GB/T 39644-2021Plain bearings—Technical specifications for Tin-based alloy plain bearings of rotating machinery (English PDF)

3.1 Bondingquality

The degree of bonding between the bearing alloy and the backing.

3.2 Bondingqualitygroups

The bonding quality (3.1) between bearing alloy and backing is classified by combining defect grouping.

3.3 Bondingarea

The area covered by the bearing alloy on the backing of the bearing.

Note: Contains the edge joint area (3.4).

3.4 Bondingareaonedgezones

The visible transition area between the bearing alloy and the backing.

5.1 Materials

The recommended bearing backing, intermediate layer and lining raw materials are shown in Table 2.Both the supplier and the buyer can choose the appropriate material combination according to their needs.

Other material grades and composition ranges that meet the requirements of use can be selected.

Note 1.The chemical composition of the bearing lining material may change during the manufacturing process, and the allowable amount of change is determined by the supplier and the buyer through negotiation.

Note 2.Some chemical elements are restricted or prohibited by the laws and regulations of some countries, and attention should be paid when related countries or regions are involved.

Group A defects. suitable for newly-made bearings with backing thickness <=70mm, without voids, holes and interruptions in the backing area. Wall thickness does not change more than Over 50%.

Defects in groups B1 and B2.suitable for newly-made bearings with backing thickness <=100mm, without voids, holes and interruptions in the backing area. Wall thickness change Not more than 50%.

Group C defects. suitable for newly-made bearings or repaired bearings with backing thickness <=100mm (if necessary, there can be gaps and holes in the backing area And interrupt). The wall thickness does not change more than 50%.

Defects in Group D. Applicable to newly-made bearings and repaired bearings whose defect groups do not belong to Group A, Group B and Group C.

Note: The combination quality grade given in this article overlaps with the group code of the surface defect grade given in 5.2.5. Please pay attention to the difference between the two when using it.

5.2.3 Dehydrogenation

Dehydrogenation annealing treatment should be carried out on the steel or forgings before the tin-based alloy is cast, and the combination should be carried out according to the dehydrogenation temperature and time curve corresponding to the thickness. recording.

5.2.4 Casting

The casting process shall comply with the verified process regulations that meet the requirements of casting quality.

5.2.5 Surface quality of tin-based alloys

After finishing the tin-based alloy layer, there should be no shrinkage holes on the surface, and it is classified according to the defect level of GB/T 18329.3. New bearing push It is recommended to use Group C or above. High-speed bearings or important equipment should use a grade not lower than Group B. See 6.3 for testing methods.

5.2.6 Repair of tin-based alloy defects

After negotiation between the supplier and the buyer, the tin-based alloy defects can be repaired, and the repaired bearing should meet the corresponding quality requirements.

5.3 Dimensions and accuracy

The size and geometric tolerances of tin-based alloy bearings for rotating machinery are different due to the specific application fields, working conditions and model requirements of the product.

Make uniform regulations. Therefore, the size and geometric tolerance requirements should be negotiated by the supplier and the buyer and indicated in the drawing.

GB/T 1804-m, the geometric tolerance without note is in accordance with GB/T 1184-K.

The geometrical quality characteristics specified in GB/T 27939 and given in Table 4 of this standard shall be selected by the supplier and the buyer through negotiation and shall be included in the technical report.

5.4 Appearance quality

The appearance of the product should be free of burrs, foreign objects, bruises, and corrosion.

5.5 Assembly quality

The positioning of the two halves of the bearing bush and bearing body should be accurate, and there should be no looseness or misalignment after re-disassembly.

5.6 Cleanliness

Product cleanliness should meet the requirements of JB/T 4058-2017 "Jie-2" or above, higher cleanliness requirements are negotiated by the supplier and the buyer determine.

5.7 High-pressure jacking pressure

The internal high-pressure oil circuit of the bearing with high-pressure jacking structure should be pressure tested.

6.1 Chemical composition

In the backing raw materials, the chemical composition of carbon structural steel, cast steel, and cast iron was tested according to the method specified in GB/T 4336, and there was dispute The chemical analysis method is used for arbitration; the raw materials of cast copper shall be tested according to the method specified in the corresponding part of GB/T 5121.

The chemical composition of the raw material of the lining shall be tested according to the method specified in the corresponding part of GB/T 3260.

In the raw materials of the intermediate layer, the chemical composition of the tin ingot is tested according to the method specified in GB/T 3260 (all parts).

The chemical composition of the material is tested according to the glow discharge mass spectrometry specified in Appendix A of GB/T 26016-2010.

In the finished bearing product, the chemical composition of the lining material is generally not required. When requested by the buyer, the chemical composition is determined by the supplier and the buyer through consultation.

The method specified in the corresponding part of GB/T 3260 shall be tested.

6.2 Combination quality

Ultrasonic testing method and penetration testing method are used to detect the bonding quality of tin-based alloy and backing. The testing methods are respectively in accordance with GB/T 18329.1 and The requirements of GB/T 18329.3 shall be implemented.

6.3 Surface quality of tin-based alloys

The penetrant inspection method is used to detect the surface defects of tin-based alloys, and the inspection method shall be implemented in accordance with the requirements of GB/T 18329.3.

6.4 Dimensions and accuracy

The geometric dimensions and accuracy of the bearing products should be tested with suitable tools and measuring tools with appropriate accuracy levels. The surface roughness should be rough. Roughness tester is used for testing.

The mandrel measurement is recommended for the clearance detection of radial tilting pad bearings.

6.5 Appearance

Visual inspection method is adopted for appearance inspection.

6.6 Cleanliness

The cleanliness inspection is carried out in accordance with the requirements of JB/T 4058-2017.

6.7 Stress test

The test parameters and methods are negotiated and determined by the supplier and the buyer.

7.1 Inspection of bearing material

7.1.1 Backing

The chemical composition and mechanical properties of the materials of each smelting furnace number should be retested. Samples should be taken from the body of the material. With the consent of the purchaser, Single-cast test bars that are cast in the same furnace and heat treated in the same furnace can be used. Castings and forgings should be subjected to performance heat treatment according to the requirements of the buyer, and corresponding hot spots should be provided Management report. The chemical composition and mechanical properties of the material should all be qualified.

7.1.2 Lining layer and intermediate layer

The material of each smelting furnace number shall be sampled for chemical composition testing, and the chemical composition of the materials shall be all qualified.

7.2 Factory inspection of bearings

Each bearing product should be inspected. The inspection items include the technical requirements that the finished bearing should meet, and the quality of the bearing Other quality report documents provided, and other factory inspection items shall be negotiated and determined by both parties.

7.3 Type inspection

When there is a change of production, a factory transfer, a resumption of work after a production stop, a major change in structure or materials or processes, or contract provisions, the technical requirements of this standard shall be followed.

Require testing, and test the bonding strength and metallographic structure of bearing products.