Hardness Test Blocks, Indenters and Accessories

Our Brinell blocks are certified to ASTM E10 and ISO 6506. Our Vickers and Knoop blocks are certified to ASTM E384 and ISO 6507. The standard follows the method the block is used for, so a lab running both Brinell and microindentation testing keeps a separate set of blocks for each.

Brinell blocks are offered for test loads from 62.5 kg up to 3000 kg, and Telebrineller test bars belong to the same family. During calibration, the force of our tester is held with a proving ring and a load cell, and the impressions are read with a stage micrometer. Both the force instruments and the micrometer are traceable to NIST.

All of our blocks are calibrated and accredited to ISO Guide 25, and the certification work is performed in an ISO 17025 compliant facility. That gives your verification records a documented chain back to national standards.

ASTM E18 is the industry standard for Rockwell hardness testing of metallic materials. This specification includes both theory and standard practice statements. For those companies Nadcap accredited in heat treat where the AC7102/5 for hardness and conductivity testing is included, an additional layer of requirements comes into play. ASTM E18 lists three types of verification testing: direct verification, indirect verification, and daily verification.

ISO 6508 specifies the method for Rockwell regular and Rockwell superficial hardness tests for metallic materials and is applicable to stationary and portable hardness testing machines. For specific materials or products, other specific International Standards apply (for instance, ISO 3738‑1 and ISO 4498).

• Standard Rockwell Hardness Test Blocks - ASTM E-18 and ISO 6508
• Superficial Rockwell Hardness Test Blocks - ASTM E-18 and ISO 6508
• Brinell Hardness Test Blocks — ASTM E-10 and ISO 6506
• Vickers and Knoop Hardness Test Blocks - ASTM E-384 and ISO 6507

If you have any other questions or would like to obtain a personal quote, please click here.

Standard Rockwell Hardness Test Blocks - ASTM E-18 and ISO 6508 use the following materials:

• Steel
• Brass
• Carbide

Superficial Rockwell Hardness Test Blocks - ASTM E-18 and ISO 6508 use such materials:

• Steel
• Brass

In tungsten carbide hardness testing Rockwell hardness of HRA is often used. HRA, named Rockwell Hardness A scale, which as the initial pressure uses 98.07N (equal to 10kgf), use a diamond pressure head with 120°cone apex angle or steel ball with 1.59, 3.18mm in diameter and then pressurized to 588.4N (equal to 60kgf).

These brass alloys are single-phase alloy, which metallurgically we call "Alpha” phase, which has a face-centred cubic structure. The solubility of zinc in copper is 32.5% at the solidus temperature of 900˚C and 30% at room temperature. The brasses used in cartridge cases are entirely alpha phase and are ideally suited to cold working having superior ductility to the copper-zinc alloys.

Looking for a quote? Click here to obtain a personalized quote!

According according to the latest ASTM E18 (v. 2022) specifications. The tolerance on the HRB test blocks are as follows:

If HRB is less than 88 the acceptable tolerance is +/- 2.5.

If HRB is greater than 88 the tolerance is +/-1.0.

Learn more by contact our qualified consultants today.

A grid matters most at the lower end of the Rockwell range and on the ball scales. Soft blocks take larger indentations, and ASTM E18 requires each impression to be spaced from its neighbours and from the edge of the block. With larger indents, freehand placement quickly wastes surface or breaks the spacing rule.

A grid gives every indentation its own cell, so the operator places each test without measuring distances and anyone reviewing the block can see which positions are already used. Every standard Rockwell block we offer is supplied with a grid.

On harder blocks the indentations are small, and an experienced operator can space them on an ungridded surface. Even then, a grid helps when several operators share the same block across shifts, because nobody repeats a position by mistake.

One indentation per cell. The grid is laid out so that each impression keeps the distance ISO 6508 and ASTM E18 require from its neighbours and from the block edge, so the usable count equals the number of cells on the block.

Once every cell has been used, the block is retired. A test block is a consumable with a finite number of valid indentations, and squeezing extra impressions between cells would break the spacing rule and make those readings invalid for verification.

To get the most from a block, keep set-up and trial indents on a separate piece of material and use the certified block only for the checks your procedure requires. A gridded version is also listed in our consumables catalogue for superficial Rockwell and Brinell blocks.

Based on ASTM Standards, distance between 2 indents is a minimum of 2 times the indentation's diagonal (dK), and 2 ½ times the indentation's width (dW).

The distance between an indentation's center and a test piece edge is at least 1 dK or 2 ½ times the indentation's dW.

Based on ISO Standards, distance between 2 indents is at least 2 times the indentation's dK, and 3 ½ times the indentation's dW.

The distance between an indentation's center and a test piece edge is at least 1 dK or 3 ½ the indentation's dW.

