Question 1

How to choose the best hardness test method?

Accepted Answer

The hardness test you choose should be determined based on the microstructure (such as uniformity) of the material you are testing, the type of material, the size of the part and its condition.

Question 2

What types of metal hardness testers can be subdivided into?

Accepted Answer

Hardness testers are roughly divided into metal hardness testers, rubber (plastic) hardness testers, gem hardness testers, cement hardness testers, etc. Generally speaking, most of what we discuss are metal hardness testers and rubber hardness testers.

The types of metal hardness testers can be subdivided into

Rockwell Hardness Tester
Micro Vickers Hardness Tester (Micro Vickers Hardness Tester)
Vickers Hardness Tester
Brinell Hardness Tester
Leeb Hardness Tester

Rubber (plastic) hardness testers are generally distinguished by English characters, such as A type, D type, C type, F type, etc., which are roughly divided into rubber, plastic, foam, etc., such as Teclock, Kori, etc. There is a Barcol Hardness Tester that can also detect plastics, aluminum products, PE and leather.

Then explain the general purpose of the metal hardness tester:

Rockwell hardness

Common test rulers are HRC, HRB, HRA, HRE and HR15N, HR30N, HR15T, HR30T, etc. In fact, Rockwell hardness testing machine can also measure plastic products whose rulers are HRR, HRL, HRM, such as detecting the hardness of substrates. HRC hardness scales are generally used to detect the hardness of hard metals and heat-treated steels, HRA are generally used to detect the hardness of tungsten steel, and HRB are used to detect the hardness of soft metals or untreated steel. As for HRE, the general inspection is aluminum products. As for HR15N and HR30N, the surface hardness is tested. HR15T and HR30T detect the hardness of thin iron or tinplate.
It is widely used for metal hardness testing of various metal parts, molds, heat treatments, etc. It can be tested immediately and quickly for checking material strength, incoming material inspection, and metal hardening energy test.

Micro Hardness Tester/Micro Vickers Hardness Tester (HMV)

The detection range is very wide, ranging from soft metals to hard metals. It can also detect the hardness of coatings, glass and ceramics. The ruler is displayed as HV. There is also a Knoop Hardness Tester (Knoop Hardness Tester), and the ruler is displayed as HK. The use load is 10g to 1kg. As for the Vickers hardness gauge, the ruler is HV, but the load is 1kg to 50kg. At present, many specifications use 10kg to beat the hardness of the material.

Vickers/Vickers Hardness Tester (HV)

It is suitable for measuring thin materials and small metal materials. The measurement range can cover almost all metals. According to the characteristics of the test, the hardness value of the material obtained after the force of the same material is similar, and the test High precision, compared with Rockwell hardness method, it is suitable for hardness testing with a wide range of changes.

Leeb Hardness Tester (HL)

It is widely used in the hardness test of large materials, special structures such as pressure vessels such as elevators and boilers, metal warehouse materials, molds, aerospace, transportation, offshore wind power and other permanent assembly components. It is not only convenient to carry, but also can use different shapes Impactor, to meet different test requirements, and can maintain stable testing in harsh environments.

Brinell hardness tester

The large load force used in the detection, the large diameter of the probe, the large indentation diameter, are suitable for the hardness testing of large-grain metal materials, such as cast iron, forging materials, non-ferrous metals and their alloys, various annealing, quenched and tempered metals, and For steel materials, for softer metals such as pure aluminum, copper, lead, zinc, tin, etc. and their alloys, the test accuracy is stable and accurate.

Question 3

What is a needle gauge?

Accepted Answer

Necessary inspection tool for needle gauge to measure precision holes

Needle gauges, also known as plug gauges, bolt gauges, pin gauges, cylindrical gauges, PIN gauges and PIN GAUGE, etc., are gauges designed to check whether products meet standards. They are made of stainless steel, tool steel, ceramics, tungsten steel, and bearing steel. A round rod with a specific size made of high hardness and other materials. It is used to check the position, measure the size of the hole, check the distance between two holes, and can also be used as a stop gauge and measure the depth of the hole. It is a necessary inspection tool for standardized inspection of holes.

