The so-called various hardness, according to the level of hardness, using different measurement methods to measure the value, according to some standard finishing, for reference, please read the relevant standards (1) Brinell Hardness (HB) However, the conversion relationship of various materials is not consistent with the hardness Q formula: The commonly used hardness indicators are Brinell hardness, Rockwell hardness, and Vickers hardness. 2. Rockwell Hardness (HR) When HB>450 or when the specimen is too small, the Brinell hardness test cannot be used instead. It is a diamond cone with a vertex angle of 120° or a diameter of 1.59. 3. Vickers hardness (HV) 1.HRC meaning is Rockwell hardness C ruler, 4. The indenter of the Rockwell C hardness scale is a 120 degree diamond cone, and the test load is a certain value. The Chinese standard is 150 kg force. 5. The Rockwell hardness indentation is very small, the measurement value is partial, and the number points must be averaged. This applies to finished products and thin sheets, and is classified as nondestructive testing. 6. The hardness value of Rockwell hardness is an unnamed, no unit. Therefore, it is incorrect to use what is called Rockwell hardness. The hardness value of the cloth hardness has units, and it has a certain approximate relationship with the tensile strength. 7. Rockwell hardness is directly displayed on the dial, and can also be displayed digitally. It is easy to operate, fast and intuitive, and suitable for mass production. Cloth hardness needs to use a microscope to measure the indentation diameter, then look up tables or calculations, the operation is more tedious. 8. Under certain conditions, HB and HRC can be checked and exchanged. Bopet Film Bopet Film,Eco-Friendly Aluminum Metallized Film,Plastic Bopet Film For Cloth Transfer,Plastic Bopet Film SHAOXING TIANPU PLASTIC PRODUCTS CO.,LTD , https://www.fulingholdinggroup.com
The hardened steel ball of a certain size (typically 10mm in diameter) is pressed into the surface of the material with a certain load (generally 3000kg), held for a period of time, and the ratio of the load to its indentation area after the load is removed is the Brinell hardness value ( HB) in kilograms force/mm2
(N/mm2).
(2) Rockwell hardness (HR)
When HB>450 or the sample is too small, the Brinell hardness test cannot be used instead. It uses a diamond cone with a vertex angle of 120° or a steel ball with a diameter of 1.59 and 3.18 mm to press the surface of the material under test under a certain load. The hardness of the material is obtained from the depth of the indentation. According to the hardness of the test material, it can be divided into three different scales:
There are three ways to measure Rockwell hardness:
1) HRA, with a diamond indenter, load 60 kg measured value;
2) HRC, measured value of 150 kg load;
3) HRB, with a 1/16 inch steel ball head, 100 kg load measurement.
(3) Vickers hardness (HV)
A diamond square cone presser with a load of 120 kg or less and a vertex angle of 136° is pressed into the surface of the material, and the surface area of ​​the material indentation pit is divided by the load value, which is the Vickers hardness value (HV).
The difference between HRA, HRB and HRC in Rockwell hardness has proved that there is an approximate correlation between hardness values ​​and strength values ​​between various hardness values ​​of metal materials. Because the hardness value is determined by the resistance to initial plastic deformation and the resistance to continued plastic deformation, the higher the strength of the material, the higher the resistance to plastic deformation and the higher the hardness value.
1. Shore Hardness (HS) = Hardness (BHN)/10+12
2. Shore Hardness (HS) = Rockwell Hardness (HRC) + 15
3. BHN = Rock Hardness (HV)
4. Rockwell hardness (HRC) = Hardness (BHN)/10-3 Hardness y: HS<100HB<500HRC<70HV<1300(80~88)HRA,
(85~95) HRB, (20~70)HRC A, B, and C in HRA, HRB, HRC, etc. in Rockwell hardness are three different standards, which are called scale A, scale B, and scale C.
The Rockwell hardness test is one of several common indentation hardness tests used today. The initial pressure of all three scales is 98.07 N (10 kgf), and the hardness value is finally calculated from the indentation depth. The ruler A uses a ball-and-ramid indenter and then pressurizes it to 588.4 N (60 kgf). The ruler B uses a steel ball with a diameter of 1.588 mm (1/16 in.) as the indenter and then pressurizes it to 980.7N. (Including 100kgf); while the ruler C uses the same ball and pyramid as the indenter, but the force after pressing is 1471N (150kgf). Therefore, the ruler B applies a relatively soft material, and the ruler C applies a harder material.
