Analysis of quality inspection methods for bearing steel

Source: China Bearing Network Time: 2013-10-15

/*250*250 was created on 2017/12/25*/ var cpro_id = 'u3171089';

Bearing steel inspection method
1. Appearance of the appearance quality of steel: The quality of the steel surface is usually viewed with the naked eye; the annealed and unannealed heats steel; if necessary, it can be ground with a pneumatic or electric portable grinding wheel. The cold drawn annealing steel and steel pipe can be fine. The flat file is twisted into three or four circumferential smooth surfaces on the whole data; it is visually inspected. The wire wire is usually also viewed with the naked eye; in addition, it can also be viewed by pickling; that is, 250 mm long at each end of the disk; After pickling by low-pick pickling process, the appearance of the skin is checked by the naked eye.
2, steel scale view: annealed and non-annealed hot-rolled round steel; with a reading value of 0. 1mm vernier caliper or caliper for scale viewing. Cold drawn steel and steel wire with a scale value of 0. 01mm micrometer for viewing. The outer diameter scale and wall thickness difference of the hot-rolled and cold-drawn steel tubes are respectively read with a reading value of 0.1 mm. The vernier caliper and the graduation value are 0. 01 mm micrometer. The thickness of the cold-rolled steel sheet and the steel strip is viewed with a micrometer. The length of the steel. The width is viewed with a steel ruler. The bending of various steels (except the coil) can be viewed with a double ruler or feeler gauge.
3. Identify steel types. Viewing steel types is usually viewed with a portable spectroscope and spark discrimination. The portable spectroscope is a semi-quantitative spectrometer; it can semi-quantitatively view the primary alloying elements in the steel; Chromium, manganese, nickel, molybdenum, tungsten, vanadium, etc. Spectral view can identify the steel number of the steel to be inspected and the presence or absence of mixed steel. The spark view is based on the spark characteristics to determine the steel number of the steel to be inspected.
4. Hardness view: The Brinell hardness test should be carried out on the cold drawn annealing strip and hot rolled annealed steel. The Brinell hardness test method is carried out according to the GB231-84 specification.
5. Fracture inspection: cold-drawn annealing and hot-rolled annealed steel with a diameter of 30mm or less should be fractured. Cut a notch at one end of the steel with a hammer or cut a fracture specimen with a press. See if there is any shrinkage on the cross section with the naked eye. Holes, white spots, cracks; overheating and other shortcomings.
6. Low-order arrangement view: Annealed steel and non-annealed steel with diameter greater than 30mm are usually viewed at low magnification. That is, the sawing thickness (annealing material) and the grinding wheel cutting machine (not annealed material) are cut at a thickness of 12~15mm at one end of the steel. The sample of the sample is ground with a grinder. After hot pickling, the nakedness is used to see the segregation, the degree of porosity is not shrinkage, the white point crack, the over-burning, etc. The hot pickling is 50% Industrial hydrochloric acid aqueous solution; heated to 70 Â± 5 Â° C; pickling time is 30 ~ 40min; after the sample is taken out, washed with alkaline water; then washed with 80 Â° C hot water.
7. Analysis of chemical composition: The chemical composition is usually sampled and analyzed according to the furnace number. The analysis method of the various elemental components of the steel number is carried out according to the national normative rules. The chemical analysis method is relatively slow; it is not suitable for the production. æŽ é¦„ é¦„ Zhuo Pu Ð£ ( (17) The stalked shell Ai Hui è° æ‚´æŽ æ‚´æŽ æ‚´æŽ æ‚´æŽ é¦„ é¦„ é¦„ é¦„ é¦„ é¦„ é¦„ é¦„ é¦„ é¦„ é¦„ é»¾ é»¾ é»¾ é»¾ é»¾ é»¾
8, high-order arrangement view: high-order arrangement with metallographic microscope to view; inspection items are: annealing arrangement (enlarged 500 times) depth of decarburization layer (enlarged 100 times); view on the cross section of steel cross section. Carbide liquid analysis, Carbide strips, non-metallic inclusions (100 times enlargement) are viewed in the longitudinal section of the steel; however, in order to reduce the number of samples; the mesh can be viewed in the longitudinal section with the same sample of strip and liquid analysis; Time; the results of the transverse section inspection shall prevail.
The number of inspections of each project shall be subject to the standard rules; after the sampler has sampled, it shall first be machined according to the rules. Non-metallic inclusions; strip, liquid, and mesh specimens shall be quenched and tempered; sorghum chrome The bearing steel tempering process is as follows:
Quenching temperature 820~840Â°C,
Tempering temperature: 150 Â° C; tempering time 1 ~ 2 h,
The surface to be inspected of the sample shall be ground and polished.
View the annealing surface and the surface of the decarburized layer; observe it with 2% nitric acid solution,
Non-metallic inclusions are polished by the inspection surface;
Carbide ribbon, carbide liquid precipitation, carbide mesh surface to be inspected with 4% nitric acid solution after etching.
9. Pulling inspection: wire and steel plate should be tested for tension; wire tension test; take a sample with a length of 250mm at one end of the wire; perform a tensile test on a tensile test machine. The steel plate is taken and prepared according to the normative rules; Tensile test. The tensile test method is carried out according to the GB228-76 specification rules.
Number of inspections of bearing steel: The inspection of bearing steel is based on batch or heat as inspection unit. Each batch of steel must be from the same steel type; the same smelting furnace number; the same heat treatment furnace; the same scale of steel composition. The quantity is based on the technical specifications of the steel ordering; the availability status.
At present, China's high carbon chromium bearing steel bars, strips and wires have three specifications. YJ284 and YB9-68 for rod and strip steel; YB245-64 for steel wire.

Recommend to friends comments close window

Bearing related knowledge

Inch Tapered Roller Bearing JLM104948/10
The basic layout of the rolling bearing analysis of the use of aviation, aircraft and helicopter bearings, the tumbling sound of the bearing can be distinguished from the problem analysis skills: the use of bearings

This article links to http://
Please indicate the bearing network http://

Previous: Bearings in SKF Industrial Fans: What are the disadvantages of quality after heat treatment of bearing parts?

Monel alloy 400 has excellent mechanical properties at subzero temperatures. Strength and hardness increase with only slight impairment of ductility or impact resistance. The alloy does not undergo a ductile-to-brittle transition even when cooled to the temperature of liquid hydrogen. This is in marked contrast to many ferrous materials which are brittle at low temperatures despite their increased strength.

Monel Fittings

Monel Fittings,Monel Tube Fittings,Monel Pipe Fittings,Monel Tube Pipe Fitting

Zhejiang Max Stainless Steel Co.,Ltd , http://www.cnstainlesstube.com