The precision specifications of the needle gauge are as shown in (below):

The outer diameter of the needle gauge size ranges from φ0.200 to φ50.00m, and the standard product is below φ20mm, and can be produced to three decimal places. 0.2mm~10.00mm, the accuracy of the general standard pin gauge is ±0.5um, and the accuracy of the ultra-precision type is ±0.3um (applicable to high-precision industries such as optical fiber).

Types and classification of needle gauges

EISEN needle gauge materials are divided into three categories

Bearing steel
Ceramics
Super hard (tungsten steel)

Needle gauge introduction Steel standard product Ceramic standards Super hard standard Material

φ0.05~φ1.499mm SKH-51 tool steel

φ1.50mm~SUJ-2 bearing steel (high carbon steel)

φ0.2~20.00mm ceramic

φ0.10~φ0.30mm ultra-fine super-hard alloy

φ0.30~ V-20mm tungsten steel

Abrasion resistance general good excellent Rustiness general excellent good Temperature effect general good excellent

Our company is the general agent of EISEN, a major Japanese manufacturer, in Taiwan. The needle gauges sold are all made in Japan and imported with original packaging. EISEN is a world-renowned manufacturer of gages such as bolt ring gauges and diamond knives. Few listed and OTC companies are their users.

Question 4

What is a limit thread gauge?

Accepted Answer

The limit thread gauge is a set of GO and NOGO. The GO can pass the thread under test smoothly, and the gauge must stop within 2 rotations (tooth) for this thread to be qualified.
Thread bolt gauge (also known as plug gauge, thread bolt gauge), thread bolt gauge is a gauge for checking female threads.
Thread ring gauge (also called ring gauge, ring tooth gauge), thread ring gauge is a gauge for checking male threads

The accuracy of ring gauges and bolt gauges must comply with "international standards" such as ISO, JIS, ANSI, DIN, BSI, etc. The accuracy test report is also attached. However, each brand has some "tolerance" in the specification. Therefore, it is recommended to use the "same brand" ring bolt gauge for testing with the corresponding manufacturer, which is less prone to tolerance disputes.

◎ Specifications
According to the requirements of different "workpiece types" and "tooth pitch", ring gauges and bolt gauges can be divided into:
M metric thread, UNC American thread coarse thread, UNF American thread fine thread, UNEF American thread extra fine thread, W inch thread, Parallel threads for PF pipes, parallel threads for NPSM American pipes, pitch thread gauges for PT British pipes, pitch thread gauges for NPT American pipes, BC bicycle etc.

Specification accuracy:
1. "ISO" metric standard: the commonly used grade of general bolt gauge is 6H, and the grade of ring tooth gauge is 6g
2. "JIS" new standard: the commonly used grade of general bolt gauge is 6H, and the grade of ring tooth gauge is 6g.
3. "JIS" old standard (divided into work and inspection): grades are divided into grades 1, 2 and 3 (commonly used grades are grade 2).
4. "ANSI" American standard: The grade classification is the same as the new JIS, but the tolerance range is different (not mixed).
American teeth: (UNC, UNF, UNEF, UNS, UN)
1. "JIS" old system standard: bolt thread gauge grades are 3B, 2B, 1B; ring thread gauge grades are 3A, 2A, 1A.
2. "ANSI" American standard: the grade is the same as the Japanese standard, but there is no difference between work and inspection, and the tolerance range is also different.

JIS is a Japanese standard. According to the purpose of use, thread gauges are divided into two types for work and inspection, while ISO standards have no such distinction.
According to the purpose of use, the Japanese JIS standards can be divided into: GP-IP (inspection regulations), GP-WP (working regulations), and GP-NP (ISO standards).

Example: outer diameter 3mm, pitch 0.5mm

Outer diameter gap Pass end Stop Precision ISO M3 x0.5 GP NP 6H JIS M3 P0.5 GP WP II JIS M3 P0.5 IP II

More

Question 5

Why do materials need to have hardness?

Accepted Answer

If metal parts come into contact with other hard or adhesive materials, they are expected to have a certain degree of hardness because metal's high hardness makes it more resistant to wear.

However, materials with high hardness are also more brittle than softer materials, so it is not necessarily suitable to fully harden the entire workpiece from the exterior to the interior.

In this case, surface hardening can be used to produce a workpiece that is tougher on the inside (because the softer inner layer can absorb stress without cracking) and harder on the surface, providing considerable corrosion resistance.