Based on JIS Standards, the distance between an indentation and a test piece edge is a minimum of 3 times the short dW. The distance from one indentation to an adjacent indentation is at least 2 ½ times the short dW, or a minimum of the long dK. If 2 indentations have different sizes, the spacing minimum is based on the short dW of the bigger indentation.

Based on ASTM Standards, measuring the distance between 2 indents or the edge of a test piece and an indent involves at least 2 ½ times the indentation's diagonal (dV).

Based on JIS and ISO standards, the distance between 2 indent centers is a minimum of 3x the indent's diagonal for copper, copper alloys, and steel, and a minimum of 6 times for lighter metals, tin, lead, as well as their alloys.

The distance from an indent's center and the test piece edge must be a minimum of 2 ½ times the dV for copper, steel, and copper allows, and a minimum of 3x for light metals, tin, lead, as well as their alloys.

Based on JIS, ASTM, and ISO standards, the proper distance between 2 adjacent indentations' centers is a minimum of 3 times the indentation's diameter.

The distance any indentation's center to a test piece edge must be a minimum of 2 ½ times the indentation's diameter.

Ensuring compliance to ISO, ASTM, and JIS standards is crucial in user-performed hardness testing. The standard under which the lab operates determines the frequency. Common reasons for performing verification tests include:

• Start of production for the day
• Changing test force
• Changing indenters

• Rockwell Regular & Superficial scales
• Vickers Micro-indentation - for loads starting from 10gf up to 1kgf
• Vickers Micro-indentation - for loads starting from 1kgf up to 120kgf
• Knoop Micro-indentation - for loads from 10gf up to 1kgf
• Brinell: HBW5/250, HBW10/1000, HBW5/750, HBW2.5/62.5, HBW2.5/187.5, and HGW10/3000.

The test blocks are manufactured in an ISO/IEC 17025 accredited lab by the American Assoc. for Lab. Accreditation (A2LA).

• We directly work with brass and steel mills for the specific chemical composition.
• We perform all machining processes in-house, at the calibration site. These include grinding, lapping, and polishing.
• We perform 100% inspections to make sure each single test block meets ASTM physical requirements in terms of flatness, thickness, parallelism, and surface roughness.
• Each Rockwell test block supports compliance to NADCAP.

Square Pattern - The entire block is grid patterned. The problem with this design is that soft blocks create bigger indents, and don't always satisfy ASTM E18-17e1 for the distance between the edge and another indent. You can use any other square to solve the issue.

Circle Pattern - The design solves the distance problem between indents, thereby meeting the standard. There are complaints of excessive space wastage. This, however, is the ASTM E18-17e1 rule.

Our Knoop blocks are micro blocks for test forces from 1 gram to 1,000 grams, the range where Knoop testing is normally used. Each block is mirror-polished, mounted and shipped in a case that protects the polished surface, because at these forces a scratch or film on the surface changes the diagonal you read.

The Knoop indenter is a pyramidal diamond like the Vickers indenter, but elongated rather than symmetrical, and hardness is calculated from the long diagonal. The shallow, narrow impression suits thin layers and brittle materials.

Blocks are available for all hardness ranges, and the hardness value and mount are confirmed at quotation to suit the stage of your micro Vickers and Knoop hardness tester. A certified Knoop diamond penetrator is also available from us.

We supply two kinds of Vickers block. Micro Vickers blocks cover test forces from 1 gram to 1,000 grams, and heavy load Vickers blocks cover 1 kg to 50 kg (2.2 to 110 lbs). Both are available across all hardness ranges.

The heavy load block is mirror-polished and has the same surface area as our standard Rockwell block, so one heavy load block carries the same number of test opportunities as a Rockwell block. Micro blocks are mirror-polished and mounted, which gives the best possible test surface at low forces.

Because the standards set a minimum distance between indentations, the usable surface decides how many checks a block will give you. Tell us the forces in your procedure and we will match the blocks to your macro Vickers hardness tester or micro hardness system.

Circle and gridded blocks are sold separately. The most common block dimensions are 6 x 2 x ¾". Other available dimensions 2 x 2" and 6 x 4 1/2 x ¾", depending on ASTM E10-17 dimension rules. Call to check for availability and prices. Materials used are brass, aluminum, or steel, depending on the hardness required.

The Master Calibration Kits we produce give customers the ultimate Quality Control tool. Every kit contains test blocks or a single block, as well as the penetrator unit used for calibrating them. Matching the blocks to a particular penetrator establishes a set relationships, which can then be disregarded as probable variables in hardness test systems. If a problem crops up, an available master kit lets you accurately and promptly determine if the source is your hardness tester.

All the blocks that come with our kits have been calibrated using a tester, the accuracy of which has been verified with NIST traceable depth and load measuring devices. The kits come with a polished wood case, as well as certificates that cover all applicable standards.

You can start with the part specifications with your customer or within your organization. Part specifications are sometimes listed with common scales like HRC, although you can't do the scale on your part - the reason being the part may be too thin or possesses a case hardness. ISO and ASTM charts provide guidance on the minimum thickness.

