Brinell Hardness Test

Test principle of Brinell hardness

The calculation formula of Brinell hardness is:

Among them, the unit of HB is kgf/
d——Indentation diameter, mm; h——Indentation depth, mm.
As long as the diameter of the indentation is measured, the HB value can be obtained by calculation or look-up table.

During the test, choose different loads and steel ball diameters according to the nature and shape of the material.

The advantages of the Brinell hardness test are strong representativeness, good data repeatability. At the same time, there is a certain conversion relationship with strength. The disadvantage is that harder materials cannot be tested; the indentation is large and not suitable for finished product inspection. It is usually used to test the hardness of raw materials and tempered parts, such as cast iron, non-ferrous metals, low alloy steel, etc.

 

Test conditions

In the Brinell hardness test, we should select the diameter (D) of the indenter sphere, the test load (F), and the load holding time (t), according to the type of metal material, the range of hardness values ​​and the thickness. There are five commonly used indenter diameters of 1, 2, 2.5, 5 and 10 mm.
The test load can range from 9.807N (1kgf) to 29.42 KN (3000 kgf).
The load holding time is generally 10-15s for ferrous metals; 30s for non-ferrous metals; 60s when the HB value is less than 35.

 

Pros and Cons

The diameter of the steel ball and the indentation left on the surface of the metal material is large. Therefore, the measured hardness value is more accurate. There is a certain relationship between HB value and tensile strength. That means we can determine the tensile strength of metal materials approximately according to the Brinell hardness value.
If the hardness of the metal is too high, it will affect the accuracy of the hardness value. Therefore, the HB test is generally suitable for measuring metal materials with a HB value of less than 650.
The Brinell hardness indentation is relatively large, so it is not suitable to measure finished products and sheet materials.

Yide casting is a leading casting foundry in China, we produce quality casting products, pursuing details required for every casting product, we have an imported testing machine to check the Brinell hardness and other parameters, committed to proving the best casting service for our casting customers.

ASTM A126 Standard Specification

Today, we will introduce the ASTM A126 Standard specification for gray iron castings, such as valves, flanges and pipe fittings. This specification covers three classes of gray iron for castings, please see as the following chart.

Tensile Requirements of ASTM A126

	1.Class A	2. Class B	3. Class C
Tensile strength, min, ksi (MPa)	21 (145)	31 (214)	41 (283)
ASTM A48 Equivalent grades	NO. 25	NO.30, 35	NO. 40

Castings should be manufactured in a manner similar to workers. In addition, the surface should be free of visible sand, scale, cracks and thermal cracks.

Chemical analysis should be carried out for each batch of products and should meet the following relevant content requirements: The maximum phosphorus content is 0.75%, and the maximum sulfur content is 0.15%.

Yide Casting is a professional iron foundry in China, with 28 years’ casting and machining experience, provides ductile iron cast, gray iron cast, brass iron cast services for our customers, you only need to show us your drawing file and requirements, we will ensure the final solution and send you a cast sample to check the quality and parameters, if you are looking for professional casting foundry, please don’t hesitate to contact us for more details.

Mechanical Properties of Ductile iron EN-GJS-400-18:

The minimum tensile strength of EN-GJS-400-18 is 400 Mpa; the minimum yield strength is 250 Mpa; and the minimum elongation is 18%.

The matrix of this grade is completely ferrite, with high ductility and impact strength. Therefore, it can be used at a temperature of -20°C. In addition, heat treatment is part of the manufacturing process.

EN-GJS-400-18 ductile iron can ensure notched impact toughness at -20°C. In terms of safety, it has more advantages than cast steel. Cast steel is prone to cracking due to its extremely high shrinkage. One of the reasons is the expansion caused by the graphite spheres formed in the ferrite matrix. This expansion offsets the shrinkage of the material (which is low anyway), thereby preventing cracking.

This grade of ductile iron has a minimum elongation at break of 18%. And due to its high ductility, it is also suitable for low temperature applications. As early as 1980, Dr. Betschart determined the allowable stress of ductile cast iron in his thesis entitled “Research in Modern Cast Metal for Structures”.

Applications of Ductile iron EN-GJS-400-18:

Ductile cast iron EN-GJS-400-18 is suitable not only for the production of safety components for cable cars and ski lifts in high mountain areas, but also for the production of heavy chassis components, automobile crankshafts and wheels.