Commonly and widely utilized heat treatments include processes such as quenching, tempering, carburizing, induction hardening, tempering, and annealing, which allow metals to produce materials with excellent structural performance.

Question 6

What is the definition of hardness?

Accepted Answer

In materials science, hardness refers to the "characteristic of a solid material to resist permanent deformation."

The ability of a material to locally resist a hard object pressing into its surface is called hardness.

The local resistance of a solid to the intrusion of external objects is an indicator for comparing the softness and hardness of various materials.

Due to the stipulation of different testing methods, there are different hardness standards.

The mechanical meanings of various hardness standards are different and cannot be directly converted to each other, but they can be compared through testing.

Question 7

How do test hardness?

Accepted Answer

The measurement of hardness is primarily determined by the depth of the indentation, the projected area of the indentation, or the surface area of the indentation.
Static testing methods include Brinell, Rockwell, Vickers, Knoop, Webster, Barcol, and others.
Among them, the Rockwell, Vickers, and Brinell testing methods are the most widely utilized; they are the primary testing methods for metal hardness inspection. In the industry, the Rockwell hardness test is the most widely used for product inspection.

Hardness testing is roughly divided by testing methods into:

Indentation hardness test
Scratch hardness test
Rebound hardness test and other hardness testing methods

Indentation hardness test
A special indenter is pressed into the material with a certain load for a period of time, and the hardness is determined by measuring the formed indentation. Materials with higher hardness produce smaller indentations.
Commonly used indentation hardness tests mainly include: Rockwell hardness test, Vickers hardness test, Brinell hardness test, etc.

Rebound hardness test
An object with known physical properties is used to strike the object to be measured at a certain speed; a higher rebound speed indicates higher hardness.
Commonly used rebound hardness tests mainly include: Shore hardness test, Leeb hardness test, etc.

Scratch hardness test
The material to be tested is scratched against one or more materials of known hardness. Leaving a scratch on the latter indicates that the hardness is ≥ the latter; otherwise, it is ≤ the latter's hardness. This type of method can roughly estimate hardness through comparison but is not precise enough.
Commonly used scratch hardness tests are the pencil hardness test, Mohs hardness test (also known as Morse hardness test), file hardness test, etc.

Question 8

How to choose the type of hardness test?

Accepted Answer

Type of material to be tested
Whether it needs to comply with standards
Estimated hardness of the material
Homogeneity / Heterogeneity of the material
Size of the parts
Whether mounting is required (sampling local structures)
Number of specimens to be tested (sampling inspection, full inspection)

Question 9

What is the principle behind hardness testing?

Accepted Answer

Take the most common Rockwell hardness as an example HR

Rockwell hardness is a rapid hardness testing method developed for production control, using direct readings, and is primarily used for metal materials. Rockwell hardness (HR) can be calculated by measuring the depth of the indentation obtained after pressing an indenter into the specimen material using a given load.

More commonly used for specimens with larger workpiece bodies
A rapid testing method primarily used for metal materials
Widely used for process testing, such as quenching, tempering, and annealing tests (HRC)

One of the common hardness tests: Vickers hardness HV

Vickers hardness is a hardness testing method applicable to all solid materials, including metal materials. After a diamond pyramid indenter is used to leave an indentation under a given load, the Vickers hardness (HV) can be calculated by measuring the diagonal length of the indentation in the specimen material. The indentation diagonals can be measured optically to determine the hardness through tables or formulas.

Suitable for various applications (quenching, surface hardness, carburizing, etc.)
A hardness testing method applicable to all solid materials, including metal materials
Includes subgroups used for hardness testing of welding points
Requires pre-processing (metallographic mounting)
Longer test preparation time

Question 10

Troubleshooting abnormal problems

Accepted Answer

1. If the surface of the workpiece is too rough, difficulties may be encountered when evaluating the corners of the indentation, especially when using automated equipment.
When using automated hardness testing, scratches from the preparation process may lead to incorrect readings of the indentation size.
Solution:
Use a polished surface.
Surface preparation requirements depend on the load applied to the material and the hardness of the material: the softer the material, the higher the quality of polishing required.