Take care when using testers by conversion or those that convert hardness scales electronically. Conversions cannot be accredited.

You use test blocks to verify the calibration of the tester, and not your part. Although it is ideal to use a block that's as close as possible to your part's hardness, it isn't that critical. That being said, blocks are selected from different heat treat lots to get the best possible match. Different indenter and force combinations can likewise affect the result of your received block value.

It is recommended that you consider the suggested hardness levels listed in ISO and ASTM documents.

While some blocks sometimes self-destruct within a short period due to heavy use, some can last for several years. In general, high force testing can destroy soft blocks in about a month, particularly when it requires daily verification.

Changes in ISO and ASTM requirements can render a block useless. This is what happened to pre-NIST traceable HRC back in 2000, as well as blocks calibrated in the absence of verified indenters pre-E180-07.

The standard dimensions of the Brinell hardness test blocks are as follows:

Square Brinell Hardness Test Blocks
Length: 152.40mm (6")
Depth: 50.90mm (~2")
Thickness: 6.85mm (~0.25")

Request quote to get your consumables price catalogue.

The standard dimensions of the Rockwell C hardness test blocks are as follows:

Square Rockwell Hardness Test Blocks
Width: 50.90mm (~2")
Depth: 50.90mm (~2")
Thickness: 6.85mm (~0.25")

Request quote to get your consumables price catalogue.

Absolutely, NextGen has the full range of regular and carbide level NIST traceable hardness test block that you need. Regular Vickers test block ranges are up to 850HV and the carbide ranges are 850HV and over. Whether you need 1200HV, 1650HV or more, we have you covered. Request quote today to get the pricing for hardness test block that best meets your testing requirements.

Do you offer expedited lead times for your NIST certified test blocks?

Expedited lead times are always an option. The prices expedited lead time will depend on our production stage. We recommend you contact us to confirm the absolute best lead time and associated cost that we can offer. It is worth noting that our standard lead times are faster than most of our competitors on the market. If waiting is an option, we will do our very best to impress you.

Yes, without an exception, all of NextGen's hardness test blocks come standard with a certificate of calibration. Soft copies can be requested for your reference.

Yes, certified test blocks can be expedited for an additional fee. The cost and the time saved depend on the block type, the hardness value and the calibration you need, so we price an expedited order against your exact requirement.

Most Brinell and Rockwell blocks are already in stock, which often makes standard shipping from stock the fastest option for those scales. An expedited request is more relevant for Vickers and Knoop micro blocks, heavy load Vickers blocks or a block that needs an additional force calibration.

For a firm date and price, send us a quote request with the scale, test force, hardness range and quantity, together with the date you need the blocks on site.

Yes, we ship hardness test blocks and test bars internationally. International orders of test blocks are prepaid in full, covering both the blocks and the freight, and the terms are set out on your quotation.

Our consumables catalogue lists test blocks and certified indenters under Schedule B code 9023.0000, which helps your customs broker classify the shipment. Blocks, indenters and anvils for the same tester can travel in one consignment.

For a delivered price, contact our team with the destination country, the blocks you need and any carrier or Incoterm preference, and we will quote the shipment along with the blocks.

Lead time for a NIST traceable Vickers block depends on the hardness range, the test force named on the certificate and whether the block carries more than one force calibration. A block in a range we already hold ships faster than one requested at a specific value or with an extra calibration.

We confirm the ship date with your quotation, based on our current stock and the calibration schedule at that moment. If the date matters, put it on the request so we can plan the calibration around it.

The simplest way to take lead time off the critical path is to plan block purchases with your verification schedule. Ordering a replacement before the current block runs out of valid positions means a new block is on the shelf when you need it.

Yes. We keep most Brinell and Rockwell test blocks in stock, and we also carry Vickers and Knoop micro blocks and heavy load Vickers blocks.

Alongside the blocks, we carry certified indenters for Rockwell, Brinell, Vickers and Knoop testing and test anvils compatible with a wide majority of hardness testers. A block, its matching indenter and an anvil can therefore ship together on one order.

Availability changes with every order, so the quickest way to check is to send us the scale, the load and the hardness range you test to. We confirm availability for each item and, if a block is out, give you the best lead time we can offer.

Yes. A single Vickers block can carry more than one force calibration, and an additional calibration is listed as its own item in our consumables catalogue. This suits labs that verify a micro hardness tester at two or more test forces and want one reference block for all of them.

Each calibration uses part of the polished surface, because the calibration indentations are made on the block before it reaches you. A block with two calibrations therefore has fewer free positions for your routine checks than a single-force block, although the mirror-polished face still leaves room for regular verification.

Our Vickers blocks are certified to ASTM E384. Tell us every force you need when you order, so all calibrations are planned on the same block and recorded together.