. 

Grout and Epoxy Curing Time Graph

As the chart illustrates, above 40°F, the working time and curing time are quick enough that the installer may not notice the difference between the product at 80°F and at 40°F. Below 40 degrees, the curing time is much longer.

Steel primer is another product that will follow a similar curve. The same steel primer that cures and can be loaded within 30 minutes in the summer may take 2 – 3 hours in the winter. More importantly, in steel primer, there are a limited amount of the solvents required for the drying process. These solvents begin evaporating as soon as the paint is applied and they are exposed to the atmosphere. Once they are fully out of the primer, it will not cure any further. The result will be will be a 75% dry tacky coating known as a cold cure.

Bleed through blue steel markers may or may not experience difficulty based on which type you use. The La-Co Markal Paint bleed through blue paint stick is mostly semi-cured paint and will perform the same regardless of temperature.

Bleed Through Blue


Bleed Through Blue Felt TipThe felt-tipped bleed through blue marker shown above left uses a liquid ink that requires evaporation and drying. While it will dry slower in cold temperatures, it will still function properly. 

Galvanized Anchor BoltsAlso subject to performance problems in colder temperatures, but for opposite reasons, is any steel item that is hot dip galvanized. Zinc melts at 787°F. Typical temperatures for the liquid zinc in the hot dip galvanizing kettles is 830°F. Once the item is removed from the zinc, the temperature drops off quickly. Once the surface temperature drops below 787°F, the surface is solidified and no further zinc can be removed. For I-Beams and larger fabricated steel, this is usually not an issue. For smaller items, especially threaded anchor bolts, this can cause serious problems if the zinc remains thick and hardens in the threads.

 

Other small part problems occur with items like galvanized slotted shims. They are typically galvanized in batches of 500 pieces. When they are brought out of the zinc kettle, they are immediately tumbled in something resembling a cement mixer. This allows the shims to stay separate when the zinc cools. If the batches were not tumbled, the shims would stick together during the cooling process and be unusable. In normal operating temperatures, the galvanizer has about 30 seconds before the liquid zinc solidifies. In near zero temperatures, that cooling time can be reduced to as little as 15 seconds.Galvanized Steel Shim

In conclusion, steel fabricating project managers, production and erection people have enough problems to deal with under normal conditions. In colder temperatures, knowing how some of the processes are affected may help avoid any new or unnecessary problems.

For further questions or information on the impact of temperature on steel fabrication, contact us by clicking below!

 

 

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Tags: Anchor Bolts, Steel Fabrication, Markers, Galvanized Steel

The Lifting Force of the Steel Wedge & Structural Bolt

Posted on Wed, Feb 18, 2015 @ 05:19 PM

The steel wedge is an extremely important aspect of any construction process.  Another way to understand the power of the steel wedge is by understanding the structural bolt.  At first, it might seem as though that the two products have nothing in common, but in reality they are the same thing.

Both the wedge and the screw are simple machines derived from the principle of the incline.  The fundamental theory is that it takes less energy to move an object up along a slope than it does to lift it straight from above.  While the steel wedge operates in a straight line, the structural bolt does the same thing, only in a spiral line.  Both are still fundamentally considered wedges, or “inclines,” depending on your preferred term.

Calculating the power whether expansive, or “lifting” (Wedge), or compressive (Structural Bolt) the equation is the same. Length of incline divided by distance of lift.

The Lifting Force of the Steel Wedge & Structural Bolt

In the case of Figure 1, pictured above, the lifting force of 12.40 can be viewed as a percent.  To lift an object straight up, it requires a force equal to 100 percent of the weight of the object.  To lift the same object using a steel wedge, requires only 12.40 percent of that force.

The Lifting Force of the Steel Wedge & Structural Bolt

Relating the same equation to the structural bolt, the incline remains the same.  It is measured as the distance between two threads.  The length is now measured as the circumference of the bolt barrel.  Note, Figure 2, above, shows this can be measured from the outer edge of the thread, the inner, or at the mid-point.  In addition, all three diameters are smaller than the actual diameter.  That is, a 1” diameter bolt has a major diameter of .9980”, a pitch diameter of .9134” and a minor diameter of .8446”.  To keep this explanation simple, we used 1” as the diameter.

The Lifting Force of the Steel Wedge & Structural Bolt

The circumference of a circle with a 1” diameter is 3.14”. Using UNC bolt specifications, there are 8 threads per inch in a 1” diameter bolt, so each thread rises a distance of 1/8”.  Figure 3, above, illustrates how the bolt is actually a wedge.  With this, the new variable is the length. However, because the length is the circumference, it now measures 3.14”.