2. For specimens with a high degree of etching, it may be difficult to evaluate the corners of the indentation, which may lead to incorrect hardness test results.
Solution:
Etching should be avoided as much as possible because it leads to a reduction in the reflective surface. If etching must be performed, light etching is preferred so that the corners of the indentation can be distinguished.
For example, etching is occasionally required when evaluating welding points.

3. Hardness values are higher than expected.
Solution:
Check relevant regulations to ensure that the correct indentation spacing was used in the hardness test.
If the hardness indentations are too close to each other, strain hardening may occur.

Question 11

What are some common examples in daily life?

Accepted Answer

Cutting tools

Fasteners

Bicycle related

Automotive parts

Hand tools

Question 12

Which materials are suitable for testing with a fully automatic Vickers hardness tester?

Accepted Answer

Taiwan Nakazawa Co., Ltd. answers you that the fully automatic Vickers hardness tester is suitable for measuring micro and thin specimens, parts after surface carburizing treatment, and for the determination of micro-Vickers and Knoop hardness of brittle materials such as agate, glass, and ceramics. It is an ideal hardness testing instrument for research institutions, factories, and quality inspection departments to conduct research and testing.

The automatic control and measurement system is mainly used for the determination of micro-Vickers hardness of various metals and some non-metallic materials. The operator only needs one action to start the automatic program measurement without any pause in between. It can perform hardness determination on various parts (machined parts, forgings, cast iron, cast steel parts, etc.), non-ferrous metals, and parts after heat treatment. At the same time, it is suitable for the determination of effective hardened layer depth, coatings, and heat-affected zones of welded parts. It can also be used for the observation of internal metallographic structures of various metal parts and for image acquisition, display, and output printing.

Question 13

What are the characteristics of a fully automatic Vickers hardness tester?

Accepted Answer

Taiwan Nakazawa answers for you: by combining an industrial computer with a hardness tester, all parameters required for testing are selected on the computer, making the display clear and intuitive and the operation convenient.
The built-in CCD image acquisition system makes the indentation display clear and intuitive, and the hardness value can be read simply by touching a button. It has a hardness scale conversion function, allowing conversion between various hardness scales.
Measurement data is automatically recorded, and hardness-depth curves can be generated and saved as CSV or EXCEL documents.
With auto-focus and automatic instrument measurement, the automation of Vickers hardness testing is fully realized.

Our company is a company specializing in providing metal testing and analysis instruments, producing metallographic pre-treatment equipment, metallographic cutting machines, metallographic mounting presses, metallographic grinding and polishing machines, and acting as an agent for the sale and repair of high-quality products such as micro Vickers hardness testers and Rockwell hardness testers. You are welcome to purchase from Taiwan Nakazawa Co., Ltd.

Question 14

What is a fully automatic Vickers hardness tester?

Accepted Answer

The hardness tester and tablet computer feature an integrated design. Equipped with the Windows operating system, it possesses all the functions of a computer.
Through the built-in CCD image acquisition system, the test indentation is displayed directly on the tablet, with touch screen buttons.
Automatically testing Vickers hardness values completely solves the method of using a microscope to measure the indentation diagonal length in Vickers hardness testers. It avoids the irritation and visual fatigue caused by the microscope's light source to the eyes, protecting the vision of the testing personnel.

Our company, Taiwan Nakazawa Co., Ltd., specializes in the production of precision metallographic testing equipment, such as metallographic cutting machines, metallographic grinding and polishing machines, Vickers hardness testers, metallographic mounting machines, and other precision equipment. Friends in need are welcome to come and purchase.

Question 15

What are the different scales used to represent Rockwell hardness testers?

Accepted Answer

Taiwan Nakazawa answers you.
HRA: Hardness obtained by using a 60kg load and a diamond cone indenter, used for materials with extremely high hardness (such as tungsten carbide, hard alloys, etc.).
HRB: Hardness obtained by using a 100kg load and a hardened steel ball with a diameter of 1.5875mm, used for materials with lower hardness (such as annealed steel, cast iron, etc.).
HRC: Hardness obtained by using a 150kg load and a diamond cone indenter, used for materials with very high hardness (such as quenched steel, etc.).

Question 16

What are the main functions of a digital automatic Vickers hardness tester?

