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Understanding AR Steel Grades

Commodity AR steel plates are rated based on their surface hardness as measured by a Brinell Hardness Tester. The higher the calculated Brinell Hardness of a material, the harder the material&#;s surface. Materials with a higher Brinell Hardness Number (BHN) will generally have higher resistance to abrasion. This grading system gives a general indication of a material&#;s service life under abrasive conditions, but suffers from two major flaws. First, being only a surface test, it gives no indication of the hardness in the plate&#;s middle. Second, it does not give any indication of the material&#;s impact resistance and tendency to crack during welding.

There is typically a tradeoff when it comes to hardness. As the hardness of a carbon/manganese/silicon-based material increases, the ductility, weldability, formability and impact resistance of that material decreases. This means that steels with higher hardness levels can be more difficult to form, fabricate or weld. When you are selecting an AR steel plate, the best option strikes a balance between the level of abrasion/impact resistance and workability.

Below are a few common types of AR steel grades, and what you can expect when working with them:

• AR200: T

  his is the earliest version of the AR steel plates, with a hardness range of 170-250 BHN. They are generally in the as-rolled (not heat treated) condition and rely on high carbon content to achieve hardness levels.

• AR400:

  This type of steel has a typical hardness range of 360-444 BHN, which offers more abrasion resistance than AR200 while retaining good levels of formability.

  AR400 was the earliest of the post-rolling heat-treated grades of abrasion resistant steels.

• AR450:

  These were the next step in the evolution of heat-treated abrasion resistant plates. These grades typically have a hardness range of 420-470 BHN while maintaining some formability and impact resistance

• AR500:

  AR500, with the typical hardness range of 470-525 BHN, offers more abrasion resistance than an AR450, but at the cost of formability and weldability.

  Commodity AR 500 plates can be prone to cracking during welding, forming, or cold weather conditions.

• AR600:

  While offering more abrasion resistance than AR500 plates, the surface hardness levels render them un-formable and extremely prone to cracking during welding. Chromium carbide overlay plates are generally a better alternative to steel plates in this hardness range.

• Alloyed Abrasion Resistant Steels: Alloyed abrasion resistant steels are the ultimate evolution of the abrasion resistant grades. By using other alloying agents like chromium, nickel, molybdenum, boron and titanium, they are able to achieve surface hardness levels equal to AR500, through hardness (unlike standard AR grades which lose hardness in the center), and the formability and weldability of an AR400. This makes them the ideal choice for use in environments with extreme abrasion and impact conditions.

Key Factors in Choosing the Right Wear Plate

When you&#;re choosing the right wear plate for the job, there are a few things that you should consider:

Abrasion Resistance

Longevity is the primary goal of AR steel plates. As surface hardness levels increase in the AR grades, the abrasion resistance increases, but generally at the expense of formability, weldability and impact resistance. With the hardness levels of an AR500, through hardness,

and the formability of an AR400, the alloyed abrasion resistant plates provide the highest overall abrasion resistance of all the available grades.

Impact Resistance

In the carbon/manganese/silicon-based AR grades, as hardness levels increase, impact resistance decreases. This means if your wear plates are in an impact-heavy environment, the higher hardness AR grades are generally not the ideal choice. With alloyed abrasion resistant grades, you can keep the abrasive life of the harder AR grades without the risk of cracking under impact conditions.

Weldability

Weldability closely mirrors impact resistance, with the higher hardness standard AR grades being much more sensitive to cracking. The softer middle of the commodity grades also makes for uneven and non-homogeneous welding conditions which can lead to surface cracking at the toe of the welds. Through-hardened, alloyed grades are substantially more welder friendly, particularly in field welding conditions.

Tricon Wear Solutions: Helping You Choose The Right Wear Plate

Choosing the right wear plate can be daunting &#; after all, you&#;re making a sizable investment into your equipment, so you want to make the right choice the first time.

If you&#;re having trouble deciding which wear plate is right for you, reach out to our team at Tricon Wear Solutions.

AR400 vs. AR450 vs. AR500 &#; Understanding Abrasion Resistant Steel

Contact us to discuss your requirements of ar450 vs ar500. Our experienced sales team can help you identify the options that best suit your needs.

In construction and fabrication, the grade and composition of the steel plate materials used make a huge impact on the final product. Abrasion resistant steel plate is a common steel plate that boasts a harder, tougher quality that lasts about four times longer than ordinary high-strength structural steel plate.

But what makes it tougher, and how do you know when your project requires abrasion resistant steel?

We get this question a lot, so here is the run-down on abrasion resistant steel plate, as well as the differences between hardness levels AR400, AR450, AR500 and beyond. You can also contact us today to get a quote for abrasion resistant plate.

What is Abrasion Resistant Steel Plate?

Abrasion resistant (AR) steel plate is a high-carbon alloy steel plate. This means that AR is harder due to the addition of carbon, and formable and weather resistant due to added alloys.

Carbon added during the formation of the steel plate substantially increases toughness and hardness, but reduces strength. Therefore, AR plate is used in applications where abrasions and wear and tear are the main causes of failure, such as industrial manufacturing, mining, construction and material handling. AR plate is not ideal for structural construction uses like support beams in bridges or buildings.

Some common applications where AR steel is used to help resist material wear and tear include:

• Conveyors
• Buckets
• Dump liners
• Construction attachments, such as those used on bulldozers and excavators
• Grates
• Chutes
• Hoppers

How the Quenched & Tempered Process Creates AR Plate

AR material is produced by quenching and tempering forged steel blocks, or ingots. During this process, the grain structure is changed to increase toughness and encourage formability (or, to be less brittle), and results in through-hardening of the material.