Practice has shown that there is an approximate correlation between hardness values ​​and strength values ​​between various hardness values ​​of metallic materials. Because the hardness value is determined by the resistance to initial plastic deformation and the resistance to continued plastic deformation, the higher the strength of the material, the higher the resistance to plastic deformation and the higher the hardness value. However, the conversion of various materials is not consistent.
Hardness means that the material resists the ability of a hard object to press into its surface. It is one of the important performance indicators of metal materials. The higher the hardness in general, the better the abrasion resistance.
1. Brinell hardness (HB)
The hardened steel ball of a certain size (typically 10mm in diameter) is pressed into the surface of the material with a certain load (generally 3000kg), held for a period of time, and the ratio of the load to its indentation area after the load is removed is the Brinell hardness value ( HB) in kilograms force/mm2
(N/mm2).
3.18mm steel ball is pressed into the surface of the material to be measured under a certain load, and the hardness of the material is obtained from the depth of the indentation. According to the hardness of the test material, it can be divided into three different scales:
HRA: It is the hardness obtained with a 60kg load and a diamond cone press. It is used for materials with extremely high hardness (such as cemented carbide, etc.).
HRB: Hardened steel ball with a load of 100kg and a diameter of 1.58mm. Hardness obtained. Used for materials with low hardness (such as annealed steel, cast iron, etc.).
HRC: It is the hardness obtained with a 150kg load and a diamond cone press. It is used for materials with high hardness (such as quenched steel, etc.).
A diamond square cone presser with a load of 120 kg or less and a vertex angle of 136° was pressed into the surface of the material, and the surface area of ​​the material indentation pit was divided by the load value, which was Vickers hardness HV (kgf/mm 2 ). "HK=139.54•P/L2. In the formula: HK-Knoop hardness, Mpa; P-load, kg; L-dimple diagonal length, mm. Vickers hardness is used in countries in China and Europe, and Knoop hardness is used in the United States. Megapascals (MPa) is the legal unit of measurement for microhardness, and kg/mm2 is the previously used hardness calculation unit. The conversion formula between them is 1 kg/mm2 = 9.80665 Mpa. Rockwell hardness (HRC), Brinell hardness (HB) and other hardness differences and conversion hardness is a measure of the degree of hardness and hardness of a material performance indicators. There are many methods of hardness test and the principle is not the same. The measured hardness value and meaning are not exactly the same. The most commonly used static load indentation hardness test, that is, Brinell hardness HB, Rockwell hardness HRA, HRB, HRC, Vickers hardness HV, rubber plastic Shore hardness HA, HD, etc. The hardness value indicates that the material surface is resistant to hard objects Press-in ability. The hardness of Hl and Shore hardness HS belong to the rebound method hardness test, the value represents the size of the metal elastic deformation work. Therefore, hardness is not a simple physical quantity but a comprehensive performance index that reflects the elasticity, plasticity, strength, and toughness of a material.
2. HRC and HB are widely used in production
3. HRC application range HRC 20--67, equivalent to HB225--650 If the hardness is higher than this range, use the Rockwell hardness A scale HRA.
If the hardness is lower than this range, use the Rockwell hardness B scale HRB. The cloth hardness upper limit value HB650 cannot be higher than this value.
The indenter of the Brinell hardness tester is hardened steel ball HBS or hard alloy ball HBW. The test load varies with the ball diameter, ranging from 3,000 to 31.25 kilograms.
The cloth type hardness indentation is large, the measured value is accurate, and the finished product and the sheet are not applicable, generally not classified as a non-destructive test.
Hardness test is the simplest and most convenient test method in mechanical performance test. In order to be able to replace certain mechanical properties tests with hardness tests, a more accurate conversion of hardness and strength is required for production.
Practice has shown that there is an approximate correlation between hardness values ​​and strength values ​​between various hardness values ​​of metallic materials. Because the hardness value is determined by the resistance to initial plastic deformation and resistance to continued plastic deformation, the higher the strength of the material, the higher the resistance to plastic deformation and the higher the hardness value.
Common hardness tester hardness indicator