This material is also widely used in the production of iron castings for wind power, forestry and contractor machinery, valves, brakes,, consoles, pressure tanks, high-pressure equipment housings, and cooling components. And when the temperature is as low as -20ºC, where the impact strength needs to be guaranteed.

Due to its many advantages, the “modern form” of ductile iron has largely replaced cast steel.

BS2789 Grade 420-12 SG Iron

BS2789 Grade 420-12 SG Iron is not a common grade material.  We use ASTM A536 65-45-12 instead normally.

It is related to BS EN 1563 GJS 420-12; 60-40-10; 65-45-12; FGS420-12; SF400; SFP400; DIN 1693 ISO 185 250.

Properties of 420-12 SG Iron

Tensile strength ≥ 420Mpa.
Elongation ≥ 12%.

Mechanical properties shown are typical and may vary subject to the size and section of this SG iron grade.

Certification BS2789 420-12 S G Iron is available with a certificate or conformity, please request when placing any orders.

The hardness of 420-12 SG Iron

The hardness of this grade is around 212 Brinell hardness.

Chemistry composition of 420-12 SG Iron

Carbon 3.40-3.85%

Phosphorous 0.10% max

Manganese 0.10-0.30%

Sulphur 0.02% max

Silicon 2.30-3.10%

Magnesium 0.07% max

 

Foundry of 420-12 SG Iron

BS2789 Grade 420-12 is suitable for applications where the optimal impact, fatigue, electrical conductivity and magnetic permeability features。

Typical applications include valves, dies, pistons and moulds.

 

Yide casting is an experienced casting foundry, specialized in casting iron for 28years, can manufacture the casting iron parts according to your drawing file and requirement. If you are looking for a casting manufacturer, please feel free to contact us for more details, and you are welcome to visit our factory for more details.

 

 

Brinell hardness is a standard that indicates the hardness of a material. Measured by Brinell hardness tester. It was first proposed by the Swede J.A. Brinell, thus called Brinell hardness.

Press a hardened steel ball with a diameter of D into the surface of the metal material to be tested with a certain load P. And then remove the load after holding it for a period of time. The ratio of the load P to the surface area F of the indentation is the Brinell hardness value, denoted as HB.

Introduction to brinell hardness

Brinell hardness (HB) is generally used when the material is soft. For example, non-ferrous metals, steel before heat treatment or after annealing.

HB refers to pressing a hardened steel ball or cemented carbide ball of a certain diameter into the surface of the metal to be tested with a certain test load. Keep it for a specified time, then unload, and measure the diameter of the indentation on the tested surface.

 

Hardness range

The Brinell hardness range is 8~650HBW.

Features

Generally speaking, the smaller the HB value, the softer the material, and the larger the indentation diameter. Conversely, the larger the HB value, the harder the material, and the smaller the indentation diameter.

The advantage of HB measurement is that it has high measurement accuracy, large indentation area. Thus can reflect the average hardness of the material in a larger range. The measured hardness value is also more accurate, and the data is repeatable.

Symbol

The symbol of Brinell hardness is represented by HBS or HBW.

HBS means that the indenter is a hardened steel ball, which is used to determine materials with a Brinell hardness value below 450, such as mild steel, gray cast iron, and non-ferrous metals.

HBW indicates that the indenter is a cemented carbide and is used to determine materials with a Brinell hardness value below 650.

How to express Brinell hardness

The number before HBS or HBW is the hardness value, and the following numbers are used to indicate the test conditions in sequence:

①The diameter of the sphere of the indenter;

②Test load;

③The time that the test load is maintained (10~15s are not marked).

For example, 170HBS10/1000/30 means that a steel ball with a diameter of 10mm is used. Under the test load of 9807 N (1000 kgf), the measured Brinell hardness value is 170 when kept for 30s.

530HBW5/750 means using a 5 mm diameter cemented carbide ball, under the test load of 7355N (750kgf), the measured Brinell hardness value is 530 when it is maintained for 10-15s.

Application

The HB measurement method is suitable for cast iron, non-ferrous alloys, various annealed and tempered steels. It is not suitable to measure samples or workpieces that are too hard, too small, too thin, and whose surface is not allowed to have large indentations.

Yide casting is an experienced casting supplier, specialized in casting iron for 28years, can manufacture the casting iron parts according to your drawing file and requirement. If you are looking for a casting manufacturer, please feel free to contact us for more details, and you are welcome to visit our factory for more details.