Hardness testing of steel is typically done on one of two scales, Rockwell or Brinell. These two scales are similar and each has equivalents on the other scale, similar to the relationship between Celsius and Fahrenheit. They differ in their testing methodology, but both are indentation hardness scales, operating on the principal that material tensile strength is directly correlated to the amount a hardened ball (or cone) will penetrate.

Hardness of steelspdf

※Divide by 1000 to change to m from mm. vc (m/min) : Cutting Speed Dm (mm) : Workpiece Diameter π (3.14) : Pi n (min-1) : Main Axis Spindle Speed

These cookies enable this website to provide enhanced functionality and personalisation. They may be set by us or by third party providers. Functional cookies are used by social networking services to track the use of their built-in features. For example, these cookies allow you to share pages from this website with your social network. Advertising cookies may be set through this website by our advertising partners based on the data obtained. They identify your unique browser and Internet device and may be used to provide anonymized demographic data, build profiles of your interests, and display advertising relevant to those interests.

SteelhardnessHRC

Substitute f=0.2mm/rev, RE=0.8 into the formula. h=0.22÷(8×0.8)×1000=6.25µm The theoretical finished surface roughness is 6µm.

Substitute f=.008IPR, RE=.031 into the formulae. h=(.008)2÷(8×.031)×1000=.258µinch The theoretical finished surface roughness is .258µinch.

The Brinell hardness testing method is similar to the above Rockwell testing method with a couple differences. A typical test on steel uses a 10mm diameter steel (or tungsten) ball with 3,000kg of force. A steel ball is used for most materials; the tungsten ball is used primarily for harder materials like tool steel. When a steel ball is used, the result is written as BHN or HBN, example 285 HBN. When a tungsten ball is used, the result is written as HBW, W is the chemical symbol for tungsten (wolfram). Brinell testing is generally considered to be more accurate because the larger ball size makes deeper and wider indentations, thereby averaging the test out over a wider amount of material. However, due to the larger nature of the indentations, it is often considered a destructive test.

HRChardnessfull form

First, calculate the cutting length per min. from the feed and spindle speed. l=f×n=0.2×1000=200(mm/min) Substitute the answer above into the formula. Tc=lm÷l=100÷200=0.5(min) 0.5×60=30(sec)The answer is 30 sec.

Approximate equivalents between the Brinell and Rockwell hardness scales, as well as their rough correlation to material tensile strength. Brinell 3000kg Load 10mm Ball Rockwell Approx Tensile Strength, psi Diameter, mm Hardness Number B Scale C Scale 2.25 745 - 65.3 - 2.30 712 - - - 2.35 682 - 61.7 - 2.40 653 - 60.0 - 2.45 627 - 58.7 - 2.50 601 - 57.3 - 2.55 578 - 56.0 - 2.60 555 - 54.7 298,000 2.65 534 - 53.5 288,000 2.70 514 - 52.1 274,000 2.75 495 - 51.0 264,000 2.80 477 - 49.6 252,000 2.85 461 - 48.5 242,000 2.90 444 - 47.1 230,000 2.95 429 - 45.7 219,000 3.00 415 - 44.5 212,000 3.05 401 - 43.1 202,000 3.10 388 - 41.8 193,000 3.15 375 - 40.4 184,000 3.20 363 - 39.1 177,000 3.25 352 110.0 37.9 170,000 3.30 341 109.0 36.6 163,000 3.35 331 108.5 35.5 158,000 3.40 321 108.0 34.3 152,000 3.45 311 107.5 33.1 147,000 3.50 302 107.0 32.1 143,000 3.55 293 106.0 30.9 139,000 3.60 285 105.5 29.9 136,000 3.65 277 104.5 28.8 131,000 3.70 269 104.0 27.6 128,000 3.75 262 103.0 26.6 125,000 3.80 255 102.0 25.4 121,000 3.85 248 101.0 24.2 118,000 3.90 241 100.0 22.8 114,000 3.95 235 99.0 21.7 111,000 4.00 229 98.2 20.5 109,000 4.05 223 97.3 18.8 104,000 4.10 217 96.4 17.5 103,000 4.15 212 95.5 16.0 100,000 4.20 207 94.6 15.2 99,000 4.25 201 93.8 13.8 97,000 4.30 197 92.8 12.7 94,000 4.35 192 91.9 11.5 92,000 4.40 187 90.7 10.0 90,000 4.45 183 90.0 9.0 89,000 4.50 179 89.0 8.0 88,000 4.55 174 87.8 6.4 86,000 4.60 170 86.8 5.4 84,000 4.65 167 86.0 4.4 83,000 4.70 163 85.0 3.3 82,000 4.80 156 82.9 0.9 80,000 4.90 149 80.8 - - 5.00 143 78.7 - - 5.10 137 76.4 - - 5.20 131 74.0 - - 5.30 126 72.0 - - 5.40 121 69.8 - - 5.50 116 67.6 - - 5.60 111 65.7 - -

First, calculate the cutting length per min. from the feed and spindle speed. l=f×n=.008×1000=8IPM Substitute the answer above into the formulae. Tc=lm÷l=4÷8=0.5(min) 0.5×60=30(sec) The answer is 30 sec.

Hardness of steelschart

It's no secret that we are known as experts in the fastener industry and have been since 1912. Our devotion to customer service, quality products, and on-time deliveries have propelled us to success since our inception.

There are seven separate scales under the Rockwell umbrella, letters A-G, but the most common scales used on steel are B and C, often abbreviated HRB and HRC respectively. The B scale is typically used on softer steels, those under approximately 115,000psi tensile. Testing on the B scale involves a 1/16” steel sphere and a load of 100kgf. The testing machines then determines the amount of indention and assigns it a hardness number, example 98 HRB. Readings above 100 HRB are generally considered unreliable, so the C scale is then used. The C scale is typically used on harder steels, like those above about 110,000psi tensile. Testing on the C scale involves a 120° diamond cone and a load of 150kgf. The test is carried out the same way as the B scale test above, and the result is written as 28 HRC. Readings below 20 HRC are generally considered unreliable, so the B scale is used.

Necessary  cookies are used to help this website function properly. For example, they provide login retention functionality.

Analytical cookies collect information about your use of this website in an anonymous and aggregated form. These cookies are used to analyze and improve the functionality of this website.