1/8 ÷ 3.14 = 0.0398

At this time, it should be recalled that the 0.0398 result can actually be viewed as a percent, and for simplicity’s sake the number can be rounded up to an even 4 percent.  That means that only 4 percent of the pressure is required to produce 100 percent of the force.

Until now, only the wedge action of the bolt has been mentioned.  The leverage created by the handle of the wrench tightening the bolt only compounds this pressure.

The Lifting Force of the Steel Wedge & Structural Bolt

In Figure 4, above, we see the standard hex head for a 1” bolt is 1-1/2” from flat to flat. With the pivot point being the center or axis, it is 3/4” to any flat edge.  The 24” handle then has a ratio of 1:32.  So the percentage shown above of 4 percent, or 25 times advantage, is now multiplied again by 32. The full advantage being created by this wedge and lever is 800 times the actual pressure being applied.  With these results, it’s easy to see how the incline for a steel wedge or structural bolt makes everything easier.

To see the specific kinds of steel wedges we offer, click below!

 

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Tags: Wedges, Anchor Bolts, Steel Wedges, Steel Wedge

Four Styles of Weldable Couplers & Anchor

Posted on Fri, Oct 24, 2014 @ 01:13 PM

As engineering standards continue to develop and improve, there seems to be an increasing need for weldable rebar anchors and couplers.   To the average fabricator, these wealth of options represent an opportunity for additional profit but requires some understanding of how each system works.

Here are four types of couplers and studs to consider:

Weldable Coupler - Threaded

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This coupler/anchor is penetration welded to its steel member. This is accomplished by being internally threaded with a tapered thread that perfectly matches the rebar thread.

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Weldable Coupler Set Screws


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For its connection to the steel member, this coupler employs the same penetration weld as the one above. The difference is that it does not require a threaded rebar. Instead, the rebar is inserted and the set screws are tightened to ensure positive anchoring.

Straight Rebar No Threads

Internally Threaded Weld Studs

Internally Threaded Weld Studs

Weld Studs have straight barrels, as in no head, and internal threads. An example of this would be a straight UNC thread with no taper. The Penetration Weld is no longer required. Weld Studs, by design, automatically have a full weld.

Straight UNC Threaded Rebar

Deformed Bar Studs

Deformed Bar Studs

These deformed bars serve the same function as weld studs, and they can be installed with stud welding machinery. However, transportation problems and jobsite safety regulations prohibit this from being done in the fabricating shop. These studs are welded in the field after erection. As a result of the positioning of the anchors, which are typically close to the grade or close to parallel steel surfaces, this becomes a two man process.

Note: All changes must be reviewed and approved by the controlling architects and engineers. We are available to speak to them directly and answer any questions they have.


 

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Tags: Anchor Bolts, Rebar Anchor, Rebar Coupler

ASTM A449 Anchor Bolt Specifications

Posted on Wed, Oct 01, 2014 @ 03:33 PM

Regarding anchor bolts, ASTM A449 is not a material that should be specified. Regardless, our steel fabricating customer often see drawings calling out for A-449 anchor bolts or fully threaded studs. This is frequently DOT Highway work, where AASHTO specs are more common.

The document that controls anchor bolt manufacturing is ASTM F1554. It clearly states the three grades of round bar it covers; A-36, Grade 55, and Grade A-105. With fully threaded studs, the names change--but the physical properties are the same. They are: A-307, Grade 55 and B-7. A-105 and B-7 that represent the strongest tensile and yield strengths.

In the smaller diameters, A-449 has properties similar to A-105, and with some attention, the engineer will often approve a switch from A-449 to A-105. The properties are not identical, with A-449 having a tensile and yield slightly lower than A-105. However, as the diameter increases, the tensile and yield strengths of A-449 continue to decrease.

For example, here are the properties for A-449:

                Round Bar Diameter range 1” and below
                                                                Tensile = 120 ksi minimum
                                                                Yield    =   92 ksi minimum
                Round Bar Diameter range 1-1/8 to 1-1/2” inclusive
                                                                Tensile = 105 ksi minimum
                                                                Yield    =   81 ksi minimum
                Round Bar Diameter range 1-5/8 to 3” inclusive
                                                                Tensile =   90 ksi minimum
                                                                Yield    =   58 ksi minimum

For comparison purposes, the requirements of A-105 are as follows:

                Round Bar Diameter range 1” and below
                                                                Tensile = 125 ksi minimum
                                                                Yield    = 105 ksi minimum

To simplify the issue for our steel fabricating customers, The Steel Supply Company stocks A-449 round bar and threaded rod with full mill certifications. Also, we will always be willing to speak directly with your project engineer or architect to provide any information they need to make any decisions regarding adjustments.

