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Oil Tempered MB Class I & II

Oil Tempered MB Spring Wire is available in two standard tensile ranges. Class 1 being the lower and Class 2 being the higher.

ASTM A229

Oil Tempered spring wire can be produced by two methods, either by traditional double lead furnace process or Induction heat treated.  The appearance of the wire is a black/blue finish and the traditional method produces more scale on the wire which can help with lubricity of the wire when forming. This product has no cast and is generally straight after the bands of the coil have been removed.

Chemistry

Element Composition, %
Carbon 0.55-0.85
Manganese 0.30-1.20
Phosphorus, max 0.040
Sulfur, max 0.050
Silicon 0.15-0.35

Tensile Requirements: Inch-Pound Units

Diameter (Inch) Class I - Tensile Strength KSI Min Class I - Tensile Strength KSI Max Class II - Tensile Strength KSI Min Class II - Tensile Strength KSI Max
0.020 293 323 324 354
0.023 289 319 320 350
0.026 286 316 317 347
0.029 283 313 314 344
0.032 280 310 311 341
0.035 274 304 305 335
0.041 266 296 297 327
0.048 259 289 290 320
0.054 253 283 284 314
0.062 247 277 278 308
0.072 241 271 272 302
0.080 235 265 266 296
0.092 230 260 261 291
0.106 225 255 256 286
0.120 220 250 251 281
0.135 215 240 241 266
0.148 210 235 236 261
0.162 205 230 231 256
0.177 200 225 226 251
0.192 195 220 221 246
0.192 195 220 221 246
0.207 190 215 216 241
0.225 188 213 214 239
0.244 187 212 213 238
0.250 185 210 211 236
0.312 183 208 209 234
0.375 180 205 206 231
0.438 175 200 201 226
0.500 170 195 196 221
0.562 165 190 191 216
0.625 165 190 191 216

Permissible Variations in Wire Diameter

Diameter (Inch) Permissible Plus and Minus Permissible Out of Round
0.020 to 0.028, incl. 0.0008 0.0008
Over 0.028 to 0.075, incl. 0.001 0.001
Over 0.075 to 0.375, incl. 0.002 0.002
Over 0.375 to 0.625, incl. 0.003 0.003