Ball Bearing Housed Unit Page A-5 Ball Bearing Housed Units-Engineering

TIMKEN BALL BEARING HOUSED UNIT CATALOG Download 3D Models and 2D Drawings at cad.timken.com A-5 BALL BEARING HOUSED UNITS OTHER CONSIDERATIONS Installations that operate at high temperatures for extended periods may lose the quality of shaft and housing fits. Carefully machined and heat-treated shafts and housings will minimize trouble from this source. In some applications, the internal clearance of bearings may be partially absorbed. For example, during the first few seconds of rotation, a massive housing may keep the outer race cooler than the inner race and balls, even if the housing is already at some elevated temperature. Also, during heat soakback, when rotation stops, heat may flow back to the bearing along the shaft. If, while stationary, the effects of heat soakback nullify Material Approximate Chemical Analysis % Temp. C , ( F) Hardness HRC -73 C -100 F -54 C -65 F -17 C 0 F 38 C 100 F 93 C 200 F 121 C 250 F 149 C 300 F 204 C 400 F 260 C 500 F 316 C 600 F 371 C 700 F 427 C 800 F Low-alloy carbon- chromium bearing steels. 52100 and others per ASTM A295 1C 0.5 - 1.5Cr 0.35Mn 21 (70) 60 STANDARD DIMENSIONAL STABILIZATION <0.0001 in./in dimensional change in 2500 hours at 100 C (212F). Good oxidation resistance. Low-alloy carbon- chromium bearing steels. 52100 and others per ASTM A295 1C 0.5 - 1.5Cr 0.35Mn 21 (70) 177 (350) 232 (450) 58 56 54 Heat stabilized per FS136. When given a stabilizing heat treatment, A295 steel is suitable for many applications in the 177 - 232 C (350 - 450 F) range; however, it is not as stable dimensionally as it is at temperatures below 177 C (350 F). If utmost stability is required, use materials in the 316 C (600 F) group below. Deep-hardening steels for heavy sec- tions per ASTM A485 1C 1 - 1.8Cr 1 - 1.5Mn .06Si 21 (70) 232 (450) 316 (600) 58 55 52 After heat-treated and tempered, it is stabilized. Carburizing steels per ASTM A534 a) low alloy 4118, 8X19, 5019, 8620 (Ni-Moly grades) b) high nickel 3310 Ni-Moly: 0.2C, 0.4-2.0Mn, 0.3-0.8Cr, 0-2.0Ni, 0-0.3Mo .0.1C, 1.5Cr, 0.4Mn, 3.5Ni 21 (70) 58 Nickel-Moly grades of steel frequently used to achieve extra ductility in inner rings for locking device bearings. 3311 and others used for extra-thick-section rings. Corrosion-resistant 440C stainless steel per ASTM A756 1C 18Cr 21 (70) 58 Excellent corrosion resistance. Corrosion-resistant 440C stainless steel per ASTM A756 1C 18Cr 21 (70) 232 (450) 316 (600) 58 55 52 Heat stabilized for maximum hardness at high temperatures (FS238). Good oxidation resistance at higher temperatures. Note load capacity drops off more rapidly at higher temperatures than M50 shown below, which should be considered if loads are high. M-50 medium high speed 4Cr 4Mo 1V 0.8C 21 (70) 232 (450) 316 (600) 60 59 57 Suggested where stable high hardness at elevated temperature is required. TABlE A-1. OPERATiNg TEMPERATUREs fOR BEARiNg COMPONENT MATERiAls - RiNgs, BAlls AND ROllERs NOTE: Bearings have been made of special material for operation at temperatures above 427 C (800 F). Consult your Timken engineer regarding the application. ASTM A295 bearing steels are suitable for many applications up to 212 C (413 F) but are not as dimensionally stable as they are at the temperatures below 100 C (212 F). This table provides standard operating temperatures for common bearing component materials. It should be used for reference purposes only. Other bearing component materials are available on request. Contact your Timken engineer for further information. the radial internal clearance, radial brinelling of the races may occur and the bearing will be rough during subsequent rotation. Bearings with greater internal looseness may be required to compensate for these conditions. Consult your Timken engineer for recommendations.

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