 

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Tags: Anchor Bolts, Threaded Studs

Anchor Bolt Manufacturing: The S-1 Supplement and its Weldability

Posted on Wed, Sep 17, 2014 @ 12:46 PM

Regarding anchor bolt manufacturing, S-1 refers to a section in the ASTM F1554 Specification. The current version is F1554-07a. Under the Supplementary Requirements, section S-1 reads;

“The material described in this section is intended for welding. This supplemental section, by chemical composition restrictions and by a carbon equivalent formula, provides assurance of weldability.”

F1554 allows for three grades of steel round bar: A-36, Grade 55, and A-105. The S-1 section of the supplement is titled, Grade 55 Bars and Anchor Bolts, and as it implies covers only Grade 55 steel. As far as we know, all A-36 steel is weldable. A-105, as a heat treated product is not recommended for welding, as the heat generated during the welding process may compromise the strength of the bolt.

In researching the S-1 Weldability supplement, metallurgists have indicated the likelihood is very high that a batch (known as a HEAT) of grade 55 round bar will be weldable regardless if it shows the S-1 supplement on the mill certification or not. What the S-1 designation does is remove any possibility of any problems with welding.

That possibility only exists due to the steel being recycled. Prior to recycling, steel was made from virgin minerals and the results would be fairly predictable. With the advent of the recycling Mini-Mills a new set of variables was introduced. The raw product is scrap steel that has very little traceability and no indication of mineral content. Often it is not the first time those minerals are being recycled. Along the way each piece of scrap picked up some sort of variation in its mineral composition. Among metallurgists the unwanted minerals are referred to as “tramp elements.”

Once the scrap is reduced to liquid, it can be analyzed. The metallurgist will be looking to make steel to the required specification, such as A-36, A-529, A-572, Grade 55, etc. Through the chemical analysis, what needs to be added to produce the desired results can be determined. In some cases, the heat is deemed to be unusable for any structural steel purpose. These rejected heats get formed in billets, eventually becoming rebar.

If the heat is closed enough to the acceptable range for the desired product, the metallurgist will introduce any additional elements to fine-tune the mineral content. In the case of Grade 55 steel being weldable, what he is looking at is an equation that shows a “Carbon Equivalent” or CE. The CE, which is expressed as a percent will insure proper balance of the alloys present to allow for the steel to be weldable. What the carbon equivalent is mainly protecting against that the steel becomes too hard and the possibility that upon welding hydrogen induced cracking could occur.

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Tags: S-1 supplement, Anchor Bolts

ASTM Specification, F1554: S-1 Supplement

Posted on Fri, Aug 22, 2014 @ 03:19 PM

The term S-1 or S-1 Supplement is taken the ASTM Specification, F1554. In Anchor Bolt manufacturing, the F1554 specification is the rulebook. It spells out all the criteria a manufacturer must follow in order to provide a finished product that will perform as the engineer intended. The current version is F1554-07a.

There are three options for round bar in the F1554 spec. A-36, Gr.55, and A-105. The numbers refer to the minimum yield strength each is required to have. Tensile strength also increases correspondingly:

Grade

Yield Strength, min, ksi (Mpa)

Tensile Stength, ksi (Mpa)

Size Range, inch dia

       

36

36

58 - 80

1/4" to 4"

55

55

75 - 95

1/4" to 4"

105

105

125 - 150

1/4" to 3"

Of the three grades, Grade 55 is the only one the S-1 supplement applies to. It assures the grade 55 steel is weldable. This will be indicated on the Mill Certification as shown below.

The S-1 indication will not appear on mill certifications for A-36 or A-105 round bar. Sometimes, instead of being on the line denoting steel grade, the S-1 indication is in the notes. Either way, a mill certification that indicates Grade 55 and S-1 indicates the steel from that heat is weldable and compliant with ASTM F1554.

Note: A-105 round bar is not recommended to be welded. It draws its strength from a heat treating process and the heat of the welding may compromise that strength. Nonetheless engineers do sometimes require the A-105 be welded.

 

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Tags: Anchor Bolts