Sprocket Hardening
All U.S. Tsubaki sprockets are made from high quality steel. Since chain loadings are evenly distributed over all engaged sprocket teeth, tooth breakage or distortion is not normally a problem. It is seldom necessary to use special high strength material.
Hardness Conversion Table
3000 KG. Load Brinell No.
Rockwell “C” 150 KG. Load
A 60 KG.
Shore Model C
Tensile Str. Lbs. per Sq. In.
10 11 13 14 15 16 17 18 20 21 22 23 24 25 26 28 29 30 31 32 33 34 35 36 37 38 40 41 42 44 45 46 47 49 50 52 53 55 57 58 60 62 64 66 68 70
27 28 28 29 30 30 31 31 32 33 34 35 36 37 37 38 39 40 42 43 44 45 46 48 49 51 52 54 55 57 59 61 63 65 67 70 72 75 78 81 84 87 91 95
91,000 93,000 95,000 97,000 99,000 101,000 104,000 107,000 110,000 113,000 116,000 119,000 122,000 125,000 128,000 131,000 134,000 138,000 142,000 146,000 150,000 155,000 160,000 165,000 170,000 176,000 182,000 189,000 196,000 204,000 212,000 220,000 229,000 238,000 247,000 256,000 266,000 276,000 287,000 298,000 311,000 324,000 337,000 352,000 368,000 384,000
183 187 192 197 202 207 212 217 223 229 235 241 248 255 262 269 277 285 293 302 311 321 331 341 352 363 375 388 401 415 429 444 461 477 495 514 534 555 578 601 627 653 682 712 745 780
Sprocket diameter and pitch determine the specific material used.
The hardening process of small diameter, small pitch sprockets is usually a one-step procedure: heat treatment (electrical induction). Large diameter, large pitch sprockets can usually be directly flame hardened. These methods are used to provide a high hardness at the wear areas, plus provide the ability of the tooth to absorb shock loads. This is accomplished by hardening only the wear area of each tooth while maintaining a ductile tooth core which is tough and resilient. The hubs and bores remain soft to permit reworking.
60.5 61.0 61.5 62.0 62.5 63.0 63.5 64.5 65.0 65.5 66.0 66.5 67.0 67.5 68.0 68.5 69.0 69.5 70.5 71.0 71.5 72.5 73.0 73.5 74.0 75.5 76.0 77.0 77.5 78.5 79.5 80.0 81.0 82.5 83.5 84.5 85.5 86.5
The general guidelines for sprockets are:
Rockwell Scales
Size
A C 68-76 35-50 63-70 25-40
Small pitch, small diameter Large pitch, large diameter
Thru Hardened Teeth Case hardened on wear surfaces with a tough, resilient core.
100 106
C-72
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