- Deep groove ball bearings
- Cylindrical roller bearings
- Aligning ball bearings
- Stainless steel bearings
- LNSERTED bearings
- Ball introduced
- Plain Bearings
- Needle Roller Bearings
- Angular contact ball bearings
- Thrust Roller Bearings
- Spherical roller bearings
- Thrust Ball Bearings
- Rolling mill bearings
- Tapered Roller Bearings
- Plastic bearings
- Linear motion bearings
| How to test the quality bearing steel ? | |||
| 点击数：6734 日期：2014/4/4 | |||
| There are several methods about: Visual inspection 1, the surface quality of the steel: steel surface quality are examined with the naked eye, annealed and unannealed Resi steel, can be pneumatic or electric hand wheel grinding spiral Tiao inspection when necessary. Cold drawn steel tube annealing and usable fine flat file into three to four circular smooth file in the whole material, with the naked eye examination. Steel plate material are also examined with the naked eye, in addition, also can use pickling test, which ends in disc material 250mm each long, low times by pickling pickling after visual inspection of the surface. 2, steel size check: annealing and not annealed hot-rolled bar, dimensional inspection by reading the value for the 0.1mm vernier caliper or calipers. Cold drawn steel and steel wire is 0.01mm micrometers were examined by dividing the value. Hot-rolled and cold drawn steel tube outer diameter and wall thickness difference were used to read the value for the 0.1mm vernier caliper and micrometer to check the index value of 0.01mm. Micrometer rolled steel plates and thickness inspection. The length, width of steel with steel ruler to check. All kinds of steel (except the disc material) bending by double ruler or check with feeler gauge. 3, identification of steel: steel check identification generally portable spectroscope and spark identification method for inspection. Portable spectroscope is a semi quantitative spectral instrument, can the main alloy elements semi quantitatively examined tapping, such as chromium, manganese, nickel, molybdenum, tungsten, vanadium. Spectral examination can find out the steel grade and there is no mixed steel case. Spark test is tested steel grade according to the discharge characteristic. 4, hardness test Brinell hardness test: for cold drawn steel and hot rolled annealed steel annealing. Brinell hardness test according to GB231-84 standard provisions. 5, examination of fracture: diameter 30mm below the cold and hot rolling steel annealing annealing of fracture surface examination. In the steel is cut a notch with a hammer or press the interception of fracture were broken. With the naked eye inspection section on whether there is shrinkage, white spots, crack, overheating defects. 6, low times microstructure examination: annealing steel diameter greater than 30mm and no annealing steel generally check the low times microstructure. By sawing machine in the steel end (annealed) and grinding wheel cutting machine (not annealed material cut from the wafer thickness) for sample 12~15mm, sample was detected with a grinder grinding. The heat after pickling visually inspect segregation, loose degree has no shrinkage, cracks, defects such as white spot burning. Water industrial hydrochloric acid solution 50% in hot acid, heating temperature of 5 ℃ to 70 ±, pickling time is 30~40min, the sample after removing the lye washing, then 80 ℃ hot water wash. Analysis of 7, chemical composition: chemical composition according to the furnace, sampling and analysis. The various elements of steel analysis method according to the provisions of national standards. Methods for chemical analysis of slow, does not apply to the production field, due to the development of science, spectroscopy at present, in the factory the chemical composition analysis of test steel method of spectral analysis. 8, microstructure examination: microstructure metallographic microscope for examination, inspection items: the annealing microstructure (500 times magnification) depth of decarburized layer (magnified 100 times), while the check in section steel. Carbide eliquation carbide, ribbon, non-metallic inclusions (magnified 100 times) examination in the longitudinal section of steel, but in order to reduce the sample number, mesh with ribbon, liquid condensate with the same specimen in longitudinal section examination, when in doubt, with transverse section inspection results shall prevail. 9, pull test: steel wire and steel wire tension to tension test, test, the specimen in the wire intercepts 250mm long, for tensile testing in a tensile testing machine. Steel plate according to the standard interception and specimen preparation, pull tests were performed in a tensile machine. Tensile test method according to GB228-76 standard provisions. The number of bearing steel: bearing steels for batch or heat as a test unit. Each batch of steel must be from the same grade, the same smelting furnace, heat treatment furnace, the same time, the same size steel. Bearing steel check number according to the technical standard of steel orders, delivery status and. At present, China's high carbon chromium bearing steel rod, bar, wire has three standard. Rod, bar steel with YJ284 and YB9-68, the steel wire standard for YB245-64. |
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