Accepted Answer

1. The optical system designed by senior optical engineers not only provides clear images but can also be used as a simple microscope, with adjustable brightness and comfortable viewing, making it less likely to cause fatigue during long-term operation.
2. The industrial LCD large screen display can show the testing method, test force, measured indentation length, hardness value, test force dwell time, number of measurements, and allows for inputting the year, month, date, test results, and data processing, etc.
3. Possessing the capability for independent research, design, production, and processing, we provide spare parts replacement and maintenance upgrade services for our machines for a lifetime.
4. An optional LCD large screen is available; the LCD large screen display is convenient for observation, and the testing conditions and testing process are intuitive and clear.

The hardness testers produced by our Kunshan Fuze Testing Equipment Co., Ltd. have high precision and stable performance, with a complete range of hardness tester specifications and models suitable for various products and tests across all walks of life.

Question 17

What are the applicable ranges of a digital automatic Vickers hardness tester?

Accepted Answer

Taiwan Nakazawa Co., Ltd. answers you, detectable items:
1. Steel, non-ferrous metals, metal foils, hard alloys, metal sheets, microstructure, carburization.
2. Carburizing, nitriding and decarburization layers, surface hardened layers, electroplating layers, coatings, heat treatment.
3. Glass, wafers, ceramic materials.

Our company is a firm specializing in providing metal detection and analysis instruments, producing high-quality products such as metallographic pre-processing equipment, metallographic cutting machines, metallographic mounting machines, micro-Vickers hardness testers, and Rockwell hardness testers. Welcome to Taiwan Nakazawa Co., Ltd. to make your purchase.

Question 18

How can you tell the quality of a hardness tester you've purchased?

Accepted Answer

Taiwan Nakazawa Co., Ltd. answers for you:
1. The distinction of types, such as Leeb, Shore, Barcol, Micro-Vickers, Vickers, Rockwell, Brinell, etc. Currently, there are many types on the market, and their prices are different. When purchasing, choose the type based on the required environment and purpose; all of this needs to be clearly communicated and discussed with the sales customer service.
2. Brand reputation is a point that requires focused investigation. The quality of a product is reflected not only in the product itself but also in the attitude of the distributor. A good distributor will solve problems after discovering them, while problematic distributors are different; their negative reviews will increase, which means the problems they have exist without being resolved.
3. When conditions permit, do not reduce the step of trial use. After all, it will need to be used frequently after being purchased. If you do not try it out to understand it, problems such as finding it unsuitable or difficult to use after taking it home will exist, and then returns or exchanges will be needed; this has a significant impact on both the buyer and the seller.

Question 19

How to distinguish between a good and bad hardness tester?

Accepted Answer

It belongs to the category of metrological testing instruments and plays an important role in ensuring product quality and stopping failure analysis. Therefore, choosing a good hardness tester is a key issue for users.
A true hardness tester complies with national standards and norms and possesses interchangeability and consistency. Although relevant departments in China have formulated national standards, some manufacturers' technical capabilities fail to reach the level of production that complies with the standards. Therefore, they adopt corrective methods to produce hardness testers. Although their products are also named hardness testers, they are far from true hardness testers. Originally inaccurate hardness testers can also meet the requirements of accurately testing hardness blocks after correction. Therefore, for users to choose a good hardness tester, they need to truly understand the characteristics of hardness testers.

Our company, Taiwan Nakazawa Co., Ltd., specializes in the production of precision metallographic testing equipment, such as metallographic cutting machines, metallographic grinding and polishing machines, Vickers hardness testers, metallographic mounting machines, and other precision equipment. Friends in need are welcome to come and purchase.

Question 20

How should a hardness tester be maintained?

Accepted Answer

1. For non-metallic surfaces, use a soft cloth moistened with a mild liquid detergent to wipe clean. Do not use too much detergent, as it can penetrate into the interior of the machine body and cause damage to components.
2. For metallic surfaces, use a soft cloth moistened with light machine oil to wipe and clean. Do not use too much oil, as excessive oil easily attracts dirt and other debris. Clean the mating surfaces between the lifting screw and the testing platform, the shoulder of the indenter, and the surface of the spindle rod. Dirt, machine oil, metal chips, and other debris on these surfaces will cause inaccurate test results during the testing period.

The hardness testers represented by our Taiwan Nakazawa Co., Ltd. have high precision and stable performance, with a complete range of hardness tester specifications and models suitable for various products and tests across all walks of life.

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