Quenching and tempering (Q&T) is a two-part process:

Quenching occurs when steel brought to a high temperature &#; usually between 1,500-1,650-degrees Fahrenheit &#; is rapidly cooled with water. This process causes crystal structures to form within the steel, increasing hardness.

Tempering is the process of re-heating quenched steel to a below-critical temperature (around 300-700-degrees Fahrenheit), and then allowing the plate to cool in normal air temperatures.

Reheating the material breaks down the crystal structures formed during the quenching process, while the long cooling allows the crystal structures to refrom &#; maintaining most of the strength and hardness, but adding to overall ductility.

Related: Exploring Steel Plate Heat Treatment Processes

What&#;s With the F?

Many times, abrasion resistant steel is labeled "AR400F" and "AR450F" (and sometimes "AR500F"). Today, AR material with or without the "F" are interchangeable, but &#; historically &#; material with an "F" simply meant that it was "formable" and could be bent to a certain degree without cracking.

When mills produced both formable and non-formable steel plate, formable was slightly more expensive. However, diminished demand and more competitive pricing has resulted in the production of formable-only AR steel.

What is Through-Hardening?

AR steel is often described as being through-hardened, but what does that really mean?

When grain structure changes during the initial heating stage of Q&T, the composition of the entire plate changes. This is referred to as through-hardening. Through-hardening differs from "case-hardening," also referred to as "surface-hardening," which only hardens the surface while allowing the metal deeper underneath to remain soft. In this case, the composition, or hardening, of the plate only changes at the surface level.

AR400 versus AR450 versus AR500+

Before we dive into the difference between these common types of AR steel, it is important to clarify that AR steels are not governed by an ASTM code or a specific chemistry, but a level of hardness.

Different mills may have different &#;recipes&#; for AR steel, but produced material is administered a hardness test &#; known as the Brinell Test &#; to determine the category in which it falls. Brinell tests performed on AR steel materials typically meet ASTM E10 specifications for testing material hardness.

The technical difference between AR400, AR450 and AR500 is the Brinell Hardness Number (BHN), which indicates the material&#;s level of hardness. Materials with higher BHNs have greater levels of hardness, while materials with lower BHNs have lower levels of hardness:

AR400: 360-440 BHN Typically
AR450: 430-480 BHN Typically
AR500: 460-544 BHN Typically
AR600: 570-625 BHN Typically (less common, but available)

So, what does this mean in terms of usability? How do you know which level of hardness your project needs?

Hardness & Wear Resistance

Applications requiring material that can resist extreme levels of wear and stress &#; such as mining equipment and concrete handling &#; typically use plate grades with higher BHNs. Project engineers for these applications may choose AR500 or AR600 plate, as they are some of the hardest AR grades and, therefore, well-suited for wear resistance.

Some applications require more moderate levels of wear resistance, such as construction equipment. In these circumstances, project engineers may opt for AR plate grades with a lower BHN, such as AR400 and AR450. These grades are durable enough to handle high wear and stress without sacrificing other desirable material qualities, such as ductility.

Formability & Machinability

Projects that require AR materials are typically those that need a specific balance between hardness and brittleness. As you increase hardness, you also increase brittleness, making the material difficult to form, shape and weld. For some projects, hardness is critical, so brittleness is sacrificed. But in other cases, the material must be formed and machined, so the level of hardness must be reduced.

As a general rule, AR400 and AR450 are the &#;sweet spots&#; in terms of good hardness combined with good formability. AR400 and AR450 are also relatively machinable, allowing for some ability to weld the material.

For projects that truly beat up the material, AR500 and AR600 will last longer and need to be replaced less frequently, but are more difficult to form. These grades also tend to be less machinable and more challenging to weld than AR grades with lower BHNs.

Material Cost

In general, abrasion resistant steel plate grades cost more than HSLA or mild carbon grades. However, AR steel is more durable and resistant to wear than these types of steel, meaning the material would need to be replaced less often. This could result in material cost savings in the long run.

The grade of AR steel can also impact material cost. Grades with higher BHNs (i.e. AR500, AR600) typically cost more than grades with lower BHNs (i.e. AR Medium, AR40), but other factors &#; such as order size and market conditions &#;&#; influence price as well.

Read more about the factors that impact steel plate prices.

AR Medium Steel

While AR400+ grades are the most commonly used types of abrasion resistant steel, AR Medium steel is also used for applications requiring a harder, tougher material.

AR Medium steel plate grades &#; which include AR200 and AR235 &#; have a surface hardness of 180-260 BHN. This hardness level makes AR Medium grades suitable for moderate-wear applications that require more wear resistance than standard mild carbon steel grades, but not to the extent of wear resistance needed in applications like mining equipment.

Sourcing Abrasion Resistant Steel Plate

There are many factors that come into play when selecting which abrasion resistant steel plate grade is right for your project, including hardness, wear resistance and ductility. Ultimately, you and your team will be the best judge of which material your project needs. Cost, of course, comes into play, as sometimes it&#;s worth having a formable material that needs to be replaced more often.

Once your team determines the correct material needed for a project, Leeco® Steel's expert team can help you source what you need when you need it. Our company specializes exclusively in selling larger quantities of steel plate, so contact us, request a quote or learn more today.

Current Leeco Steel customers can also buy AR500 steel plate online via our ecommerce website, Leeco Pro. Leeco Pro streamlines the order process and allows buyers to order the grades they need anytime, anywhere. Learn more and buy abrasion resistant steel plate online.

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